Okay I got an 86 IROC 305 tpi auto. Whenever the car is started cold it stales out the first time i start it up, then on the second time it has a hard time to keep going but in the end it runs. Could this be a fuel pump or filter problem? i am sort of sick of starting it twice. Thanks

Marty

 

I'd change the fuel filter first, then check the fuel pressure. Also, it could be your cold start injector. Try starting it by giving it a little pedal the first time. I had an '86 and it wouldn't start at all cold without actually giving it gas. If that doesn't fix it , it may be your fuel pump.

 

cold start injector, especially if it's stock.
the fuel filter is a possibility but it wouldn't change that much when it was warm. If it's clogged when it's cold then it will be clogged when its warm. If it was a mechanical fuel pump then I would say that could be the problem but since its electrical I would say when it goes you wont most likley wont be able to start it at all. I'm not saying it's not possible but more likely it's the injector. But it's best to replace the filter also and try that first cause it's cheaper.

Boz

 

another possibility is the MAF sensor. i know when it went out on my 87 it ran like absolute sh*t. no matter what temp the engine was.

 

Well it runs great after it warms up, past the 100 degree slash, I guess i will start at fuel filter. Thanks guys

Marty

 

You can also check your MAT, what it does is sence air density, if its cold it will richen your air/fuel mixture to start up much easier. They tend to go bad. Its located underneath the plennum right in the back.

 

You should also check if your fuel system is "leaking down". A common problem is leaking injector o-rings. The problem is if you don't have a good seal through out you fuel system, it will not hold pressure properly. In my experience, the symptoms you describe are usually fuel system leaks. Get your self a fuel pressure gauge, and with the ignition off and a cold engine, pull the shrader valve cap off, then surround the hole with a rag and preferably with safety glasses on release the pressure slowly with a pointy object of some sorts, just like you let the air out of a tire. There probably won't be any fuel coming out but make sure to shield yourself in case. Put on the fuel gauge and turn the key to the on position till the pump stops wining. Is the pressure over 35 psi and maintaining or is it barely readable and dropping? If it is holding normal pressure then look elsewhere, however I am pretty sure it will be low and bleeding off. If the pressure is low and dropping turn over the engine once and wait till the pump stops wining again, now check the pressure, it should be higher because combined with the first attempt at building psi it should be more than the first attempt. If this is the case you have a leak in the fuel system most likely in the o-rings, but possibly in the fuel rail fittings. Once the car is running and the pump is feeding at a continuous rate, a leaking o-ring can be undetectable because optimum pressure has already been reached and the fuel pump is capable of moving more psi than the leak is losing. As someone stated it could be also be a weak pump, but start with a psi test and go from there.