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Still stalls on acceleration

16K views 17 replies 8 participants last post by  kevinswj 
#1 ·
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.
 
#3 ·
When you talk about the camshaft target runout, do you mean the target for the camshaft position sensor?
 
#4 ·
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?
 
#6 ·
I´m 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?
 
#7 ·
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.
 
#8 ·
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.
 
#9 ·
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.
 
#10 ·
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.
 
#12 ·
When you want to measure a wire for continuity, you have to disconnect it from both sides and put an Ohm meter over it. Don´t know what type of meter you have, but if you have the one which can make a sound when there is continuity, then you don´t 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.
 

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#13 ·
I'll try to answer in order.
I can make this happen in any gear, including park. If I hold at a steady rpm, let off, and then floor it, it will stall. When driving on the parkway, I can be in OD at a steady rpm and out of the blue, it happens. I gotta say though, it mostly happens (on it's own) when I pull onto the parkway ang getting to cruising speed. Most times when it just shifts into OD, at that moment it dies. Keep in mind, I can replicate this in park. It hasn't ever stalled when parked at idle.
Frango - I'll follow through with this.
Again, thanks to all who keep giving me things to look for. Sooner or later somethings got to fix it, right ??? :)
 
#14 ·
Searching on the net i found almost the same fault description as you gave. You only have to pay for it to get their solution, so no ideia if its good or not. You could use it maybe as a last try before you blow up your jeep:lol:.
Here is the address: http://d-tips.com/BrowseTips/421.html
 
#16 ·
yeah swapping in a 4.7 to replace the 4.0 usually fixes most problems :p enjoy the new wj, the 4.7L can be a beast :)
 
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