After Car sat for 8 months. Now Idle is around 1800 rpm now.

[robplus4]

After Car sat for 8 months. Idle is around 1800 rpm now.

I think the gas went bad so I, Drop the tank and drain it and flush the system.
Before the idle was 850-900 rpm. When the car is cold, it idles around 1000rpm.When it warms up the idle moves up around 1700-1800 rpm. I unplug the idle speed regulator, the rpm drops down to 1200. With the rpm?s being that high, the ignition vacuum advance control is kicking in. If I pull the hose off the distributor, the idle drops to 850.
The car runs fine, except the idle.
Any ideas ?

Thank you

[Bitsyncmaster]

Are you running my idle ECU without the idle switch? The idle switch would turn on the advance solenoid and cut off advance.

[robplus4]

Are you running my idle ECU without the idle switch? The idle switch would turn on the advance solenoid and cut off advance.

Idle ECU is stock and I am running all stock switches.

[Bitsyncmaster]

Idle ECU is stock and I am running all stock switches.

Make sure both connections on the advance solenoid are connected. The idle switch provides the ground and the green wire should have 12 volts. When powered it should cut off the vacuum advance.

[robplus4]

Sounds good,
Should check for 12 volts running or not running, hot? will there be power when it's cold?

Thank you for help,
Your advice has help me in the past.

[Rich]

I'm with Dave on this.

Simplest test of that part of the idle system is done with the car in a quiet place.

With ignition ON, engine OFF slowly open the throttle a bit by hand, then slowly let it close again. You should hear the distributor vac advance solenoid behind at the center-rear of the engine bay click once when throttle first opens and then click again as throttle approaches idle position.


Make sure both connections on the advance solenoid are connected. The idle switch provides the ground and the green wire should have 12 volts. When powered it should cut off the vacuum advance.

[robplus4]

I open the throttle by hand. I heard the distributor vac advance solenoid click then click when i released the throttle. So sounds like the mico switch is working.

[robplus4]

One more thing.
Does it matter which side has the 12 volts on the distributor vac advance solenoid? Because the plug can go on both ways.

Thank you,

[Bitsyncmaster]

One more thing.
Does it matter which side has the 12 volts on the distributor vac advance solenoid? Because the plug can go on both ways.

Thank you,

Does not matter. Either way works. If you heard it click you may have a hose on it wrong. Your original post said pulling the advance hose brought your idle down so somehow it's getting vacuum advance

[robplus4]

When the distributor vac advance solenoid actuate does that make the advance have full vacuum?

[Bitsyncmaster]

When the distributor vac advance solenoid actuate does that make the advance have full vacuum?

No. When solenoid is powered, it turns off vacuum and bleeds any vacuum that was going to the distributor. If that electrical connector gets knocked off, you get full vacuum at idle. If your hoses got swapped on the solenoid it won't bleed off that vacuum.

[robplus4]

Just what out to the car to check the micro switch that go's to the ignition vacuum advice solenoid. I adjusted the screw out so it would engage later. but the idle still too high, causing ignition vacuum advice solenoid to engage.
With car warmed up, I pull the idle speed regulator plug, the idle drops to 850. I pulled the idle speed regulator and it moving freely inside.
Any ideas?
Thank you

[Bitsyncmaster]

Just what out to the car to check the micro switch that go's to the ignition vacuum advice solenoid. I adjusted the screw out so it would engage later. but the idle still too high, causing ignition vacuum advice solenoid to engage.
With car warmed up, I pull the idle speed regulator plug, the idle drops to 850. I pulled the idle speed regulator and it moving freely inside.
Any ideas?
Thank you

Adjusting the screw out will make you get advance at idle. You want to be sure the switch is pressed in (on) at idle.

Pulling the idle motor connector really is not a good test. The idle motor swings back and forth at 60 HZ. So you may pull it when it's open or may pull it when it's closed.

[robplus4]

So, How do I test it?
Thank

[Bitsyncmaster]

So, How do I test it?
Thank

Get it to not have vacuum advance at idle is number 1

Then report your idle RPM cold and RPM hot. Then we can get you testing to trouble shoot the problem.

[robplus4]

Cold 1100 rpm everything hooked up
Hot 1600 rpm.
Can't get idle low enough for the advice not to kick in.
unplug idle speed regulator, idle drops to 1000.
Messed micro, backed off throttle nut and made sure that ignition vacuum advice solenoid micro switch is engaged at idle. open throttle about 1/8

[Bitsyncmaster]

Cold 1100 rpm everything hooked up
Hot 1600 rpm.
Can't get idle low enough for the advice not to kick in.
unplug idle speed regulator, idle drops to 1000.
Messed micro, backed off throttle nut and made sure that ignition vacuum advice solenoid micro switch is engaged at idle. open throttle about 1/8

Have you tried backing out the curb idle screw? The is the screw below the idle switch screw. It may just be your throttle is holding open to much.

