fuel issues

[Toyvet1]

I am having a issue with my 1990 z. Yesterday I replaced the injectors and plug wires. Didnt have any issues during the install.

Car fired up fine. Idle was good at 750. Filled the tank with gas and headed out nfor a ride to check out -=jeff=- car. The car ran strong half way there and that when things turned. The car back fired and stalled and was hard to restart. Got to jeffs and shut the car off. When i went to leave the car would not start. Crank but no fire, spark was good. Jeff called pete and recommended fuel pump. So we swapped out primary and secandary pump. ( sorry jeff didnt plan on taking you away from your car, pictures of the car dont do it justice) Car fired but ran like crap,billowing white smoke. raw gas out the tailpipe. Sounds like a vacuum leak also.

So Im thinking replacing both fuel pumps for a start. Ive seen 94 an 96 Suburban fuel pumps recommended here. What fuel pump do need?

Once I replace them I see how it runs and look into the vacuum problem. Im hoping I dont have to remove the plumun but Im betting it will come off.

Any ideas what to look for............

[bradslt5]

before you replace the pumps do a pressure test on them . have jeff show you where the schrader valve is if you dont allready know . i would hate to see you spend 140 just to find out thats not the problem. . ck to see if the vac hose to the map sensor is connected. if its not i could do what you are saying is happening . hope this helps

[Toyvet1]

check pressure before swapping pumps, 50lbs drop right to 10lbs.Didnt check after swap. Checked map hose and its connected.

What pump 94 or 96??? Would like to get them orderd and replace to play it safe...

[Jeffvette]

So goes up to 50 psi then drops to 10 psi immediately?


The pumps you need are #25163473, if you really need them.

[LGAFF]

Use the Suburban pumps....can get them in stock from Autozone.

LGAFF
92 ZR1
#234

[Pete]

Now that i think about it sounds like you might have a bad injector stuck open and pooring feul like a faucet.
If pressure drops real fast.
Take plenum off have somebody turn ignition ON and check the injectors.
First check make sure everything is in order spark plugs,spark plug boots pushed in all the way
vacuum leaks etc. before you buy new pumps.
Let us know what you find.
Good Luck.
Pete

[bradslt5]

petes got some good suggestions . from the sound of jeffvettes post you most likely dont need fuel pumps. if you just replaced your injectors you might want to ck you connections with the injectors and the fuel rail you may have an Oring thats leaking there . jeff and pete are 2 of the most knowledgable guys here . thay really know these cars . hope this helps

[tomtom72]

You checked the F/Press regulator hose for gas??? That's the only other thing that jumps out at me after checking what Jeff & Pete said to check.

Let us know what you find.

:cheers:

[Toyvet1]

I check those think tonight when I get time to work on it. But if in need pumps the question still is what year suburban do I need pumps from. GM number is ok but I most likely wont go to the dealer. Advance , autozone and Napa all differant part numbers for 94 and 96 the years most mentioned. Ill need to order these so I have them on hand.....17 years old might as well change them to play it safe.

Thanks.......

[tomtom72]

try this link....hope it helps

http://www.zr1netregistry.com/Old_Proj/old_proj11.htm


:cheers:
Tom

[tomtom72]

In the fuel pump assembly.....not in the pumps but attached to the assembly that ya pull out to change the pumps....is a thing called a Pulsor...if that goes south you will not hold F/Pres at the schrader valve for very long during the KOEO test.

Just a fwiw.. oh, don't forget to get a new sock filter.:o

:cheers:
Tom

[bradslt5]

tom thanx for the info I didnt know that. so it will do what he said his did?

[-=Jeff=-]

Ken,

I would almost pull the plenum and remove the injector rails with injectors and turn key on, put a pan underneath the injectors to verify if one is leaking..

[flyin ryan]

Ken,

I would almost pull the plenum and remove the injector rails with injectors and turn key on, put a pan underneath the injectors to verify if one is leaking..sounds like the best plan to me as well.

