Date: Mon, 28 Apr 2025 00:05:36 +0000
Reply-To: madvws <madvws@COX.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: madvws <madvws@COX.NET>
Subject: Re: Vanagon Stalls Out While Driving
In-Reply-To: <1924461237.2154114.1745690173223@mail.yahoo.com>
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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
On Saturday, April 26, 2025 at 10:56:35 AM PDT, Markus Benne <mbenne@m-bass.com> wrote:
Ok, following the digifant tests in Bentley 25.61, there are a couple issues so far.
1. Probably minor - tps when fully open, infinite resistance. The other ranges are fine. Would not effect start.
2. Air flow sensor. Different results w and w/out syndrome wire. W/out, resistance moves w the changes in the vanes. With the wire, it doesn't seem to move. Car didn't start w or without it.
3. This may be something. Step 5, injectors. Resistance is infinite between pins 12 and 14. Resistance on a specific injector does fall in the correct range. I'm testing this with ignition off.
Pin 12 is for the injectors, pin 14 is for the digifant control relay.
Maybe one of the relays is flaky. Either the fuel pump relay or the control unit relay since they seem to be intertwined.
I am confused by wiring diagram 97.206 (1990 bus). Do all injectors fire at the same time?
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