'88 Ranger runs 2-5 seconds then stalls
 

Hi Everyone,
I have an '88 Ranger which I recently bought as a yard/plow truck. When the truck will starts it will run at around 2,000 rpm for between 2-5 seconds, then cut out. If you hit the gas while it is running and keep the RPM around 3,000 it will stay running for up to 20 seconds before it quits. Both the sending unit and fuel pump are working and it has 40 psi at the rail, the fuel pump relay seems to be operating properly.

The problem seems to have been around for a while because the previous owners have installed a new distributor cap and wires, new MAP sensor, and bypassed the inertia switch. The previous owners also rigged an aftermarket fuel tank in the bed.

The check engine light is on and I have been unable to scan it. I have tried cleaning the IAC, testing the fuel delivery system, and checking the grounds for the computer. I would like to get this truck running without throwing parts at it, any advice on testing I can do is much appreciated. Has anyone heard of this problem before? Thanks in advance!

John

The codes may help in diagnosing.

What would concern me as well is the "rigged" aftermarket fuel tank....

Well either the fuel is being shut off or the spark is.

Do you have a timing light?
Hook it up to a spark plug and see if spark dies.
Bad ICM(ignition control module) or coil could cause that.

Fuel pressure doesn't mean fuel flow, does pressure stay high as engine starts to die?
Can you, did you, check fuel pressure with fuel pressure regulators vacuum line unhooked?

Sock in the fuel tank can get clogged up, so engine will start and run then die as you describe, then as fuel slowly comes thru clogged sock it will restart and die again.

Remove or loosen gas cap, let some air into the tank, while it doesn't fit your short stall time bad gas tank vent can cause an air lock in the tank.

Power.........check voltages at the coil and fuel pump as engine dies, you could have a corroded connector feeding lower voltage to one of these.
Battery voltage, key off, should be 12.3v to 12.8volts
Battery voltage engine running should be 13.5v to 14.8volts