We bought it and were told that the only thing wrong was the fuel pump. Put a new fuel pump in and it still won't crank. It will turn over but just won't crank. If you pour fuel in the throttle body for about 3 seconds it will crank and stay running, idles good, cut the key off and it won't crank back. New plugs, wires, rotor button, cap, fuel pump, fuel filter and oil change. Any ideas as to were to go next? Has the V6 3.9 engine. This is driving me insane. The truck had set for 8 years before we bought it. A/C is still cold, I need to get this ride fixed!

 

When you first turn the key to on, does the fuel pump run briefly and then quit? (briefly is for a second or two and you should be able to hear it) Am I right to think by what you said that the truck has not run at all in the past 8 years unless you pour fuel into the throttle body? Once you prime it and get it started it will run on its own systems until you shut it off?

 

Correct, has not run in 8 years unless you pour fuel into the throttle body. After you get it started it will sit there and run fine, until you cut it off with the key. If it stalls on its on and you just try to start it, it will start unless you cut the key off. Yes, the fuel pump comes on for a few seconds when you first turn the key. The guy that had it before was told that the computer was bad so he bought a new one and put in it, to find out later that it was only a broken wire.

 

Might be worth trying to bypass the ASD relay by pulling the relay and jumping across the wires that go to the contacts, these will be the heavy wires. This is only for trouble shooting and cannot be left like this.

I believe you will need a noid light to find out if the injectors are firing when cranking.

 

So....the question here is.... What is causing the engine's fuel system to supply the engine with fuel after it's running with a prime?

I wonder if the cranksensor is getting weak and requiring the rpms to work? Just thinking out loud here! I believe the crank sensor supplies info to the computer for the injectors.....

OP....I was a little confused by the use of the word "crank" until I realized you were using it instead of run. FYI FWIW..... IMO...the word "crank" came from the days when cars were started with a crank instead of an electric starter motor...

 

Manyhobbies, I don't think there was a crank sensor until the Magnum motors came out in '92. This one is an '88.

 

Okay.....what else could it be? Does this thing use a computer?

 

Manyhobbies; Yes it has a computer. The computer fires the injectors and controls about everything else. SixGun is correct that there is no crank sensor in the 88s. The signal to fire the injectors and the spark comes from the Hall Effect sensor in the distributor.

 

Injectors are firing, already checked that.

 

Sorry for being from the south. The truck will run after you get it started by pouring fuel in the throttle body but it will not start on its on.