white/blackss

IDLE.AIR.CONTROL.
its the idle air control valve on the throttlebody.

Black1995Z

I have the same problem, have you checked your oil to see if it smells of fuel?
I've changed my injectors and fuel pressure regulator and still have the problem. I also bought a new fuel rail and thats when all of this started! Ideas?
My oil pressure is awfully low too; from being thinned out by the fuel.
Of course after the hard start it starts right up!


And I have a new starter too.

MyShibbyZ28

That's right, sorry, i was drawing a blank on IAC, but could that really cause a bad start? because sometimes it won't idle right or it'll be just a little off and then when i push on the gas it'll start idling like a new engine. How much is that part? hopefully not $140 like the fuel pressure regulator that i was told.

gasnmyveins

Whatever came of this? I'm having the same problem with a 96. When I crank it, it takes several seconds (5 or 6?) to start. Then it BARELY runs. If I blip the throttle, it idles like nothing was ever wrong. If I blip the throttle as I start it, it starts and idles just fine. I shouldn't have to do that, though.

MTL_Z28

I did a search and came upon this thread since I was having the same problem today. I just replaced the starter last season before putting the car away. Same problem... When it sits for a long time it cranks for a while(3-5 seconds maybe) and then starts... or cranks for a while and then idles poorly and barely runs. Today I even had to push start it to get it going But if I've been driving for a while and then shut it off it will start right back up within like 20 mins. No other symptoms really.

Just wondering if anyone had found what the problem was? IAC valve maybe?

shoebox

A weak coil can cause extended starts.

wrd1972

Reviving this from the dead.
Car starts up fine cold. Sometimes when warm, say 20 minutes after turning it off, if you go and start it, it will crank and crank up to 5-8 seconds. Sometimes it will spit and sputter at under 500 RPM and require a little tap of the gas pedal to smooth it out. Really pissing me off.

Injectors are new with less than 1K and yes it did it with the old injectors too. Fuel pump is original with 82K miles. Coil is a MSD red coil and appears good. ICM is grounded well. GM Opti has less than 4K miles.

Any other sure fire fixes for this?

jetset9

it sounds like you are flooded it, I was told if (my car) does that (by a Mechanic) just to hold it to the floor it when you turn the key to start it, it worked 3 different times this winter for me. ( as a couple of you described that your cars act fine after throttling them after this happens.) the car clears out itself from flooding itself when u do this.
just a thought.

wrd1972

Update.
Pulled the vac line of of the FPR. No leaking gas or smell.
Checked the pressure again. Vac line on make 40#, vac line off makes 45#.
Pressure remains steady after the motor is turned off, no bleed off so the injectors appear fine too.

It would appear that the FPR is perfectly fine. I will look at the ICM.

any other ideas aside from the coil which I will be looking at?

Krutifing

i have a 94 camaro z28 that was doing the same slow start up and long crank ups and sometimes is seems like the starter was going out. i put a new starter, fuel filter, and my air filter thinking maybe it wasnt getting enough air but i still had the same problem. i then thought it was a bad fuel injector or fuel pump or even a bad conection on the ignition. i put a new ignition switch under the dashboard and it solved the problems. so try that and let me know if that solves your problem

wrd1972

Wow. Never would have guessed that would be the problem. I will look into it.

97z28_MENACE

IM HAVING THE SAME PROB AS U GUYS
GO TO START ON A COLD START CRANKS JUST FINE AFTER ABOUT 3-4 SECS AND RUNS FINE BUT IF I LET IT GET UP TO RUNNING TEMP AND TURN IT OFF AND TRY TO CRANK IT AGAIN SOMETIMES IT WILL CRANK REV TO 900-1200 RPM THEN DROP TO 200-400 AND SOUND LIKE ITS GOING TO SEND A ROD THROUGH THE DASHBOARD AT ME, IF I CAN TILL IT GOING TO DO IT FAST ENOUGH, I CAN GAS IT I LITTLE AND U CAN SE THE TACK MOVE 300-400 WITHOUT MOVING THE GAS, IT WILL RUN LIKE CRAP FOR A MIN OR TWO THEN RUN LIKE A BAT OUTTA HELL.
I GOT A NEW ICM AND COIL, GETTIN READY TO DO THE OPTI BUT TRYIN NOT TILL I HAVE TO.

AND FYI IAC = IDLE AIR CONTROL VALVE/MOTOR

ANY HELP WELCOME

wrd1972

Okay,
I am going to shift gears here a bit.

I left the fuel gauge on the fuel rail over night. It read 0# pressure this morning. I went to start it and it fired up immediately and ran perfect.

Yesterday I drove it for 20 minutes the parked it. Went out 30 minutes later and checked the gauge. The pressure dropped from 40# to 30# and when I went to start it cranked for about four seconds before starting.

I waited another 20 minutes, repeated the above procedure and got the same result.

I waited even another 20 minutes but this time I turned the key to on, off then on, off then on to prime the line three times. The motor fired up immediately. I think this rules out anything electrical.

HTF can it fire immediately cold with no rail pressure but not fire immediately when its warm and has 30# on the rail.

I am going to plum the fuel pressure gauge into the outlet side of the filter tonight and let it pressurize to see if it holds steady or bleeds off. This will rule out the FPR and the injectors and I can go from there.

wrd1972

Update.
I am now 100% convinced the slow start condition is NOT fuel pump related. But I do think it is pressure related. Sounds wierd.

Again when the engine is warm, if I turn the key off/on two or three times it fires right up.

I have begun to think that the left side of the header y-pipe is too close to the steel fuel line and MAY be causing the fuel to boil once the engine is turned off. Maybe its causing an air bubble in the line or something wierd like that.

I have created new brackets to move my fuel lines from about 1" to more like 2-3" away from the y-pipe. I have also put some heat sleeves on the fuel lines too.

I have not been able to test these changes yet. I will be able to test the theory out this weekend.

I will post my findings.

Injuneer

Why did you want to plumb the fuel pressure gauge into the fuel line after the filter? Why not just hook it up to the Schrader valve? The FPR is in the return line, so measuring the pressure right after the filter is no different than measuring it at the Schrader valve.