[Ccmano]

sounds like the best plan to me as well.

:iamwithst

Bet you it's an injector...

Hans
:cheers:

[bradslt5]

thats what it sounds like to me also , but i think he said he just changed them? guess one could be bad out of the box .

[Toyvet1]

Game plan is to replace the pumps and pulsator in the morning. I betting the plugs are gone so they get replaced. Jeff you think with gas out the pipes the oil might need replaced(LOL). Oil gets changed. Im going to start it up and see what happens. If the problem is still there the plenum comes off. Ill pull the injectors and check for leakage. I have a hard time thinking one or two injectors would make a car run as bad as it is. Both pipes billowing white smoke would be more than a injector from what Ive seen.Jon from Fuel Injector Connection called and offered what ever I need when I found the proble. What costumer service!

[Ccmano]

One things for sure, if it's billowing white smoke from both sides of the exhaust it's not the fuel pumps causing the smoke.

A bad fuel pump (had it on my car) will usually show itself as a lean or loss of power condition at high rpm or the car won't run at all.

A stuck injector will cause an over rich condition on one side and usually results in rough running and black smoke. Gas coming out the tail pipe is possble but only on one side.

You don't have an X-pipe on there do you?

In my experience with white smoke on a manual trans car is usually a bad head gasket, but again only out one tail pipe, the side with the bad gasket.

You mentioned you just fueled the car before this happened, is it possible you got a bad batch of gas? Wouldn't be the first time.

Bottom line for me, this really doesn't sound like fuel pumps, there's something else going on here

GoodLuck,
Hans
:cheers:

[tomtom72]

Good catch Hans! I read right past the "white smoke" !

Ken, you 100% that the smoke is white?.....as in steam = white??, or it just looks kind of white...could be gray to charcoal color type of smoke but it's a "hard to tell" deal????

JMHO, white could be a head gasket, like Hans says.....or....the injectors are not leaking, rather they are not working so the white smoke is a lean condition....JMHO.
I hope if the smoke is truly white, that it's a lean condition.:pray

tom

[bradslt5]

where is the pulsator located on the fuel pump . think i may ahve a bad one as i pull the fuel rail assembly cuz she wasnt holding pressure but found no leaking injectors, or any leaks at the fuel rail. could a finicky schrader valve cause this ?

[-=Jeff=-]

Well, the thing is, when he went to restart at my house, it would not.. AT ALL.. that is why we thought Fuel pump, we swapped the pumps and it would run.. but not right..

He will swap pumps to be safe and check pressure, if it falls off, he will pull the plenum..

now how many injectors need to be stuck open to cause the FP to go from ~55 to 0 in about one second?

[Toyvet1]

Okay heres the latest. Replace both pumps this morning. There is no pulsator on my 90. Pipe from pumps go right to the top. The only thing on the sending unit is a baffle on the vent tube, its welded to the assembly so its not replacable.

Changed the oil, and plugs, 1,2,5,6,7,8 were rich and 3,4 look fine. Funny thing 3,4 had leaking injectors.

Pulled the plenum to check injectors, one primary two secandary leaked. Replaced them with a couple of factory ones.One was a drip but two were full flow. Got the car back together and it fired right up. Idles great and after about five minutes the smoke disapated.

Even with no injector leaking fuel pressure still drops, so that only leaves the regulator?
Ill test drive it later and let you know how it drives

[-=Jeff=-]

cool Deal!! I assume replacement are on the way?

[Jeffvette]

So what injectors were these?


Trouble shooting the regulator is fairly easy, and I've only ever come across one that failed.

[Toyvet1]

Need to make a call on the replacements, Dont see any problems there. If the car runs good is it worth changing the regulator. I changed everything out on my other car and still have the bleed-off problem but car runs good..

