Plenum pull veterans I have Q's [Archive]

tomtom72

10-06-2005, 08:26 AM

Hi all, First let me thank all the senior members who have provided info for pleebs like me to study at this site and the regional sites. Thanks so much! The members make this car fun to own. :thumbsup:

I have three common issues I'm going to try to address. Breather oil leaks, secondary throttle vacuum leak and a few bad injector coils. I have a Helm for my 90 and most all of the parts. Easier to list what I didn't buy: DIS module, starter, alt., linkage parts for 2* butterflies, CTS, fan switch and mounting plate for coils. I think I'll buy the two sensors as soon as I eye the connection on the CTS.

Q1: It looks like there is enough room to just move the A/C comp. enough to get at the breather cover bolts without discharging the A/C gas?

Q2: To do breather gasket leak the inj. housings should be R & R'ed because all that is in the way?

Q3: P/S pump doesn't have to come out to move A/C comp.?

Q4: Helm doesn't say T/B & Air horn extension & plenum & Inj. H. bolts need loctite, I missed it in reading the book?

Q5: Parts CD says there are different style connectors on CTS for 90 Z, I read this worng?

Q6: To change injectors the fuel rails should be separated from the distribution block by disconnecting the lines at the rails? And those O-rings are the same as for the fuel filter?

Sorry for taking up space! I never worked on FI before now. Got me some rented work space for a month so I gotta get straight before I start to disassemble anything. I'm sure I overlooked something. If so, shout at me! :o

Thanks,
Tom
As a P.S. to all this I just noticed someone else's post about injectors. I purchased RC #205 and it seems I got the wrong ones? It seems I should have bought #225? Any help on this would be great! Thanks again. :thumbsup:

haber rj

10-06-2005, 09:57 AM

tomtom72

10-06-2005, 10:33 AM

Hi haber rj, Yea I guess we all gotta start learning at some point! Did you check out Jeffvette's Pacfic NorthWest web site? It has some great step by step lay outs of the plenum pull.
Good luck with your project!!
:cheers:
Tom

Jeffvette

10-06-2005, 01:36 PM

Q1: It looks like there is enough room to just move the A/C comp. enough to get at the breather cover bolts without discharging the A/C gas?

There is enough slack/flex in the system that you can remove the AC compressor to get it off of the breather box and sitting down by the water pump with no issues.

Q2: To do breather gasket leak the inj. housings should be R & R'ed because all that is in the way?

No, the breather box should come out with out removing the injector housings (it does make it easier though). You will have to remove the secondary butterfly linkageand the actuators to get the breather box out.

Q3: P/S pump doesn't have to come out to move A/C comp.?

No, PS pump can stay put unless you are removing the driver side cam cover.

Q4: Helm doesn't say T/B & Air horn extension & plenum & Inj. H. bolts need loctite, I missed it in reading the book?

No loctite in any of the serviceable top end stuff.

Q5: Parts CD says there are different style connectors on CTS for 90 Z, I read this worng?

There are two different CTS sensors on the driver side injector housing. One is for the ECm reading, the other is for the gauge. To my knowledge these are the same for all years. One is a standard clip, the other is a spade connector.

Q6: To change injectors the fuel rails should be separated from the distribution block by disconnecting the lines at the rails? And those O-rings are the same as for the fuel filter?

Don't remember off the top of my head what the size for the fuel rail block is. I know you can either get them from GM or Kurt White.

As a P.S. to all this I just noticed someone else's post about injectors. I purchased RC #205 and it seems I got the wrong ones? It seems I should have bought #225? Any help on this would be great! Thanks again. :thumbsup:

The 205's will be fine. 225's are recomended for larger motors or Nitrous applications.

Jeffvette

10-06-2005, 01:40 PM

Hello Tom, I am also in the process of replacing all my injectors and with the modification that I have done ( bolt ons, headers, corsa exhaust, new prom) they told me to run 24lb or 257cc injectors. I am not familiar with replacing injectors or the removal of the plenum, but I guess that there is no time like now to get in and learn. It really doesn't look that difficult, taking the upper plenum off should be ok if I take my time.

haber nj

As I replied in Tom's post, the 205's will be fine. With bolt on's, headers and even porting the 205's will be fine.

