Ok, I need some help with a high idle.

meyervw

The idle is staying at 1050rpm. I checked the Throttle position switch and it checks out per VW specs. I checked the AFM and it checks out. I also sprayed around for intake leaks. The only thing I found was the Temp sensor (to the ECM), and it was out of spec. I replace the sensor for the temp but no change. I am kinda stumped at this.
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Gustav 1987 Wolfsburg Edition

meyervw · Posted: Sat Dec 06, 2008 7:08 pm Post subject:

Oh 1 more thing. Everytime I start the engine it races up to 1900rpm. This does this hot and cold. Everytime.
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Gustav 1987 Wolfsburg Edition

Tristar Eric · Posted: Sat Dec 06, 2008 7:45 pm Post subject:

Unplug your aux air valve / idle stabilizer.
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dcdubs · Posted: Sat Dec 06, 2008 7:52 pm Post subject:

vacc leak or bad idle stabilizer or the infamous vanagon ecu ground connection failure.....that is if you already have all good bosch tune up parts.
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meyervw · Posted: Sat Dec 06, 2008 8:50 pm Post subject:

OK, I unplugged the ICV and nothing happened. Now this should be working all the time right. No matter if the motor is hot or cold right.
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Gustav 1987 Wolfsburg Edition

meyervw · Posted: Sat Dec 06, 2008 9:34 pm Post subject:

Also does anybody have a spare good one the would loan me for testing. I would hate to pay $180 for one to find out it is something else. Although I do suspect the valve I would just like to be 100% on this one.
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Gustav 1987 Wolfsburg Edition

Dogpilot · Posted: Sun Dec 07, 2008 8:32 am Post subject:

The idle is indeed controlled by the Idle Computer. It uses a few inputs to do its job. It gets engine speed from the Hall Sender, Temp II does send it info, etc, etc. It adds air, or subtracts air via the Idle Control Valve. It should be set to a neutral setting by measuring current. Kind of difficult for most of you. So if you disconnect the hall signal to the Idle Computer, it will go to its neutral setting (not really, but close enough). You want to set the minimum air that can enter the system, kind of the floor on the idle. The electronics can only add to this but not subtract more than the amount set by the Big Screw.

You want to set the mechanical idle via the BIG SCREW on the Throttle Body. In for slower and out for faster. Set the idle there, warm at around 850 RPM's. Then see if the system works. If your Throttle Body is worn, then it will not work well either. If your Idle Mixture is not set properly, it will not work well either. There is a relationship between Idle Mixture, Idle Speed and Timing that needs a bit of back and forth, one effects the other a little bit. So adjusting one may effect the other.

This is why you want to get the sensors, wires and such to be their best, then start tweaking stuff. Better be prepared to check and adjust it all. Kind of why I don't recommend fiddling with the AFM.

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Geology with a Syncro rocks!
86 Syncro Westy AKA "The Bughunter"
98 Disco I
08 Range Rover SC
08 VW Rabbit S
1951 O-1G

Dant · Posted: Sun Dec 07, 2008 1:33 pm Post subject:

OK, this may be a good place to post my idle deal? This is the 91 Syncro.

I have searched alot and have read many of the usual Suspect's treatise'seseses. You guys are great! Here are a couple of my favorite searches: (an old one from The Dogpilot Man?)

http://www.thesamba.com/vw/forum/search.php?search..._chars=200

http://www.thesamba.com/vw/forum/viewtopic.php?t=143164&highlight=unplugging+idle+valve

So this is my story and I am sticking to it:

New Boston Engine engine, running good I must say. Just a little over 700 miles on it. So far I have had various idle's (idle's?) but my results have been very consistant now.

I have checked most probable issues, adjusted the throtle switch, fixed some grounds, looked for vacume leaks, checked timing (advance works) etc....

I have swapped the idle valve with one other (and cleaned them out), swapped the idle controller with two others. New temp II and checked resistance and continuity at the ECU. The resistance on the temp II looked like 500 after it had cooled some and went up to 1000 after a while. Seems like it's working.

Anyhow...first start when cold: a little rough but smoothes out, then RPM rises to maybe 3000. Bump throttle and it drops, then goes back up.

So, when it's high, I unplug the idle valve and it drops right down, plug it back in, and it runs PERFECT. So alright, leave it plugged in and adjust idle down with the TB screw. Leaving the ICV plugged in I have to turn it all the way down and the idle won't go lower than maybe 1200 RPM.

My question could be: With the ICV plugged in, it seems like the warm up is working ok, but warm up doesn't seem to go off. When I unplug the ICV, the "warm up" does go off and I can plug it back in and it stays off. Is this valid? The warm up working and not shutting off, but shutting off by unplugging the ICV?

Man, this idle thing seems to be really common, lots of results from searching. Good luck Meyervw! That's it for me for now!
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schoonerman · Posted: Sun Dec 07, 2008 2:31 pm Post subject:

My idle on my 87 Westy has always been 1000rpm and everything is fine.

