'88 with possible ECU problems

Two of my three XJ's are '88's w/4.0L, AT, Limited. I had semi-retired "Black" and now (as a result of a significant disagreement with a large, immovable gatepost past weekend) I need to "canibalize" "Red" and put "Black" back into service. "Black" has been running really poorly with lots of cutting-out/dying/ etc. The problem is something perriferal . . . athe engine itself is great. Some months ago, I had a shop install a used ECU and I've since-suspected it as being the culpret. I've also replaced the MAP sensor and checked a few other items.

My only real question for you guys, at this time, is regrding trying "Red's" ECU in "Black." "Red" runs perfectly! And, I'd like to eliminate my concern about "Black's" replacement/used ECU by swapping them . . . . Here's the question: Is anything more than unplugging, swapping, and re-plugging them in involved?

Thanks!

Don

That's all there is to it. Just unplug and swap. The Renix boxes don't learn or remember anything.

Thanks, Paul! Over the years, of course, I've done a lot of monkey-wrenching on my XJ's but, I've never "messed with" the ECU/etc . . . I'll try my "experiment" this weekend. Thanks again for confirming what I thought to be the case. Don

as long as they are both automatic or manual. you cannot use one for an automatic in a manual or vice versa. but if they are both limiteds, i wouls guess they are both autos

Yes, they are and thanks again! Don

Actually you can use the ECU back and forth. The only difference is that the ECU for the auto has an input for the NSS or a simular sensor. I ran my manual on both ECU's before I put in an auto and I have tried it with both ECU's with no problems.

Have you fixed it? How about checking the CPS?

The CPS only has about 9K miles on it. The wires are not contacting the exhaust . . . . . nevertheless, I'm beginning to think it does seem like CPS problem.

Sure does seem like it.

I have a new CPS in my '88... damn think shook loose and was giving me a crapload of problems. Make sure those bolts are TIGHT. I actually got longer bolts and screwed them thru and put nuts on the other end.