TheSamba.com :: View topic

Sat Jun 21, 2025 2:00 pm

Recently bought a 1987 2.1 Vanagon. Was trying to figure out the throttle body but does not appear to be a standard type (see pic 1). I think it’s a bit wider than most and does not have any place for a throttle position switch. It does have what looks like a fuel emissions line that goes from the throttle body (pic 2) towards the vacuum purge valve in the rear passenger wheel well (pic 3; which then connects to charcoal canister). The throttle body line is not actually connected to anything at the moment, is just hanging, though looks like it should be connected to the purge valve. I also see that my Intake Control Valve has another emissions line (pic 4) that goes to this same purge valve and is connected on the top side of it. Questions:

1. Anyone familiar with this kind of throttle body? Wondering if I should keep it or swap for more standard type.

2. Does it make sense for TB emission line to connect to purge valve?

3. I have not seen other Intake control valves connect to the purge valve, does it make sense in this case?

Just trying to understand this system.

Thanks in advance!

Sat Jun 21, 2025 3:08 pm

ijergas wrote: 1. Anyone familiar with this kind of throttle body? Wondering if I should keep it or swap for more standard type.

...[it] does not have any place for a throttle position switch.

Never seen that before. If the van is still running the original Digifant injection system, the ECU (it's my understanding) needs the throttle position switch inputs.

ijergas wrote: 2. Does it make sense for TB emission line to connect to purge valve?

3. I have not seen other Intake control valves connect to the purge valve, does it make sense in this case?

Yes. The stock throttle body has the same connection, albeit the original vacuum tube was purple.

The Digifant idle control valve does indeed have a vacuum tube (white) going to the same "vacuum vent valve". Factory diagram:

fewil wrote:

Sat Jun 21, 2025 10:35 pm

Thanks Kamz for that diagram. Very helpful! BTW, where did you find that diagram?

Sat Jun 21, 2025 10:40 pm

this throttle body could be of tencents early models maybe around 2008. I know
he was developing a throttle body machined from billet aluminum back then.

Phil

Sun Jun 22, 2025 12:54 am

ijergas wrote: Thanks Kamz for that diagram. Very helpful! BTW, where did you find that diagram?

It's a sticker on the electrical junction box in the engine bay, often gone...

Sun Jun 22, 2025 9:05 pm

Thanks for the tips everyone! I will try to contact tencent.

Sun Jun 22, 2025 9:23 pm

You may not be able to pass the equipment part of the evil smog inspection with that setup. Those bastards once failed me for a perfectly functional non stock hose from the intake to the idle valve. They made me buy the factory hose.

Good luck, keep,us all informed on how this works out.