hi Bruce,

I had a similar idle problem with my van as yours. A rebuilt ICU didn't
solve the problem... The problem was solved after I replaced the rubber
seal behind the throttle body and replaced the Temp2 sensor... I don't know
which one solved the problem, but I know a small leak the throttle body
seal can cause erratic idle and "lazy" slow to react Temp2 sensor can
cause erratic idle too.

I hope this helps.

On Sat, Sep 26, 2020 at 4:34 PM Bruce Todd <beeceetee@gmail.com> wrote:

> Good day everyone -
>
> I am curious to know whether other stock vanagons typically - when started,
> spike very briefly to about 2000 rpm for several milliseconds and then drop
> to about 950?  Eventually as the vehicle warms the idle drops a little bit
> more to about 900 rpm for regular operation.
>
> That has always been the way my van (2.1 digifant) has started when
> healthy.  I replaced the control unit about 2 years ago after having a
> fluctuating idle that would slowly begin to increase to 1800 to 2500 to
> 3000 rpm as the van warmed up and when the van was in neutral or stopped
> with the clutch in.
>
> During this issue - I swapped out the ICU with one I borrowed from a
> mechanic I have known for many years and everything went back to normal and
> so I ordered a new ICU and haven't looked back.  Again the start up process
> whether with the borrowed or the new ICU had the very quick spike in rpm
> once started - enough to kick the battery / alternator indicator off and
> then would settle down to about 900 rpm or so.
>
> Last week - I started the van and the idle was flat - no quick spike and
> just set high enough not to stall - about 850 rpm or so.  I had to nurse
> the motor a little with the throttle for about a minute and then give it a
> little gas to shut off the battery indicator.
>
> Once I get through the rough idle on start up - it drives fine.  The idle
> stabilizer vibrates with key on and prior to start up and the throttle body
> "clicks" in the low throttle and higher throttle position.  I plan to go
> back and try out another ICU - but before doing this I wanted to know if
> this sounds like a problem with the ICU or whether it could be another
> gremlin lurking in the engine compartment.
>
> Other than this little issue - we have a great summer of camping and
> problem free driving.
>
> Bruce
>
> 86 Syncro Westy
>