air leak ???????

[s2 rich]

hi my 1991 s2 is severley loosing boost it is currently at a garage but they dont know what is really wrong with it it does it worse in third and fourth gear when it is under the most load. the car almost stops and it feels like you are trying to push a bulldozer up the road. i was thinking maybe air mass or maybe the diaphram in the dump valve has collapsed but they are all pricey to investigate hope someone can help ..

[Crawford_S2]

Can i heartily recommend the search button on boost leaks. Loads on here on this subject, suspects are split hose on inlet side, intercooler o-ring leak etc. Start there and most of us have had to pressure test the inlet side to track down leaks too, this is also fully explained elsewhere on here so search away

[Ross]

Hi,

Not too pricey to investigate if you goto the right places! A specialist such as MRC or Quattronics know these cars inside out, or even a local forum member if you know any that has a bit of experience, will be able to help diagnose the problem pretty quickly. Better to travel and spend 2hrs with one of these guys than goto a local garage who will give you a much bigger bill and a knackered car at the end of the day.

DVs wearing out are common, it's about £25 to replace (use an S3 dv) or get a Forge DV if you're willing to spend a bit more - they're more durable.

A boost leak can be found by pressurising the system, find someone with a pressure testing kit - leaks are common at the Intercooler O-ring (replace with "Mark H" mod, about £20) and the DV connections, and at joins between hoses & intake pipe. Make sure they're all tight, can make a world of difference!

Also ensure the MAF is cleaned, if neccesary borrow a known-working one to use in your trouble-shooting, and the WGFV is connected + working. As it's a '91 (3B) also check the plugs (they can be loose, losing compression) and the contacts on plugs + leads. Get some contact cleaner and an old toothbrush!

Good luck getting the car right!

Ross

[newsh]

Shrewsbury, you are near Greg_S dad's garage

[Greg_S]

Yeah only a stones throw away www.billsmith.co.uk