ok i have an 1988 gta 5.0, well here for the past week it has been hard to start. if i hold the gas to the floor itll fire up in a second or two, if i let it crank without touching the gas then it will crank for about ten seconds then struggle to idle then clear up and idle fine. also if i floor it through first and at the end of second then it will start to like lunge like its starving for fuel or missing badly. after i run it like that then it will continue running badly just putting around town until i let it sit for a while, its had a full tune up including new fuel filter. now if i dont run it hard its fine unless im at highway speeds then it will start that lunging stuff slightly. the fuel pump also makes a loud whining noise if im below a 1/4 tank and hit the brakes kinda hard or are turning. ive checked the fuel pressure and it primes up fine before starting and holds steady while running but as soon as i turn off the car it loses all pressure in the lines. any help would be greatly appreciated!!!

 

ttt

 

bump

 

I'd check the fuel pressure regulator. My buddys tpi camaro did the same thing. The fuel pressure would bleed down while running causing the car to run like crap. Also check for any vaccum leaks.... Just a suggestion good luck.

 

thanks whiteknight, that was a thought because it went bad on my 2004 se-r and it was hard to start. ive replaced all dried vacuum lines with new except the cruise vacuum hose, does that one matter other than using cruise?

 

It will cause the engine to run erratically, forgive the spelling, My buddy's camaro last summer started to run like crap at start up but drove fine. I traced the problem to that vaccum hose. I would fix that first then check into to pressure regulator, both sound like could be your problem. hope this helps

 

thanks whiteknight! im gonna definetly fix that tomorrow then, the regulator isnt that expensive so i think im gonna replace it anyway. i really appreciate the help man this is my first third gen and my first chevy.

 

Yeah I just had a hair puller on my Firebird, Fuel pump would cut in and out causing a hard start, would drive fine. Then it died the other day I listen to the pump it'd run then not run.. Finnaly check the wiring to the pump is good , the pump is bad but intermitent . I had replaced it less 7k miles ago.. I'm glad you got urself a third gen nothing compares to driving one. I hope you never have to pull the tank its a son of a gun!!!!!!!

 

yea i know what you mean, after coming from 4 bangers to these kinds of cars is unbelievable. never knew a car can have this much torque from the factory! btw i thought you could replace the pump without dropping the tank? isnt it right behind the back seat?

 

Sounds like it could be an issue with leaky injectors. I had the same problem years ago.

 

so what would you try then? new o-rings for the injectors? would that be whats causing the car to stutter or lunge?

 

where would they leak from? The o-rings are just a seal if they leaked they would leak onto the engine not into it. Not sure how this would happen with tpi?

Is the CEL on?

Do you have access to a scanner? Id take a look at the integrator and block learn values if you did.

Did you check the fuel pressure just at idle try checking it at other rpms as well. I would say the reason you lose pressure when you shut it off is b/c of a bad check valve in the fuel pump. Try turning the key to on for 1-2 seconds before you go to crank this will let the fuel pump prime. Still doesnt explain the cutting out when driving.

I think it could be an intermittent pump or bad pressure regulator.

 

well when i turn the car off i can faintly smell gas under the hood but have yet to see any leak...

 

When you turn your car off, you should still have around 40psi at the rails. If your injectors are not closing all the way, they will drip fuel into the engine until there is no fuel pressure left. I had this problem, and it was due to a few of my injectors being slightly dirty. I've seen this problem with quite a few TPI's. I wouldn't call it uncommon. I sent my injectors to be cleaned, and it fixed the problem.

After letting the car sit a bit, it would take two long cranks to start due to the flood condition. When it did start, it would spit and stutter for a few seconds until the flood condition cleared up. Putting the gas pedal to the floor and cranking puts the car into "flood mode" as some people like to call it. When it's cranking, it will not fire the injectors, which will make it start faster due to extra fuel not being dumped in on an already flooded engine.

If it starts way faster with the gas to the floor, I'd think you have a flood condition due to the injectors or fuel pressure regulator.

 

after driving car shut engine off and remove vac. hose from fuel press. regulator.if you find raw fuel diaphragm has ruptured if not then concentrate on checking for injector leakdown.

 

Being an 88 wouldnt it have rochester injectors? I thought that problem only happened to the bosch style? Or was that a crossover year?

 

when the fuel pressure was checked i did rev and held it at different rpm's, read anywhere from 39-43 psi. ive tried letting the fuel pump prime before i start and it makes no difference. after i turn the key off it immediately loses pressure in the line. only place i could find about cleaning my injectors was a guy at o'reillys and he wants $46 a piece to clean em. any of you guys know a way of cleaning them effectively while there off the car? im going to clean them while i replace the regulator. oh almost forgot, the cel is not on...

 

http://www.cruzinperformance.com/

 

thanks for the link iroc... but you know the more i think about it i dont think its the injectors, because the car runs fine other than hard to start the sputtering if you run it hard, would a bad regulator cause it to sputter and lunge if its bad?

 

what about your cold start injector? the temp switch for the injector is a ground switch, right? ground it and see if it fires up... or unplug the injector temp switch, as it could be faulty ...

 

I think 5.7 is on the right track, the injectors are dirty so the needle wont seat right and it will leak fuel into the engine (explains why it starts when you floor it, cleaing all the extra fuel out) and dirty injectors will cause sputtering when driving.

Do you have bosch or rochester style injectors? Bosch styles are notorious for getting dirty

 

You can send your injectors to us. We will flow them for you. If there is nothing wrong with them we will not charge you, if there is...we charge $15per injector or we can give you a good price on bosch lll's. It's up to you.

www.southbayfuelinjectors.com

 

well like i said i dont think it the injectors because it doesnt do it all the time, really only time it does it is when you run it hard then itll do it when your cruising or continue to run it hard. it feels like the fuel pump cant keep up or something. how do you check to see which injectors you got?

 

If you can get the part number off of the injector i will be able to tell you

 

How does the fuel pump itself sound when it runs? Meaning does it have a whine like sound ????

 

yes it does have a slight whine especially if its below a 1/4 tank and i hit the brakes moderately....

 

It could be the fuel pump

 

welp finally traced down and fixed what was making it spit and sputter, grant it that it runs tons better but still hard to start but youd never guess what the culprit was: the tps was adjusted way out, i would of never thought they were that sensitive. im suspecting the fpr as why its hard to start. probably could use a new fuel pump since it whines alot too.
thanks to all that have helped!!!