Idle cut off switch, boing, boing.

T.Hanson · Post by **T.Hanson** » Wed Aug 12, 2009 9:50 pm

I swear the silly thing is set perfectly. Clicks off, cam at the last bit of travel to close the throttle butterfly.

Still, there is a perceptible feeling in / on the throttle pedal, surging. As if there are rubber bands in the linkage. Rubber in the drive line. Boing, boing accelerating, working the gas pedal.

I'm not one to disconnect things, but pulling the two wires to that switch seems to make it drive more as it should. I believe the switch is working.

What's happening ?

YouTube · Post by **Peter Florance** » Wed Aug 12, 2009 10:10 pm

which ecu do you have in the car?

T.Hanson · Post by **T.Hanson** » Thu Aug 13, 2009 8:59 am

ECU: Electronic control unit. Aluminum box inside passenger fender next to the washer fluid container. Box stock, no reason not to be original, looks like the one in the '79 and two spares. If there is a difference in serial numbers from '79 to '81, that causes trailer hitching, I'm more than happy to discover it.

Otherwise, I believe what came out went back in, it's plugged in correctly and if it did it before it wasn't quite as pronounced. And, the '79 doesn't do it at all, both switches connected. That's why I'm motivated to fix it.

Mike W. · Post by **Mike W.** » Thu Aug 13, 2009 1:01 pm

Check your timing, too much advance can make it run better, but also cause the idle surge you have. If you decide to disconnect it, you only have to pull one wire, not both.

T.Hanson · Post by **T.Hanson** » Thu Aug 13, 2009 1:49 pm

I thought timing was one, two, three, easy. (FAQ) Now, I'm confused or think all you do is twist the distributor until it runs nice.

Retimed, 2000 rpm. Is 2200 less advance ?

Rpm 2000. Turn distributor to center the ball, the RPM changes. I think drops, but the question is: do I adjust RPM back to 2000 ? Leave the distributor alone, or center the ball again ?

Finally, when do we turn the brass throttle body screw to get 800 RPM idle ? Might it be in/out enough to effect throttle response, idle switches, timing.

Thank you for your patience.

alotawatts · Post by **alotawatts** » Thu Aug 13, 2009 3:39 pm

Peter Florance wrote:which ecu do you have in the car?

I think Peter means the glove box brain !
Does it surge with the engine hot and cold ?

T.Hanson · Post by **T.Hanson** » Thu Aug 13, 2009 3:56 pm

I'd like to meet the wizard who decided acronyms were peachy.

The silver box in the GB is the 1 tht's bn thr snce blt.

Now, what am I going to do with the .9 seconds I saved not typing the whole words ?

****

Note: I am irrationally furious at my Karcher pressure washer. Hardly used, always a pain to make run. You want fun ? Try calling customer service. No people, web only. Fifteen forms, demand all personal info. Try a local service center: Bring it in, $80 an hour. Lady says, " Non-commercial ($160 cheap) washers aren't very reliable."

"Is that so ?"

Brian Smith · Post by **Brian Smith** » Thu Aug 13, 2009 6:28 pm

T.Hanson wrote:I'd like to meet the wizard who decided acronyms were peachy.

The silver box in the GB is the 1 tht's bn thr snce blt.

Now, what am I going to do with the .9 seconds I saved not typing the whole words ?

Can you send me the 9 scnds?
I'm spending about 10 times that amount trying to figr out what blt stnds fr!

T.Hanson · Post by **T.Hanson** » Thu Aug 13, 2009 7:50 pm

Built.

I apologize. No offense meant to individuals trying to help, especially those educated and conversant in the acronyms frequently used as shorthand on this board.

AFM, ICU, ECU,...Air Force Mechanics, Intensive Care Unit, Economic Council Underwear. I know, I deserve surging. Probably smoke too.

Mike W. · Post by **Mike W.** » Fri Aug 14, 2009 11:19 pm

T.Hanson wrote: Retimed, 2000 rpm. Is 2200 less advance ?

Yes, the lower the RPM you time it to the more advanced it is.

Rpm 2000. Turn distributor to center the ball, the RPM changes. I think drops, but the question is: do I adjust RPM back to 2000 ? Leave the distributor alone, or center the ball again ?

It all depends, how does it run? Can you run it on regular and do you care if you don't?

Finally, when do we turn the brass throttle body screw to get 800 RPM idle ? Might it be in/out enough to effect throttle response, idle switches, timing.

When you have it timed where you want it. It should not affect the idle switch as it doesn't move the linkage, it just opens an air bypass to allow a change in idle speed. The only time it should affect throttle response is maybe if you have it idling at 400RPM or something like that.

One more thing on your idle surge, I have seen bad (overpressure) fuel pressure regulators cause that. But they very rarely fail.

wkohler · Post by **wkohler** » Sat Aug 15, 2009 6:20 am

T.Hanson wrote: AFM, ICU, ECU,...Air Force Mechanics, Intensive Care Unit, Economic Council Underwear. I know, I deserve surging. Probably smoke too.

That made me chuckle.

YouTube · Post by **Peter Florance** » Sat Aug 15, 2009 1:50 pm

T
Somewhere I have an ECU that I modified to have a higher RPM fuel cutoff point
If I find it, do you want to try it?