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