90 ZR1: Oh crud, did I break it?

[GTOger]

Happy Thanksgiving everyone. The wife and I decided to take the ZR1 to the family turkey extravaganza about 15 miles up the road. It ran great all the way there and half-way back. At the half way point, things got ugly.

All of a sudden there was a loss of power and the engine was running rough. Definitely not hitting on all cylinders. Pulled up at a stop light and it didn't really want to stay running. Without giving it little throttle bursts, it would have died.

There was no "drama" leading up to this. I hadn't been hot-rodding. There wasn't any bang or other indication. Gauges remained normal and no indications on the cluster.

At the next light I saw that there was smoke coming out the back when I gave a little gas.

We limped home and into the garage and I shut it down. It smells to me like there's unburned fuel in the exhaust. We unloaded the leftovers (mmmm... turkey....) and then came out and lifted the hood. No signs of external trauma. Nothing leaking, seeping or oozing. Oil is still full (and clean).

Started her up again and it continued to run like crud. White smoke from the exhaust.

Just under 28k miles. No mods save for a B&B exhaust and K&N filter from previous owner.

I'm trying to reassure the wife that the car we got 3 weeks ago will be alright again. I know the injectors are notorious on these cars, but maybe it's spark.

Any recommendations on where to start? Maybe this looks familiar to somebody.

[XfireZ51]

Pull plugs and see which if any look like they've been steam cleaned. It may not be a head gasket. If it looks like either #4 or #3 cylinder, it can be the IH to head interface. Coolant port runs very close to the primary runners of those cylinders. Very little material separating the port and coolant. Over time it can corrupt the gasket and burrow its way under it especially during high vacuum situations like idle or decel.

[GTOger]

Blown head gasket? Ew.

The radiator over flow bottle has water in it.... not much. It's at the "cold" line. Engine's been off for about an hour. Garage is about 45 deg.

What else should I look for to confirm/deny it? And I guess next question... how hard is it to replace (find?) an LT5 head gasket? <ducking>

[GOLDCYLON]

What else should I look for to confirm/deny it? And I guess next question... how hard is it to replace (find?) an LT5 head gasket? <ducking>

Shaving cream milky sustance on the oil dipstick. About $89.00 per side on Ebay

[GTOger]

Thanks Xfire751. I guess next I will need to figure out how to pull the plugs on this beast. They look well buried, and I have very little experience with this car. Dumb question: what's the "IH" in "IH to head interface"? Lucky for me... there's a shop manual in the back!

[GTOger]

Man, you guys are QUICK on this board. Not used to that! :)

Goldcylon, the oil dipstick looked nice and normal to me and I checked within 2 minutes of pulling in the garage.

I may wait till daylight for more digging since lighting in my garage pretty sell stinks.

[GOLDCYLON]

Thanks Xfire751. I guess next I will need to figure out how to pull the plugs on this beast. They look well buried, and I have very little experience with this car. Dumb question: what's the "IH" in "IH to head interface"? Lucky for me... there's a shop manual in the back!

IH ="s Injector Housing

[GTOger]

Dumb question: what's the "IH" in "IH to head interface"? Lucky for me... there's a shop manual in the back!

Duh. Injector Housing. Got my service manual out and I'm going to study. Thanks gents for the input. Anything else you think I ought to know, hip me to it. I'm grateful for the knowledge here.:notworthy

[Jagdpanzer]

Do you smell gas and does the smoke come out of only one exhaust pipe? If so could be a blown fuel injector. If it is you will quickly burn out the cat on the side with the bad injector. Very same thing happened to ZZZZZR-1 David.

[GTOger]

Hey Jagdpanzer. Matter of fact, I don't smell gas. It smells sweet. Which leads me to think Dynomite was onto something from the git-go with the water. Understood on the cat though. Just went through that on a buddy's Acura.

Just looking through the service manual to get to the IH and related gaskets. Sweet Jeebuz what a PITA! Looks like it's about the same amount of labor to get to it or the head gasket.

What I didn't want = project car. Too bad I'm already hooked on the thing!

[Kevin]

do an oil change and see what the oil looks like. the good/bad is you're closeish to corry henderson if anything did go south on you http://www.hendersonperformance.com/

[Kevin]

hopefully the previous owner didn't use dexcool in the car

[bdw18_123]

You might want to also check the MAP sensor hose. If it comes off, the car will run like crap.

http://i13.photobucket.com/albums/a292/bdw18_123/LT5toprearview.jpg

[1990 415]

What color is your coolant? Green or Orange? If it isn't green, you better replace both of the head gaskets. Dexcool destroys the gaskets in the LT5. Hopefully the previous owner wasn't foolish enough to put in Dexcool. You can save yourself a lot of grief by taking the beast to Corey Henderson and having him replace the head gaskets. While the engine is apart seriously consider porting and doing a 368. You won't regret it.

[Pete]

You might want to also check the MAP sensor hose. If it comes off, the car will run like crap.

http://i13.photobucket.com/albums/a292/bdw18_123/LT5toprearview.jpg


Also check MAP if filled with oil.

Pete

[GTOger]

Good grief, this board is crazy helpful. If nothing else, I've learned this ZR1 crowd is way cool. That may sound odd but coming from the groups I've known before, I don't take it for granted.

