98REDXJ2

alright guys got a tech question.

just replaced the fuel pump on the womans 98 cherokee and the pump is working and the fuel rail is full of fuel but all it does is:
hear the fuel pump turn on
cranks over
no spark
plugs are dry when i pull them out

im lost

Radi

Got a fuel pressure gauge? I"m assuming it ran before you changed the pump?

tjwalker

Was the fuel pump changed because it didn't start? Did you check for spark at that time?

It's possible that the problem wasn't the fuel pump, but rather something was inhibiting spark, like the "crankshaft position sensor".

Bob98Classic

Or a bad camshaft sensor, or both like it was in my 97.

Bustedback

I don't feel good today, a heart transplant should do the trick. DIAGNOSTICS, use it.

Gee oh Dee

This.

Check fuel pressure. Check coil, crank position sensor, maybe cam sensor but thats uncommon.

I hate seeing people just toss money at parts guessing that the problem will be solved, yet no testing or diagnostics were done.

98REDXJ2

I do not yet know we're the cam sensor us. I'm hoping it's not the crank position sensor I'm Prolly gna have to borrow a meter to test it. The pump was not working before I changed it now it turns on and fuel is getting to the rail

Bustedback

The cam sensor in under the distributor cap, AKA the pickup coil.

ihscoutlover

Apparently my post to this got missed. You need to test the CPS, and test the Cam sensor. The cam sensor is typically under the dist cap, can either be a cover looking unit, or a small unit that slides on and off the shaft the rotor goes on. From working on and testing my '94, I found that the computer will not fire the injectors or spark, if the CPS and other sensors during the key on ignition off sequence don't test within the computer's start up specs. When my unit wasn't getting fuel to the fuel rail, and I hotwired the fuel pump directly to the battery, I got nothing. I replaced the fuel pump, and then that part was working, but I still had no spark. Replaced the CPS, then I had spark, but not real good. So I replaced the coil, got a good blue spark, and then it was checking for other issues. After I replaced the dizzy, I still haven't gotten it to run correctly, and thus have gone through 1 set of intake pushrods. Lesson learned.

Jeff

98REDXJ2

By cam sensor do you mean the rotor under the dist cap?

Ig I'll have to wait till I can look to know what the cam sensor looks like. I've never replaced one before

Bustedback

Not the rotor, the plastic plate under the rotor.

98REDXJ2

well so far ive only been able to narrow it down to a spark problem

CCKen

Try swapping the ASD relay with the radiator fan relay in the PDC and see if it runs.

CCKen

Also, check the fuses marked "Fuel Injectors/Coil" and "ASD" in the PDC to see if they're blown.

98REDXJ2

I've tried swapping the asd and cooling fan already and all the fuses under the hood are good