Recently my engine warning light has been coming and coming.

One time last week after turning the key the engine was fluctuating really badly revs going really low to around 300rpm to 1500rpm. The engine nearly cut out and the interior light nearly went out.

I took it to a friend the other day was it was checked on the diagnostics, it showed that the forge dump valve had made the light come on.

Does anyone know why?

Phone the guys at Forge they will advise you and take the valve in for service - normally FOC.

Although - re-reading your post, I don't think the valve would cause that, I think they are fobbing you off mate.

The DV is held closed by spring pressure until you lift off the throttle. The turbo wouldn't be on boost at idle and therefore that system would not be in use

But if the DV isnt sealing completely then un metered air is drawn into the inlet, this can cause idle problems.

I'd strip the DV down and give it a service myself.

Yeah, good point Ross. Didn't think of that doh!!

The problems with piston valves are piston wear and the grease causing it to become sticky.

i had the same problem ,but not enough to get the lights on, forge 006 was as dry as a bone inside,quick clean and a bit of light greasing had it cracked

Well ive emailed forge who have sent me a service kit which consist of red grease, ring/seals and some metal thing, any ideas on what im supposed to do? (havent had the chance to look at it yet)

Forge DV Service Intructions.

http://www.forgemotorsport.co.uk/valve_service.pdf

do dv30's also need servicing?

do dv30's also need servicing?

Yes they can be serviced, not sure how often but spoke to them when I fitted my DV30 to find out what lubricant they use. Was told it was a "seceret recipe" and that they will service the valve if I sent it back when the times comes, although they have some valves returned for servicing a few years old/50,000 miles with the original lubricant in and still working fine

Thanks Geoff thats exactly what im looking for.

Double check all the hoses around the intake and TIP. I had a hose come off (my own fault )which led to really bad idle at start up, but run ok after 30 secs or so, with no check engine light. Dealers had it overnight and couldn't find a problem

As Ross says, unmetered air entering is a possibility.

Ive still not had time to service the dump valve yet, but when i started it up today, the same thing happened, i pressed the accelerator to rev it but there was no response whatsoever, stomped on the pedal a few times and it was ok...

Right ive put the stock dv back on for now, was ok for 2 days and the same thing happened the other day,fluctuating between 350-700rpm on startup????

What was the code that showed on the diagnostics?

What was the code that showed on the diagnostics?

7.

I dont have a clue what the code was, gonna check it again shortly, ill let you know.

Sure its not a coil pack or maf?