Date:         Thu, 1 May 2025 17:54:08 +0000
Reply-To:     Markus Benne <mbenne@M-BASS.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Markus Benne <mbenne@M-BASS.COM>
Subject:      Re: Vanagon Stalls Out While Driving
Comments: To: madvws <madvws@COX.NET>
In-Reply-To:  <589548904.1282434.1745798736715@mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8

Super info!   Thanks.
So as an update, I found two things very wrong.
1.  While testing the impdence of the temp2 sensor from the cpu plug, I noticed it drifted wildly, even when the plug was bridged.   So a wire issue.   Kludge in place, still didn't start.  This may have been the root cause tho.
2. I found a super YouTube vid that provided a very simple test to confirm many ecu behaviors.   You guys probably know this already, but if you ground out the center pin on the hal sensor plug (1990 bus), the computer thinks the engine is running and will start the fuel pump, send juice to the coil, and fire the injectors.   I'd did that, and all that happened (I had a noid on an injector, and the center distributor wire near ground).  It was beautiful.
So issue was the hal.  Which I may have introduced by opening it up and unplugging the wire to the hal because all the plastic parts were brittle and crumbled.  Put in a new distributor.
It's running now (still have to time it) and time will tell if the stumbling/dying is solved actually.
Thanks for all the support!
 
 
  On Sun, Apr 27, 2025 at 8:35 p.m., madvws<madvws@COX.NET> wrote:   Your confusion is understandable.VW slightly changed the injection wiring over the years but the Bentle yTesting steps don't properly reflect these changes.In the 1990 model year injection harness the injector ohm test between ECU connection pins 12 and 14 is INVALID.If you look at the wiring diagrams for late 86 and 87 you can see that those 2 pins do connect to each side of the injectors in the early Digifant years and the pins12-14 test step procedure is valid for those years.
Yes, all 4 injectors are wired in parallel and all fire at the same time.The hall unit in the distributor feeds pulses to the ECU that trigger each ignition spark and also triggers all of the injectors to fire together for each individual spark.The "extra" injection pulses simply put fuel mist spurts into each of the 4 intake runners and the fuel/air mixture waits in each runner until it gets sucked into the head when the corresponding intake valve opens.
I should warn you that the Bentley 88/89 diagrams are wrong in the FI relay wiring area and the diagram listed in the Bentley as 90 is actually a better match to 88/89 FI wiring.There is no fully correct 90/91 FI wiring diagram in the 80-91 Bentley, sorry.You can find improved wiring FI diagrams through The Samba. PM for a link if you need it.
Mark