Bus starts but turns off right away

[Spike0180]

First thought, from a bit of a newbie, how is your positive battery cable connection? If a bad connection gets too much power through it, it'll cut out sometimes all together from the increased resistance? (something I've seen more than I could explain) This would prevent power to your ignition and therefore your spark. If it is kinda loose or corroded, I'd start by fixing that.

Id also check all the connections off the alternator. Follow the wires and just make sure they aren't corroded or loose and that they match the diagrams.
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Brutis Patches Izabich: 1970 VW Transporter - 1776cc DP
Current State: Projects never truly end...
Location: Grosse Pointe, Michigan
Other cars: 2003 F150, 2003 Jetta GLI vr6-6sp

Sambastic: adj; the quality of being nit picky, elitist, expecting everyone to do things the way they believe is best with no regard to situation, "sambastic"

[kurtwil]

ill check for reverse charge but no spark when I connect anything.

Tomorrow ill check the ground strap on the transmission and go from there.

I have a battery charger right now on the battery charging at 2amp and the bus run great. As soon as I switch it to 10amp the bus die.

Im using a deep cycle crank battery right now in the bus.

ill change the positive cable from the Batt to the Starter tomorrow, it is the original cable still.

I tried removing the batt al together and use the booster cable from my running car and no joy.
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1975 westy

[Wildthings]

Maybe a bad coil or condenser that can't handle the higher voltage, these parts see a much higher voltage than the rated 12v so if you are upping the voltage from say 9 volts to 12 volts they may actually see a voltage jump from 200 volts to 300 volts which could cause internal arcing.

[kurtwil]

[SGKent]

My thoughts on this fall into two paths - the first being a reverse battery or revered charge. The other being that the additional voltage changes the wave form on the electronic ignition just enough that the ECU can't use the baseline form to make injector pulses. It is known that some electronic ignitions do not work with FI.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[kevin77westy]

If it runs without the VR wired up then I would suspect that or the alternator. Easy enough to swap out the VR. If its not the fix then you have a spare. I had a bad one that would make my bus shut down but it took minutes, not seconds. VR got sizzling hot in that short amount of time. Replaced it with a Bosch solid state and was back on the road. Tell us about your alternator. I can't help but think its some weird demon in the charging system.

[kurtwil]

Today I replaced the strap on the transmission (ground) I also redid de ground
terminal on the left side of the plenum and the ground for the double relay.
I changed the coil, distributor cap. had a spare VR so I swap it.

I also removed all fuse S1-S12. removed the fuse for the backing up switch.


I have the alternator disconnect but only the plug. tomorrow I'll disconnect it completely and Ill keep just the essential wire on the starter.

Received the new AFM, definitely runs better but will shut down.


The bus ran for 1 hr today but as soon as I put more current it die.

While it was running I though about checking the timing. I couldn't plug my meter it die right away.
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1975 westy

[SGKent]

do you have the old distributor with points in it? If so try it. Some electronic ignitions will not work well with FI. The reason is that the FI system uses the waveform from the coil to initiate the injector pulse. If that waveform is other than how the ECU was built to work with the ECU fails to read it so the injector pulse goes away.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[kurtwil]

Ok today I Replaced the batt cable going to starter, replaced all terminal on the
wire going to the starter.

Disconnecting all wire and only keeping the essential to run the bus did nothing.

Im suspecting the ECU, Coil, maybe the alternator.

Maybe the bus is not able to run while a battery charger on the batt at 10 amp.
but it should, I can't even boost the bus.

I think what happen is I had the bus in the garage with a trickle charger on the
batt and the key stayed in the on position for a while and fried something..... but what?? double relay? coil? ECU? VR?

It run but only with the alternator disconnected.

I tried to go for a drive but the batt was getting low so it was bucking a bit.

Tomorrow Ill double check the blue wire going to the alt light on the dash.
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1975 westy

[kurtwil]

just to close this thread.

The issue was the Coil and ignition module. put the point back in and the issue disappear.

Its funny that for 10 year the ignition system work, replaced it and the same
snag was there. so I got a bad one from CIP1and the old one got broken from
me letting the key on in the bus all winter with a charger on ( bad move on my part).

Thank for all the help. now the bus can go in the garage all winter and im ready for the spring.
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1975 westy