Searched my rear off, but.... According to my 85 shop manual, this little rascal kicks up RPM when the A/C is turned on.

JamesC

 

I don't know the p/n, but these guys have a lot of q-jet stuff http://www.carburetion.com/quadrajet.asp . It's not shown, but you can give them a call.

 

Try a 17068272.

 

Hey, lotec,

The above p/n is showing as an idle stop solenoid from Napa and CarQuest.

JamesC

 

They might call it something else, but there is only one idle speed motor/ throttle kicker/idle speed solenoid/whatever you want to call it that bumps the idle up on a CC Q-jet. It's mounted on the drivers side in front of the carb. I would get one and take a look at it, compare it to your old one.

 

Actually I did. I mounted the so-called idle stop solenoid (which certainly looked like the OEM part), but it isn't the correct one, is defective, or I fouled the adjustment because I can't get it to kick the RPM's up with the A/C on.

JamesC

 

Did you verify the wire is getting juice with A/C on?
If so, does the solenoid move at all when A/C is turned on (might need an extra helper for this)?
I believe that the solenoid can be adjusted in or out to fine tune the RPM increase.

 

Yes, to juice.
I've made several adjustments, but they appear to have no effect--which would certainly be the case if the plunger doesn't move. Guess I'd better give it a look.

JamesC

 

There is power to the solenoid when the key is on, whether the A/C is on or not. Is a manual tranny supposed to have an A/C kick up?

JamesC

 

Yes a manual trans has the solenoid.

No the solenoid, even in a brand new car, does/did not have enough power to "kick" the idle up when the AC is turned on. It has enough guts to hold it up, but not to raise it.

The solenoid is also controlled by the ECM, such that if the TPS is at idle and the engine speed is above about 1400 RPM, the solenoid will hold the idle up. This prevents the throttles from slamming closed while shifting or when the gas pedal is otherwise suddenly released, which produces a large blast of HCs and other emissions. It makes the idle come down "gently". At least, a manual car (mine) does this; I'm not sure about auto ECM programming.

 

Humm, well, if I adjust the curb idle speed (little spring-loaded screw near the throttle lever) to 700, then with the AC on, adjust the solenoid to, say 800, and then turn the AC off, the curb idle speed increases. Blipping the throttle doesn't seem to affect the results.

JamesC

 

I think this is part of your problem. Should not have power with the A/C off. Does the solenoid move when you disconnect/reconnect the wire?

 

Again, I don't know for sure how the auto cars do that; but, on some older cars, that thing was actually an "anti-dieseling" solenoid, and had nothing to do with the AC at all.

If however your ECM and AC are supposed to have control over it, and it has power all the time, then most likely the driver for it in the ECM is smoked.

 

Should it actually be an anti-d solenoid, should the curb idle be set with it? If so, then I assume the screw normally used to set curb idle becomes useless?

JamesC

 

If it's that, then you set curb idle with the solenoid pluger; and you set the idle to something like 450 RPM with the screw, with teh solenoid unplugged.

 

JamesC, this should help:

 

and this

 

RB was right about the increase in RPM during decel. These are all from my 84 manual, but should be the same for your 85. Quote from the manual:

"The idle speed solenoid is a bracket-attached to the carburetor and is a two position electrically operated control used to maintain the idle speed as determined by the A/C being "ON" or increased idle during decel. In the de-energized position, the plunger is retracted and throttle plate is closed to a curb idle position. In this position, an idle speed screw determines idle speed. When the solenoid is energized, the plunger extends and contacts the caburetor throttle plate lever to increase idle speed. If the A/C is turned "ON", the solenoid is energized and idle speed is manintaind to compensate for the increased load of the A/C compressor.
The idle speed solenoid is controlled by a relay which is controlled by the ECM. When the vehicle is started, the relay is energized through ground at terminal "E" of the ECM. The solenoid is de-energized unless the A/C compressor is "ON". During decel at approx. 40 mph to 35 mph, the relay de-energizes and the solenoid energizes regardless if the A/C compressor is on or off. This application is on non A/C vehicles. Because the solenoid is energized, there will be a slightly higher decel idle speed until speed is below approx. 35 mph."

Hope all of this helps. I have a wiring diagram if you need that also.

 

Many thanks Lo-tec! I'm getting closer to finding an answer.

[QUOTE If however your ECM and AC are supposed to have control over it, and it has power all the time, then most likely the driver for it in the ECM is smoked. [/B][/QUOTE]

If I read Lo-tec's info correctly (and I many not), I assume this means replacing the ECM?

JamesC

 

You're welcome.

Use the flow chart to figure out if it's a:

-cut or open wire
-bad relay
-bad solenoid
-bad ecm

PM if you want a color copy of the wiring diagram. I can email it to you.

 

JamesC

 

Is the "fast idle relay" the same as the choke heater relay? I'm wondering if the idle stop solenoid, choke fuse and choke heater relay are somehow related: I caused a short when messing with the idle stop connector, which popped the choke fuse.

Also, where is the "Ground Diagnostic test term"?

JamesC

 

Don't know. They may share the same ign power source to the relay.

Ground diagnostic test term...I'm assuming the ALDL, but don't take my word for it. Manuals at home and I'm at work. Maybe someone else will chime in.

 

Well, I found the fast idle solenoid relay (GM 14078915). I'll throw that part at it and see what happens.

JamesC