TennesseeT

Well things didn't go as expected. I drove my XJ for one day with out any problem on cylinder #2, it was great.
But, the next day it made it about 2 miles and #2 was out of action once again.
This on again, off again, problem led me to think it could be a bad ground wire. I unwrapped the wiring harness at the ECU, planning to do a pulse test.
But, I suddenly have a "Zero Oil Pressure" problem. When I get this issue resolved, I'll be back with an update on the #2 cylinder ground wires condition.

lawsoncl

Argh. Intermittent problems are the worst to diagnose.

Unwrap and inspect the wiring harness where it crosses to the firewall. I know you've been in there enough to replace plugs, but you might need to look further back. I've seen chaffing and flexing damage those wires and cause intermittent issues like this, and in one case blow the injector driver in the ECM. Flex and wiggle the harness while idling to see if you can make it drop out or change. The usual cause for wiring damage there is bad motor and transmission mounts causing excessive movement and flexing of the harness.

Saudade

I had a similar issue with my '88. #3 injector was intermittent. As Lawsoncl says above, Renix is wired the opposite way. Using my multimeter and a noid light, I connected to the injector plugs (one at a time) and wiggled the harness. Eventually I found an open ground to #3. Peeled back the wrapping and found all 6 injectors grounds were spliced together near the firewall. The splice was very corroded so I clipped, stripped and resoldered them all. I also changed the 12v wire all the way to the #3 injector and put on new injector connectors on all of them. Problem solved.

On your 2000, you should get 12v on all of the + side of the injectors as Agreen said. If you use a jumper to ground each injector (engine off, key in run), you should hear the injector click. You may need to pull the connector off the PCM and check each injector for continuity to the injector ground side.



Your oil pressure sensor also connects to the PCM on C2 (pin 23). Perhaps that not a coincidence.

TennesseeT

Thank you so much!! I have checked all the plugs and all of them have 12 volts to all the plugs. The intermittent loss is only on #2 ground. If my Zero Oil Pressure issue is only in the sensor, (will check actual oil pressure on Monday), then I'll do a pulse check of the #2 ground at the PCM.
Unfortunately, #2 was working fine when I started the ground wire at the PCM check, and the oil pressure issue popped up. With the oil pressure issue out of the way I may have to drive the XJ to get #2 to act up.
The problem with #2 seems to occur, most of the time, after the engine has heated up, coincidence?
If no joy with the above, the next step will be to run the harness wires around the fire wall.

TennesseeT

Sorry for the long break, I'm a contractor and am currently building a house. My little darling has been run fine ever since the oil pressure problem began. If you remember from the last post, while I was trying to ID the problem with a dead number 2 cylinder, the oil pressure went to zero. I bought and installed a sending unit. Still zero. Bought an oil pressure test kit. Engine cold and at idle oil pressure is 58. Engine at operating temp is 38. I have been driving the XJ and it's running like a top. I need to close up the wiring harness and keep my fingers crossed.
So, I'll be reading up on "Oil Pressure" issues. I ran a gauge test and the oil pressure gauge performed as expected. So, I guess that leaves me with the plug or the sending unit. Any words of wisdom are greatly appreciated.

lawsoncl

You installed a sender and not the switch right meant for the dash with just the idiot light?

TennesseeT

That could be the issue. I bought the sending unit at Auto Zone and I've read posts that advise getting a Mopar unit. I plan to see if I can get one.

TennesseeT

Went to my local Chrysler Dealership and asked if there are two different Oil Pressure sending units. One for idiot light only and one for meter gauge. The answer was, "there is only one sending unit OEM for a multitude of Chrysler products". So the unit I bought at Advance should meet OEM requirements. That leaves me with only a few possibility's. The new sending unit is bad. The EMC is bad. The...well that's about it. This is were I could use a bit of help to run down the answer. As always, any suggestions are much appreciated. Thanks in advance.
I really need to get this issue fixed so I can get started on a few other issues that need attending.

Cummins93

Who you gonna believe Us or the dealership? (You know they will tell you to run atf4 In your trans)

What is the part number you installed and what type of dash do you have ( gauges or lights)

lawsoncl

I looked at the 2000 parts list, and there is only a pressure sensor not a switch listed. Still could be a defective or wrong sensor, or the wiring is damaged. I'd probably try backprobing the sensor with the engine running versus off and see if the signal changes.

TennesseeT

I installed a (5149062AB). The dash is gauges. Thanks for the help.

97grand4.0

Exactly. Anyone who pays a dealer for work gets what they deserve. Key word being 'pays. Milking info or work out of them is excepted.

Cummins93

So looking at what the parts stores list it looks like 98 to 99 was the switch from the 2 terminal to the 3 terminal sender.