The coolant is the standard green glycol stuff. I think it's safe in that respect. I'll look at that MAP sensor when I get some daylight.

I've read up on Corey and in fact have had a couple guys I know locally mention him & his shop. Nothing but good stuff. If it turns into a project, he's certainly going to get a call from me. First I'm going to go local. We do have a shop in town that's qualified on LT5 and recommended by a buddy of mine so I will give him a call in the morning as well.

I'm actually still astonished I'm getting any input at all, much less helpful input.

[Pete]

Oh forgot.
Welcome to the jungle.
Happy Thanksgiving.

Pete

PS
Head gaskets are not very common unless overheated,run lean or something silly.

Can i get some pictures of your Firehawk?

[Kevin]

Good grief, this board is crazy helpful. If nothing else, I've learned this ZR1 crowd is way cool. That may sound odd but coming from the groups I've known before, I don't take it for granted.

The coolant is the standard green glycol stuff. I think it's safe in that respect. I'll look at that MAP sensor when I get some daylight.

I've read up on Corey and in fact have had a couple guys I know locally mention him & his shop. Nothing but good stuff. If it turns into a project, he's certainly going to get a call from me. First I'm going to go local. We do have a shop in town that's qualified on LT5 and recommended by a buddy of mine so I will give him a call in the morning as well.

I'm actually still astonished I'm getting any input at all, much less helpful input.

the only shop that I know of that does lt5 work in texas is corey, what's the name of this shop? not saying your buddy is wrong, but I just don't want to see you take the car to a shop that's going to do more harm then good.

[GTOger]

Oh forgot.
Welcome to the jungle.
Happy Thanksgiving.

Pete

PS
Head gaskets are not very common unless overheated,run lean or something silly.

Can i get some pictures of your Firehawk?

Yeah... I'm obviously more than a little concerned about the problem, seeing as how it's got me up at 3:30am.:dontknow:

Oddly enough, I don't have a bunch of pics of the 92 'hawk handy, but I'll pm you when I do, if you like.

the only shop that I know of that does lt5 work in texas is corey, what's the name of this shop? not saying your buddy is wrong, but I just don't want to see you take the car to a shop that's going to do more harm then good.

Corvettes of Dallas has a service department and they're reportedly competent with the LT5. But don't worry... I've had enough experience with specialty cars that if they don't know what they're doing, the car will go elsewhere.

To be honest, I'm still on the fence about tearing into it myself. Thing is I still have the motor out of the GTO and I don't like the idea of having 2 cars in my garage pulled apart at once.

[Kevin]

Corvettes of Dallas has a service department and they're reportedly competent with the LT5. But don't worry... I've had enough experience with specialty cars that if they don't know what they're doing, the car will go elsewhere.



I have a dealer near my place who was well known to be the place to take your car....i realized that was crap after they washed my engine and sprayed orange clean on it. if it was me, I'd drain the oil and go from there

[Jagdpanzer]

You might try looking up Jim Milstead known on here as "TheLurker"
He's from the Dallas area and knows the ZR-1 & LT5 as well as anybody and a great guy. I'm sure he can direct you to a competent local shop.

[GTOger]

Well, I wasn't able to get with "The Guy" at the shop today due to it being a holiday weekend and all. Same story at Corey Henderson's shop down in New Braunfels. So I'm going to have to try and exercise a little patience. The tech I talked to at Corvettes of Dallas (now Corvette World as of a couple weeks ago) says he's never broken down an LT5. He's never heard of one blowing a gasket like this. (Perfect... leave it to me).

He did mention that in order to get at the heads and pull the thing apart it could be necessary to pull the engine out of the car. That doesn't sound like any bit of fun. It sounds like a whole lot of money. Anybody have any words for me? I'm starting to get a little scared. A $10k engine rebuild is not within my realm of possibilities.

[Z51JEFF]

Replacing the plugs are fairly easy but #8 can be a challenge.What works for me,a telescoping magnet,2 inch 3/8 extension and a 3/8 ratchet with a pivoting head.On the difficult plugs I drop the plug socket in the plug hole then the 2 inch extension loosen the plug.Fish everything out with the magnet.Im sure everybody has a different methed but this works for me.Other than the smoke Id have to say its a coil-injector problem.Id start the car and start pulling plug wires and listen for a no miss.If you work on your own car this LT5 is no different.Would like to see some pictures of that G.T.O. When I was a kid my Mom had a 67 4-speed.Wish I had it now.:(

[Kevin]

Well, I wasn't able to get with "The Guy" at the shop today due to it being a holiday weekend and all. Same story at Corey Henderson's shop down in New Braunfels. So I'm going to have to try and exercise a little patience. The tech I talked to at Corvettes of Dallas (now Corvette World as of a couple weeks ago) says he's never broken down an LT5. He's never heard of one blowing a gasket like this. (Perfect... leave it to me).

He did mention that in order to get at the heads and pull the thing apart it could be necessary to pull the engine out of the car. That doesn't sound like any bit of fun. It sounds like a whole lot of money. Anybody have any words for me? I'm starting to get a little scared. A $10k engine rebuild is not within my realm of possibilities.
about the only thing i know of that will pop a head gasket on the LT5 is dexcool. did you check the map sensor?

