Thread: Quadrajet idle control soleniod problem?

Tweet

Sorry if this is in the wrong forum. I just installed with the help of my dad a rebuilt quadrajet for my 85 GMC. Everything is going ok except for the idle. When I crank up the truck without the a/c, the idle is perfect. But, when I turn on the a/c the truck idles down pretty low. If I tap the accelerator just a tad, the truck will idle back up where it needs to be with the a/c on. Now, if I turn the a/c off, the truck revs up a little because of the a/c going off. If I lightly touch the accelerator, then the truck will idle back down to normal again. We finished this up kinda late tonight and my dad mentioned that it could be the idle control soleniod. I was going to buy on and put it on but its about $30 and once I plug it in I can't take it back. Can these things kinda go bad? Or, do they either work or not work? If you need more info, I'll be glad to give it. Thanks in advance for any help.


Kevin

Wire it in so it is only activated with AC compressor on. And yes they either work or the don't. I have one on my 75 Duster and it works great. Once installed you'll have to play with the adjustment to get it where you want it. Also make your throttle return spring is not binding up.

Well, seems like all isn't as well as I thought. I don't know how I managed to drive home from my dads without this happening, but, when I try to crank my truck now, the engine revs up real high! When we first cranked it up at my dads, he was under the hood tinkering with the linkage so I guess this didn't have a chance to happen. But, it seems like from a cold crank now, the engine revs to high heaven. I'm totally lost now. What does this sound like? Where do I start?

Just a guess, but it seems to me that your return spring on the throttle linkage isn't doing its job.

Not doing its job how? Not enough tension to return the linkage? Binding up? It's hooked up right, I've checked that. I don't understand why I didn't catch this before. I drove about 20 miles home, fast slow, stop and go and this didn't happen. Why would this happen only when I first start it up? Thanks for the replies.

Kevin

Street, it is right in front of the linkage, but, it isn't activated by the key (unless mine isn't working). It seems to be activated when I turn on my a/c. It does have a plunger with a hex head on it. You can turn it with a wrench to adjust. It barely touches part of the linkage to idle it up a bit when the a/c pulls the motor down.


My dad hooked up the spring(s). I don't know about the smaller spring. HOnestly, I only saw the big one. I'm gonna go out right now and check it out. Is the smaller one actually inside the big spring or inside as towards the carb? thanks


Kevin

Sorry for my limited knowledge on this subject but here is somemore info. Streets, both springs are hooked up, I just verified that. Its like two springs woven into one. But I'm on to something about my reving up. Forgive me, cause I dont' have a clue as to the names of parts I'm trying to describe. I guess my carb isn't tuned perfectly so when I mash the accelerator to start it, it starts its high rev. I ran around to take a look while it was reving, and the part of the linkage that hits the idle adjustment screw was about 1/4" or so away from hitting the screw. I tried movign the linkage towards the screw and it wouldn't budge. But, this QJ has an electric choke on the passenger side of the carb. Between the choke and the carb body is I guess/think two levers. One is narrow and one is kinda flat with two letters stamped on it AH, or AW something like that. I can push the flat level down adn it releases my linkage on the otherside of my carb so it now rests on the idle screw. Does this make since? When I pushed that lever down, the truck reved as usuall as it did when I left my dads. Its 1:30 here in TX, so I'm calling it night. I don't want to wake the neighbors. Thanks so much for all the help.


Kevin

Thanks Streets, I'm doing what you suggested now.