86 5.0 fires then immediatly dies

[91lxvert]

my friend has a 86 5.0 with 78k

he just changed the upper and lower intake gaskets

car fires easily and for the second its going sounds fine, b8ut it just shuts off, it doesent stumble or anything

dist is in correctly, sparkplugs are new and gapped correctly, spark plug wires are correct

tps is at .98

can hear the fuel pump prime, two clicks from under the hood

crank it, car fires up to 2k, then shuts off immediatly

almost as if something is not telling the fuel pump to turn back on after the prime

anyone got any ideas?

thanks

 

[HISSIN50]

does it fire back up after it dies?

were it me, i would have a FP gauge hooked up and an inductive light on the coil wire - try to see what you are losing.

one could try to pull codes for fun, too.
good luck.

 

[Dark Knight]

not up on FI cars, but I think they have a fuel pump relay under the seat.. check it as well as the crash sensor in the trunk..

 

[91lxvert]

yeah you can stqart it as many times as you want, just dies instantly

ok if either its loosing fuel or spark where should we look to remedy this problem?

thanks

 

[nito88stang]

Must not be gettin enough air at idle. Screw in the throttle screw a bit and see if that helps. That happened to me when i put in a new TB.

 

[Daggar]

A fuel pressure guage I think is going to be your best bet at this point. At least you'll be able see what's going on. My guess is that your fuel pump relay is good but the fuel pump itself is bad... gas leaking through the seals or check valve in the pump and going right back into tank instead of the fuel lines when it's running (saw this once before). A guage will be able to tell you and also help rule out the regulator and return system. Hope this helps.

 

[89lxsport50]

This is exactly what happened when my fuel pump went out.

 

[87TTopGT]

I had the same problem, posted it and got the right answer for what was wrong with MY car. Mine would fire right up, then die-the tach would go to zero, heard the fuel pump shut off. I could just touch the ignition and hear the fuel pump go on and the gauges move- in other words the ignition wouldn't stay where it needed to to keep electrical working. I could barely wiggle the ignition lock and things would come on and shut off.
I replaced my ignition lock (the key assembly) for $11, still didn't fix it. Then I replaced the ignition SWITCH (located on the steering column under all the trim pieces-$10) and now it works perfectly!
I hope yours isn't more complicated than this, try turning the key to the start position and move it back and forth with just a little pressure- if things cut on and off there is your problem. Good luck!

 

[DropTopR]

I ran into a kid with the same problem. He actually had the starter solenoid wired up wrong. He had the wire for the fuel pump on the starting side, so it only got juice when cranking, then would stop pumping and die. Just something to look at.