Dog pilot...is this something which should be adjusted by the big screw or just leave alone, as all seems fine as is???
Thanks

GrindGarage · Posted: Sun Dec 07, 2008 5:34 pm Post subject:

Dogpilot · Posted: Sun Dec 07, 2008 8:18 pm Post subject:

If your running 1000 RPM, it is close enough to leave alone. Other small issues with idle. The Throttle Switch, as it ages, does not always actuate. The other problem can be the Throttle Body, its return spring and the cable. The spring can be weak, the TB needs lube, and the cable can be rusty along its length. The cable can get somewhat rough on either end and fail to return to stop unless a slam full to idle gives it some inertia.

The Throttle cable is cheap and can cause all kinds of different effects, not a bad one to pay attention to on both the pedal end and the TB side, or just put a new one ($18 ) in.

The idle computer, located behind the Passenger taillight, is in a lousy location. As 10¢ suggested, it would most likely live longer if it was right next to the ECU in the warm, dry, van interior. Present wiring does not allow that, but if a replacement loom ever came along, it would be a good mod. The little box does fail and also act up. Why they are so expensive is beyond me.
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Geology with a Syncro rocks!
86 Syncro Westy AKA "The Bughunter"
98 Disco I
08 Range Rover SC
08 VW Rabbit S
1951 O-1G

meyervw · Posted: Mon May 27, 2013 1:30 pm Post subject:

The throttle switch is the failure. Test everything and then came the throttle switch. While I can hear clicking there is a problem inside it. It is original. So I disconnect it and the engine instantly smooths out. Plug it in and it goes crazy. Will order a new one up. Thank you all for the info and help.
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Spelling in my post may or may not be correct.
Gustav 1987 Wolfsburg Edition

meyervw · Posted: Thu May 30, 2013 5:05 pm Post subject:

Also found my temp sensor not even close to spec. The temp sensor pointing towards the drivers side is in spec. However the one that face forward is out. I have 200ohm at 70 deg C. According to the book it should be around 400 ohms. Correct?
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Spelling in my post may or may not be correct.
Gustav 1987 Wolfsburg Edition

randywebb · Posted: Tue Jun 11, 2013 12:14 pm Post subject:

bump for info on Vans with automatic transmissions...

- there is some sort of adjustment at the transmission relay lever on an automatic Vanagon that was mentioned on this bbs, but no details were given...
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1986 2.1L Westy 2wd Auto Trans.

Tobias Duncan · Posted: Tue Jun 11, 2013 3:01 pm Post subject:

Tobias Duncan · Posted: Tue Jun 11, 2013 3:13 pm Post subject:

Unbump, looks like mine is just linkage.

Do I read this thread right? Did it take OP 4.5 years to fix this idle issue????

meyervw · Posted: Fri Oct 04, 2013 8:49 am Post subject:

OK I found the real problem so I am very happy to report back. This drove me nuts for a very long time and as a mechanic it also saddens me that it took this long. The culprit is the two air lines. One is to the throttle body and one goes just under the idle control valve to a diaphragm valve way back by the firewall. The line that went to the ICV was disconnected. I redid the air line from the throttle body and the one to the valve. Problem solved. Idle back to normal due to the air leak and however that valve is controlling the throttle body. Solved.
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Spelling in my post may or may not be correct.
Gustav 1987 Wolfsburg Edition

meyervw · Posted: Fri Oct 04, 2013 8:52 am Post subject:

Also when taking off it had very poor acceleration in all gears but would intermittenly hit and take off normal. Lack of power. All solved.
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Spelling in my post may or may not be correct.
Gustav 1987 Wolfsburg Edition

MtnVan · Posted: Sun Apr 20, 2014 10:06 am Post subject:

Idle probs here too. New owner 87 weekender auto 115k. I've adjusted the tps so I can hear the "clicking" and cleaned out the ICV real good. I still have an erratic idle. My question relating to this thread is the two Vac lines near the ICV. The purple one on mine it attached to the throttle body but is hanging freely behind the firewall. Where does that attach to? Oh, and as of yesterday, a sudden power loss. 10-15 after start (attempting our first overnight camping trip, no less!) a long subtle downhill of 3-4 miles, wet conditions. I noticed a lack of and sporadic power loss. Seemed better when I floored the pedal. Pulled over and it died. Looked around the engine bay for a sec, then started it back up, and to my wife's dismay, turned back for home. It ran a bit rough right as we got going, which seems uncharacteristic of V-Syndrome. My short list is: main grounds, Tps adjusted but faulty, O2 sensor, AFM/Vanagon syndrome, temp II. I'll start going thru those and keep taking drives around town to see if I can replicate the issue. Looks like I'm going to learn how to use this fancy new multimeter I just bought:-) any suggestions?
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'87 Westy Weekender Auto

meyervw · Posted: Sun Apr 20, 2014 11:49 am Post subject:

Behind the wall there is a canister that that line connects to. You can feel it if you reach in there. For random shutting off as mine did it ended up being the air meter.
_________________
Spelling in my post may or may not be correct.
Gustav 1987 Wolfsburg Edition


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