3B with surging boost.

[newsh]

We've been doing some work on a 3B today, It had a few small leaks, the WG boost feed was cracked, someone had fitted a bit of rubber water hose to it. Small guage vac stuff all needs replacing but we got it airtight, then it was really over boosting.. Found a non standard spring in the WG which had one of those bolt type arrangements with a locking nut, this was screwed a long way down. Replaced that with my spare cap with what I believe is a stock spring, the car now drives without overboosting but surges on boost. It'll boost to 10PSI hold it there for a few seconds, then bump up to 15PSI then back down again.
Anyone seen this type of behaviour before? I've suggested changing the DV (already ordered) and the WGFV. When pressure testing we could hear a small leak from somewhere down near the DV but thought it wasn't worth taking the bumper off with no spare to fit. I suppose it could be a leak that builds up pressure then lets go..

[Greg_S]

DV sounds like a good place to start. is it a standard DV or aftermarket one?

[Sammo]

The one thats on there is standard. The one i'm replacing it with is a Forge one.

[newsh]

Possibly wastegate worn and sticking

[4WheelDrifter]

Try sucking on the vacuum line to the DV, you should be able to feel if the diaphram is leaking.
It might be worth checking the WG diaphram too.

[newsh]

Had a chat with Pete Berry today, he suggested the Wastegate, I'm hoping to get one to try out

[Sammo]

Your getting brave John. Especially after the headache of trying to find the boost leak.

[newsh]

Your getting brave John. Especially after the headache of trying to find the boost leak.

The jobs not over till the fat lady sings (or we get a consistant 1Bar of boost)

You do the DV and replace all the little tubes then bring it back down and we'll take it from there.

[newsh]

Whats the milage on your car? I forgot to look.

[Sammo]

Whats the milage on your car? I forgot to look.

Approx 114,000

[newsh]

Ah, just run in

[Sammo]

Ah, just run in

Hehe yeh only just. I will let you know once ive changed all the bits over.

[Rusty]

has it been remapped, hence the new WG spring?

[Sammo]

has it been remapped, hence the new WG spring?

Not as far as I know. Although the place I bought it from didnt know a whole lot about it so something may have been done.

[Rusty]

Might be worth getting a standard 3B ECU in it. If you've got problems and don't know the history of the car then I'd get it back to standard first, thus eliminating the effect of crap modifications by numpties

COuld be a MAF problem, try a spare MAF... might be a case of trying a spare everything! Hope you get it sorted chaps.