My XJ recently started acting up. It all started after driving through 2' of standing water that was sitting on an on ramp. Everything was fine for the first 20 miles and then it began:

The jeep was in drive, highway speeds, and it would just lose power. The RPMs would drop to idle and the gas pedal would not effect it at all. It would downshift, rev up and continue as normal. At first I thought it was a one time thing. Then it happened again, and again and again. It pulls fine and shifts fine usually...It has plenty of power. It idles steady at ~750. At first I thought this was the transmission, now im thinking it is electrical problems...?

TPS? Automatic Transmission Sensor?

 

Something got wet... I'd suggest opening up all electrical connectors that were anywhere near the water and drying them out for starters. O2 sensors, transmission harness, etc.

 

I have been advised to check the distributor cap for water. Could it be my TPS?

I drove my jeep without oxygen sensors for a while without any problems, would water interfering with the oxygen sensors really cause this kind of problem?

Im at a loss right now as the Jeep is my DD and I need it to commute to and from work. Any specific things I should check in addition to the ideas already listed?

 

Water might not bother the o2 sensors directly, it's shorts in the connectors or wiring that raise havoc. Certainly worth checking the distributor, in fact I'd check anything that unplugs, unsnaps or unhooks, lol. There's probably moisture sitting somewhere.

 

It turns out the 02 sensor was electrical taped together... I dried it off and retaped it temporarily.

Same symptoms: It started fine, drove for a bit and then the gremlins attacked: It keeps dying and almost dying (sputtering and backfiring). Now it wont even start and is displaying the P0351 code (Primary coil Malfunction)

Ive done some research and am starting to think its the crank shaft position sensor. I was told to only buy OEM and stay away from the O'Rilleys/Action Auto knockoff brands.

 

Mine was doing this 95ltd with same code replace the coil ran fine for 20/30 k's and just stops, backfires etc turn her off and start it up again runs fine again for 20/30k's ended up being the fuel fitter down near the tank

 

Since you're getting a coil related code why not check for spark from the coil wire to the distributor and at the plug wires?

 

- I tried the jeep again and it started first try. It idled for a few minutes and then died and would not start again.

- I had the battery tested (it passed)
- I cleaned the terminals and the ground points
- All of the connectors have dioelectric grease in them.

- After removing the battery, testing it and reinstalling it, the jeep started first try, idled for a bit, died and would not start again

- There is no spark from the wires (I cranked it over, with a screw in the end of one of the wires and held it to the engine block and it did not arc when cranking it over)

- I am still thinking its the Crank Position Sensor

- The Jeep Dealership quoted me for $140
- I can buy it from O'Rielly's for $80

If it is not, what else should I check/replace?

I'm thinking:
- Camshaft Position Sensor
- ECU
- Fuel Filter

 

Primary ignition coil means the ignition coil on a distributed engine. Meaning one coil for all plugs. If you had a bad crank sensor it would through the corresponding code, or you would have no spark or injectors opening. I got the same code today with the no start. Im changing the coil tommorrow and will let you know the results. I recommend anyone to use obdcodes.com they give great explanations and show possible causes.

 

Update- did the wiggle test on the coil connector, and it acted up. Ill be putting in a new connector soon. Details to come