[Z51JEFF]

:cheers:

Sometimes you just have to do it :D

http://i287.photobucket.com/albums/ll142/dynomite007/ZR1/Enagineout.jpghttp://i287.photobucket.com/albums/ll142/dynomite007/ZR1/Engine.jpg
http://i287.photobucket.com/albums/ll142/dynomite007/90%20Corvette/90cutout.jpg

These pictures are a little misleading.If I didnt know this was a base car Id swear this was your Z with a chunk lopped out of it.

[Aurora40]

I don't know if I missed it, but why do you think the headgasket is shot?

[Z51JEFF]

A $10k engine rebuild is not within my realm of possibilities.

I wouldn't let my mind go too crazy just yet.When one of the injectors died in my 8000 ZR-1 I had what sounded like a rod knock I thought I was dead in the water.The knock turned out to be the flywheel-cam chains making a racket with the dead cylinder.Getting to the IH looks like a big job,it is a pain in the a$$ if you've never done it but get tons of pictures as the thing comes apart and its a piece of cake.The most valuable asset is right here,a bunch of guys that have done it.

[A26B]

I'm with Bob here..... I think we may be doing the chicken little thing regarding the head gasket.. Should save the worst for last. Worry when needed. BIG difference in replacing injector housing gaskets & replacing head gaskets.

EZ check for head gasket leak. Remove the radiator cap (while cool of course) watch for bubbles in the coolant.

Injector housing bolts do get loose. Loose bolts could let coolant leak into the intake runners, causing miss, white smoke & sweet smell in the exhaust, along with low coolant in the overflow reservoir. Could leak into cyl's 1,2,3 or 4. Plugs would be white. Remove plugs only when engine is cool to prevent seizing. Do a little sniff test on each cylinder while the plug is out.

Don't stress. Pretty unlikely to blow a head gasket just tooling down the road......especially on Thanksgiving with your wife in the car!

[Jagdpanzer]

If it is a blown head gasket or injector housing gasket coolant leak do not attampt to crank the engine over before removing all of the spark plugs or you run the risk of greater damage if a cylinder is full of coolant. With the spark plugs removed crank it over to make sure the cylinders are clear. Then install the plugs and start it up with the cooling system pressure cap removed. If the head gasket is blown bad enough to cause to the running problems you have discribed you should see air bubbeling out of the coolant pressure tank.

[GTOger]

about the only thing i know of that will pop a head gasket on the LT5 is dexcool. did you check the map sensor?

I'll get out there and start looking. I'm not exactly sure *what* I'm looking for yet. :) I've never seen a "good" one, but based on some pretty good pics I saw earlier :notworthy: I've got to think I could probably at least rule it out. It doesn't appear to be dexcool related.

I don't know if I missed it, but why do you think the headgasket is shot?

Based on advice so far and my experience with old cars (60's muscle)... steam in the exhaust & burning glycol usually says "blown gasket". Of course, I'm just not used to thinking about an IH gasket so my head doesn't automatically go there. Yet.

I wouldn't let my mind go too crazy just yet.When one of the injectors died in my 8000 ZR-1 I had what sounded like a rod knock I thought I was dead in the water.The knock turned out to be the flywheel-cam chains making a racket with the dead cylinder.Getting to the IH looks like a big job,it is a pain in the a$$ if you've never done it but get tons of pictures as the thing comes apart and its a piece of cake.The most valuable asset is right here,a bunch of guys that have done it.

That's a very diplomatic way of saying "calm down, dude." :) OK. I will. All my tools are at my office so I'll either find some usable implements I've forgotten about in the garage, or I'll pick up my tools tomorrow and dig in. Thanks for the motivational words.

[ittlfly]

I"ve got a Universal Block Tester Kit I bought to use on my old LT-1 after I thought I blew a head gasket. there is approx a half bottle left of the testing fluid. It has all the instructions on how to test (really simple) for a head gasket leaking, cracked block etc. A simple matter of watching the fluid turning form blue to yellow is a leak is present.

If you want the kit I"ll send it to you for nothing but I"d like to get the postage back. If your interested, drop me a PM...

[Kevin]

I'll get out there and start looking. I'm not exactly sure *what* I'm looking for yet. :) I've never seen a "good" one, but based on some pretty good pics I saw earlier :notworthy: I've got to think I could probably at least rule it out. It doesn't appear to be dexcool related.
.
from page 2
http://i13.photobucket.com/albums/a292/bdw18_123/LT5toprearview.jpg

you may have to pull the plenum to check the bottom side of it but that's an easy job.

[Ccmano]

Geezzz... you guys can scare the new guys half to death with this head gasket talk. While I agree that the stated symptoms may point in that direction there are other possible causes. There is a simple and quick way to check for a blown head gasket. Go down to your local Autozone or Kragen and rent a cooling system pressure tester. Hook it up, follow the directions (important) if it holds pressure you don't have a blown head gasket, if the pressure won't hold and there's no puddle of coolant under the car you have either a blown headgasket or a blown IH gasket. Once you've done that we'll talk.
H
:cheers:

[rhipsher]

I had the same thing happen 4 years ago. It was two bad injectors and an intermitten problem. Like you at the time I didn't know squat about the car (of course all of that's changed now). Took it to corey Henderson. Took him no time to chase down and fix what was wrong. But again it was to bad injectors. Running great and in a split sec ran like it was gonna self distruct.

