Coraphix

So here is where i am at. engine will crank forever, but won’t turn over.
When i first started, i tested battery, it was dieing so i got a new one.
after new battery i tested for spark, it was a good clean blue spark.
then i checked gas to the rail. it was there.
then i shot some brake cleaner up the air intake, it started to turn over then died. we determined it was the fuel pump. so i replaced that with the filter.
still would crank but not turn over or start.
i rented some noid lights to check injectors and they were good. tried the brake cleaner in the air intake again, and same as before, crank, turn over, then die immediately.

because of the brake cleaner test it would say that i have a fuel problem,

now i have been recommended to check fuel pressure to test regulator. but the only way i could get a hold of a fuel pressure is to buy it new, which i dont have the money to do. but i was told that on earlier cherokees, there is a fuse that will blow causing this same effect. i looked through my fuse box and my owners manual but couldn't find anything.

here are some pics incase you guys might know about this fuse, what should i be looking for? (the first 2 are of the same fuse box under the dash. the last 1 is of under the hood. i could only find the 3 relays and no fuses, is that right for an 87? or should there be another fuse box under the hood?)

DeadCellM60

It could be a fuse or relay and I agree with you assertion that something is amiss with an electrical component somewhere but what's to say it's not an issue with the actual timing of the spark? It could be you have a problem somewhere within that control system.

Slick761

On the duel pressure, prime the pump and hit the relief. It should spray pretty good. If you have good pressure its likely the injectors aren't firing which could be cps.

Domaas

Without knowing the exact fuel pressure...everything else is going to be a guess...troubleshoot your way to the solution,dont swap parts.

When you turn the key on to you here the pump "prime" for approx 3 sec?


you would only have 3 relays under the hood i believe if you dont have ac..4 with. fuel pump relay is the second one in line from the front.

Slick761

He replaced the pump so it is possible but not likely ,the problem..,if the pump is new and he primed it and it sprays fuel 99:1 its good. If he has some pressure it will chug and sputtered like its trying to start.if there's absolutely no POP and he has some pressure the problem is somewhere else.

Domaas

True...but new dosent always mean good...lol.personal experience.
But he does state he has injector pulse tested with a noid light.?

Slick761

Didn't see that... the trouble tying to diagnose online is you can't fu. Tests yourself. The stator or cps could be bad could be good. I'm just saying with low pressure ne should sill get a little pop.

Domaas

I agree...sucks.

I had the same prob with my 88..ended up being a bad injector driver in the cpu...had pulse...but it was firing all the injectors at once.

I wanna know i little more history..did this happen all at once? ya know came out of 7-11 and bam! it took a dump???Hard start for awhile?

ogmeme

Change your CPS, they go out without warning. Wont necessarily give you a code. Part not to expensive, so if it original part, should be time to change anyways. Seems to be most common problem with jeeps when engine cranks but won't start.

Coraphix

1st, i changed the cps in mid january because of starting problems. shouldnt be that.
2nd, history, for a couple weeks before it wouldnt start i was having stalling problems while four wheelin. on bumpy roads it would die on me and have troubles starting on me. but when that happened it would crank, turn then poop out.

• it was after a trip up a local road it died on me 5 or 6 times in 20 min, we shut it off on the paved road at the bottom, and it wouldnt start back up.
• That was when i started doing all these tests.

3rd, i did do the noid light test that showed i had good injectors. as fr the pump, when i first turn key on it will prime for a good 3 seconds, quite loudly.
Finally, i only have the 3 relays under the hood because i do not have AC. so i will test the middle fuel pump relay. i wasnt sure what all those were at first.

Coraphix

using this picture for my test here is what i came up with.

• test 1 with multi at terminal 1&2 i got 65 ohms.
• test 2 with battery at 1&2 and multi at 3&4 i could not read any ohms, which means the switch isnt closing. althoug it did click when i hooked up battery.
• now not in this pic i do have another prong where the X is in the pic. only with battery connected, the X prong to terminal 4 it reads .5 ohms.

a few questions on this...

• am i testing right?
• is my ohm reading on the 1st test a good number or is it off?

Coraphix

what my relay looks like with labels from the one in previous picture.