Wont start after fuel injector swap.
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Junior Member
Joined: Jul 2011
Posts: 37
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From: Holly Springs, NC
Car: 91 GTA
Engine: 5.7 liter v8
Transmission: 700 r4
Wont start after fuel injector swap.
I am about to freak out I finally got new injectors in and put everything back together now when I put in the key to crank the motor I get engagement from the starter but it will
not turn the engine whatsoever. The plenum and runners have only been off the car for 2 days. I have accounted for every bolt and have put everything back together. It just ran four 4 days ago and would crank, now it does not. I can't believe I did all this work just to find this out. I get 12.5 volts at the battery, hear it totally engage with power but will not turn the engine. Any ideas?
not turn the engine whatsoever. The plenum and runners have only been off the car for 2 days. I have accounted for every bolt and have put everything back together. It just ran four 4 days ago and would crank, now it does not. I can't believe I did all this work just to find this out. I get 12.5 volts at the battery, hear it totally engage with power but will not turn the engine. Any ideas? Thread Starter
Junior Member
Joined: Jul 2011
Posts: 37
Likes: 0
From: Holly Springs, NC
Car: 91 GTA
Engine: 5.7 liter v8
Transmission: 700 r4
Re: Wont start after fuel injector swap.
Went back outside and tried it again. For whatever reason it loosened up and finally cranked. Let it warm up and now I definitely notice some more knocking in the valves or under the plenum it sounds like. Anyway it seems to idle fine but when I put it in reverse to back out of driveway it cuts off on me when I give it gas in drive or reverse. All I did was replace fuel injectors and Egr with new gaskets. Could it be iac or something else going on?
Joined: Sep 2005
Posts: 27,867
Likes: 2,429
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Wont start after fuel injector swap.
Just needed to prime the fuel rails...
WHenever I swap injectors in a car, I do the key on (not to Start, just to On) - wait 2 seconds - key off - wait 5 seconds - key on - etc. thing about 6 times, to make sure everything is full of fuel. That way it cranks right up the first time.
You may need to drive the car around for a bit and let it re-learn its fuel constants; or, disconnect the batt for a couple of minutes and let the ECM forget them, and then re-learn. Try jsut driving it around kinda normally for a little while and see if it doesn't improve.
WHenever I swap injectors in a car, I do the key on (not to Start, just to On) - wait 2 seconds - key off - wait 5 seconds - key on - etc. thing about 6 times, to make sure everything is full of fuel. That way it cranks right up the first time.
You may need to drive the car around for a bit and let it re-learn its fuel constants; or, disconnect the batt for a couple of minutes and let the ECM forget them, and then re-learn. Try jsut driving it around kinda normally for a little while and see if it doesn't improve.
Thread Starter
Junior Member
Joined: Jul 2011
Posts: 37
Likes: 0
From: Holly Springs, NC
Car: 91 GTA
Engine: 5.7 liter v8
Transmission: 700 r4
Re: Wont start after fuel injector swap.
Haha I will try that but I couldn't even make a turn off my street before it cuts off on me. I brought it back home in the driveway. all I can say is doing the fuel injector swap has totally screwed up up my car 50 * worse. I am getting all this knocking an I cant even drive my car now. b 4 I just believe it was a fuel injector problem because the car would have a rough idle once warmed up, now I am having 10 more problems it seems after the.swap.
Joined: Sep 2005
Posts: 27,867
Likes: 2,429
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Wont start after fuel injector swap.
Yeah definitely try driving it...
The ECM "learns", by way of the feedback loop from the O2 sensor, how much fuel to put in based on it's "eyes" on the outside world (sensors) which tell it all it can possibly know about what's going on. It starts out life with a table of timing and fueling values created as some kind of "average" by the factory, then constantly tweeeeks some "compensation" values (block learn, long-term integrator, etc.) to a point where its output under any given circumstances needs almost no further adjustment. But when you go and upset it by changing something as fundamental as how much fuel comes out when it opens the injectors, all of that "learning" becomes WRONG and has to be re-learned.
Give it a try. Might turn out a whole lot better than you're giving it credit for, after just a few minutes of driving it.
The ECM "learns", by way of the feedback loop from the O2 sensor, how much fuel to put in based on it's "eyes" on the outside world (sensors) which tell it all it can possibly know about what's going on. It starts out life with a table of timing and fueling values created as some kind of "average" by the factory, then constantly tweeeeks some "compensation" values (block learn, long-term integrator, etc.) to a point where its output under any given circumstances needs almost no further adjustment. But when you go and upset it by changing something as fundamental as how much fuel comes out when it opens the injectors, all of that "learning" becomes WRONG and has to be re-learned.
Give it a try. Might turn out a whole lot better than you're giving it credit for, after just a few minutes of driving it.
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Thread Starter
Junior Member
Joined: Jul 2011
Posts: 37
Likes: 0
From: Holly Springs, NC
Car: 91 GTA
Engine: 5.7 liter v8
Transmission: 700 r4
Re: Wont start after fuel injector swap.
It shuts off on me as soon as I put it in drive or reverse and give it gas. Cuts off right there. So give me some other ideas.
Thread Starter
Junior Member
Joined: Jul 2011
Posts: 37
Likes: 0
From: Holly Springs, NC
Car: 91 GTA
Engine: 5.7 liter v8
Transmission: 700 r4
Re: Wont start after fuel injector swap.
Alright after putting a screwdriver to my ear the clicking sound is really heavy at the fuel rail. It sounds just like valve tapping. The only thing I could think is that I hooked up something wrong she putting in the new fuel injectors but I seriously cannot think of anything.
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