[Hammer]

Geezzz... you guys can scare the new guys half to death with this head gasket talk. While I agree that the stated symptoms may point in that direction there are other possible causes. There is a simple and quick way to check for a blown head gasket. Go down to your local Autozone or Kragen and rent a cooling system pressure tester. Hook it up, follow the directions (important) if it holds pressure you don't have a blown head gasket, if the pressure won't hold and there's no puddle of coolant under the car you have either a blown headgasket or a blown IH gasket. Once you've done that we'll talk.
H
:cheers:

I'm on board 110% with Hans here. Save yourself a lot of time and get the cooling system tester. I'll never troubleshoot a cooling system again without using one of these. I had a leak in BG this year, once I got home I replaced the water pump (I was positive it was the pump as I saw fluif dripping off a lower pump bolt) before testing the system. After I replaced the pump there was still a leak so I decided to get the tester. Found a leaking hose. It was brand new set of Samco's and the hose going to the upper radiator had a small slit in it. I used the original clamps (spring type) and think they caused the problem. Don't know how the fluid got down on the pump bolt (if it did). There was a puddle of fluid right under the hose on the frame now. Samco replaced the hose and I used their clamps this time. Problem solved. But...now I have a water pump that may or may not be bad because I didn't test the system.

Hope that helps a little. The tester will absolutely tell you if you have a coolant leak. If you do this, pull the plugs first.

GL

[rbidwell]

I am just curious if the car ran the same with the power key on as it did with it off. I had some secondary injectors go bad and the car ran rough with the key on, but ran OK with it off.

Ron

[TheLurker]

I emailed you GTO but have not heard back from you.

Jim

[FU]

I emailed you GTO but have not heard back from you.

Jim

Hello there Jimbo :wave:

[GTOger]

OK, Update.... first of all, thank you for all the follow-ups and it's not that I've been ignoring you, but I got nasty sick on Friday and was down for most of the weekend. I dragged my sniffling self to work this morning just 'cause I didn't really have a choice. Now I'm feeling better so it's time to get the ZR1 feeling better!

NOW... for the excitement... This morning I came downstairs after getting ready for work and the wife says "it smells like gasoline down here". Being stuffed up still, I took her word for it. Until I got to the back hall and sure enough that was gasoline I smelled. I opened the garage door and it was really strong. Looked around under the car and found no puddles. Had to go to work.

Came home tonight & I managed to get all the plugs out except for 8. I'll go back and search for all the tips on how to get at 8, but what was GM thinking there?! :icon_scra

I compared all the plugs and they appear original (almost 28k miles on the car). #5 looks very fouled.

I bumped the starter a few times and watched for water to burble out one of the cylinders. When it hit #5, a geyser shot from the engine to the garage wall... on the far side of a 3 car garage! And it was gasoline.

I made another revolution with the starter and got the same result with slightly less gasoline bursting out. I got little "poofs" out of the others.

So now I'm thinking it's probably NOT water in there, but unburned fuel making its way out the exhaust valves and burning/evaporating off the inside of the hot exhaust, and that was the smoke I was seeing. Wouldn't that say "bad injector" to you? In which case, isn't that a big relief vs. it being a head gasket?

Whadya think?

[Jagdpanzer]

Appears you have found the problem.
Time to pull the plenum and replace the injectors

[GTOger]

Alright, now I just need to sift through some existing posts on the best injectors to get. I know better than to start that debate here! :)

[GTOger]

OK, I lied. I tried to find the definitive answer but couldn't. I need some advice for good injectors that will withstand ethanol and not break the bank. I found some on Ebay
http://cgi.ebay.com/ebaymotors/1990-1992-ZR1-lt5-Bosch-Rebuilt-Fuel-Injectors-/310271671038

I'm really not sure what "rebuilt" means in this case, however.

Suggestions / recommendations / warnings are appreciated!

[tccrab]

OK, I lied. I tried to find the definitive answer but couldn't. I need some advice for good injectors that will withstand ethanol and not break the bank. I found some on Ebay
http://cgi.ebay.com/ebaymotors/1990-1992-ZR1-lt5-Bosch-Rebuilt-Fuel-Injectors-/310271671038

I'm really not sure what "rebuilt" means in this case, however.

Suggestions / recommendations / warnings are appreciated!

From cheapest to most expensive:
FIC Rebuilds
Accel
RC Engineering
.
..
...
Original Multecs from GM (avoid at all costs)

Here's a link to Dynomites Solutions page:
All the info you'll need. Put on your reading cap.
http://www.zr1.net/forum/showthread.php?t=11619

I put Accels in my Z about 3 years go, still working fine.
I've read good things about FIC's, definitely the cheapest solution.
RC Engineering are pricey but are supposedly the best out there.
Stay away from the original Multecs, they were not engineered for fuels with ethanol. They are the most expensive and are absolutely guaranteed to fail.