Tom thanks for the plug on my site. It's www.pnwzr1.net (http://www.pnwzr1.net) The tear down info is in the tech section.

tomtom72

10-06-2005, 02:01 PM

Jeffvette, :handshak: and :worship:

I'm now a little more at ease with this. Your site should be required reading for all rookie owners along with the stuff on the NetRegistry!

Thanks on the injector Q also! I was thinking if I can't even order parts correctly what am I doing taking the plenum off. I feel better hearing the voices of experience. I would sent the stuff to you but I don't know yet how long my Uncle will like his S500 Merc sitting out side :eusa_shhh
I told him can I have two weeks & he didn't seem to mind. I don't want to push my luck. I guess a little 600 wet and LPE's paint plus maybe some clear & a little 3000 wet will have to do this time.

Thank you for responding & helping me out!
:cheers: :thumbsup:
Tom

Jeffvette

10-06-2005, 02:07 PM

Not a problem Tom. And depending on the color you choose, I could get it done quickly. Not like another week would kill your uncles Merc.

tomtom72

10-06-2005, 02:26 PM

Jeff,
I'm not brave enough to try to remove the cam covers! :o
Besides the budget took a big hit with all the parts I bought. I'm gonna go get the two sensors and I may try to rebuild the starter & alt. The jury's still out on the DIS module. All the vacuum parts, coils, magnecor wires, 16 injectors, gaskets and breather box stuff.

I guess you can tell I don't want to go back under there any time soon! Besides I have to save $ for gas for next season because I have alot of places I want to go with the Z.
Tom :mrgreen:

Jeffvette

10-06-2005, 02:36 PM

I hear ya. I got my own projects for the winter. Good luck!

Nick

10-06-2005, 03:38 PM

I got my own projects for the winter.

:happy1: :happy1: :happy1: :happy1:
:mrgreen:

Jeffvette

10-06-2005, 03:43 PM

:happy1: :happy1: :happy1: :happy1:
:mrgreen:

Yes, you can get a ride after I get done.:wave:

haber rj

10-06-2005, 04:22 PM

Well gentlemen it looks like I will be taking on the job of installing the new injectors in my 91Z, if all fails and I screw it up I will send for CAA and have it towed to my friends performance shop and have it fixed correctly, he is to busy to do it right now and I can't wait. Thank you for all the help and recommendations, this is my first time talking with other ZR1 owners on the site and I think with all the people who own such a marvellous we are a special breed. Stay close I might (WILL) need more HELP.
haber rj

Z Factor

10-06-2005, 04:41 PM

Hello Tom, I am also in the process of replacing all my injectors and with the modification that I have done ( bolt ons, headers, corsa exhaust, new prom) they told me to run 24lb or 257cc injectors. I am not familiar with replacing injectors or the removal of the plenum, but I guess that there is no time like now to get in and learn. It really doesn't look that difficult, taking the upper plenum off should be ok if I take my time.

haber nj

Hello, and welcome to the forum. :handshak:

I would say that "24lb or 257cc injectors" might be a bit much considering the stock injectors run 220cc/min. I will be addressing Toms question on the matter, and a response or two he has gotten, but in the mean time, reconsider going up to that injector unless there is a sound logical reason to do so.

:cheers:

Z Factor

10-06-2005, 05:05 PM

As a P.S. to all this I just noticed someone else's post about injectors. I purchased RC #205 and it seems I got the wrong ones? It seems I should have bought #225? Any help on this would be great! Thanks again. :thumbsup:

You were probably referring to my recommendation about getting the 225cc/min injectors vs. the 205's that you ordered. As Jeff posted, the 205's will be fine for your application, as would the 225's and will not cause any harm. Both have been used by different ZR-1 owners, and it is a matter of splitting hairs as to which is better. Some people actually use the 205's for primaries, and the 225's for the secondaries. Flow rates vary for several reasons, not the least of which is based on the amount of pressure when measuring them. RC uses 43.1psi (if memory serves me correctly) to bench injectors. If you use greater psi, it will have an effect on the final numbers. Strictly speaking, using GM's numbers, the correct injector by RC will be their 225cc/min which is closer to the stock 220cc/min or 21lb injector, which RC would confirm if you were to contact them. However, that is not to say that a 19lb injector which flows at 205 (psi being equal) will starve the engine of fuel. As Jeff said, if you were to mod your LT5 then having the 225's would make sense, so anyone considering that in the future may as well go with the 225's now.

