New stepper motor, now won't idle.

[deadbeat son]

Last night, my 94 RRC started dying at stoplights. After a restart it would idle fine until the next light. After doing a search here, it seemed like the iac valve was the culprit. I figured since the truck has 103k on it, I may as well just replace it as opposed to cleaning it. I bought a new one for a V-6 Chevy Astro as mentioned in other threads. Sure enough the old one was full of carbon and looked pretty rough. After installing the new valve, my truck won't idle at all now. Is there anything I should try before setting the base idle? I'm off to go take it for a quick drive to see if that lines things out...

-JP

 

[deadbeat son]

Okay, so here's what I did. I simply turned the throttle adjustment thumbscrew by about a quarter turn or so and it idles fine now. I took it for a drive before and after the adjustment. Before, it simply wouldn't idle. Afterward, it does fine. Idles at stoplights, idles in and out of gear, etc. Will this cause any issues? The only drawback I can think of is that my throttle is probably partly open now. Will this flood the engine when it's not running?

Thanks,
-JP

 

[eliaschristeas]

. . .i dont know if its easy to flood an engine without a carburator. I wouldn't worry about that, but from what I've also learned, manipulating the base idle can mask other casues for poor idle - thus making those worse over time. . . After I changed to the chevy iac, i serviced the dizzy by putting on a new amp, coil, cap and rotor (i also cleaned out the cavity that contains the pick up and reset the air gap). "Holy Crap!" will most likely be your reaction too once this is done!

 

[luvs2getmuddy]

Check your vacuum connections going to the round ball shaped canister behind the driver side headlight. I had the same problem recently, and that took care of it.
I replaced my IAC months ago and it worked flawlessly. Then one day, it would die at lights but would drive fine when giving it gas. Anyway, long sotry short, one of the two little rubber hoses going to it had developed a crack and popped out. I cut it, and plugged it back in, VOILA!

 

[deadbeat son]

Thanks for the info guys. I didn't think it would be as easy to flood a fuel injected engine as it would a carbureted model, but I wanted to doublecheck. I also thought you were supposed to start fuel injected engines without touching the throttle, and this would effectively be doing that.

Thanks for the advice on the vacuum hose as well. I'll check that out over the weekend when I get a chance.

When I get a chance, I'll check out the distributor as recommended as well.

Thanks again!

-JP

 

[batmac2k]

but.

so my idle jumps up sometimes. and other times it seems to catch itself from dying. could my culprit be the same rubber hose issue. i have replaced some of these before to fix my cruise control. similar issue. anyways. i have been told different things about my idle. but was not sure if this post was relevant since my truck is newer.

'96 D1

 

[luvs2getmuddy]

Sounds like your IAC is starting to go.