I have a 87 TPI 5.7 IROC Z28 and when I try to start the car after it has sat like overnight it takes maybe 20-50 turns for it to start up,I have installed a NEW fuel pump could this be something MINOR or what do I check?THANKS

 

I had a very similar problem. The issue was worn out fuel injectors. I replaced them with a set of the modified bosch design III from Jon at FIC. Now my car starts right up, regardless of how long it has sat, or what the weather is outside. The whole thing only cost me $220 delivered to my door. This included the gaskets for the intake runners. If you still have the original multec injectors in there, chances are they are getting worn out.
You can double check that you have good fuel pressure when you turn the key to the on positon and when you are cranking.

 

My 97 did this. It turned out to be a hole in the plastic fuel line that hooks to the pump. Did you replace that with the pump? Check the key on pressure (motor off) and make sure it comes up. If not,go on and start the car while watching the pressure gauge and see if it starts at the same time the pressure comes up. If it does thats the problem.

 

What's good fuel pressure when doing this test and does the gauge hook up to the nozzle on the fuel rail?THANKS

 

LT1's run around 42 psi. I dont know what the TPI's run but it should go at least 40 psi. The gauge hooks to the fitting on the fuel rail. Another tip off you have a leak is to turn the key on/off several times and then try starting it. If it starts better it's likely you have a leak in the tank also. If your cranking the motor over and the pressure jumps up and it starts you have a leak in the tank. It's a cheap fix just a pain to get to.

 

I got mine from autozone for about $35. Get the one for mpfi engines, not for TBI engines. They only have those two kinds. It will come with the correct fitting to hook up to the shrader valve on the fuel rail. You will have to remove the disributor cover and unbolt the map sensor from the plenum in order to gain better access.

 

I am thinking maybe there is a small leak in your gas line when shutting car off gas drains back through the lines Try turn key to on position wait a couple seconds then try to crank it over this lets the lines prime.


good luck