Ive recently installed a re-man cc q-jet on my LG4 and have it set up properly (tps at 0.48, dwell at 30 etc) and the electric idle solenoid that opens the throttle slightly when the a/c is on is acting crazy. it keeps the idle speed at 2000 rpm permantly, regardless of weather the a/c is on or not. the day before i put the new carb on it worked fine like it should. but after the new carb was put on is acts like above. I made sure i didn't trap the wires or anything. so i have disconnected it. appart from this the new carb runs great. there seems to be a constant power feed to the solenoid with the engine running, maybe a relay??
I thought maybe the new solenoid is broke, so put the old one on and it does the same. any idea's?

 

Here are the throttle kicker troubleshooting pages from the '84 Firebird service manual. It should be the same as '83. It sounds like it could be a bad throttle kicker relay.

Besides the problem you're having now, the RPM with the solenoid energized is set too high. It should be around 1000 RPM with the A/C compressor clutch plug disconnected. The idle solenoid plunger has a hex head on the end so it can be turned in or out to set the energized RPM speed.

 

Great, just what i need, i'll check it out. thanks

 

Have had the same issue with my 87 LT.

 

Dens71TA - What book is that? I think I need to see the rest of that chapter. I'm not sure what test terminal that chart is talking about. ALDL pins A-B?
I'm a still little confused about how this thing is supposed to work. Everything I had read until the page you posted said that it was just supposed to kick the idle up when the A/C was on. Now this says it will be on ALL the time unless the key is off or over 40 mph? Doesn't that seem strange?

'86 Camaro Berlinetta 305 LG4

 

The pages are from the factory GM '84 Firebird service manual. This page only refers to the operation with A/C. With the A/C turned on the solenoid is energized below 40MPH. The test terminal is the ALDL under the dash, pins A and B.

Normal operation for the solenoid for non A/C cars or with the A/C turned off is for the solenoid to energize between 40-35MPH during decel and then de-energize. This has something to do with exhaust emissions.

 

First off, thank you for your expertise in this matter. It REALLY helps to have someone who knows what they're talking about in your corner.

Here's my issue: I followed the troubleshooting tree exactly and it tells me that the solenoid is operating properly. However, when the engine is running, the plunger is out 100% of the time.

Maybe I missed something?
-I started with engine and a/c off, key on => plunger extended

-I jumper terminals A and B on ALDL with engine off and a/c off key on => plunger retracted

-I turn a/c on => plunger extended

-I turn everything off, remove jumper from ALDL and start engine => plunger extended

-I let it warm up, cycle a/c on and off, put it in drive and the plunger is still extended no matter what.

Ideas?



'86 Camaro Berlinetta 305 LG4

 

It does more than just raise the idle for the A/C.

It is also an emissions control device: it prevents the throttle from slamming closed when you take your foot off the gas and thereby producing a puff of extremely rich exh gas.It's particularly important in stick shift cars.

It's supposed to be adjusted to an idle speed of something like 1300 RPM (not sure the exact # but it's something like that) when engaged. It's supposed to operate such that as long as the throttle is open and the idle speed is above some value (1600 or so), it stays engaged; but then as the idle speed comes down - SLOWLY - toward its setting, it's supposed to drop out.

Back it off until it behaves better. Screw the head of the screw looking thing that hits the throttle lever, inwards, and shoot for something like 1300 RPM.

 

That sounds a bit odd. My emissions sticker under the hood tells me to set idle to 550 rpm with the solenoid disengaged and 650 rpm with it engaged.
(I don't know how accurate my digital Berlinetta dash tach is, but it seems to like the 750-850 rpm range better.)
This is the first I have ever heard of any gradual release on this solenoid. Is it controlled completely by the ECM in this mode? Is there a manual anywhere that mentions this operation?

 

It is completely controlled by the ECM, as well as the A/C. Either system can command it to operate.

I'm quoting the #s from the factory service manual for 83; same system. My memory isn't great - like "they" say, my memory was the 2nd thing I lost as I got older, but I can't remember what the first one was - so I could be a couple hundred RPM off.

No comment on the discrepancy between your emissions sticker and the service manual. It's not impossible that the setting is differnet for auto vs stick cars but I'm too lazy to go find my FSM.

IN any case, experiment with its setting. Iif it is set too high the ECM will think you haven't taken your foot off the gas and/or the idle hasn't come down low enough yet and will hold the solenoid up forever. If it is set too low you may have the problem where you take your foot off the gas suddenly and the car wants to die.

The key here is, the solenoid is the cause of the problem, and you can easily experiment with it to find its "sweet spot", REGARDLESS of what the "spec" is. We call this process, in general, "tuning".

 

Solenoid engagement at idle (with AC off) may also indicate a problem with the TPS. The ECM relies on the TPS voltage to tell it where the throttle is. If this voltage is too high at idle the ECM will not release the solenoid.

It may not engage the solenoid at start up, but only after the ECM sees the MPH threshold met. I can't confirm this in the earlier models though.

You can easily check your TPS voltage by testing the B and C terminals (may have to penetrate the rear of the connector with some thin wire) with key in 'run'. Should be near 0.40-0.50 volts. I don't recall the exact voltage but something as low as 1.5 will engage the solenoid.

Unplugging the TPS is not a valid diagnostic as it will cause a WOT (actually full-rich) signal in the ECM. I don't know how the solenoid would respond in this case.

 

Hey, Dens71TA I'm wondering if you have the "Replacement Check, Chart C-1" mentioned in the bottom most center result, and if so could you upload it? I am having this same problem on my '83 and it tested to the point where I need to check for an opening in my wire from B of the relay to E of the ECM. I will have to test that some other day since it's getting dark here. I can't find this information in my 83 Pontiac Factory Service Manual... If you have that page I would greatly appreciate an upload!

Thanks!