So I bought a real pretty 87 Cherokee pioneer 4.0 with 208k miles for 750 bucks. Didn't run when I bought it. Under the hood it was a filthy oily mess. Probably hadn't been tuned up since the Cretaceous era. Distributor cap nubs were completely corroded. Injectors were all gunked up. I put new tuneup parts in it and eliminated the c101 connector. It fired up and ran great for a couple of minutes, then the revs slowed and it ran rough but it did rebound and run good for a couple more minutes, then it did it again. Tried to drive it but it kept stalling. But it would still start again. Put new volvo 746 injectors in it as well as a new fuel filter. Now it won't start. Got no fuel pressure. I can hear the pump prime as its supposed to but still no start. When I depress the Schrader valve I get nada. Put a new fuel pressure regulator in it, but still no fuel pressure. I can't even get it to fire with starter fluid. I have concluded that it must be the fuel pump, but I might be completely full of beans.

Since I am not at all an expert on this clunker, can one of you gurus suggest other diagnostics before I put another fuel pump in it. It has a new IAC, TPS, and CPS in it. Upgraded the grounds, put new battery and cables in it but still no start.

The previous owner said he was driving it one day when it suddenly just quit running . Had it towed to his house and parked it til' his wife told him to get rid of it.

I welcome any input.

 

I think you've covered the bases. The only other thing I can think of is to run 12v and ground directly to the pump at the connector and see if that changes things. If it doesn't, it's clearly the pump.

 

You could also try priming the pump a couple times to see if it builds pressure.

 

Have you checked the easy things like relays and fuses?

 

I missed that part so never mind what i posted earlier. If it wont fire using starter fluid, it wont start with fuel so priming the pump to build pressure is pretty much pointless.

Im just thinking out loud here so bear with me.

1. fuel pump primes but theres no fuel pressure. Im thinking fuel pump or pressure regulator. Maybe both?
2. engine doesnt start using starter fluid so i doubt a working pump will help. See #1.
3. do you have spark? See #2.

It is a Jeep so im sure theres an electrical gremlin hiding in there somewhere, but i keep coming back to those three things.

 

Test your CPS output.

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