I hope that helps to also ease your mind since I did not want you to be concerned based on my other post. I should have explained it in more detail so there would not be any misunderstandings.

:cheers:

tomtom72

10-07-2005, 08:30 AM

Hi & thanks Z Factor for taking the time to hold class!! I may yet get my GED in ZR-1's! Well at least I should pass Plenums 101! :o

I thank you for helping me out. I have a better handle on the injectors' size now. Yes my motor is box stock & mods are way out of my budget. You hit it on the head as I thought fuel starvation!! I'm happy the way it is & I don't have any trouble keeping up with the other newer corvettes I play with :mrgreen:

Another couple of rookie Q's if I may impose on every one's good will. The injectors are a press fit into the fuel rail? I'm trying to figure that out as I've never seen a fuel rail. I understand that the hold down brackets press the rail into the I/H but what holds the injectors into the rail? Just the hold down brackets? The last vette I worked on had a holley! :o

Also, I went to Samco's web site and tried to look up cooling hoses by application. I didn't find any. Did I miss something? :???:

Thanks again Jeffvette & Z Factor for your help!! :thumbsup:
Tom

Jeffvette

10-07-2005, 01:19 PM

Tom, when assembling the injectors onto the rail, they are a press fit in. You just insert use a little pressure and twist some. One thing that will help a little is use a little spit on the o-ring itself. Won't harm the injector or rubber. Then when putting rail back ont to the injector housings, there are two methods.

One: get everything aligned up and alternate tightening the 4 bolts for the rail.
Two: Get the bolts started and lightly tap over the rail.

I use method one.

http://www.pnwzr1.net/Nick/Plenum/IMG_0182a.JPG

tomtom72

10-07-2005, 01:33 PM

"I see" said grasshopper! Thanks Jeff! I've been away for awhile, ahem, holley carbs, yea right I can work on FI! :mrgreen:

Bad enough I'm a rookie Z owner but I'm 30 yrs behind on auto technology to boot!

Seriously, thank you & I agree with method #1. I sound like a broken record but you senior members make this possible for us rooks to learn and I thank you guys for that! :thumbsup:

Thanks,
Tom

Z Factor

10-07-2005, 01:42 PM

You hit it on the head as I thought fuel starvation!!

Another couple of rookie Q's if I may impose on every one's good will. The injectors are a press fit into the fuel rail? I'm trying to figure that out as I've never seen a fuel rail. I understand that the hold down brackets press the rail into the I/H but what holds the injectors into the rail? Just the hold down brackets? The last vette I worked on had a holley! :o

Also, I went to Samco's web site and tried to look up cooling hoses by application. I didn't find any. Did I miss something? :???:

Thanks again Jeffvette & Z Factor for your help!! :thumbsup:
Tom

I am no expert Tom, but I figured you were concerned and I try to help out when I can.

As to the injectors there are clips. Also the fuel rail has bolts that help seat the injectors into the housing.

As to the Samco question, stay tuned to the Samco Air Duct thread

http://zr1netregistry.com/forum/showthread.php?t=833

because we are about to make a group purchase for the Air Duct and coolant hose kits as well. Samco does not sell to the general public, and the stock for the LT5 is very limited. So since they make everything by hand, there has to be a large enough demand for a production run.

:cheers:

haber rj

10-07-2005, 03:23 PM

Gentlemen thank you very much for the much needed information on the injector selections and the istallation method. I am going to be running a 125 shot of NOS and I think that I will go with the 225cc units, One more question if you don't mind are the RC units stainless and are they a good choice or is there another source that would be better, but more money.
haber rj

Jeffvette

10-07-2005, 03:39 PM

RC's are stainless, so no corrosion worries. If you are spraying the 225's are your choice.

haber rj

10-07-2005, 03:55 PM

Jeff did you have Aaron at South Georgia Corvettes do work for you, the reason that I am asking is, he is working with me on this project (long distance) and he made my new chip and suggested the 24lb. 257cc injectors. I am trying to get the car ready to take down to him on the weekend of November 18th when he has his gathering, sure hope it happensd.

haber rj

Jeffvette

10-07-2005, 05:43 PM

Yes he did some of the work. I am unsure why he wants to go that large. The man to talk to on Nitrous is Julio. I'll ask him if he minds if I forward his info over to you.