[dn010]

One thing that happened to me and worth checking - one of the wires for the idle speed motor broke at the connector. I couldn't see it because of the rubber boot that goes over the wires to the connector. Once that was fixed, the correct idle speed was restored.

[robplus4]

Good Morning,
I backed out the curb idle screw on the throttle where it's not touching. It's all the way closed.

[Timeless]

One thing that happened to me and worth checking - one of the wires for the idle speed motor broke at the connector. I couldn't see it because of the rubber boot that goes over the wires to the connector. Once that was fixed, the correct idle speed was restored.
+2 happened to me when I was K-Jet. Good new is a replacement is available.

https://www.napaonline.com/en/p/CRB218545

[Bitsyncmaster]

Good Morning,
I backed out the curb idle screw on the throttle where it's not touching. It's all the way closed.

Now you may have to back out the idle switch screw a little if it's holding it open. But make sure the idle switch still closes at idle

Then post your RPM cold and hot. If it's still high we will give you more things to try to track down the problem.

[robplus4]

when screw on micro switch is pushing down on it, is that open or close.
At idle the micro switch is pushing down.

[robplus4]

Same - Cold 1100 rpm
Hot 1600 rpm.

[Bitsyncmaster]

Same - Cold 1100 rpm
Hot 1600 rpm.

Is your idle motor buzzing? You can feel it vibrating and you don't need the engine running, just the key on.

[robplus4]

Yes, it is.

[Bitsyncmaster]

Yes, it is.

Since you said it was running good 8 months ago and your sure the throttle is fully closed, I would check your deceleration valve springs to see if you have the ones that go bad. To check them you need to pull the "W" pipe. Then you can see them when you open the throttle. The bad springs will not have even spacing.

A large vacuum leak can also cause increased idle RPM.

[robplus4]

71996

[Bitsyncmaster]

71996

One looks bad. Never saw them white color. Here are mine that caused my high idle RPM on a hot engine.

[robplus4]

I think the car is running lean. I think that's why it look white.
Back to the spring. Do you know where I can get replacement springs or a throttle body.
Do you think this causing the high idle?

[dn010]

I would suggest sealing the valves closed with hot glue.

[Bitsyncmaster]

I think the car is running lean. I think that's why it look white.
Back to the spring. Do you know where I can get replacement springs or a throttle body.
Do you think this causing the high idle?

I would say it is causing some high idle issues. I know one owner where the springs were so loose you could touch them and they could open. They are calibrated to open above the normal idle vacuum. Look for a used body. They don't show up often but maybe asking here some EFI owners may sell you one.

What my car did with the springs I showed was idle correct RPM cold but when hot it ran at 1000 RPM.

You can test if this is all your problem by some clever testing. Maybe can force some shims into the springs to get them to apply more pressure. Or as others have suggested to hot glue the holes closed. Those would just be for testing.

I tried running the car with no springs and holes sealed. It does affect your idle deceleration. I did not like it that way but if you can't find a replacement soon that could work.

[robplus4]

do you know how much tension the springs are suppose have. I can depress them with my finger pretty easy.
I can replace the spring, but I need to know how much tension.
Thanks for info

[robplus4]

How does the car act when you plug the holes on the plate? I do have a 5-speed.
I have been told it makes a difference if you have a 5-speed.

[Bitsyncmaster]

How does the car act when you plug the holes on the plate? I do have a 5-speed.
I have been told it makes a difference if you have a 5-speed.

From what I remember the RPM would drop below the 775 RPM sometimes.

You would need someone to test the spring rate on a good unit. Probably with a scale pressing on the spring.

[robplus4]

7200072001

Can you tell me where to find the throttle body part number or any of the parts in the throttle body.
Thank you

[Bitsyncmaster]

7200072001

Can you tell me where to find the throttle body part number or any of the parts in the throttle body.
Thank you

My old one has 74 01 269 402 cast into it.

Below that is FAMS 1 also cast into it,

[robplus4]

Do you know of anybody that has replaced the springs or run with them plugged up?
Not having any luck with finding a throttle body.
Thank you

[Bitsyncmaster]

Since you have the plates removed, why don't you just put a screw with some washers and o-rings to seal up the holes. That is what I did to run the engine when I had bad springs.