VIN 4519: 14-year "garage find"

[Rich_NYS]

I think I have all vacuum hoses connected with no leaks.

The idle is very high, ~1200-ish IIRC.

Idles a bit rough when cold, around 5000-7000. Once warm, it steadily climbs. I do think the throttle spool needs attention, but I also noticed if I push on the idle speed screw/lever thing (at the microswitch,) I can get the idle to normalize.

I'm wondering if the idle speed is something I should mess with first, or only after clearing a few other items (?)




I also noticed the radiator fans don't come on, so I'll diagnose that asap as well.....I think I have air in the system.

[powerline84]

Those switches go bad fairly often if they are original. I think I sent you mine but it was acting up . I am not sure . The one that goes on the throttle body was newer but the one that is the idle kickdown switch on the throttle spool was origional to my car and I don't think it was working. I believe they are available new though.
Also I had the same issue wirth my car with the fans not coming on. I blead the system at the radiator first then the water pump and it fixed it. That otterstat is sensitive to bubbles. Mckeens new digital otterstat looks pretty cool.

[Rich_NYS]

Those switches go bad fairly often if they are original. I think I sent you mine but it was acting up . I am not sure . The one that goes on the throttle body was newer but the one that is the idle kickdown switch on the throttle spool was origional to my car and I don't think it was working. I believe they are available new though.
Also I had the same issue wirth my car with the fans not coming on. I blead the system at the radiator first then the water pump and it fixed it. That otterstat is sensitive to bubbles. Mckeens new digital otterstat looks pretty cool.

I jumped the otterstat and the fans came on, so I'll bleed the system tonight....I'm pretty sure there's air in there.

[Rich_NYS]

I got the air out, fans are cycling now.

The car runs nice, but I have an idling & cold start issue. I think the microswitch is bad....it doesn't seem to affect the idle when I trip it.

[powerline84]

I noticed when I took mine off that it was sticking and for a while mine was idling high. Makes me wonder if it was the switch to.

[Jonathan]

Check the "Tetris puzzle piece" looking electrical connectors for the full throttle microswitches as well. These are the microswitches that the throttle spool rotates around and pushes into when you press the accelerator pedal all the way to the floor. Manual transmission cars just have the one microswitch ("with flap") and automatics have a second microswitches stacked right on top the first. That microswitch can be sticking as well and cause idling problems. You can disconnect it at the connector while you troubleshoot as you don't need them if only idling.

If you can physically push the end of the throttle spool lever arm in when idling and change the RPM's, then yes, you need to make some kind of small adjustment to either the little peg that pushes into the metal tab end of the idle speed motor microswitch or the peg below that which is the one to stop the whole lever arm from rotating back too far as it comes to rest. The rest position adjustment should be done first and let you have the butterfly valves inside the intake come to rest completely closing off the air (they rotate along with that lever arm and you can see them doing it if you have the "W" pipe off). Then adjust the other peg to engage the idle speed motor microswitch just as the lever arm comes to rest with that first peg.

[Rich_NYS]

Check the "Tetris puzzle piece" looking electrical connectors for the full throttle microswitches as well. These are the microswitches that the throttle spool rotates around and pushes into when you press the accelerator pedal all the way to the floor. Manual transmission cars just have the one microswitch ("with flap") and automatics have a second microswitches stacked right on top the first. That microswitch can be sticking as well and cause idling problems. You can disconnect it at the connector while you troubleshoot as you don't need them if only idling.

If you can physically push the end of the throttle spool lever arm in when idling and change the RPM's, then yes, you need to make some kind of small adjustment to either the little peg that pushes into the metal tab end of the idle speed motor microswitch or the peg below that which is the one to stop the whole lever arm from rotating back too far as it comes to rest. The rest position adjustment should be done first and let you have the butterfly valves inside the intake come to rest completely closing off the air (they rotate along with that lever arm and you can see them doing it if you have the "W" pipe off). Then adjust the other peg to engage the idle speed motor microswitch just as the lever arm comes to rest with that first peg.

Thanks Jonathan,

I noticed there's no change to the idle when I toggle the microswitch while warm...does that indicate a faulty switch, or should I do the same test while cold?

I'm thinking I should just try changing the switch...

[Jonathan]

Thanks Jonathan,

I noticed there's no change to the idle when I toggle the microswitch while warm...does that indicate a faulty switch, or should I do the same test while cold?

I'm thinking I should just try changing the switch...

Are you talking about the idle speed microswitch when you say toggling the microswitch?

If you're talking about the full throttle microswitch, I don't recall what happens when you press on it while the car is sitting there idling. That switch is not affected by what temperature the engine is at. As far as I know. When you floor it and the throttle spool engages that microswitch, it is supposed to "enrich the fuel mixture" i.e. add a little more gas. It should do that whether the engine is warm or cold. If it doesn't change the idle by pressing on it, it might be seized on. So disconnecting the wiring at that Tetris connector would be a good next step. Do it while the engine is running and see if the idle changes from high to something lower when you disconnect it.

[Rich_NYS]

Are you talking about the idle speed microswitch when you say toggling the microswitch?~snip~

Yes, the idle speed microswitch. When I pressed it, it "clicks" but there was no change to the idle. The engine was warm.

[Bitsyncmaster]

Yes, the idle speed microswitch. When I pressed it, it "clicks" but there was no change to the idle. The engine was warm.

As far as I know pressing the idle switch does nothing to the idle ECU or idle motor. It should add the vacuum advance on a warm engine and you should hear or see that change the idle for a moment. Have you verified you get vacuum in the hose going to the advance on a warm engine? Disconnecting the electrical plug on the advance solenoid also should let vacuum get to the advance.