Fuel injector question

[-=Jeff=-]

Okay.. would a LT5 run like complete crap and load up on fuel with one leaky injector? or is there some other issue?

I do know, swapping injectors (all 16) fixes it and I do know one of the ones removed leaks (drivers side injector closest to firewall)

the set with the leaker is newer, I have gotten a replacement for the leaker and want to swap out my Multecs, but I want to see if that one would have been causing my issues for loading up..

Also that one injector was a steady drip, drip, drip with key on

Thanks

[secondchance]

Could you explain "loading up"?
Do you mean the car feeling as if it's choking?

My 94 was running fine when in open loop but as soon as she went into open loop she would ping at light load part throttle.

I replaced all 16 and in retrospect, even when cold,Iwas not quite getting all 405.

Although I did not test old multecs (threw them out vengefully!), my theory was one was leaking (excess fuel). When cold, a little excess would be tolerated but once warmed up, O2 sensor would read excess and trim back resulting in the rest of 3 cylinders running lean, back to normal, rich mixture... and so on.

[tccrab]

I can't speak for leaky injectors, but I had two primary injectors fail and my Z ran like sh!t.
My guess would be that anything that causes the air/fuel ratio to significantly differ from the optimal 14.7 : 1 will cause problems.

TomC
"Crabs"

[-=Jeff=-]

Could you explain "loading up"?
Do you mean the car feeling as if it's choking?

My 94 was running fine when in open loop but as soon as she went into open loop she would ping at light load part throttle.

I replaced all 16 and in retrospect, even when cold,Iwas not quite getting all 405.

Although I did not test old multecs (threw them out vengefully!), my theory was one was leaking (excess fuel). When cold, a little excess would be tolerated but once warmed up, O2 sensor would read excess and trim back resulting in the rest of 3 cylinders running lean, back to normal, rich mixture... and so on.

Loading up on fuel.. too much fuel, but then the one bank would show lean and then it would adjust to go rich but then see too much fuel on the other bank from the leaker. but that just does not make sense

[secondchance]

I suspect mine was doing the same thing. Perhaps not as severe.
When hoked to Tech 1, I was told by the mechanic that one bank (I guess 1-3-5-7 and 2-4-6-8 are processed separately by one O2 sensor each), passenger side, O2 reading was fluctuating.

It wasn't too bad untill about 2 months ago when it got real bad. I suspect initially one injector was probably leaking and then finally it died. I did not bother to check injectors after removal so I don't know this for sure.

As you know, after replacing w/ FIC injectors she has been running flawless.

To answer with your question, based on my experience, one leaker was making mine run like crap. Especially when in closed loop.

Good luck!

[-=Jeff=-]

I suspect mine was doing the same thing. Perhaps not as severe.
When hoked to Tech 1, I was told by the mechanic that one bank (I guess 1-3-5-7 and 2-4-6-8 are processed separately by one O2 sensor each), passenger side, O2 reading was fluctuating.

It wasn't too bad untill about 2 months ago when it got real bad. I suspect initially one injector was probably leaking and then finally it died. I did not bother to check injectors after removal so I don't know this for sure.

As you know, after replacing w/ FIC injectors she has been running flawless.

To answer with your question, based on my experience, one leaker was making mine run like crap. Especially when in closed loop.

Good luck!

you have a 94 and are running FIC injectors with no issues?

I have FIC injectors ( new ones) the leaker has been replaced but I have been hesitant to reinstall them.. the force it takes to install the new ones is less then the old ones

[secondchance]

you have a 94 and are running FIC injectors with no issues?

Yes.

I have FIC injectors ( new ones) the leaker has been replaced but I have been hesitant to reinstall them.. the force it takes to install the new ones is less then the old ones

Based on my experience, pulling old one were tough (probably due to years and stiffend O rings).

New ones, after being greased with Vaseline, were easier to slip into rail as well as into IH.

Did you make sure you got the right set talking to Jon?

[-=Jeff=-]

you have a 94 and are running FIC injectors with no issues?

Yes.

I have FIC injectors ( new ones) the leaker has been replaced but I have been hesitant to reinstall them.. the force it takes to install the new ones is less then the old ones

Based on my experience, pulling old one were tough (probably due to years and stiffend O rings).

New ones, after being greased with Vaseline, were easier to slip into rail as well as into IH.

Did you make sure you got the right set talking to Jon?

Yes.. I bought FIC last year.. had issues (kept running rich), sent them back, he sent another set, but I ran my old with Multecs all year to verify car was good with no issues.

Went to install the FICs in Feb/March, Jon asked to send them in to be checked (these were never opened from Package). Sent them back, he sent another set.

