Thread: Disco 1 charcoal thingy again

Would it be a good thing to do to find out why it seems to be "pressurising"? Blocked cannister springs to mind.


Have never heard my one operate, but I know the valve is free to move & has been lubricated.

You'd hear mine! Screw driver test not required; I think it'd take out your ear drum ... There's a small air intake near the in/out pipes that sucks pretty hard (if that's it's job!) so that seems to be working OK but the funny thing is if I touch the throttle lightly it stops, only to start again when rpm drops to idle.
Go 'Drrrrrrrrrrrrrrrrr' and, ignoring the funny looks you get, that's exactly how it sounds!

Fro the manual it states purging will normally take place at engine speeds ABOVE idle,

The valve gets its signal from the ECM - so you could have a stikky valve or a faulty signal (loose/dirty wiring connection)

The valve, I think is the only moving part - so in my view I would look at that first.

I cannot see you overpressurising the canister, and I wouldn't have thought a blocked canister would give you that problem - but I may be wrong.

I am assuming you have the standard canister and not the advanced evaps system where the 'canister' is generally oblong

Seems I have two problems then:
Valve operating at wrong time/rpm;
Valve operating very loudly.

Point two I can address; at least by removing and cleaning etc. But I can't figure how a poor connection could make the valve fire when it does. Surely it wouldn't go at all or at least intermittently?

And yes, it's the common or garden black cylindrical thingy.

Originally Posted by markyc

Seems I have two problems then:
Valve operating at wrong time/rpm;
Valve operating very loudly.

Point two I can address; at least by removing and cleaning etc. But I can't figure how a poor connection could make the valve fire when it does. Surely it wouldn't go at all or at least intermittently?

And yes, it's the common or garden black cylindrical thingy.

Those are definitely hooked up to the EFI system and are definitely ONLY supposed to open and allow purging/emptying of the canister at engine speeds above idle

My thought was if there was a loose/dirty connection it may be picking up a stray signal that could activate the valve

And if the earth is bad that can also cause this sort of thing

Righto, time to play follow-the-cable. Thanks for the input fellas, I'll let you know what I find!

Marky

According to the manual there are two wires

One white/purple comes/goes to terminal 87 on the fuel pump relay - which apears to be the 12v supply

The other is grey/yellow from the Engine control module (ECM) terminal 17