Regulatori

I did some searches and have Adrian's book but I must be overlooking it.

I have a few issues...
-Random CEL at start-up. Sometimes it goes off after a few minutes, sometimes it stays on, then I'll have weeks of no CELs.

-Idles great when cold. Soon as the engine is warm I get hunting idle.

I've cleaned the ISV so I'm guessing it's either my O2 sensor or my idle microswitch.

Tonight I was playing with the switch and get an instant "click" when I press it forward. Here is my question. When I release it when it's forward, should it make an additional "click" before coming to a rest? I only get the single initial "click" when I push it forward. Thanks

Nader Fotouhi

I do not remember for sure, but I think there is only one click to hear. My wife's car displayes the same symptoms of CEL. In her car, it is caused by the accelerator not returning all the way back. The best I can tell, the floor matt is the problem, especially since I have modified the pedal for easier heel and toe at the track.

I adjusted the cable once from the pedal based on instructions I got on RL. Do a search under my name or Garrett376 (he provided the instruction) which helped. However, it has happened again. I am going to remove the matt and carpet and replace it with a board or aluminum.

Regulatori

Yeah, I thought about the floormat but mine have a rear strap/clip in the back that I rigged shorter to make sure it's not close to the pedal cluster.

Still curious about the microswitch click on the release though.

elbeee964

The idle microswitch adjustment was the bane of mine for the first 3 years I owned my car - only I didn't know it.

The throttle cable was set slightly too tight, so the idle microswitch (foot off the accelerator) would sometimes click, sometimes not - only I didn't know that.

Only when I received my Scantool hookup and ran it for the first time did I find the trouble.
As my car sat there idling in the garage, Scantool's output said the Idle switch was 'off', just like the WOT microswitch.
Turned off the car and, sure enough, the idle microswitch was at the hair-trigger point of clicking on & off (as I toyed with it).

So, looked around this forum I found a thread by Jason re this microswitch's adjustment. Saw that there's no way to adjust the microswitch, but that its engagement is 'adjusted' by the throttle's position. Too tight a throttle cable and the microswitch registers this as your foot still being on the pedal. Adjust the cable to have a little more slack and the throttle can finally engage the microswitch - as I did, verified by Scantool.
And my problem was solved. A steady, burbling 830 rpm idle every time, hot or cold.
(WOT reading snaps from 'off' to 'on', as well, per Scantool when I fully depress the accelerator.)

Jason's thread describes the throttle cable's adjustment nut under the car, just ahead of the tranny.

I sometimes wonder how many erratic idles around here are caused by too-tight accelerator cables...
Without Scantool, I'd probably still be ignorantly whining about LWF, the car's age, bad valve adjustment, or some other hex I was living under.

Good luck, sir.

Regulatori

So I did some more searching and different answers.

To give the throttle cable an extra bit of length, do I have to adjust it under the car (near the transmission) or can I simply do it because the gas pedal?

I saw multiple people posting different ways and wasn't sure if one adjustment was the main and the other was a secondary.

elbeee964

Reaching into the accelerator like a circus contortionist, or sliding under a jacked up car?
I'll choose the going-under-the-car method, every time.

I understand the pedal adjust is primary, under car is secondary.
Going the secondary route was good enough for me. YMMV.

Regulatori

I'm a small guy so getting to the throttle cable behind the pedal cluster isn't too bad. I checked it today and found it's not overly tight.

So I tried squirting some WD40 all around the throttle body spring/microswitch see if it's just simply gummed up. After a good squirt it seemed to move easier....and after manually pushing the throttle forward, it now makes the "click" when I move it forward and the click when it comes back/resets.

I got the car warmed up on a test drive and no CEL or idle surge at stoplights...the idle is rock solid.


My car doesn't get the best gas mileage and I always blamed it on FVD chip (installed by previous owner). After I got the microswitch working I noticed my exhaust doesn't smell as rich (no cats)....if the idle microswitch wasn't clicking back after releasing the throttle, could that have an effect on the computer/mixture?

Regulatori

Maybe I didn't ask the right question.

Would an idle microswitch staying open while driving or already opening when starting (initially starting the car) have any effect on the ECU running in closed/open loop? And could that effect fuel economy/making the car run rich?

My idle is perfect right and the revs fall a lot faster after I cleaned the springs around the throttle body. I haven't driven it enough to check mileage but I've always had poor mileage/running rich. I'm thinking it's the 02 sensor but I've noticed the car doesn't seem to stink so much (rich) after fixing my idle microswitch issue. Not sure if the lack of smell is just in my head though.

elbeee964

I'd believe a faulty O2 sensor affecting mileage before ladling out blame to that idle microswitch.

And to be clear, the microswitch is 'On' when the foot is off, and 'Off' when the foot is on.