vetteboy
NAXJA Forum User
- Location
- morganville, nj
My stock '94 ECU fried after 180k flawless miles...after mounting it horizontally with the coilover swap, it filled up with water. Oops.
So I grabbed the ECU out of my '92 parts XJ, and everything worked fine off the bat. After a few trips it threw a trouble code for 'ballast resistor relay circuit open/shorted', not surprising because I don't have a ballast resistor, as they were eliminated prior to '94.
Lately it's been doing this weird thing where if I turn the key on, it'll run the aux fan immediately, regardless of the engine temp or A/C switch position. If that fan is running, it won't give power to the fuel pump or ignition coil. It's almost as if the auto-shutdown relay has been tripped due to engine temps being too high, except I checked the shutdown relay and the temp sender at the front of the block, and both are OK.
If I cyle the key on and off enough times it eventually stops turning the fan on, and when that happens, it'll fire up with no problem. Almost like the temperature is back in operating range, as described above. While this is a decent temporary solution I'd rather not rely on this to get going again in the middle of a trail.
I doubt it makes a difference, but my '94 ECU was for a 5-speed, and the '92 came from an automatic. The fact that it's currently a 4.6L stroker shouldn't matter either as I used all '94 sensors and wiring on it.
As much as I've done to this thing (see sig), I've been very fortunate in that the few OEM parts left have been pretty trouble-free, so I don't have a lot of experience tracking down engine and electrical gremlins. :dunce: Anyone ever come across this particular issue before?
So I grabbed the ECU out of my '92 parts XJ, and everything worked fine off the bat. After a few trips it threw a trouble code for 'ballast resistor relay circuit open/shorted', not surprising because I don't have a ballast resistor, as they were eliminated prior to '94.
Lately it's been doing this weird thing where if I turn the key on, it'll run the aux fan immediately, regardless of the engine temp or A/C switch position. If that fan is running, it won't give power to the fuel pump or ignition coil. It's almost as if the auto-shutdown relay has been tripped due to engine temps being too high, except I checked the shutdown relay and the temp sender at the front of the block, and both are OK.
If I cyle the key on and off enough times it eventually stops turning the fan on, and when that happens, it'll fire up with no problem. Almost like the temperature is back in operating range, as described above. While this is a decent temporary solution I'd rather not rely on this to get going again in the middle of a trail.
I doubt it makes a difference, but my '94 ECU was for a 5-speed, and the '92 came from an automatic. The fact that it's currently a 4.6L stroker shouldn't matter either as I used all '94 sensors and wiring on it.
As much as I've done to this thing (see sig), I've been very fortunate in that the few OEM parts left have been pretty trouble-free, so I don't have a lot of experience tracking down engine and electrical gremlins. :dunce: Anyone ever come across this particular issue before?