For checking grounds it is not sufficient to just check the ring terminals
and screw connections. The wires are now reaching a point that the corrosion
can be so bad at the crimp for the connection to be bad and often the wires
will actually break or disintegrate within the insulation even a few inches
away for the connections. You have to test for stray voltages at the grounds
for each of the sensors. There is also a connection point for grounds within
the FI harness and this can go bad also. The reset indicates an O2 sensor
circuit problem but for it to run normal for up to 8 minutes indicates there
is more going on. Coolant temp at ~120 or above the ECU should be trying to
go closed loop in ~1 minute. How is the O2 sensor reacting when it is
connected? This will tell you something.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Scott - IMAP
Sent: Sunday, August 14, 2016 1:24 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Weird running issue with 86 Vanagon , tried dozens of things

The Presenting Symptom ..
once warmed up ( takes about 8 minutes ) there is almost no throttle
repsonse from idle, but if I shut it off and start it back up ..it's fine
for a few minutes.

I can even turn the key off in gear when  when it does it, and it'll be fine
for a few minutes.

If I'm working on it back by the engine and it does this 'no throttle
repsonse thing' and I just hold wide open throttle .....it runs very rich
and may eventually clear out.
Shutting it off and restarting fixes it every time, until it does it again.

the Subject with this system is ..
86 Vangaon with brand new rebuilt auto trans ..rebuilt by German Transaxle
of Bend , oregon. I don't think the trans has anything to do with it.
it starts and runs cold just fine.
The lopng block  happens to be a 1.9 rebuilt engine with new reground
camshaft and new lifters.
Great compression, no intake leaks, starts nicely, idles just fine , goes
farily well ...just has this one issue....once warm it just won't repsond to
throttle until I turn off ignition and restart.

have done the following ..
tried several ECU's.
ran two different distributors.
tied two different known good Air Flow Meters, with and without adapter
harness.
Checked carefully that throttle switch is making contact at idle and WOT
..tested that clear to the ECU pins in the main harness.
igniton timing is correct.
compression is good. No intake leaks.
installed a new Temp Sensor II.
checked for shorted oxygen sensor wire.
ran with and without oxygens sensor connected.
Don't think it has anything to do with Idle Air Valve or control unit for
it.

I know it's not a clogged or restircted cat as I put a hollow one on for
testing.
Muffler is decent quality brand and new.

I'm about to install and try out  another Main EFI  harness .

  Grounds ..I believe those are all ok as it's a fresh install and I
generally fuss over every little thing I come across that needs attention,
cleaning, tightening etc.

I almost never put anything together without 'something' on every threaded
fastner, electrical connection etc.

so ..other than trying another 2.1 Digifant EFI which I have ..
I am open to suggestions.

thanks !
Scott