Order up some plenum gaskets from Jerry's Gaskets, his are hands down the best out there and Jerry is really a nice guy.

Too bad you're not local, I'd gladly pull your Z into my garage and replace them for you.
It's not that difficult, but you do need to pay attention to details.
It's very busy under the Plenum, lots of things to mess up if you're not careful.

TomC
'Crabs

[GTOger]

So as I understand it, I will need to get these injectors:
http://www.corvetteinjectors.com/shop/viewitem.php?productid=33

and this gasket kit:
http://jerrysgaskets.com/store2/root/index.php?main_page=product_info&cPath=16_19_20&products_id=459

I guess it could be a lot worse!

[A26B]

Jon's (FIC) injectors come with Viton o-ring seals already on the injectors. You could save some $'s by buying the gasket/seal kit items separately and omitting PN 17112222-24V.

Gaskets & seals included in this kit are as follows;

PN 10168684 Gasket Set, Intake Plenum
PN 14104675-V Seal Set, Fuel Feed & Return Pipe (VITON-A)
PN 17112222-24V Seal Set, U-Primary & Secondary Inj & L-Secondary Inj (VITON-A)
PN 10067600-V Seal Set, L-Primary Inj (VITON-A)

There is a Tech Data Sheet on the web site regarding replacement of the lower primary o-ring seals, PN 10067600.
http://jerrysgaskets.com/store2/root/index.php?main_page=product_info&cPath=13&products_id=446

Lube all of the o-rings with a light coat of engine oil before re-installing the injectors. Makes assembly a lot easier and protects the o-rings from damage.

No sealant or adhesive required on the plenum gaskets. Clean & degrease the gasket surfaces is all that is required.

Lay the gaskets on the injector housings to get them oriented properly, then take the gaskets off and set aside (lay on the windshield is good). When the plenum is ready to be bolted down, raise each side of the plenum just enough to slide the plenum gaskets in place. Hand start all the bolts and tighten in sequence & torque.

There are some maintenance items you should perform while the plenum is off. Lots of great pictoral posts available here in the forum. http://www.zr1.net/forum/showthread.php?t=7614
For example;
1. Tighten all injector housing bolts
2. Tighten Crankcase Ventilation (PCV) Box bolts
3. Check secondary vacuum lines for leaks

[Paul Workman]

Now aren't ya glad ya didn't crank it before pulling the plugs?

And, whata relief! (Not a head gasket, I mean!)

You'll want to change oil and filter before venturing out again. I think most of us are following Marc Haibeck's recommendation and using Amsoil AMO 10-40; it has the "right stuff" in it for our flat tappet cams.

That #8 plug... I bought a plug socket with the built-in knuckle on top. To that I installed a 2-1/2" extension and taped the two pieces together to keep them from parting when extracting the socket from the plugs. Then, the socket will slip into the #8 and the knuckle allows the extension to follow right in, leaving the end of the extension peeking over the top of the hole when the socket is seated over the plug. I have a swivel-head ratchet that easily slips onto the end of the extension, and after torque is broken, the wrench comes off and I can hand turn the plug out. (Don't forget to put a little anti-seize lube on the plugs before installing them. Ya don't want them to seize and possibly damage the aluminum threads next time you extract them.;))

FWIW, I installed new Accel injectors about a month ago. Oh, what a difference it made...Shweeeeet!

Glad you found your gremlin. You can put that behind you for and other dozen years or so!:thumbsup:

P.

[Kevin]

OK, Update.... first of all, thank you for all the follow-ups and it's not that I've been ignoring you, but I got nasty sick on Friday and was down for most of the weekend. I dragged my sniffling self to work this morning just 'cause I didn't really have a choice. Now I'm feeling better so it's time to get the ZR1 feeling better!

NOW... for the excitement... This morning I came downstairs after getting ready for work and the wife says "it smells like gasoline down here". Being stuffed up still, I took her word for it. Until I got to the back hall and sure enough that was gasoline I smelled. I opened the garage door and it was really strong. Looked around under the car and found no puddles. Had to go to work.

Came home tonight & I managed to get all the plugs out except for 8. I'll go back and search for all the tips on how to get at 8, but what was GM thinking there?! :icon_scra

I compared all the plugs and they appear original (almost 28k miles on the car). #5 looks very fouled.

I bumped the starter a few times and watched for water to burble out one of the cylinders. When it hit #5, a geyser shot from the engine to the garage wall... on the far side of a 3 car garage! And it was gasoline.

I made another revolution with the starter and got the same result with slightly less gasoline bursting out. I got little "poofs" out of the others.

So now I'm thinking it's probably NOT water in there, but unburned fuel making its way out the exhaust valves and burning/evaporating off the inside of the hot exhaust, and that was the smoke I was seeing. Wouldn't that say "bad injector" to you? In which case, isn't that a big relief vs. it being a head gasket?

Whadya think?

if you think that #8 is bad on the lt5 you've never had an L98 or LT1/4 those are a nightmare. I think I still have scares on my hands from my L98. I haven't really been following injectors recently, but I need to. I know that RC used to be the standard for our cars, no idea who makes the best value for money now

[GTOger]

Oh, I had an old LT1 Trans Am, but got rid of it before it was close to needing plugs. Yech.

