Volkswagen: VW 1977 Camper Van, mass air flow sensor, vw camper van

Question
Hi there,

I have a mint condition 1977 VW Camper Van with 58,000km on it, fuel injection. It was my uncles and he just handed it down to me. I have recently restored all of the parts and put everything back in. I am fairly good with cars and it looks like everything is where it should be.

When I go to start it, the van will start really well, but the moment I move the switch back to the run position, it will turn off.

I am assuming it is either a electrical or fuel injection problem, but I can't figure it out!?

Any advice is greatly appreciated!

Thanks,

Owen

Answer
Hi Owen --

That is certainly a great year to have a VW Camper!  I'm pretty sure I know where your problem lies -- either on the double relay or at the contact of the intake air sensor. (MASS AIR FLOW BOX -- Looks like a waffle iron on top)

Here is how the system is supposed to run:

1) You turn the key to 'start' and the start function runs the fuel pump until the bus engine starts.

2) Once you release the key, the engine suction pulls open the flap on the mass air flow sensor.  The flap is connected to a sweep contact that turns on the fuel pump when you let go of the key.

The purpose of this is if there was an fuel leak /  accident / fire, the flap on the MAFS closes, cutting the fuel pump off, preventing fuel from continuously spraying everywhere.

The best way to track this down is to remove the air filter, turn the bus to 'on' on push in the flap with a screw driver.  This should activate the fuel pump.

If not, check the contacts on the double relay, check the contacts on the plug for the mass air flow sensor.

In my experience, it is usually the double relay that goes bad.  They are readily available at vintage vw places.  

Let me know how you make out!

Thanks,

Ron