Was driving my 96 4.0 Cherokee down the highway today and the XJ just lost power...

Was driving my 96 4.0 Cherokee down the highway today and the XJ just lost power, I got to the side and it was just barely running, really low idle almost, kicking and just running REALLY rough... a few seconds later it died


I tried to start it, it would turn over but when you started trying to start it, the engine would buck and kick a little

I think I could smell fuel...

the shrader just only sprayed a little bit

I pulled the fuel line and I could hold back the fuel pressure with my pointer finger

someone suggested that my crank/flywheel sensor might be bad... any thoughts on this?

That's scary stuff my friend, glad you parked it safely. Hopefully it's off the road now and in a place you can work on it.

I would go after the fuel pump. I'm not exactly sure if you can check the voltage to it or if that matters, but checking fuel pressure would be a good option. I think the specs for my Renix were 39 psi with the vacuum regulator unplugged and 30 with it running properly. Your fuel pressure specs are probably slightly different than mine, but I would be surprised if they are more than a few psi off. Look up your numbers to be sure.

I think you can borrow the psi tester at one of the chain stores - it just threads onto that schrader valve.

Good luck!

ETA:
If you could smell fuel, check for leaks. Start at the fuel tank/pump and follow the lines up to the rail on top of the manifolds. I don't trust the quick-connect fittings they put on my '88 very much. I do think you'd have to be leaking an awful lot of fuel in order to lose enough pressure to cut out the engine. I'd still inspect the lines/injectors just to be safe.
ETA2: Also just remembered you actually have a computer in that thing. Are you getting idiot lights on the dash? Can you have someone pull the codes for you?

no codes, no warning lights...

that is why I am leaning toward fuel

What have you done with it since it quit on you?

A quick search "naxja fuel pressure" on google says a '97 gets about 47 psi from pump (unregulated) and 32 with functioning regulator.

When's the last time you changed the fuel filter?

I would do this:
1 Check for leaks before anything else
2 Get a volt meter, unplug fuel pump, turn key to ON (not start) and see if you're getting power the pump
3 Get the psi tool from one of the chains and test the fuel rail pressure (I think you need a running engine to get the vacuum regulator working- so you'll probably be looking for the higher (unregulated) pressure
4 Go from there...

I don;t think the 96 has a regulator

normally I would use a fuel pressure tester, but I was on the side of the road...

OK... I have spark... I have fuel... but it will not start... it tries... a little sputter here and there... but it is not starting

keep in mind it is a 1996, first year for OBD2 but only has 1 O2 sensor

there are NO codes and NO check engine lights

ericfx1984 said:

OK... I have spark... I have fuel... but it will not start... it tries... a little sputter here and there... but it is not starting

keep in mind it is a 1996, first year for OBD2 but only has 1 O2 sensor

there are NO codes and NO check engine lights

Click to expand...

My 99 did this same thing in the middle of winter and i had it towed home to find out it was my rotor inside the distributor.

96 is a bastard year.

It does have a regulator, in the tank. It's a dead-head fuel system like the 97+ but has a different regulator/pump/etc.

Anyway, I had a problem similar to you in a 96 once upon a time. It ended up being a bad wire going to the fuel pump. It got crushed somehow under the rig. Anyway, one day it just stopped running. Took a while to figure that one out...

Get under the rig and check for voltage at the fuel pump harness. Good luck finding the wiring diagram/pinouts. Like I said, 96 is a bastard year with a lot of parts or combination of parts unique to that year and that year only.

ChicksDigWagons said:

96 is a bastard year.

It does have a regulator, in the tank. It's a dead-head fuel system like the 97+ but has a different regulator/pump/etc.

Anyway, I had a problem similar to you in a 96 once upon a time. It ended up being a bad wire going to the fuel pump. It got crushed somehow under the rig. Anyway, one day it just stopped running. Took a while to figure that one out...

Get under the rig and check for voltage at the fuel pump harness. Good luck finding the wiring diagram/pinouts. Like I said, 96 is a bastard year with a lot of parts or combination of parts unique to that year and that year only.

Click to expand...

I saw the regulator when I replaced the pump... it was under warranty and only took 20 mins...

yeah I wish I was that lucky... the pump fires up... it makes pressure at the rail...

THE GOOD NEWS is Advanced auto parts not only gave me a new pump, BUT they insisted on giving me my money back... so it worked out ok... would have been better had it just have been a pump...

blazenjeep said:

My 99 did this same thing in the middle of winter and i had it towed home to find out it was my rotor inside the distributor.

Click to expand...

I might look at it again... but the cap and rotor look almost new on the inside :bawl:

followed this test...


http://www.jeepforum.com/forum/f9/4-0-will-crank-but-wont-turn-753696/#post7019813

everything on the CPS seems to be within spec :eyes:

so that is not the problem

I am getting fuel at the rail... but I kinda doubt I am getting fuel to the combustion chamber... if I was the fuel injectors should be soaked in fuel

ok the only code I could find is code 12 which just means I had disconnected the battery sometime in the last 50 keycycles

THIS might be useful to some of you guys

http://www.go.jeep-xj.info/HowtoECUcodes.htm

well I went to the Junk yard and got a CPS off a running Cherokee... the problem remains the same...

however I found a set of aftermarket shackles while I was there... look almost new... rough country from the looks of it... around 6" eye to eye... got the pair for $4.50!!!

it does not start with starting fluid... so... it is not an issue with fuel...

I am leaning toward cam timing...

pulled the valve cover and turned the engine over... all the rockers move

my guess is that the cam has jumped timing...

it could even be a damaged distro that jumped timing

Same thing happened to my '96 Sport while working in Cochise County, Arizona.
After a 30 mi. tow, it ended up being the coil itself exploded, from age and heat.
Are you getting spark?

I am getting spark yes

well I have confirmed that the distro is in the correct position when cylinder 1 is on TDC... so where to now?

Eric, you say it won't start when spraying starter fluid into the intake;
does that mean that it won't hit and try to start?

If you have spark, then the starter fluid should make it hit a few licks,
and act like it will start.

I'm leaning toward it being a bad cam position sensor inside the
distributor. On your 96, it's the plate that's under the dist cap
and lifts out. Replacement takes less than a minute.

(However, when the cam sensor goes bad it should trigger a CEL
on a 96, and also store a code...???)

How about the rotor itself? Is it broken?