Thanks for all the help and input. Have I mentioned... This board ROCKS!

I've ordered some injectors from Jon and some gaskets & O-rings from Jerry. I'll stock up on some oil & filters and we'll get ready to go to town on this bad boy. Hopefully by next week I'll be back kicking some asphalt!

[VetteMed]

Glad to hear that things are looking up!

[tf95ZR1]

After MANY years following the LT-5, it's AMAZING how many
times the problem is faulty injectors. It seems like this is the
weak link! And being underneath the plenum, the trapped heat must
add to the stress. I wonder if another design would be better?
Hey, how about a carburetor on top of the engine! What a concept!

[GTOger]

You'll want to change oil and filter before venturing out again. I think most of us are following Marc Haibeck's recommendation and using Amsoil AMO 10-40; it has the "right stuff" in it for our flat tappet cams.
P.

I've never used Amsoil in anything. Not because I don't like the product, but for my applications haven't "needed" the product enough to deal with the hassle of working through their MLM network.

However, I now find it can be ordered online, and it's roughly half the price of the comparable Mobil 1 Racing oil (which also contains the cat-busting, tappet-saving zinc additives). Maybe it's worth giving the Amsoil a shot.

Thanks for the tip.

[Hog]

After MANY years following the LT-5, it's AMAZING how many
times the problem is faulty injectors. It seems like this is the
weak link! And being underneath the plenum, the trapped heat must
add to the stress. I wonder if another design would be better?
Hey, how about a carburetor on top of the engine! What a concept!
I also wonder if using a more modern design might be bette? Fuel injectors have come a long way since the early 90's. Even if you had to change connectors, having greater injector reliability would be worth it to some.

peace
Hog

[Paul Workman]

I also wonder if using a more modern design might be bette? Fuel injectors have come a long way since the early 90's. Even if you had to change connectors, having greater injector reliability would be worth it to some.

peace
Hog

Well, yeah, technology improves, and has improved; the stainless Accel injectors as an example. But, we're talking about 20 year old injectors with a known problem with alcohol. But, a carburator? Oh, really now! Maybe for a drag or dedicated track car...maybe. But, my wife has a carb'ed Vette, and I can tell ya from a performance point of view, temperature/altitude/humidity/heat soaking/choke settings/gas mileage(!), I never wanna go back to carbs!

Just a major 20-year tune up: Install new injectors, yank the secondaries, re-build the starter, change plugs, wires, and coils and ya should be all set for another 20 years!:dancing

P.

[GTOger]

Hi Race Fans.
OK, tonight the wife and I got familiar with the plenum removal technique. It's off. Hooray. But I'm afraid I'm in trouble now.

http://robin.virtbiz.com/cg/ZR1 - plenum-off-uhoh.jpg

If you can see from the pic (it's hard to get a good shot), there's water in one of them there holes. How bad is that?

[Hammer]

Hi Race Fans.
OK, tonight the wife and I got familiar with the plenum removal technique. It's off. Hooray. But I'm afraid I'm in trouble now.

If you can see from the pic (it's hard to get a good shot), there's water in one of them there holes. How bad is that?

Can't see at all, but it's fairly common to have some drippage from removing the plenum. I would say if there's standing water, it's a problem. But if it's just water drops in the hole, wipe it out and reassemble. GL

[GTOger]

Hey John
Oh no... this is no droplet collection. It's standing water. Maybe this is a better pic:
http://robin.virtbiz.com/cg/water-in-port.jpg

So tell me: how screwed am I?

[tomtom72]

Hi Roger, the good part is that the water stayed in the hole and didn't go any where else.....pull that plug and stick a clean rag down to see if any got to the cylinder.

Sorry, I'm behind on this saga so bring me up to speed. You were not running the motor right? You had just done a few crank overs with the plugs out to see if anything shot out...like coolant or in your case gas. Right?

My guess is that after buttoning up after the last plenum pull you tore a gasket...any sign of that on the plenum gasket from that side?

Oh, sorry, use a rag or paper towels to soak up that coolant as much as possible. The I would carefully pull that I/H so I could see the condition of the I/H to head gasket...that may have a tell tale as to where & how the coolant got into that port. Check me on this thought, that is a secondary port, I think? God bless the secondary port T- blades, maybe.

:cheers:
Tom

[XfireZ51]

Hi Race Fans.
OK, tonight the wife and I got familiar with the plenum removal technique. It's off. Hooray. But I'm afraid I'm in trouble now.

http://robin.virtbiz.com/cg/ZR1 - plenum-off-uhoh.jpg

If you can see from the pic (it's hard to get a good shot), there's water in one of them there holes. How bad is that?

It's not good especially since there isn't a source of coolant nearby. I can understand 1-3 or 2-4, but 6? Use a turkey baster to pull coolant if that's what it is. Get a coolant system pressure tester and see if you can determine where leak is coming from.

[GTOger]

Hey Tom
Actually, I'm Chris. But Roger works I suppose. Or Clarence or Victor. Or Ted Striker. :)

Long story short... driving home from Thanksgiving, car started running like something brown and stinky. Appeared to have white smoke. Thought I smelled glycol. Assumed the worst, then started thinking maybe it's just a bad injector. Plugs 3 and 5 are completely fouled. 7 & 8 appeared oily. No water appeared to shoot out when I bumped the ignition with the plugs out, but a bunch of gas did come flying out of 3. Like... a bunch.

