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97 4.0 stalls while driving

F

Fred

NAXJA Member
NAXJA Member
Location
Colorado Springs, CO
We've had some ongoing issues with this 97 with 165k miles, and an AW-4. It has new plugs, wires, cap, rotor, coil, TPS, IAC, CPS, clean throttle body. It runs well when it runs. Now it dies while driving. No sputtering, no warning, just dies. I get a code PO351, no check engine light. The code is a fault in the primary/secondary ignition coil circuits. It has a new Accel coil, but I never checked before replacing it, so the fault could be elsewhere in the circuit. It may have nothing to do with the stalling. It was running fine for awhile, then started stalling, and finally wouldn't start. Replacing the IAC fixed the no start. It had fuel pressure at the rail when it wouldn't start.

I have another coil to replace the current coil, but it's a PITA to replace the HO coil, so if anyone has a better suggestion, I'd love to hear it.

Thanks,

Fred
 
When you mention the CPS--are you talking about the synch sensor in the distributor or about the CPS/CKP crank sensor? Terminology has flopped around a bit over the years.

Not doubting you, but the IAC shouldn't prevent spark, to my knowledge. If replacing it restored spark, I would be concerned about the PCM and the harness.

So, you are sitting there with out spark again? You have 12 volts to the coil from the ASD relay? Tried swapping relays?
 
Last edited:
Crank Sensor. When it wouldn't start this last time, I didn't check spark. I did replace the TPS with no results, and then the IAC that the Advance Auto guys suggested. I put it the IAC because it did fire up WITHOUT the IAC in the T-body. It fired right up and drove home fine. A day later it started dying while driving(and no it wasn't drinking while driving:)), so I cleaned the T-body. There was carbon in the IAC gizmo on the side of the T-body. This did allow the beast to start normally, before the cleaning it took one depression of the gas pedal to start up easily.

So now it starts normally. It just dies while driving.

I'm not sure I could get it to your house, Frank. It died 3 times just driving around the block.

At least I got the damn fence done, so now I can move on to the next project in the Cottage.
 
Ok, you need to verify the missing element when it dies--damn frustrating sometimes with the intermittent stuff.

Get a NOID light, should run about $3. When it dies and won't start plug the NOID into the injector harness instead of the injector and crank it--if it flashes light then your are getting a firing pulse to the injectors, no light, you have a problem with the synch sensor in the distributor or the harness.

Get a multimeter, if you spend about $20 you can get one with an audible continuity tester. When it won't start test the CPS/CKP crank sensor. See Tim_Mn's post here: http://www.naxja.org/forum/showthread.php?t=1032597&highlight=crank+sensor
 
And it starts up again, after stalling, so I can't see what plugging a noid light into the fuel injection harness would accomplish.

If I let it idle until it dies, and then check the circuits?
 
I read that, and more on the CNET tech forums. Seems to boil down to either the connectors to the PCM, the screws holding the cover on the PCM, or the PCM itself. I'll go home tonight and start with the cheap options. :)

Thanks.
 
Fred,

I have had the P351 code on my '98 XJ since installing a MSD-6a ignition and MSD Blaster coil back in '99.
The code is caused by the PCM not recognizing the ignition components, but has not affected the engines operation.
Several years ago I had a similar problem with the engine shutting off. I would crank and crank, but not start.
Found the problem to be the Camshaft Position Sensor inside the distributor shorting out on the grounding plate attached to the base plate. This was caused by the factory original distributor shaft bushing wearing out and allowing the shaft to wobble around.
Replaced the distributor and CPS; the engine restarted....
 
Well, the 351 code is gone, it was replaced by 3 codes PO125, 700, and 1695. The first was a TPS code, the second a failed TCM, and I don't know the third.

The sequence this time was to go home, start it, wiggle the PCM connectors vigourously for awhile, stop wiggling them, and then a minute or so later, the engine just died, no stumble, no miss. Took the PCM out, cleaned the connectors with spray cleaner, cleaned the grounds in that area, unscrewed the cover screws on the PCM, tried to replace one with a shorter screw, its not metric, looks like a 6-32 but won't screw into a 6-32 nut, left them screwed out, put it all back together, and tried to start it. Couple of stumbles, that's it. Showed the new codes, I cleared them, and that's it. No start, no codes. It has fuel, I can smell it.

I'm thinking the computer, since messing with it made it worse, but I suppose the cam position sensor could have just given up the ghost finally.
 
1695 is no CCD comms with BCM. The XJ doesn't have a BCM, are you sure it isn't P1698 no CCD comms with TCU?

It's sounding like the ECU to me. I hate to diagnose a problem as that because every shadetree / hole in the wall mechanic says it's "the brain" or "the compootarbox" at the first sign of an electrical fault, but I don't see much else it can be aside from the cam position sensor or crank position sensor, and messing with it did make it worse...
 
How new is the crank position sensor? My 97 has 141k and is on it's 4th sensor. I had one last only 6 months. I've heard the factory had problems from the beginning. Mine was changed first under warranty at 17k. Jim C
 
JimsXJ said:
How new is the crank position sensor? My 97 has 141k and is on it's 4th sensor. I had one last only 6 months. I've heard the factory had problems from the beginning. Mine was changed first under warranty at 17k. Jim C
Click to expand...

The Crank Position Sensor on my 98 had over 100K miles on it and when I did a clutch job on the Jeep I replaced the CPS due to easy access. Kept the old CPS as a trail spare.
If you have gone thru 4 sensors then I question the quality of the sensors being used. When I replaced mine I used a factory sensor due to ready access (have a Jeep friend that works in the parts dept and gets great prices).
 
CharlesS said:
The Crank Position Sensor on my 98 had over 100K miles on it and when I did a clutch job on the Jeep I replaced the CPS due to easy access. Kept the old CPS as a trail spare.
If you have gone thru 4 sensors then I question the quality of the sensors being used. When I replaced mine I used a factory sensor due to ready access (have a Jeep friend that works in the parts dept and gets great prices).
Click to expand...

That was exactly my point to Fred. -Jim C
 
I did the replace the factory sensor with an aftermarket. The CPS/CKS I took out tested fine. I'll test the replacement, who knows?
 
I tested the CPS, it showed a resistance greater than 20 megs. Checked the relays, they all seem fine. It actually started up easily, and idled fine for 5 minutes so we took it for a spin, and one block later it stumbled and died, not to be restarted. We strapped it home and I ordered a reman computer. Update in a week.
 
If it is a CPS problem, it may only be a problem after the engine/sensor warms up. That's when my problems occurred. It would stall on the highway and not start again until it cooled down. Whatever the problem, good luck finding it! It sounds like you've put a lot of time and energy into it. -Jim C
 
Installed the reman computer, no love. Still doesn't start. And I am in the middle of replacing u-joints, brakes, front coils, steering, front shocks. Discovered that the previous owner had replaced the new style axle shafts with some old style 260 ujoint shafts after removing a ujoint and discovering that the new 760 joints wouldn't fit. Bought different shafts. Now I have a bunged up bolt for the unit bearings that is giving me fits. M12 x 90mm, 1.75 fits.

Wouldn't be so bad if I didn't have to got to PA for a funeral and return just in time for CO Fest. Hope tomorrow is a more productive day. :)
 
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