High idle after warm up?

[USGSHYDROMAN]

At cold start, idle speed perfect! On warm up idle speed jumps to around 2000 rpms.
checked and adjusted throttle switch.
unplugged O2 sensor and idle stablizer control value connector, engine idle perfect.

Okay, now it idles okay after warm up sometime.
acceleration on starts is very sluggish, sometime. Runs okay once RPMs get going

Where do I need to go from here?

[USGSHYDROMAN]

Problem solved, almost. Found an air leak around the idle stablizer valve and also the ISV was stuck open, sprayed cleaner through it and hit it with 12volts a couple times seem to get it working. Still think there another vac. leak some where, however compared to how it was running before i'm batting a 1000.

[sc1out]

Feels good to get a handle on something like that. Good work!

[USGSHYDROMAN]

I spoke to soon guys. This seem to be an on again off again problem. I checked all the vacuum hoses, tighten all the clamps down. Put it all back together and it cranked up fine, idled at normal level for a couple of minutes then it jumped up to around 2000 rpms. ISV is vibrating as it should be, idle switch checks out ok. Again, when I unplug the ISU and OS it idles at normal levels. I'm running out of things to try here. Temp S. checks out okay but I'm wondering if it may be going haywire when cranked up????? The idle screw on the throttle body is tighten all the way down, no where to go there.
Acceleration from idle is good most of the time, the other time its hesitates. What sensor is used by the idle control system and during acceleration? The only one I can determine is the temperture sensor. Any suggestion would be greatly appreciated!!!!!

On another note, can anyone tell me where I might find a replacement gasket that goes between the thorttle body to intake distributer?

[Bassyaks]

look at the vaccum hose going to the fuel pressure regulator, they offen collapse and won't allow the idle to come down

Good luck
Steve

[USGSHYDROMAN]

I talked to the previous owner, the O2 sensor has never been replaced. The van has 142,000 miles on it. When these sensors fade, do the reading get higher. If thats the case, the ECU would see a low fuel to Oxygen mixture and bump up the amount of fuel being delivered to the injectors. Thus, I get a high idle. During acceleration, the ECU would see a high oxygen level and dump to much fuel, giving me hesitation off the line. I'm thinking out loud here, going to look in the bentley to see how to check the O2 sensor, may just replace it, any suggestion?

_________
1987 westfalia

[hdenter]

You did not post what year you have. If it is an early, pre '86 van, think about installing the later heated O2 sensor if you diced to replace it. The later one has three wires, one for the sensor signal and two for the heating element. The later one gives a more consistant signal because it is less effectied by heat veriations in the engine exhaust. All that is needed is to pull a hot lead and a ground from an available circuit on the ignition. There have been threads on this topic and which circuit to tap into for the heater.

Good Luck!

Hans
_________________
'79 triple white convertible bug
'84 sunroof vanagon
'85 weekender

[USGSHYDROMAN]

Replaced the O2 sensor tonight and now it idles even higher, go figure. Hesitation off the line has been reduced greatly so i think i'm going in the right direction. Only other sensor being used by the ICU is temp. I've checked it at air temp. but not at operating temp. Will these things act up as the temp. rises?
If the CO is not adjusted right, could that cause it to idle high?
Vaccum hose looks good.

Its interesting on start up(cold), seem to idle okay. Goes to high idle when it starts warming up.

[vanjoe]

If you are questioning the temp 2 sensor it is a cheap part just replace it and then you can eliminate it as a problem. Just my 2 cents. You can also get the throttle body to intake gasket from Go Westy. It is good to replace it because the do dry out and don't seal that good when they are old.

[USGSHYDROMAN]

Can someone give me a link to the throttle body to intake gasket from Go Westy. I've looked all over their web site and can not find it
Thanks

[CQ]

Bus Depot Link
http://busdepot.com/details.jsp?partnumber=025133073
Van Cafe
http://www.van-cafe.com/home/van/page_161_137/throttle_body_to_intake_manifold_gasket.html

Cant find the go Westy one tho.
_________________
82 Westy 'Betsy'
72 Bus 'Bertha' -Sold
Learning about 2.0L AFC Everyday.

[USGSHYDROMAN]

Found on Ben's web site a way to check your CO mixture using your O2 sensor. According to this test, my CO mixture was way off. However, once I got it dialed in the engine was still idling high, 2700 rpm. Cut the van off plugged the O2 back in, still idling high. I unplugged the idle stabilizer valve connector, van idles fine. There is now no hestation at the line as well which i believe is due to the proper CO adjustment.
I have read in a couple of places that disconnecting the ISCU will not damage anything. I only unplugged the valve, do I need to pull the ISCU out? What the difference between pulling the ISCU and unplugging the valve? Still going to replace the temp. sensor.

[OldBlueSyncro]