[-=Jeff=-]

FIC Bosch rebuilts I believe.. the guy at FIC will stand behind them. they also have a 3 year warranty

[Jeffvette]

Need to make a call on the replacements, Dont see any problems there. If the car runs good is it worth changing the regulator. I changed everything out on my other car and still have the bleed-off problem but car runs good..

Well, if it's not maintaining pressure, you could start with a hesitation/stumble. if pressure is to high you could run into a rich condition and start setting off some codes.

BTW, I got your vacuum harness packed up for BG.

[Jeffvette]

In my experience with white smoke on a manual trans car is usually a bad head gasket, but again only out one tail pipe, the side with the bad gasket.


Hans, it's not uncommon to see white smoke after a plenum pull. Most people do not get all the coolant out of the top before yanking it off and it just goes directly into the runners and into the cylinder. But yea, white smoke can be indicitive of a bad head gasket.

[Jeffvette]

FIC Bosch rebuilts I believe.. the guy at FIC will stand behind them. They also have a 3 year warranty

Doesn't mean much if I have to pull the plenum and start replacing things that should work right out of the box. That's another 2 hours I could have done on something else other than warranty work.

[-=Jeff=-]

Doesn't mean much if I have to pull the plenum and start replacing things that should work right out of the box. That's another 2 hours I could have done on something else other than warranty work.

I know. but I guess it could happen with anything.. New or rebuilt.

[Jeffvette]

I know. but I guess it could happen with anything.. New or rebuilt.

Higher odds with rebuilt. I avoid anything rebuilt unless it's my last option.

[-=Jeff=-]

Higher odds with rebuilt. I avoid anything rebuilt unless it's my last option.

yes i agree, at the same time though in a business scenario, you are better off with new.

I bugth the FIC rebuilts too, but I was looking at it more as a cost issue.. I got a REALLY good deal on mine.. all 16 for less the a set of 8 Accels. but I am also taking my chances that there are no issues.. so far I have not had any, but I have to just watch it..

[Ccmano]

:iamwithst

Bet you it's an injector...

Hans
:cheers:

Looks like somebody called it! ......:D

Hmmm... how many bad injectors? All just rebuilt? Fuel pump inop? I would go back look at the fuel quality as I said earlier. There might be something gumming up the works.

Hans
:cheers:

[-=Jeff=-]

Looks like somebody called it! ......:D

Hans
:cheers:

Who might that be???

:sign10:

[Jeffvette]

Looks like somebody called it! ......:D

Hans
:cheers:

You called "an injector". Not multiple injectors. :hello:

[Ccmano]

You called "an injector". Not multiple injectors. :hello:

:blahblah: ... splitting hairs?

Did you guys read the rest of my post? Multiple bad, newly rebuilt injectors? A bad fuel pump? smoke from the exhaust? Just got gas?:icon_scra

There may be more than meets the eye here.

Hans
:cheers:

[Toyvet1]

Its not going to be lost time pulling the plenum. I need to pull when I finally get the secandary vacuum assm. So Ill replace everything at once.Time to go for a ride and see how it runs.....

[Jeffvette]

:blahblah: ... splitting hairs?

Just keeping you in line :D

[Toyvet1]

I took the car for a ride and was not happy. The car runs okay at low speed and up to half throttle. When you drive it hard the car doesnt run and better with power key on or off. Im going to replace the injectors with something new. Might even throw the old ones in for the weekend. Car ran great before I started this project.

No more smoke after running a few minutes. How much abuse can the converters handle when raw gas goes through them?

As far as the gas goes I filled my other car 15 minutes earlier and no problems...

[XfireZ51]

Just keeping you in line :D

Don't listen to him Hans. You're fabulous! :wink: :worship:

[Toyvet1]

Im getting a new set of injectors tomorrow. Will install them and see what happens.

When I removed the plenum it looked like coolant was leaking into the number 3 and 4 intake runners. Could not have been to bad of a leak, the cooling systen held 15lbs for 12 hours. That explains why two plugs were so clean.

That would explain the white smoke. Hope the next set of gaskets is of better quality.