Installed the new set in the car, idled fine.. as soon as I drove (within the first 1/4) it was stumbling and loading with fuel..

I have over 100 emails of Jon and I back and forth, what to try check etc.

I got some bits from him the other day and last night found that the pieces I already had were the correct ones.

I know guys running FIC injector with no issues.. you are the 1st one i have heard of with later IH running them. I also have Later IH (93-95) in my 90. The FIC injectors are going in the same distance as the Multecs. they go in a bit easier then the multecs, which makes me think it is vacuum leak on the injector. I have a couple things I need to check on my injectors ( the FIC) ones when I get home, but I am at a loss as to the problem. unless it was that one injector causing issues.

not sure what to do, I need another set of Gaskets for a plenum pull as I am not sure mine will last much more.. but the car runs fine with Multecs for now.. I really wish I knew the exact problem

I mean I can tell it is getting rich, but if there is a leaker it should go lean.. and not get loaded with fuel.

[secondchance]

It's a tough one.
I think 90 thru 92 had 2 different lbs for primary and secondary. Are you running 21 lbs injectors for both?

If I remember correct, 90-92 had smaller flow rate for primary and higher flow rate relative to 93-95.

Is it possible your primary injectors may have higher then original resulting in flow too high even for ECM to control?

I am trying to get hold of 90-92 owner who may know what flow rate injectors came from the factory.

Anyone out there know this info?

If I get the answer I will post ASAP.

[-=Jeff=-]

It's a tough one.
I think 90 thru 92 had 2 different lbs for primary and secondary. Are you running 21 lbs injectors for both?

If I remember correct, 90-92 had smaller flow rate for primary and higher flow rate relative to 93-95.

Is it possible your primary injectors may have higher then original resulting in flow too high even for ECM to control?

I am trying to get hold of 90-92 owner who may know what flow rate injectors came from the factory.

Anyone out there know this info?

If I get the answer I will post ASAP.

possible yes to the different rates as I don't know either, but right now I am running 16 secondary OEM injectors with no issue, so I don't think that is it.

[secondchance]

http://www.zr1specialist.com/HAT%20Web/articles/Fuel%20Injector%20Replacement.pdf

Interesting. This article talks about retro fitting 93-95 injectors to 90-92 motor.
On page 2, it says lower body of 93-95 injectors are 0.027" smaller (I guess they mean in diameter) and says will require larger injector O-ring.

Interesting article by ZR1 Specialist.

It sounds as though flow rate is not a major issue. Nonetheless, I will see if I can get exact flow rate for early LT5.

[-=Jeff=-]

http://www.zr1specialist.com/HAT%20Web/articles/Fuel%20Injector%20Replacement.pdf

Interesting. This article talks about retro fitting 93-95 injectors to 90-92 motor.
On page 2, it says lower body of 93-95 injectors are 0.027" smaller (I guess they mean in diameter) and says will require larger injector O-ring.

Interesting article by ZR1 Specialist.

It sounds as though flow rate is not a major issue. Nonetheless, I will see if I can get exact flow rate for early LT5.


yeah but since i am using 93-95 IH that should not be an issue either

[secondchance]

yeah but since i am using 93-95 IH that should not be an issue either

True, bottom of injector go into IH.

[secondchance]

Are you running 21 lbs? Any mods to the motor?

Loading up on fuel.. too much fuel, but then the one bank would show lean and then it would adjust to go rich but then see too much fuel on the other bank from the leaker. but that just does not make sense

Once again, I think when one injector is rich system tries to compensate and keeps going back and forth.
I imagine, when one is clogged, it may do the same (lean, detect richen, too much, back off, lean, and so on).

I would pull the plenum carefully, replace the leaker then, for now, patch where gasket breaks (if it does) with a dab of O2 sensor safe, high temp sealant, see if its a fix and if so, replace with the new gasket.

Good luck and keep me posted. Don't give up! I chased my problem for years finally to be resolved recently.

[-=Jeff=-]

Are you running 21 lbs? Any mods to the motor?

Should be 21lb.. Will check with Jon

mods:

headers, Exhaust

93-95 IH and plenum

car is a 90

[secondchance]

See edited version above.

[-=Jeff=-]

yeah gaskets are holding okay.. only done 4 plenum pulls with them.. I bypassed coolant from the plenum so the job is not that bad.. but still

Yeah going to check a few things, get them ready and do another pull to swap the Multecs for the FIC.. Talking to another Owner, sounds like it is possible that one leaker would cause those issues too..

[Toyvet1]

Jeff I had one secondary leaking a small stream on passenger side a dropplets leaker on drivers side and you saw how the car ran when it got towed home. But coolant was also leaking , so it might be time to try the fic injectors

[-=Jeff=-]

Okay will do..