This evening we pulled the plenum and found this little swimming pool in one of the IH ports. So here we are.

I'll try and get the IH off tomorrow and see what I can see. I note that even though I tried to be careful with the plenum gaskets, one of them just came to pieces. Guess I'll be hitting up Jerry again for IH to head gaskets.

If the port towards the back of the car is the secondary, then yes, this is secondary #5.

[GTOger]

It's not good especially since there isn't a source of coolant nearby. I can understand 1-3 or 2-4, but 6? Use a turkey baster to pull coolant if that's what it is. Get a coolant system pressure tester and see if you can determine where leak is coming from.

It's actually #5, but same difference, I guess. I'll get it cleaned out, alright.

[tomtom72]

:o I didn't see that picture.

Hey Dom:wave:, ain't that #5 secondary? Yea, there isn't any coolant passage close to that cylinder.

Crack somewhere? In the I/H? I hope.

[tomtom72]

:o Sorry Chris. I'm battin' 1000 tonight.:o

Do as Dom suggests. I should have read thru the entire thread before posting up. I apologize. :o

I can't quite figure how coolant gets that far back to flood the secondary port on an I/H unless there is a crack or a bad head gasket ( I hope not ).

The plenum gasket that fell apart was from that side of the plenum, the side with the coolant in #5 port?

[GTOger]

The plenum gasket that fell apart was from that side of the plenum, the side with the coolant in #5 port?

Actually, it was the other side - the passenger side - that went to pieces.

But HOLD THE PHONE. As suggested I went back out to clean the port. Since it was just glycol, I used the trusty little shop-vac. That might have been a mistake. I think it was actually gasoline in there.

In hindsight, now I've destroyed the "evidence". :mad:

Worse, though, I could have blown up the garage if something was sparking in the vacuum. [-X I really should have known better. Kids, please learn from my stupidity.

However, after kicking myself (easier said than done, BTW) I fished around in the port with a rag and my finger. The sniff test says gasoline, gasoline, gasoline. There's a little drip of coolant where I pulled the plenum off. That smells like coolant. The port doesn't smell at all like coolant.

I went back and looked at the plugs again. None of them look "steam cleaned". #5 is filthy black, fouled really bad.

So I thought it was coolant in there just by the looks of it. But maybe that was just the lighting.

This is a roller-coaster for sure.

Alright, if I promise to quit being stupid, what do you think my next move ought to be? I'm really hoping for a good outcome here.

[tomtom72]

Okay Chris, I like the smell of gas .... at least in this situation really bad injectors are waaaaay better than a crack in a head or some other expensive place!

Root around in the shop vac's tank and see if you can see anything & or smell anything. That would cinch the deal on the liquid being gas.

I feel much better for you now.:handshak: Order up some gaskets from Jerry and order up some injectors of your choice. Just one other thing, humor me I'm old & senile...that's my excuse! Check the fuel pressure regulator and it's hose for liquid gas in the hose or in the dome of the regulator....gas in either place = replace the F/P regulator.

One thing I would want Dom or Pete or Jerry or one of the other guys that know stuff is an opinion on with that much fuel being dumped can you hydro-lock a cylinder with gas????? I do not know the answer to that question....I would only be guessing.

:cheers:
Tom

[sammy]

if i remember right you could ck the injectors even though the plenum is off. just keep the fuel system connected pull the injectors out of the housings rut a towel over the motor have the injectors on top of the towel and turn the key on for 2 sec and then off you should see the leaky injector if its that. pete isnt this ok to do ???

[Paul Workman]

I fished around in the port with a rag and my finger. The sniff test says gasoline, gasoline, gasoline. There's a little drip of coolant where I pulled the plenum off. That smells like coolant. The port doesn't smell at all like coolant.

I went back and looked at the plugs again. None of them look "steam cleaned". #5 is filthy black, fouled really bad.

It's always best to troubleshoot one problem at a time, Chris: divide and eliminate! Otherwise it can get a bit overwhelming and easy to become distracted and go off on tangents!! :icon_boun I'm never in favor of changing stuff till the problem goes away (e.g. many auto "repair" shops, including some dealers!), and commend you for testing. But, I sense you're having an issue with pulling the trigger. At some point enough is enough.

OK...First things first: the most obvious...Let's review:


With the plugs out (sans #8) cranking resulted in fuel squirting out of #5. (Strike One)
Add to that #5 plug was really fouled and NOT "steam cleaned" in appearance. Strike Two)
Then you have liquid that smells like "gasoline, gasoline, gasoline" pooling in #5 secondary. (Strike Three!).


Given those findings, and keeping in mind the well established issues with those injectors in the presence of alcohol...I'd say that was enough to justify replacing the injectors. Yeah, there are even more tests you could do, but I recommend you replace the injectors and both the IH and plenum gaskets before becoming distracted with any other items (that may or may not be at issue too).

Alright, if I promise to quit being stupid, what do you think my next move ought to be? I'm really hoping for a good outcome here.

