Well I may have found the problem, or at least one of them.

I noticed that the part numbers for the overboost control valve and the egr controller valve were the same so I put a vacuum gauge on the port leading to the wastegate and it failed to hold. When I put vacuum to the same port on the EGR control valve I have good vacuum.

Since I don't have maintenance manual nor do I have diagnostic manual for the rather complex vacuum system on these I can't say this is a problem but I find it unusual that I would get different results for the same valve on the same port.

When I put vacuum to the wastegate I get a good reading, as in the diaphram doesn't appear to leak. If it did leak I would expect to have boost of some kind, as it is perhaps the control valve is applying vacuum all the time?

Any comments on this?

Thanks guys

Steve A

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Steve A
92 W140 OM603
97 VW Jetta TDI
90 Passat variant TDI 6 speed MT
94 Chevy K1500 6.5TD
05 E320 CDI
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