87 waggy/4.0/4WD

Morning all,

Having intermittent high idle issues. Have run through Cruiser's list (thanks for that info!) New IAC, grounds refreshed, replaced TPS in spec, MAP new, fuel pressure at rail checked out fine, new fuel filter, recent O2, etc.

Noticed that if I let the pump run several times before cranking that I don't have this issue. Mine does not have the ballast on the fender wall, so that's not it. Would having to prime before cranking be a symptom of a failing fuel pump?

Thanks in advance!

 

Yes.

 

Certainly a failed check valve but not necessarily the pump. I've been priming my XJ for years, anytime it sits for over an hour. Not clear what the issue is other than a defective design. Have a `92 S10 and a `00 Tundra, neither require priming.

 

Where is the check valve if not integrated into the pump?

 

It's in the pump assembly. You can keep priming the fuel system every time you start the engine, or replace the pump. Your call.

 

That's what I was getting at. It needs a pump.

 

I have a '00 ranger that won't start without priming. I replaced filter, then pump. Still no dice.
Weird thing is no sound from the pump, but my 87 xj's pump almost howls, and it never starts hard.