Rough idle fix - how I did it.

[MrPolak]

There are numerous write-ups on curing a lumpy or incorrect idle in a Vanagon. My Westy idled like a small wash machine, ok, not that bad, but you get an idea.

Things I checked:

1. Spark plugs - replaced with my favorite Bosh platinum +4. Runs good, but no difference in idle.
2. Cleaned ALL the grounds when I installed my DJ-code WBX, so that was not the problem.
3. Checked for vacuum leaks by spraying various vacuum lines and intake areas with carb cleaner. I found a tiny leak at the base of the idle control valve. No change after fixing that.
4. Timing was spot-on at 10 BTDC as per DJ-code spec, with a total of 40 degrees advance.

I happen to get a set of fairly new injectors off of another '89. I put them on while my wife was making dinner. It didn't take long since I had the whole assembly with brand new fuel lines and good fuel distributors.

BINGO! She now hums along happily and runs more smoothly too.

BUT... when I tried to set the idle I noticed after plugging the idle control unit the idle went up about 150 rpm. EH? I had a spare ISV laying around. I cleaned it and put it on.

BINGO! The idle now stays put. The write-ups mention the ISV, but the one I replaced moved freely and hummed like it should. The problem was that it bypassed vacuum when fully closed.

So, there you have it. Just one more thing to add to your rough-idle checklist, the injectors.

[MarkWard]

ISV? Idle solenoid valve?
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[floggingmolly]

I think it's Idle Stabilization Valve, because it's something I have to check. But it also reminds me I need to have the injectors cleaned.

Thanks Mr. Polak. What year is your van?
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'85 Wolfsburg Weekender

[MrPolak]

Mine is an '84 with an DJ-code WBX from an '89 Syncro camper. I transplanted the whole enchilada with wiring harness, ECU, cooling system and so on.