Well, I got rid of my hard warm starts entirely with new injectors, but now its got a bad cold start issue, it just turns and turns and turns and sputters and coughs and tries then dies, takes usually 3 times to get it running then its perfect, runs strong, fuel pressure when its warm when i got it to my shop was 40 psi right when the key is on and it held it. No amount of turning the key to ON, waiting, back of, wating, then back on makes a difference. If the car sat for like 5-6 hours, does this again, hard start. But if u come back in an hour or 2 it fires of immiediatly. What could be the deal? I was thinking possible air intake temp sensor? fuel pump?

I went thru this when I put in th 3800 injectors on my TGP. But then it went away. Maybe the injectors were breaking in, or, well I dont know. The only posibility I have is that there is air somewhere still in the fuel system. Once I took it out for a 500 mile trip, and about 6 runs at a 1st gear race, it quit having problems.

fuel pump.

Ken

I thought with fuel pumps they were either good or bad pretty much...

I have the same exact problem btw, been tryin to figure it out too...

maybe the new injectors need a bit higher fuel pressure to properly atomize the fuel......or something? LOL

just a shot in the dark but after it does this does it smoke ?  like blowing raw fuel out of the exhaust?  Maybe you got some poor injectors, possibly check them for leak down? 

Also the in-line fuel filter?  Maybe your in-tank filter is clogged?

Quote from: meltboy11 on May 18, 2008, 07:20:30 PM
I thought with fuel pumps they were either good or bad pretty much...

I have the same exact problem btw, been tryin to figure it out too...

Yes when they do fail but sometimes they develop an internal leak and will be hard to start after resting overnight or a few hours.  My suggestion is to go buy a 50 dollar fuel pressure tester and test the fuel system at the rail.  Not running with the key on you should be around 46-48 psi, running 40-42 psi.  You should also be able to hit the key on (dont start the car) and then turn it off after about 1 minute and the pressure in the gauge should not drop more than 2 psi , IE it should hold rail pressure for a fuel minutes. If it does not you have a leak, could be injectors or the pump.  I would replace both......like I did.

Ken

Quote from: 93luminaz34 on May 19, 2008, 10:57:59 AM
maybe the new injectors need a bit higher fuel pressure to properly atomize the fuel......or something? LOL

I don't see why that would be, the C302 injectors have pretty much the same flow as our stock multecs.  Mine runs perfectly fine with the C302s  :dunno:

Quote from: cobracmdr on May 19, 2008, 11:56:33 AM

Quote from: meltboy11 on May 18, 2008, 07:20:30 PM
I thought with fuel pumps they were either good or bad pretty much...

I have the same exact problem btw, been tryin to figure it out too...

IE it should hold rail pressure for a fuel minutes.

I laughed for a min on that one... lol

opps typo  :laugh:

Well, i have not seen a puff of smoke or raw fuel smell at all when this happends, no smells at all. The fuel pressure was 42 when running, and 40 when you hit the key to on, and it held the pressure for like 10-15 minutes or so, thats how long i kept the tester going. The Filter has less than 5k on it, i need a fuel level sender anyway, so i might as well replace it and the pump. Now im not sure wich pump to get, i thought ours were special, but they cross reference to all other w-bodies on www.partamerica.com and im worried these may not be the right ones. Id like not to spend over 100 on the pump.

If your going to replace the pump here is the pump to use but be carefull fake ones are out there http://www.tgpforums.com/index.php?topic=3222.0 It won't solve your sender issue since its only the pump.
Tim

just to follow up, my cold start has been solved! New fuel pump. either my pump was bad, or the pulsator was allowing the gas to just spew back into the tank, because that pulsator was gapped out, wouldnt even stay on the pump or the sender assembly. Car starts up quick every morning so far!

ahh What replacement pump did you use, a Walbro?

Napa part number P74037 crosses for the corvette. Works great, maybe a little loud, but i can deal with it.