Maybe this weekend

[-=Jeff=-]

Drove car today with Multecs.. runs fine

Swapped to the FIC ones tonight

hoping weather is nice in the next day or so to try

[secondchance]

Can't wait to hear the car is running perfect!

[-=Jeff=-]

Can't wait to hear the car is running perfect!

well at least there is one person thinking that

I honestly have my doubts

[secondchance]

I chased the same demon for years! I know the frustration.
Can't help but noticing that you didn't wait for the weekend but tore in on Thursday (probably after work or called in sick because it was driving you nuts, didn't you?).

I know the feeling.:thumbsup:

[-=Jeff=-]

I chased the same demon for years! I know the frustration.
Can't help but noticing that you didn't wait for the weekend but tore in on Thursday (probably after work or called in sick because it was driving you nuts, didn't you?).

I know the feeling.:thumbsup:

Actually I drove the car yesterday.. I figured i would R&R the Injectors last night after kids went to bed.. this way if nice weather today or tomorrow or Sunday I can drive it around the block.. I should know rather quick if there is an issue.

It is not driving me nuts, but I am baffled.. most who have FIC injectors have no issues, why do I, then now knowing you have FIC on a 94, says the injectors should work fine/ fit fine. I am hoping the one leaker was the root to the fuel issues

but I am very pessimistic about that being the problem

At least I know the car runs great with Multecs and the only change is injectors so it is narrowed down

[secondchance]

I think it was one leaker.
Once installed, your saga, I am resonably sure, will end.:cheers:

[-=Jeff=-]

I think it was one leaker.
Once installed, your saga, I am resonably sure, will end.:cheers:

We will see.

Weather is crppy so Either Sat or Sun we will know

[VetteMed]

We will see.

Weather is crppy so Either Sat or Sun we will know

Hope you find that it runs well... sounds like you've got it well isolated, we'll keep our fingers crossed for you.

[-=Jeff=-]

put about 16-18 miles on..

so far so good

[secondchance]

put about 16-18 miles on..

so far so good

Got my fingers crossed!:cheers:

[Kb7tif]

put about 16-18 miles on..

so far so good

I have been keeping track of your experience here. I know mine in the 92 will need replacing as when checking the spark plugs 1 plug was wet, due to a leaker. The car runs fine no backfire and idles smooth. I have a set of the NOS stainless that will go in-sometime-.

[-=Jeff=-]

I have been keeping track of your experience here. I know mine in the 92 will need replacing as when checking the spark plugs 1 plug was wet, due to a leaker. The car runs fine no backfire and idles smooth. I have a set of the NOS stainless that will go in-sometime-.

Yeah, nice day today but did a lot of outside work so no vette time.. I think all is good, but need to get some more miles on it

[secondchance]

Well???

[-=Jeff=-]

Well???

Drove it yesterday to and from work

so far so good

Driving it to my club meeting tonight

I think all is good

Jon @ FIC is awesome to deal with

he said on my issues alone we had over 100 emails back and forth..

I would not hesitate to buy from there again

[secondchance]

My experience with Jon Banner was excellent also.
Also, it worried me that all gas around hear has ethanol added and it may have an adverse effect on Multecs. Now, I am worry free and loving it!

Glad all is well again.:cheers:

[zr1don]

I have a 90 I replaced 16 injectors w/RC's. RC recommended their 19.5 lb injector (all 16 the same flow rate) and it runs great. I believe the stock multecs were rated at 21 lbs (again all 16) but RC recommended the 19.5's for a direct replacement.

[secondchance]

I have a 90 I replaced 16 injectors w/RC's. RC recommended their 19.5 lb injector (all 16 the same flow rate) and it runs great. I believe the stock multecs were rated at 21 lbs (again all 16) but RC recommended the 19.5's for a direct replacement.

I believe you are right that factory was 21 lbs. FIC recommended 21 lbs as well.
Within reason, ECM will most likely adjust pulse rate based on O2 reading.

[-=Jeff=-]

I believe you are right that factory was 21 lbs. FIC recommended 21 lbs as well.
Within reason, ECM will most likely adjust pulse rate based on O2 reading.

yeah sort of.. OEM are 214cc/mm FIC ( or min are 2210-230cc/mm

I will adjust my injector constant first and see if that helps..
I have not done that yet

[jonszr1]

jeff could you give me jons email or send him mine .i need to get ahold of him . thanx . mine bradleyjontaylor@hotmail.com

[secondchance]

Jonszr1,

I PMed Jon Banner's phone numbers to you.