Fuel vapour suction noise

[GTVeloce]

Ok, I have been putting the final touches on my GTV TS rebuild and have currently got most of the interior out. When I run the engine I have a loud sucking sound from the fuel relief valve which is currently accessible. As I accelerate the noise diminishes and then returns as manifold vacuum returns.

I am wondering if this is normal and you can't hear it because of the interior (rear seats etc) or I haven't quite set it up sufficiently? I replaced all the hosing from the tank to the plastic tubing and cleaned the relief valve and the canister. The engine side of the plastic tubing connects directly to the manifold.

On the 75 I think there is a charcoal canister and an electronically controlled device that goes between the plastic tubing and the manifold which I do not have. Is this a problem? Anyone know how the electronically controlled device operates?

Thanks
Julian

[LukeC]

I assume that you mean the pressure relief valve on the fuel tank...?

Be careful connecting this line directly to the inlet manifold. As you may have worked out, there is a lot of vacum in the inlet manifold at idle and the fuel tank is not designed to cope with this. Normally, this line is connected to up near the tappet cover and and relies on a very small amount of the vacuum on the induction system to draw the fuel vapour from the charcoal canister.

I am not 100% sure how the electronic valve in the Aussie 75 was controlled... the TS currently in my GTV came out of a vehicle from Hong Kong that had no Cat or emissions equipment, but I suspect it was by the Motronic computer.

With my GTV-TS, I drilled and tapped a port for this line into the oil vapor separator at the front of the plenum. This position will have the same level of vacuum that the original line had.

[GTVeloce]

Thanks Luke. Your words make sense. In the short term I have disconnected and plugged the line. Long term I will try and source the necessary TS parts which I believe are controlled by the motronic computer.

Does anyone have the charcoal canister and the electronically controlled device from a 75 TS they are willing to sell?

Cheers

[four90s]

I can help you out with those.

I'll need to do a little digging to find the box.

Cheers
Steve
Adelaide.