on a cold start it will crank for a long while, until i see the oil pressure gauge go up to about the middle, then it starts to turn over.. the car never did this until i had to change out the ecu. its from an 86 car, but i swapped the chips out.. any ideas why it cranks so long before it starts??

 

come on guys,, need some help here.. i checked all the fuses, non were blown, could it just be a fuel pump?

 

I used to have the problem, the car could take up to a minute on cold starts, and it would crank and it was firing, but it would sit there and sputter to life eventually. I put a new 67gph (future-needs =D) BBK Fuel Pump in, because the old one was shot, and bam, it generally fires up as soon as I turn the key.

Put a fuel pressure gauge on, and see what the cranking pressure (priming) is. When I had the old/bad pump, it was at 3 psi, and it wouldn't hold pressure. The priming pressure is supposed to be 47 psi.

If there's not a lot of pressure, then I'm thinking you have a bad fuel pump. Check your fuel filter, though.

You say that you swapped out the ECMs? That just confuses me as to the coincidence of this issue. Maybe that is a bad ECM?

 

thanx mp81, would i be able to install a 255lpg walbro pump on a mostly stock car (if it is the pump) because future plans include a procharger. and that was recommended on the power adder section for what i want to do. so my question is can i run a bigger pump before its needed? doing it twice would be silly.

 

My pump is the same as yours (as in 255 lph = 67 gph), and it's fine (I have minor mods to the engine, but it's still the LB9). The regulator is ultimately what controls how much pressure is "let into" the engine. It'll fit right in.

 

Does that tell you anything? When did the Trans Ams go to a SD setup instead of a MAF? Get the right ECM for your car and I bet it runs fine.

 

i thought the maf systems were on 86-89 and 90- up were speed density? my 89s stock and its got the maf system

 

I mean, I was thinking the same thing as Slepewesel, fuel pumps generally don't just die instantly like that (well, not die, but dead enough). If you need to replace it eventually, you can do that whenever, but I never swapped ECMs in my car, and it was the pump.

And yes, SD came out in 1990, so his car is most likely MAF still.

But still, try a '89 T/A ECM and see what happens.

 

89 is maf 90-02 is sd.. ecm's are the same 86-89 just different proms. i am going to try to check the fuel pressure over the weekend. before i order a new copmuter.