Topic: Idle Controller keeps going bad

[tgalatis]

Hi all:
I'm new to this forum, so please excuse my ignorance.  I did a topic search, but did not see anything on my question.  I have a 1987 YJ with a 2.5L 4cyl with TBI.  The idle controller keeps failing.  I'm on my third one in as many months.  Does anyone have any idea what could cause it to go bad so quickly?  I was thinking computer, but I replaced that earlier this year.  The YJ sits most of the time, and is only used on weekends at hunt camp, where it stays.  I have a quick disconnect on the negative pole on my battery which I disconnect while YJ sits in between weekends.  Sometimes it sits for several weeks in a row, but I use it at least once a month.  It will start in the morning, but will not start after it warms up.
Thanks,
Ted

[sharpxmen]

seen this before on another type of vehicle (a FIAT), was a TBI as well - what was happening was that the blowby was so much that it would cover the idle valve pin which would seize due to that, the controller which was builtin on a board on the valve motor was getting damaged by trying to move the seized pin. Not sure if this is your case but you might want to have a look and see if the pin or stepper motor is not seizing in any way. Hope this helps.

[tgalatis]

Thank you for your quick response.  I have been spraying carb cleaner regularily, so as not to allow any buildup of crud around the TBI and the idle controller - so that does not seem to be the problem.  I have a feeling it is an electrical problem judging by the worn look of the wiring harness in and around the TBI

[sharpxmen]

it's a stepper motor in there, i'm not sure where the driver is for the Jeep TBI, could be on the same housing - the only thing that i can think of is if the components would overheat and fail and that could occur if (like i said before) the driver keeps the motor activated b/c is not moving, or might be if you have a bad ground somehow on that driver circuit so you could be onto something there. I would take it our and just put the contact on to see how it moves around too, you might find it that is continuously activated and that can be the problem (not sure what the cause would be though)