elbeee964

Ran ScanTool v.4 for the first time on my '93 C2. All was pretty normal. But...

Fully warmed up, at idle, both Idle and WOT sensors indicated 'off'.
System adaptation said it couldn't complete its process at this point because either the engine wasn't up to temperature or the Idle sensor was 'off'.

a) Does ScanTool's system adaptation process work?
b) What's the remedy for Idle sensor indicating 'off' when the engine's clearly at idle?

-Lonnie

sundog

There is an idle switch that tells the computer when the throttle is completely closed. Your throttle is probably adjusted so that the switch is not closed, or the switch is not sending the signal.

The system adaptation works very well when that is working.

elbeee964

Bingo.
Just found this thread, checked the switch and there's this hair-trigger toggle point to the throttle mechanism. At this point, fully closed is riiiiight at the microswitch's toggling point.
(Time to search throttle adjustments, it seems...)

But now I find that WOT isn't showing 'on' when I (from the engine bay) manually open the throttle all the way.
(Time to search WOT adjustments, it seems...)

Edit: Correction -- I was pulling on the cruise control cable, I believe. (The one cable most obviously seen after opening up the engine bay?)

[frustrated thought to myself] How can the engine run so nicely when half the indicators are crap-adjusted???

adamfogerty

I don't mean to hijack the thread, but at what point are you meant to perform the adaption via ScanTool?

Immediately after a cold start? Or once you have got the engine up to temperature?

Is there any requirement to go for a spirited drive after the adaption button is pressed?

Thanks in advance,

Adam

elbeee964

Engine at full-op temperature.

Can't tell if you're pulling my leg, here... [visions of laptop bouncing all around the cabin during 'spirited drive'] lol
But, no, the system adapt [SA] isn't assisted/detracted by how you drive afterward. And the SA is done at full-op temp while idling.

elbeee964

...wish I hadn't found this post.


[sigh]
once more, into the breach...

jimq

Thats not really true. The computer is always learning as you drive and changing its settings. I have done it the old fashion way after a battery change and letting it idle for 2 minutes then the ***** out to set it and just starting up and driving off normal. I also tried the scan tool set up and again not a whole lot of difference if any. I cant tell any difference as the car quickly learns on its own. Of course the ***** out way is more fun

elbeee964

I agree w/ jim. All points.

Found satisfaction: Backed off the throttle cable tension (maybe 2-3 turns) and the Idle Switch engages 'On' every time, now. (Also, I found my WOT switch does the same when pedal is 'on the floor'.)

(I just got a ScanTool interface this weekend [thanks Richardo] and I would have been oblivious to this, otherwise...)

Radical difference in "rolling up to stop sign" idling character. No rpm-undershoots or hunting-idles, now... (I've got a LWF, too.)

I've got a theory... Perhaps a number of rpm-undershoot/stalls/hunting-idles are caused by improper set throttle cables: because Idle position microswitches not being activated when going off throttle.

As I said above, my cable tension vs. idle switch was at a hair trigger setting. Sometimes the idle switch would click, sometimes it wouldn't. Release a couple turns of the cable pre-tension nut, and now the idle switch fully clicks every off throttle. (And there's No rpm-hunting at that point, as there had been.)

I could see my throttle cable adjustment nut was knocking off the car's original underside coating of that factory-sprayed wax/cosmoline/shellac/elf snot. That made my eye brow lift -- and not just because it was falling in my eyes... Nobody before had messed with that cable tension set nut.

I haven't yet tried the infamous loaded electrical system at idle scenario... so who knows what will happen then.

So, a question for the Gray Hairs, here:
Idle Switch = Off (while off-throttle) = more sensitive engine management = hunting idles/rpm-undershoots/stalls?

(or is this all old hat and I've just 'rediscovered' a mega-posted issue.)

fly2low

please forgive the hijack. I am new to this section. I have Durametric for my 996TT. Just got (paid for but not yet in garage) a 93 RSA for the track. What is the scantool?

LouZ

Basically, an OBD1 reader. It does most of the needed functions, but not all.

Great for the DIY guy. Search for some ways of making, or buying the interface.