If all goes well, I should be at the gathering.

tomtom72

10-08-2005, 07:51 AM

Hi Guys,Yea it's me again! :o Okay I have another couple of Q's.
I got as far as the plenum & fuel rails are off. BTW, nice tool Jeff!! :thumbsup: Always knew I would find a use for that thing eventually!

Q1) The "reference vacuum signal" and it's sensor(under ECM) is an expossed single vacuum line leaving the valley thru the driver's side?

Q2) What is the vacuum line that's in the right(passenger)side injector harness? It has a grey connector, this goes along with Q3.

Q3) What is that thing it connects to just in front of the coil mounting plate? It has three vacuum lines on it, the one from Q2 and one from the evap/purge and another that I forgot where it came from. The 3-way connector looks to me like a vacuum switch, it's very big to be a "T-ee".

Oh yea, I should have brought a rope ladder to this party, man is that valley deep! I was amazed how far it is to the valley floor! Oh, I almost forgot this:

Q4) One of my actuators looks like it has a lot of stress on the arm from the diaphram. It has a steep angle towards the center of the valley. The other actuator's arm is nearly parallel to it's head. What's up with that??? Is that what GK was talking about with the upside down thing??

Q5) I drained the radiator from it's petcock till it stopped; do I have enough coolant out or is there something else I shoul do??
Thanks Guys for the help!!!
Tom

Jeffvette

10-08-2005, 04:17 PM

Q1) The "reference vacuum signal" and it's sensor(under ECM) is an expossed single vacuum line leaving the valley thru the driver's side?

Didn't really see a question here, but yes, the MAP sensor there is for the secondary operation.

Q2) What is the vacuum line that's in the right(passenger)side injector harness? It has a grey connector, this goes along with Q3.

It goes to the HVAC system to control the doors.

Q3) What is that thing it connects to just in front of the coil mounting plate? It has three vacuum lines on it, the one from Q2 and one from the evap/purge and another that I forgot where it came from. The 3-way connector looks to me like a vacuum switch, it's very big to be a "T-ee".

It's a valve for operation of the HVAC system.

Q4) One of my actuators looks like it has a lot of stress on the arm from the diaphram. It has a steep angle towards the center of the valley. The other actuator's arm is nearly parallel to it's head. What's up with that??? Is that what GK was talking about with the upside down thing??

Take a vacuum tester and hook directly up to the actuator. It should open freely with no binding with 8" of vacuum. If it hitches or binds, test it flipped right side up. If it has trouble opening that way, replace it with a new one. But make sure you test the new unit at the delaer and be prepared to get some bad ones.

Q5) I drained the radiator from it's petcock till it stopped; do I have enough coolant out or is there something else I shoul do??

Little excessive, but yes, that should be enough. Be prepared to have a little still in the plenum when you pull it back.

tomtom72

10-08-2005, 08:06 PM

Thanks Jeff, You are indeed a way big help to me. Sorry for the side track Q's but I was curious about the HVAC valve and the other vacuum lines. I had some notion that the only vac lines I was going to see were the secondary stuff. How naive of me!

Okay I feel fairly proud of myself after a couple of hours last night and about five hours today, I have made some progress. The new injectors are in a clean & AIO'ed fuel rail. The T-body & air horn are cleaned and painted. The plenum is cleaned up and I AIO'ed it and now it looks good under my halogen work light. The paint got a bit darker after a good rub with the AIO but I think it's a match to the LPE paint.

We rookies are very lucky to be members in a club where knowledge is freely shared. Thanks to all the members that have helped me with this little project. :thumbsup:

Tomorrow I'll do the vacuum tests on the actuators that I bought, and the stuff that's still in the car. Then I'll take the rest of it apart to clean up the oil mess from the breather box, yuck. Oh, no mice took up residence in there!

