Car is a 1992 Loyale, e82 5 speed.The tech would not allow the car to pass CA smog because the idle was 850 rpm.  I checked all hoses for vacuum leaks- all good.  I tried the air bleed screw on the side of the TB and it made some difference but in the end I backed out the throttle stop screw.  Now it idles nicely at 700 rpm, but as the car warms up, I get an intermittent CEL that flashes randomly. Once the car is hot it stays off.  Any ideas ?

Probably because that's not the proper way to adjust idle, have you removed and cleaned the IACV?

But what is the code for?

Edited October 10, 201312 yr by 987687

I hear you.  I haven't removed the IACV yet.  If the symptom persists today, I'll put the throttle stop screw back to where it was and see how it reacts.

I need to study up on how to retrieve codes too. 

Never addjust hard stop tells ecu that you have ft on gas when you do not will lose idle contact switch if mess with hard stop idle is addjusted by screw behind idle motor from side of TB

Putting the idle stop back to where it was should put me back to where I started though right?  Can the idle switch on the other side of the TB get damaged by backing out the stop screw?

Spec for idle on that car is 700 rpm +/- 100 ......so, that means 800 should still be acceptable.

 

The inspector is being a picky jerk if he's saying 850 is too high.

 

I would check all the vac hoses and replace any stiff/cracked ones.  A tiny vac leak can cause a bit of high idle.

I agree about the smog guy. I think they have some latitude for the spec.  It was my wife who took the car there, and the first time the timing was at 23 degrees BTDC, so I set that back to about 20, so at least that is now right. He called foul on the idle at the re-test.

 

The reason I backed out the throttle stop screw was because even with the idle air screw all the way in (gently seated) the idle was over 800.  I then backed that stop screw out and when the engine was hot, and had a very stable 700 rpm idle.  I thought I was set.

 

This morning the car started, but did not have the cold engine high idle, and was balky.  I would up putting the stop screw back to where it was and I think the cold idle function is back, but so is the generally high idle when hot.

 

I found another TB at the wrecking yard today and also pulled all the little solenoids etc.  This weekend, I'll remove my TB and pull off the IACV to clean it.  I'll have an extra one now too to compare against.  I'm hoping I'll find a base gasket leak causing a vacuum leak, or that the IACV is hanging up or something.  The car consistently idles at about 1,000 rpm when first coming to  stop, then within 15 seconds, it slowly goes down to 850 or so.

The TB has a o-ring type gasket. You would be better off removing the alternator to get at the IACV

Just curious, where is it you are located that has such strict inspection? I set my carbd gl to idle at 1k. 800 seems low to me let alone 700. The automatic loyale idles at about 900 in neutral. So strict!

Oakland California.  But I have never seen this before.  My wife too the car in so I haven't met the guy.  I have an older smog printout for the same car (different shop) that passed it with an idle of 1025 rpm.  I'll clean the IACV and adjust the throttle sensor and see where it sits then.

In the end I pulled the throttle body, and adjusted the throttle stop so that after the screw just starts to move the butterfly,then I turned it in 3/4 turn more.  Then I adjusted the TPS to the book using feeler gauges.  The switch now has continuity when the throttle is closed, but opens at about 0.028".  I cleaned the IACV, put a new base gasket on the throttle body, replaced the fuel filter and replaced all questionable vacuum lines.  The Idle air bypass screw is about 2 1/2 turns out from seated.  The coolant temp sensor was also intermittent when I tried to ohm it, so I got one off an '89 in the wrecking yard, (along with the throttle body for good measure) 

 

The idle is now about 700 +/- 50 rpm.  I do hear an irregular phtt phtt phtt from the exhaust, so I replaced plugs, wires, cap and rotor.  The car runs really well except for the slight miss at idle that sounds like a lean idle condition on a carbed motor.  Any ideas on this?  I think I'm getting close!  No CEL at the moment...

Edited October 21, 201312 yr by yblocker