Late last night I removed all the connectors from pcm, sprayed contact cleaner then mild compressed air in both socket and connectors. No connection to OBD2, no fuel pump hum when key was turned to on position, Removed ground from battery, disconnected oil sensor, cam sensor, coolant sensor, crank position sensor, map sensor, throttle position sensor and tcm. Reconnected neg cable to battery. No OBD2 connection.
Reversed the entire process and no start, no fuel pump hum, no spark, no OBD2 connection.
(btw...this is cool, I'm 39000 feet in the air right now..lol)

 

You forgot the oxygen sensors, vehicle speed sensor, battery temperature sensor and neutral safety switch.

 

First and foremost I would like to give a big shout out to Jordan96xj.
As you can tell by this post he helped and guided me through a number of specific tests to test circuits based on my description of what was not happening with my Jeep. At one point, after a number of tests, he said it may be time to try a good PCM. Since I was leaving on vacation I ordered a replacement PCM from Flagship One in New York. They flashed it to my VIN and mileage as well as making sure it was the same part number. $210 delivered and a lifetime warranty. Dropped it today and the Jeep rumbled to life then smoothed out as it warmed up. No fault codes and runs like it always has.

Again, that is all I spent, $210, and that is because of the direction Jordan96xj gave me. I cannot say thank you enough or how much I appreciate you sharing a wealth of knowledge with me/

He is why this forum was created and still exists.

 

Still got the old PCM?

 

Did you ever have any problem with that ECU? I ask because I have the same problem. But the current price for the same ECU now is almost $1200
Edit: I've found one on Ebay, by Flashmasters for $500. I've heard of a case where someone replaced the ECU and some short time later it failed again. Which is why I'm curious if you ever had any further issues over the years?

Edit 2: I've also found a company on Ebay that offers to repair your ECU for $130, only a $35 test fee if it can't be repaired. Has anyone here ever tried this?

I'm sorry to revive a dead thread, but I wasn't able to direct message you.

 

Cant believe they went up THAT much. I would still look to pay around $200. About 5 years ago I bought one for my 1997 grand, from Advance of all places. I think it was a Carquest rebuilt, guaranteed, it didn’t need flashing because 1997 and it worked fine out of the box, for about $120 with exchange.

 

The ECU/PCM from Flagship One is still performing perfectly. At this point I have 233000 miles on the Jeep. I think because of of the dwindling amount of actual ECU's available to be refurbished and of course the recent rapid increase in the rice of everything has contributed to the huge price increases. Before spending $1200. I would make sure that I could get a couple of years of service from the Jeep.
Hope this helps

 

yeah, I tried an ECU from Car Computer Exchange, that ECM didn't work.. it acted like ECU that failed

 

Thank you. Appreciate your response so much! I'm going to try the repair option... The Jeep runs right now on a 98 ECU, but not very well at high RPM. I had this Jeep for 8 years before the ECU failed, this was the first time it had left me stranded. I love my XJ, I don't want to let her go.
Again, thank you so much for responding, I'm so glad to hear that your ECU works years later.

 

Quick questions... if you don't mind man. Your thread has been a high beam of information and I do apologize for any inconvenience I'm causing. I'm just dying inside to try and get my XJ back on the road

I had my distributor replaced same as you, just before my ECU failed... yours was installed 180 off right? Do you think that had anything to do with the ECU failure? You rotated your distributor back to correct position right? And your new ECU has been fine? I'm just curious if you think there's a connection. And now I'm convinced I should pull my Jeep back in my shop and see if the mechanic done the same thing to my distributor...

again, thank you so much, I really do appreciate you and the wealth of information in this thread.

 

I really don't think it had anything to do with it. Though the cam sensor is powered by the ECU it wouldn't recognize if the distributor was 180 out and the spark plug wires changed accordingly. I had it corrected more for my ADD than anything mechanical.

Connect with member Dave51 if you want to open up your original ECU and see if it may be a broken solder or a burnt resistor. That would probably be the most inexpensive fix.

hope this helps

 

Hey, any idea is an idea at this point. Thank you. I'll see if I can get a message to him

 

There's a number of fixables with XJ PCMs:

The grounds are bad.
Broken solder joints.
Blown capacitors (I have a bunch of 220 μF 35V and you are welcome to a few if you want)(you may have 25V but these are better).
Fried coil drivers.
Fried injector drivers (may be able to get these)(used to, anyway).
Board fried (mortal wound).

BUT...

In reviewing your other thread, it's not clear if the original PCM has/had a problem. AAMOF, your description of "starting on the second try" sounds more like a pressure regulator issue (need to prime the system) than a PCM.

So IIWY I'd do some good diagnostic work to determine (read sig):

 

Well that "2nd try" did seem to go away when I arrived at the shop to pickup after the distributor was installed. It fired up instantly. And I mean instantly. There was barely a crank and it started. I almost held the starter too long from old habits. And the temp gauge was bottomed, I assumed it was a full cold start.

My next question is... Why does it run on the 98 ECU... and not the 96, if it isn't an ECU problem? I can step out right now and start it on the 98 ECU. Idles great. 3000 rpm sounds like garbage, especially under load. 96 ECU is no start, no fuel pump, no fuel rail, no spark. IIRC. My diagnosis run was over 2 years ago. This is where I started researching and came to the conclusion it was the ECU. 2 years ago I just didn't have the time and money to throw at it. Now I do. Just running off memory now.
edit: The 98 ECU does have trouble starting again btw. Sometimes the starter "hangs" kinda gently. I'm guessing that's actually a misfire causing a lash to the starter.

One final thing, we can move this discussion over to my thread if you prefer,, I hate to bury all the useful information in this thread.