89 xj -high idle woes,dammit!!

[bcmaxx]

the gremlin has returned, seems to happen when underhood temps are higher. 2500 to 3000 rpm. shut the truck off, restart with tps unplugged, then plug it back in problem solved till it happens again. I have already ran battery ground to the tps grounds. I noticed with key off all four terminals to the iac are ground, key on the 2nd and 4th are ground. Can I run battery ground to the two that are constant ground or not such a good idea?? My next plan of action:
replace the fusible link to the latch relay, run a load from the latch relay to the harness connector on the ecu, and the same for the four wires going from the ecu to the IAC. Anything I'm missing?

 

[bcmaxx]

calling renix experts, high idle back again!!!! starts running at 1100rpm then progresses to 2500rpm, unplug tps to trans and fixed (temporarily), NEW FINDING unplug b+latch relay and idle levels back to normal, plug it back in and high idle,and have tried swapping relays,no change. If I disconnect the battery after it cools off its good for well just about two weeks, any suggestions? the only thing left Is maybe an ecm or tcm ,I dont know if the tcm would be related. It Isn't a ground issue for all I can figure. would it be advisable to jump the wires to and from the b+ latch relay?? I'm almost lost on this one!!!


Only happens once underhood temp is up to operating temps,so I think it may be a connection/wiring harness problem, it it really feasible to run new wires off the ecm to the b+latch relay and the iac? I'm positive its the iac troubling me, getting sick of this!! help!sos!

 

[Muad'Dib]

calling renix experts, high idle back again!!!! starts running at 1100rpm then progresses to 2500rpm, unplug tps to trans and fixed (temporarily), NEW FINDING unplug b+latch relay and idle levels back to normal, plug it back in and high idle,and have tried swapping relays,no change. If I disconnect the battery after it cools off its good for well just about two weeks, any suggestions? the only thing left Is maybe an ecm or tcm ,I dont know if the tcm would be related. It Isn't a ground issue for all I can figure. would it be advisable to jump the wires to and from the b+ latch relay?? I'm almost lost on this one!!!


Only happens once underhood temp is up to operating temps,so I think it may be a connection/wiring harness problem, it it really feasible to run new wires off the ecm to the b+latch relay and the iac? I'm positive its the iac troubling me, getting sick of this!! help!sos!

When is the last time you replaced your o2 sensor??

 

[bcmaxx]

When is the last time you replaced your o2 sensor??

been a little over a year and a new motor 1 month ago

 

[Muad'Dib]

been a little over a year and a new motor 1 month ago

Since this problem happens when the engine is warm, and is effected when you unplug the +b latch relay (are you sure this is the one your unplugging??) then that points me to your 02 sensor. Have you ohmed out the heater element in it? Do you have a known good one that you can test with?

You know, now that i think about it more, i had a similar problem that was solved by replacing ALL of the relays that were on my Jeep with SPDT BOSCH's. That may be one inexpensive thing to try before anything else.

 

[bcmaxx]

Since this problem happens when the engine is warm, and is effected when you unplug the +b latch relay (are you sure this is the one your unplugging??) then that points me to your 02 sensor. Have you ohmed out the heater element in it? Do you have a known good one that you can test with?

You know, now that i think about it more, i had a similar problem that was solved by replacing ALL of the relays that were on my Jeep with SPDT BOSCH's. That may be one inexpensive thing to try before anything else.

I will try and replace them ,I have some known good ones, the b latch is the second from the firewall, no havent tested the 02 but will, I just got my hands on a fsm. thanks

 

[bcmaxx]

Found the problem. feel a little stupid, I went to re-check the grounds at the dipstick bolt, saw three perfectly connected grounds and noticed they were a little taught, I un hooked it pulled back the loom and found a single wire broken about four inches up covered by the loom ,since fixed it and I now have very smooth consistent idle as well as good throttle response and seems like it takes less pedal to do the job.party/celebration time.
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