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Fri Apr 19, 2024 9:24 pm

Crank No Start Issue with 1984 Vanagon 1.9: ECU?

Hey all,

Recently acquired a 1984 Vanagon 1.9 and dealing with a crank-no-start issue. When I jumper the fuel pump relay, the van starts up fine. Bench tested the relay, it's good. However, seems the issue lies with the switched ground (pin 20) from the ECU. Checked continuity from pin 86 to pin 20 which is fine, and full voltage on pin 85. Question: Have I overlooked anything or ECU replacement needed? Appreciate any insights or suggestions!

Thanks!

Fri Apr 19, 2024 11:32 pm

Adanj01 wrote: Crank No Start Issue with 1984 Vanagon 1.9: ECU?

Hey all,

Recently acquired a 1984 Vanagon 1.9 and dealing with a crank-no-start issue. When I jumper the fuel pump relay, the van starts up fine. Bench tested the relay, it's good. However, seems the issue lies with the switched ground (pin 20) from the ECU. Checked continuity from pin 86 to pin 20 which is fine, and full voltage on pin 85. Question: Have I overlooked anything or ECU replacement needed? Appreciate any insights or suggestions!

Thanks!

Grounds first, remove and polish your grounds.
These units are finicky with dirty corroded grounds.
Look on the heads, look around the coil mount.

Once these are clean, search for other causes.

Sat Apr 20, 2024 5:48 am

It sounds like you have narrowed it down to the transistor in the ECU that turns on the fuel pump relay.
That transistor can be damaged by someone probing the relay socket wires or using an improper test light on them or jumpering the wrong pins in the socket while trying to bypass the relay.

Borrow a working ECU for a test or put the suspect ECU in a running van for a test.

Mark

Adanj01 wrote: Crank No Start Issue with 1984 Vanagon 1.9: ECU?

Hey all,

Recently acquired a 1984 Vanagon 1.9 and dealing with a crank-no-start issue. When I jumper the fuel pump relay, the van starts up fine. Bench tested the relay, it's good. However, seems the issue lies with the switched ground (pin 20) from the ECU. Checked continuity from pin 86 to pin 20 which is fine, and full voltage on pin 85. Question: Have I overlooked anything or ECU replacement needed? Appreciate any insights or suggestions!

Thanks!

Sat Apr 20, 2024 4:44 pm

I’ve pulled the ecu from the van and I’m just wondering if you know what transitor controls pin 20?