90 cherokee no start. yes, another one.

to verify, yes, I SEARCHED before posting this, but came up with nothing.


1990 cherokee 4.0 aw4.

the PO started it to sell for me (long story) a few days ago, and when he did, the throttle assembly was stuck open, so it was high-revving. well, he just shut it off at hi-rev.

now it won't start and it smells like gas under the hood.

anyways, It cranks and cranks and won't even sputter now.

I pulled the plugs, obviously they were wet. let them dry, and I spun the motor around for about 12 sec. to clear it of any gasoline in it.

still won't start.

did that again, and tested for spark that time.

has spark.

still won't start.

fuel pump is coming on as it should, ballast resistor is just fine, no leaks in the fuel line it appears.

I sprayed some starter fluid in the motor and it seemed to sputter a bit, but didn't start.

what's wrong?

it could be your fuel pump. test the pressure at the fuel rail. you will need a fuel pressure gauge. the pressure should be at about 33-35 psi i believe. however, if you're getting a strong fuel smell while trying to start it, then it could be the crank position sensor. my 87 had the crank sensor out and it sounded exactly like what you described. it acts just like a bad fuel pump, except for the fuel smell. the crank sensor is on top of the bellhousing of the transmission. good luck and hope this helped.

yep. I know exactly what the CPS is.

problem is, that it has spark.

now, I've messed with alot of these cherokees...I build comanches and cherokees almost exclusively. this one has just got me boggled.

the fuel pressure is 34psi, I forgot to say that. so the ballast resistor is out of the question as well.

the ICM works too, since it does put out spark.

if there's enough fuel to soak the plugs and spark at the plugs, the only things left necessary to run is compression and correct timing. As it started a few days ago when you bought it, I wouldn't think the rings went bad sitting-- I'd look into timing. Maybe a slack chain that jumped a couple teeth when he started it and shut it down at high RPM?

--Shorty

that's possible...it does have 251k miles on it.

I actually traded him a 95 4.0 auto 2 door xj to him for 3 xj's and $150.

reason I traded the 95 is that I'm sick of that thing...a friend owned it and blew up the tranny on it. so he sold it to me and I fixed it. then, I sold it to a friend who did nothing but bitch about the gas mileage after he got it...but he HAD to have a jeep. well, I was gonna buy it back....then he blew the t-case on it. yet another fix. it had rusted rockers that the first friend bondo'd, and halfass repaired floors, but had literally every factory option but power windows/locks/seats, and air suspension.

I just was sick of it and traded it for these...sadly, now this one don't run, I'm driving the 86 4 cyl (happy with that one), and i've scabbed the 85 as parts.

anyways, he was trying to sell it for me when this happened.

is it firing at all or is it just turning over? I would say timing issue as stated before,


spark plugs in the right order?

it's firing now, but it cranks, fires, cranks, fires, cranks, fires at a predictable interval.

I'll put in new plugs...these ones are fouled and have bad threads.

the next thing is to take out a fuel sample...I'll just use the fuel pressure test spot to spit it out, and figure out what's in it.

if it's not fuel, and it's not spark plugs, then it's timing.

the spark plugs are set to fire in the correct order.

I also cleared the PCM by removing the battery overnight.

any other ideas?

if I can't get it to run It's no big deal...I just didn't want to pay to get it home, or borrow my grandpa's truck and trailer to get it home either. this xj is getting parted with the np242 from it going behind the 86 comanche, the 3.55 front end being rebuilt for the 86 comanche (mine's bent), trans. and an np231 will go in a 91 comanche I'm converting to 4wd with 3.07's for a guy.

Take a fuel sample off the rail, let it sit over night and see what it looks like, in a clear container. see if it seperates out?

Not sure if it will help, might be a longshot, but play "musical relays" and move all of them down one slot, check fuses and fusible links. I ran out of gas yesterday:doh: and it quit under power. tried to start and start, same thing, had spark but no bang. I let it sit and moved and wiggled everything I could and then it started and ran perfect. I'm worried! Checking the fuel is a good idea too!
Good luck and God bless!

34-35 PSI means your pump, filter, ballast, etc is fine.

IIRC, there are only 3 electrical things that could make a Renix XJ not start.
First is the distributor, but I assume it's there & working as the XJ has spark at the plugs. Next is the CPS; which CAN send spark and be bad; spark at the wrong time will not start an XJ. Another thing which will not allow an XJ to start is a bad MAP sensor (on the firewall above the valve cover); check the vacuum line going to it & the electrical connections.

The high-revving sounds like a MAP or TPS issue, but I believe the XJ can start w/o the TPS working, or even unplugged.

Also, try unplugging the cruise control under the hood; I had a 89 XJ that revved all the way on it's own one day - caused by cruise control gone wild!

the cause of the hi-rev was the linkage that the gas pedal goes to. it was hung up and dirty...so it got stuck, and held the throttle open.

it could be the MAP sensor, and it could also be the CPS too...it has had CPS issues in the past and the PO just tapped it with a breaker bar and it worked again.

does a 2.5 CPS work on a 4.0? I only need it to work for about 45 min. to get it home, like I said, that's all I want out of the truck. I'm sick of driving to fix the focking thing and it not being fixed after I waste my time on it...and I absolutely refuse to ask to borrow my grandpa's truck and trailer, and don't have $$$ to pay to tow it.

fixed it.

bad ground at the spark plugs was one aspect of it...

I think though, that water in the gasoline...didn't help much.

disconnected the fuel line at the fuel rail, took a fuel sample, saw it seperate almost immediately, so I took a rubber hose and connected it to the line, leading into a gas can, and drained the last 6 gallons of gas/water that were in the tank. put new 93 octane in, still wouldn't start. put $10 worth of spark plugs in, that fixed the issue...I got it to start on the first crank then. 3 plugs had hairline cracks on the insulators, and the threads were all dirty as hell.

so thanks guys for your help!

Glad its running.

me too.

now I can get it home and cannabalize the b*sh.

I'm not gonna try and save it...too many miles, too much rust (driver's door has to almost be held up as you open it so it don't fall off, and the door handle is riveted on), etc.

but...

this is a Laredo 2 door

power windows/locks, cruise control, a/c, rear wiper/defroster, OHC with temp and directional gauge, tilt column, vent wing windows, rear vent windows, cargo cover, fullsize spare, class 3 tow kit.

oh, it's also got an np242 t-case in it 3.55 gears, tow hooks, and skid plate too. not sure on rear axle, haven't looked.

so it'll have a fair amount of parts to give up! can't wait to use the 2dr power wires to put power windows/locks in the MJ.