My fluctuating idle is starting to drive me nuts. I've searched and can't seem to find my *exact* problem, though no doubt it's out there somewhere.

My idle bounces from ~750 and then up to ~950 at every stop. The only thing that really stabilizes it is activating the A/C compressor (which'll be extra fun in January).

Anyway, it gets bad enough sometimes where my gauges are starting to fade and needles drop 'cause they aren't getting enough juice.

All this, and I wanna install a 4-channel amp and a sub here in the next year or so. I don't see that happening in its current condition.

I'm running pretty heavily modified, PFC, single turbo, mildly street ported, Optima battery in the back bin, etc.

Any help?

-E

 

p.s. The problem was exacerbated by a radiator replacement install and smog pump removal kit install about a month or two ago. Any connection to the smog pump?

-E

 

Has the car idled that way since the street port? A street port can make the car run rougher at idle just like a cam in a piston engine, because there is less vacuum.

You might need to adjust the idle to something a little higher ... I think you do this on the throttlebody, but that's a question for those with more knowledge than me

kyle

 

See that's the weird thing. It definitely had a rougher idle after the street port, but *nothing* compared to the severity of what it's doing now.

I feel like there's belt slippage or something, but everything looks fine, and I'm afraid to tweak anything if it's just a tuning issue.

-E

 

What kind of stereo mods do you have? One of my friends killed his stock alt because he has a sub and cranked it up too much.

 

I have had the same problem. Good idle with a/c load, terrible withough. Go in the PFC and set your non-load idle to 900rpms. That should clear it up.

 

"I have had the same problem. Good idle with a/c load, terrible withough. Go in the PFC and set your non-load idle to 900rpms. That should clear it up."


Does that mean I just up the idle bounce so that my floor is 900rpms? That'll definitely work. 900 will keep things running fine.

I'll have to give it a shot

 

None. I don't even listen to the radio. My center speaker quality drives me nuts, plus I'm running an open WG, so...what's the point unless you're on a long trip.

 

if you have a PFC then dont worry about throttle body idle adjustment. also you might want to check your grounds. i.e. clean off connections and put on new wire. its better to actually fix the prob than just cover it up IMO.

 

Are you describing a surgeing idle? Where it hunts for a proper idle back and forth about once a second. If so, I would look at your Idle mixture. Look at your O2 volts during Idle. See what they are and if they are. Lean Idle mixture can cause an annoying surge. Good luck.
Jay

 

Also, if it hunts, you may have an intake leak somewhere, mine would hunt over a 500rpm range constantly when my lower intake manifold gasket was cracked/blown, turning on the a/c did settle the idle as it kicked the rpm's up a bit.

You can check for intake leaks by spraying carb cleaner around all the possible locations for leaks while idling...if the car starts choking or revving up when you spray around a certain place, you found the leak.

k

 

Hmm...don't think it's the grounds, but I'll check. I just had everything "re-grounded" and added another large ground after I got it back from RP. I'll check again though. Thanks. And definitely, I want things fixed, not masked. This thing needs to make reliable power without glitches regardless of cost. That's what I bought it for...oh yeah, and for lots o' fun.

 

It may be. When "hunting" does it also move up in rpms? At the moment, it seems more like it can't sustain the idle, it drops off, and then picks back up when it hits a "floor rpm parameter" or something...this would be around 750rpms.

I know my mechanic has played with the mixture already to enrichen things at idle, but I don't know what he did. Need to ask more questions.

I started having a few problems when I disconnected the smog pump (when it was plugged in my DP was a nice orange glow - now it's cool). Now with the pump completely removed and bypassed it feels even worse.

nocab, I'll take a peek with some carb cleaner as well. Since I'm a relative newbie to all of this, where do you suggest I begin looking for leaks?