Jeep Garage  - Jeep Forum

Jeep Garage - Jeep Forum (
-   Engine Performance/Intake/Exhaust (
-   -   Still stalls on acceleration (

NJ99 07-31-2010 04:41 PM

Still stalls on acceleration
99 WJ with 4.0 - 199,000. Ok everyone, here's the deal. I have replaced both the cam and the crank sensors. Took out for a test ride and stalled on mild acceleration as it had prior to changing sensors. Stopped to read codes and none showed up. So... I hooked up so my passenger could read the codes as it happened and check fuel delivery. Hit the gas and stalled, BUT it cleared the handheld as if we lost power as well. Tried again and got new codes P0340 and P1391. Once we got them I tried three more times to see what would happen. 2 of the 3 it cleared the handheld again. This is consistant with P1391, but what;'s the deal with P0340 and how do I check the camshaft target wheel runout??? Need help, brain hurts.

Scottina06 08-13-2010 02:52 PM

Re: Still stalls on acceleration
no one with a 4.0 can help our Jeep brother?

Frango100 08-15-2010 10:08 PM

Re: Still stalls on acceleration
When you talk about the camshaft target runout, do you mean the target for the camshaft position sensor?

Escape 08-15-2010 10:37 PM

Re: Still stalls on acceleration
Sounds to me like the cam sensor isn't seated properly allowing to large of a gap between the sensor and target wheel on the cam shaft.

Did you thoroughly clean the area around the sensor before and after you removed the old one?

Either that or your contacts are dirty. Did you inspect them and add some electrical contact grease?

Beepatajeep 08-16-2010 01:59 AM

Re: Still stalls on acceleration
know this is probably a stupid response, but maybe just an O2 sensor somewhere? I haven't had anything like this on my WJ, but had something like it with my ZJ. Just stalls out because theres not enough oxygen getting to the engine somewhere. Just a thought

Frango100 08-16-2010 08:33 AM

Re: Still stalls on acceleration
Iīm not familiar with the 4.0 engine, but looking into the service manual i see that the cam sensor is in fact not directly looking at the camshaft, but is mounted on top of the oil pump drive shaft assy. On top of this assy is a pulse ring, where the cam sensor gets his pulses from.
But due to the fact that you loose the connection with the PCM when the stall occurs, it looks more as an electrical interruption to the PCM. Did you check/clean the PCM connectors already?

NJ99 09-25-2010 01:32 PM

Re: Still stalls on acceleration
UPDATE : First, thanks to all who tried to help. It's been over a month and I'm on 5 forums with no luck. I just installed a reman PCM and it does the same thing :mad:. Do I really go and replace the harness? I'm at the point of not wanting a Jeep any more.

Frango100 09-26-2010 05:04 PM

Re: Still stalls on acceleration
It looks as a wire problem. Just let the engine idle and try to move gently the connectors on the sensors and on the PCM. Also check the wire bundle for chafing or if it has made contact with some hot exhaust part, which could have melted the insulation. Because it only happens on acceleration, maybe the torsional movement of the engine makes it contacting some wire.

NJ99 09-26-2010 07:01 PM

Re: Still stalls on acceleration
I'll give it another try. I did do that after the failed PCM try. I spent about a half hour and tried all connections and every wire that wasn't in a loom and all loomed bundles. Should I try to redo all grounds? If anybody has ANY thoughts, I'll give it a shot. So bent about this. Not so much a money issue because I've pretty much replaced all the big dollar items, it just gets old chasing a phantom issue. Would someone be able to tell me how to test wires? I have a meter, but need a lesson on how. BTW-my radio fades in and out when accelerating. I took the radio out, cut power wire, ran a new wire as a temp directly to battery, still happened. Did the same with the ground wire (to ground). Same result. Just throwing it out there in case it helps with one of those "A HA" moments.

Escape 09-26-2010 07:09 PM

Re: Still stalls on acceleration
Check the output from your alternator and the voltage of your battery. The electrical systems are very touchy. Checking all the grounds wouldn't hurt either.

Is this stall occurring during small, mid or hard acceleration? You may want to check your spark plugs, plug wires, ect.

Unholyskorn86 09-27-2010 10:21 AM

Re: Still stalls on acceleration
Overdrive coil in the transmission? Does it happen more when you tend to baby it between first and 2nd or right after 2nd? Or does this just happen while idle etc? The camshaft code or some other things could maybe be just from it dying? I dunno keep us informed bro.

Frango100 09-27-2010 11:12 PM

Re: Still stalls on acceleration
1 Attachment(s)
When you want to measure a wire for continuity, you have to disconnect it from both sides and put an Ohm meter over it. Donīt know what type of meter you have, but if you have the one which can make a sound when there is continuity, then you donīt have to look at the display all the time, but just listen if the sound stops. Attached a schematic with the wires for the cam and crank sensors. My manual is for my 2004 WJ, so there could be some difference with your car. There are sometimes differences between the 4.0 and 4.7, but you can see that in the schematic.
As mentioned before, have a look at all ground wires if there is no corrosion or loose contact somewhere. Also look at both battery connections if they are clean and well fixed.
In the Power Distribution Center (that is the relay and fuse box in the engine bay) there are some fuses for the PCM and there is also the Auto Shutt-Down Relay. Look into this Center if everything looks clean and no corrosion present.
Not sure if this Auto Shuttdown relay could cause your problem.

All times are GMT -5. The time now is 02:42 PM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community