Besides taking a chill pill? ;)

With the new injectors installed, and before putting the plenum back on, you could do a fuel pressure leak down test - even brand new injectors have occasional "infant mortality". (You can get a fuel pressure test kit at AutoZone and if you take it back, you get your security deposit back and net no-charge for the rental!). If all is OK now, then you can move onto renting a coolant pressure test kit.

I'm going to guess and say (hope) you don't have a coolant leak. However, having installed new gaskets, there's no time like the present to test for leaks. Again at AutoZone you can rent a coolant pressure test kit (as suggested) and check for leaks. With new IH and plenum gaskets you will have eliminated the most likely sources for any leaks, and you will likely be back on the road soon. Again...I would change oil and filter before heading out again to avoid problems caused by fuel contamination in the oil.

Keep us posted.

P.

[Hammer]

Chris,
I'll bow out here as you have people helping you that are far more knowledable about the LT5 than me. My experience is general in nature and these guys have been around the LT5 internals before. GL

[Pete]

if i remember right you could ck the injectors even though the plenum is off. just keep the fuel system connected pull the injectors out of the housings rut a towel over the motor have the injectors on top of the towel and turn the key on for 2 sec and then off you should see the leaky injector if its that. pete isnt this ok to do ???


Yeap.

That kind of water you might have a leaky plenum or IH gasket or head gasket these are the only ways to get water in the cylinders.

If you were cranking it, injectors will keep firing unless you go WOT with TPS connected.


Pete

[GTOger]

Well... Santa Claus came early to the GTOger Garage...

:-D We're back on the road! WOOT! :-D

I can't thank you guys enough for the advice, support, and general camaraderie. I've had a lot of cars in my day from pretty much every continent known for car making. I've even had a C5 vette. Nothing compares to the ZR1 community. Not close.

In case anybody is wondering, it was injectors. The #5 & #7 primary injectors look like they've been leaking for a while, based on the fouling of the plugs. I got a new set of injectors from FIC and gaskets from Jerry's Gaskets. Both vendors shipped very quickly and I found the parts to be of good quality.

My wife and I spent one evening tearing down, removing the plenum, pulling the plugs, etc. Man... they sure do cram it in that engine compartment. I guess the main concern was not ease of servicing! :icon_scra

Unfortunately we had to wait a couple of weeks to put it back together due to other pressing business. So this evening we started putting everything together and I'm happy to report the Z fired right up.

There was a bit of a buildup of unburned fuel left in the exhaust, apparently, because it burned off for a bit (smoke out the tailpipes). I watched all gauges and kept an ear peeled for funny noises. She just purred like a kitten. Once I was sure there was plenty of coolant and all the pressures & temps looked normal I gingerly headed out for a spin around the block. Which turned to another. And another, this time faster. Next time put my foot into it a bit. Then I turned on the secondaries. Yee haw!

All the unspent fuel did burn off and now she's running clean. And she's running MUCH smoother than ever before.

Tomorrow: oil change.

Thanks again to everybody who posted here. I'm really proud to be a part of this community.

PS: do I get a bonus rating on my avatar now for having passed the ritual of a plenum pull? :blahblah:

Merry Christmas, y'all.

[Nacho_ZR1]

Well... Santa Claus came early to the GTOger Garage...

:-D We're back on the road! WOOT! :-D

I can't thank you guys enough for the advice, support, and general camaraderie. I've had a lot of cars in my day from pretty much every continent known for car making. I've even had a C5 vette. Nothing compares to the ZR1 community. Not close.

In case anybody is wondering, it was injectors. The #5 & #7 primary injectors look like they've been leaking for a while, based on the fouling of the plugs. I got a new set of injectors from FIC and gaskets from Jerry's Gaskets. Both vendors shipped very quickly and I found the parts to be of good quality.

My wife and I spent one evening tearing down, removing the plenum, pulling the plugs, etc. Man... they sure do cram it in that engine compartment. I guess the main concern was not ease of servicing! :icon_scra

Unfortunately we had to wait a couple of weeks to put it back together due to other pressing business. So this evening we started putting everything together and I'm happy to report the Z fired right up.

There was a bit of a buildup of unburned fuel left in the exhaust, apparently, because it burned off for a bit (smoke out the tailpipes). I watched all gauges and kept an ear peeled for funny noises. She just purred like a kitten. Once I was sure there was plenty of coolant and all the pressures & temps looked normal I gingerly headed out for a spin around the block. Which turned to another. And another, this time faster. Next time put my foot into it a bit. Then I turned on the secondaries. Yee haw!

All the unspent fuel did burn off and now she's running clean. And she's running MUCH smoother than ever before.

Tomorrow: oil change.

Thanks again to everybody who posted here. I'm really proud to be a part of this community.

PS: do I get a bonus rating on my avatar now for having passed the ritual of a plenum pull? :blahblah:

Merry Christmas, y'all.

CONGRATS! Perhaps a friendly run on the dyno will be on the agenda sometime soon :icon_boun

[Brillo1990]

Good thread, you gotta love happy endings. :thumbsup: The more I read about those injectors the more I think I should just tear mine apart and replace them before we have warm weather. :rolleyes: