87 ranger starts runs a few seconds then dies

draco275 · Jul 17, 2014

87 ranger starts up then dies

87 ranger 4x4 2.9 v6

my truck will star up run and sound great for 5 to 10 sec then die..when i try to give it gas to keep it running it dies immediatly..ive put alot of new parts in thinking it was a fuel issue..i have good pressure at the fuel rail as well.
im stumped and need my truck running again..any ideas would help..
its my daily driver and i need to get to work tomarrow

new parts are

new lift pump
high pressure pump in frame rail
fuel filter
plugs
wires
cap
rotor
throttle position sensor

Spott · Jul 17, 2014

It really sounds like you're (still) not getting enough fuel.

Here's the (paraphrased) testing procedure for the '88 2.9l, from the factory manual:

1. Make sure you have gas in the tanks
2. Check for leaks
3. Check for electrical continuity, measure 5 ohms or less across the high pressure pump wires, verify 12v supply, verify good ground
4. Check pressure and flow
A. key in run (engine off) should be 30-40 psi at the rail
B. Unhook fuel return, run a return hose to a container, and run pump for 10 seconds (key in run, ground the pin on the "short side" of the test connector).
C. Good results = 35-45 psi fuel pressure during test, minimum 5.6 oz fuel from the return line, and minimum 30 psi fuel pressure right after you turn the pump off.
D. If it meets those 3 specs, your fuel system is good, look elsewhere for the problem.
E. If pressure is good but flow is too little, check filter and lines for blockage.
F. If pressure and flow are good but it won't hold 30 psi afterwards, check for leaky injectors or fuel pressure regulator. If those are good, replace fuel pump.
G. If there's no pressure and flow, check for leaky injectors or fuel pressure regulator. If those are good, replace fuel pump.

Also, you can test the lift pump, it should deliver 16oz fuel in 10 seconds, before it goes into the filter or frame pump.

Let us know what you find.

draco275 · Jul 17, 2014

it has new lift pump and frame rail pump im getting good pressure...a friend of mine said to check the iac could that be an issue?

Spott · Jul 17, 2014

New doesn't always mean "good".... Mostly it means "untested."

If it were the IAC, it would run well when you press the throttle. So, no, it's unlikely to be the IAC.

If you know you've got enough fuel flow (not just pressure) to the rail, then I'd look at injectors or wiring. But you don't know that until you test it.

The reason they make these testing procedures is to provide a systematic approach that eliminates the most common problems first and arrives at solution with the fewest number of new parts required. Yeah, you're gonna have to spend half an hour testing it, and yeah, you're gonna have to learn to use a multi-tester, but once you've done it then you can be certain.

87 ranger starts runs a few seconds then dies

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