• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

ECU burning up????????

P

pb_beaker

NAXJA Forum User
Location
in a van down by the river
Well this is the second ECU i have gone through. I got the 86 xj from my father in law and he never had this issue. When i got it i had to put a cat on it to pass emmissions. Could that be why its frying on me??? Any suggestions???
jeep015.jpg

jeep020.jpg



jeep018.jpg
 
See if you can figure out what pins on the ECU connector are connected to the burnt components...and then work back to the sensor, injector, or circuit those ECU pins go to...something must be shorting out...
 
McQue said:
See if you can figure out what pins on the ECU connector are connected to the burnt components...and then work back to the sensor, injector, or circuit those ECU pins go to...something must be shorting out...
Click to expand...

That's exactly what I was going to say. Once you figure it out, you might be able to replace that component and not have to get a new ECU. You could fix your other one too and sell it!!!

It's really easy to trace back to the pin on the connector. Ask if you need some pointers... You do need a multimeter though. A cheap walmart one that measures resistance will do the job.
 
Well.... i tracked it down to pin #8. The WOT (WIDE OPEN THROTAL SWITCH) So what can i do? Can i just leave it disconnected or is this something that needs to be there?
 
If it's the 2.5 4cyl we are talking about.....those are renix aren't they?

Correct me if I'm wrong here but IIRC about the only thing I can tell you is the WOT switch sends your engine into open loop mode upon wide open,heavy acceleration.....and I believe its also responsible for turning your fuel injector(s) off in the event that you hold the accelerator to the floor while trying to start a flooded engine.
 
Last edited:
yes its for the 2.5 4cyl, i take freeway to work and home 1 hr both ways and i have 33's on it, so its screaming. My question is if i unhook the switch will it still be drivable at highway speeds? And not burn up the next ecu. And whats renix and iirc
 
Renix is the computerized engine management system on 87-90 4.0 jeeps.Don't know for sure if the 2.5 was amc or renix controlled.I should know I used to own a 2.5 back in the day.....

IIRC = if I remember correctly
 
well the first time it happened nothing would work after it burnt up, no spark no fuel pump. so i started tracing wires and alot of them went to the ecm. i figured it was a good place to start and wanted to eliminate everythin. took the cover off and BAM!!! Replaced the board and everything worked. A second time and checked the box and it was toasted. Soooooo i was thinking, since i drive an hour away at about 70 to 75 mph what would happen if i take out the WOT switch. will the engine be fine? Will something else burn up?
 
You must log in or register to reply here.

Similar threads

M
92 XJ ECU connector
Replies
5
Views
138
Rob Mayercik
R
T
Random Starting Issues - ECU / PCM Problem?
Replies
12
Views
2K
TEX-J99
T
9
Low B+ voltage according to the ECU
Replies
4
Views
1K
90xj06
9
O
2000 XJ Failed Colorado Emissions high CO
2
Replies
27
Views
2K
Ken M
K
O
0331 Strikes Again...?
Replies
11
Views
301
Ol Blue
O
Back
Top