My car seems to have 2 different idles. At about 1100 rpm, vacuum reads a very healthy 18-20 in/Hg on my el cheapo Autometer boost/vacuum gauge. My car also has a much lower idle (which seems to occur probably 1/2 of the time),around 400-500 rpm, and when the engine idles this low, vacuum reads at only 11-13 in/Hg.

The car does need to get the vacuum hoses replaced (the last owner replaced most of the hoses that you can see with silicon tubes, but as you all know, the majority of the vacuum hoses are hidden unless you start unbolting engine parts). And I'm guessing that this will likely cure the 2 idles... Anybody know exactly how to cure the 2 idle issue?

Are other folks here seeing the same thing? Lower the idle lower the vacuum readings? Any help would be greatly appreciated.

Thanks!

 

Lower idle will give you lower vacuum readings. At 400-500 rpm (why is it so low?) the vacuum will certainly be around 11-13 inHg. Since you have good vacuum at 1100 rpms (mine is exactly the same as yours, 18-20 inHg @ 1000 rpms, and I just got my hoses re-done two weeks ago), I'd think your hoses are fine. You should ge that idle fixed, though. 1100 is too high and 500 is too low. Do a search on idle problems and see if that helps.

BTW, if you think the hoses need to be re-done b/c they haven't been done and you seven has higher miles on it, it's certainly a good idea if you have the time and/or money to get it done.

 

How do you adjust the idle? I just got my new motor/turbo running and the idle kept surging alot, so I tightened the screw below the throttle body all the way down, and it fixed the surging, but it idles really high now...anywhere from 1400-1800rpm. I would like to get it back down to around 1000-1100 or so.

Is the idle adjustment screw that same one? I saw the fast idle screw on the side of the throttle body and I have it as loose as it can go. I know this is a very simple question, I am just too lazy to look up the answer.

Thanks,
Scott

 

I'm bumping this message up again. I've never been able to solve this "double identity" of my idle (and I've owned the car for over 3 years), although I'll admit I haven't spent much time trying to, as even when the car idles at 400-600 rpm, it's NEVER stalled.

I can provide a little more info though. I've also got the manual fan mod in my car. If I switch the fan on (without turning on anything else electrical like the lights or A/C) the idle drops a bit further either at the low or high idles. But, if I turn on the lights when it's in low idle, the rpms actually rises a little bit and stablizes some (at around 750-800 or so rpm) and the vacuum reads more or less a consistent 16 in/Hg.

Is there a good procedure for adjusting the idle? I've been using the screw on the throttle body which is probably not the best way...

 

have you tested your TPS switch?? that can sometimes give you some idle probs.

 

Where's the TPS switch? The complexity of the 13BEW amazes me. I've owned them for 6 years, yet I've only scratched the surface of knowledge.

A little bit more info. If I let off the gas at 3-6k rpm in first or second gear, I immediately see 22-24 in/Hg of vacuum on the boost gauge.

 

go through and make sure all of the vacuum lines are hooked up. chances are you missed one. it is a very common cause for high idle.