Thanks again, Jeff!
:cheers:
Tom

haber rj

10-11-2005, 10:16 AM

Hello Jeff i am so confused at this time i think that i will just wait it out and see what comes up. I am taking your advise and i have spoken with Asron at SGC and he still tells me the 24lb. so I will speak with him at the gathering, unfortunately I will not have the car there.

haber nj

sledutah

10-11-2005, 01:27 PM

Great learning for me. Keep up the questions/answers coming :worship:

haber rj

10-11-2005, 01:49 PM

This reminds me of when I ran my J/stock Corvette, some guy would go 100th quicker than me and I would spend thousands trying to keep up. The main difference in this case is that we have fellow members who have the knowledge to help us and guide us along and it is all genuine information. I have had 17 Corvettes so far but this has to be the best that I have owned, it might not be the fastest any more, but when I go some place I very rarely see another one, up here in Canada any way. I am ordering the injectors today and I will be putting them in as soon as they are delivered.

haber rj

zr1mom

10-11-2005, 06:13 PM

Here is a picture of the vacuum system: http://www.zr1netregistry.com/gifs/vacuum.jpg

haber rj

10-12-2005, 07:18 AM

At this time I would like to thank you all for all the help and like I said before I have ordered my new injectors and they are going to be shipped to me today. I have all my notes thanks to all of you and my manual, I am armed and ready to go. I will be starting next weekend and hopefully all will be fine. With a supporting cast like you fine gentlemen I am confident it will all turn out well. Thanks again for all the valued advise,
haber rj :)

tomtom72

10-14-2005, 09:19 AM

I'm gonna try to put a period on this thread. If for no other reason than as a rookie Z owner I read these "how to" threads like a text book so I can learn about my car and how to work on it.

The problem started with a miss. It was barely there at first but didn't take long to be really obvious. Do get a Helm manual for your mod. Yr. Z! Gordon's stuff helps too. His classes probably help even more. Check for codes. Scan the car while it's running in "closed Loop" because the Integrator #'s & Block Learn #'s will tell you alot. I checked all the usual suspects: spark, plugs, wires, fuel pump pressure & filter, water in gas, all came up good. The scan is what showed me how the motor was using fuel and that lead me to the injectors. They didn't set a DTC in my case. I'm not sure that bad coils on the injectors would set a DTC. I learned by "seeing" the ECM trying to control bad injectors on a scan tool. The miss got worse the longer the motor ran.

This looks like a tough job but with the info Z owners have: Net Registry site, Pacific Northwest site(Jeffvette's site), Big Country Corvettes(Texas Z owners), Corvette Action Center and our own forum. You will have enough real motors to look at & study before you turn a wrench. Those sites will take the edge off and it is time consuming but not beyond the skill level of most shade tree wrencher's. In fact, after you do it you will see it is just alot of detail work and not impossible for a rookie to do correctly. You also will be proud of yourself because you just passed "plenum's 101". I know I am. :mrgreen:

When you put it back together after fix'in what was wrong be as careful & pay as close attention as you did when you started disassembly. That part is important because the same details that made you pay attention during the removal will be important on the return trip. Remember, if you forget something you gotta pull the plenum back off to fix what you missed.

Good luck and ask Q's. The other owners will answer. That's what makes these cars worth owning, the members!

Thanks to all the members that helped to teach me! :thumbsup:
:cheers:
Tom

Aurora40

10-14-2005, 02:16 PM

So how's it running now Tom?

tomtom72

10-14-2005, 03:10 PM

Hi Aurora, You're famous!! :thumbsup:

I typed that conclusion in advance of putting the plenum back on today, Friday, after work. :o I have to go pick up my new slave cyl and put that in after the plenum's buttoned up. I better stop looking or I'll find another project to start as I was eyeing up how to get at the passenger side air bag sensor. Don't ask what I was doing there...I dropper a nut and had to pull the fender off to get it. :o

I have faith in the result of the project & that I may finally feel why a C4 needs beam plates. See what happens if I get a garage to work in! :)

How are you coming with your Z and the possible injector problem?

:cheers:
Tom

P. S. The results are very :mrgreen:

Jeffvette

10-25-2005, 04:05 AM

Nick

10-25-2005, 11:16 AM

Spent 3 hours tonight pulling the top end of a 94. Of that 3 hours I spent 40 minutes entertaining Bob bloyer on the phone regarding his transmission and how he's going to get it.

Anyways, this is not brain surgery here.

http://www.pnwzr1.net/Jeff/Powdercoating/DavidB/DavidB.jpg

http://www.pnwzr1.net/Jeff/Powdercoating/DavidB/DavidB1.jpg

Oh my GOSH!! Are you crazy for taking all of that apart, all by yourself? You'll NEVER get it back together again! :mrgreen:

Tell Bob I got him covered; in a few weeks, unless he wants it sooner. :cheers: