Running problem

[CJY08]

I got a 95 GMC 1500, fuel injected truck... Everything was fine running great, and the starter went out... Change that out, and now the truck will start idle for a second then die, start idle for a little longer then die, like its not getting fuel, fuel pump is good I changed out the TPS on it and its doing the same thing...Any Ideas...

[jwmbishop]

My best guess based on all the facts you provided is that it is NOT the TPS.

 

lol

 

Umm the only thing you did was change a starter - two wires? On my 97 there is one wire that goes from the starter to the oil pressure switch then to the Fuel Pump relay so that the fp is only powered when either the starter is engaged or there is oil pressure. Check to make sure the FP has power after the starter is done cranking.

[ps 72]

whats ur fuel psi at when the key is turned on and when it starts what is it.

[jwmbishop]

Check for power first. Check the simple first then go more complex. Check all the wires and connectors you could have leaned against, looked at wrong or otherwise done something to have disrupted the ECU loops.

I am only aware of the relay to starter circ cuz on mine the relay itself went bad - I did not want to just put in a new one and hope it was a bad relay and not a short - so I traced the circ and fixed some crispy wires down by the starter.

Pinch off at rubber part or block off return line and check full pressure.

If pump has full pressure with return line blocked and low pressure without it blocked most usually the fuel pressure regulator is leaking or not holding pressure.

should have 60-66 fuel pressure.

Cold start should be 64-65 lbs of pressure.

Engine running should be 60-66 lbs pressure depending on engine load.

Full pressure with return pinched off should be 75-85 or more.

And if it has a fast leak down after shut off you have a leak in system.

[carguy]

If you disconnected the battery to install the starter(first thing you always do) and now it won't stay running. What has happened is that the computer has gone back to the factory settings and is closing off the idle air control motor too far, clean the throttlebody, it is very possible that it's just very dirty and can't get enough air around the throttleblade, not allowing enough air into the engine. I have found ac delco x-66a spray works the best if you can find it from someone that sells delco products. The longer it runs the computer will relearn and bring the idle where it is suppose to be