kuuva86

I recently changed my variable resistor, cause I had bad idle (or should I say that I had no idle at all) and after the change, I was able to get the idle working... After I got it working, we adjusted the variable resistor and now it does not idle at all... And I know NOW that the variable resistor is NOT ment to be used in adjusting the idle. But somehow it had an effect on the idle.

Now the 87 NA wont idle at all. My variable resistor (or both of them) do not have continuity between terminals A and C or B and C. Is there a remedy for this other than changing it again ?

Is it possible to break your variable resistor that adjusts the idle mixture ?

Pictures and more information on my blog: Project Genesis
Blog is in finnish, but luckily there is google translator

RotaryEvolution

iTrader: (30)

actually the variable resistor IS meant for adjusting the idle, as it adjusts the idle fuel mixture, so if the engine develops vacuum leaks or the AFM gets slightly out of whack the VR can be used to adjust for minor variances to tune the engine. just because it isn't an "idle speed screw" doesn't mean it doesn't have a relatively large impact on idle speed.

yes, it is quite common for gorillas to turn the VR screw too far and break the internal locks and break the VR so that it doesn't work anymore. default iirc will be to the leanest position on the VR if it has no continuity/broken internally.

if you need another i have them for sale. it's also likely someone with a fair bit of time could repair one by cutting out the back seal epoxy and repairing the brushes and stops internally, however i have not tried it because up until now they have been easy to find but if people keep breaking them... i have never managed to break one and i have adjusted a fair amount of them, honestly i have no clue how anyone else unless they're thinking "well it runs best at full rich but the screw stopped, maybe if i turn it a bit harder!". if you feel it stop turning in one direction, there is a reason for it.

kuuva86

Yes, it turns out that the continuity is in the far left (lean) side of the variable resitor. I connected an multi meter to the resistor, turned the screw with the special tool I had (49HC27140) and searched for continuity... And there it was. Multi meter confirmed it. Both of my VR are fine. What a relief !
Thanks Lyger !