Fluctuating Boost Pressure

[diesel1995]

Okay guys, ive got an interesting problem here.

Going down the road at a sustained speed, my boost fluctuates. At cruising speed (60 MPH) it goes from 5 to 0 then to 5 and back to 0 with no change in vehicle speed or throttle. I can even hear the change in boost.

Also, under hard acceleration the boost seems to do the same thing, but less noticably.

Any ideas?

[charliepeterson]

0-5#'s is a big change but don't forget that the engine needs to be under some what of a load to make boost.

[patrick m.]

sounds like a wastegate problem

[diesel1995]

I would say that you have the solution to my problem charlie, except for a few minor details.

1. It NEVER did this before about a week ago.
2. Under almost any kind of consistent load, the boost fluctuates i.e. pulling my gooseneck grossing 10,000 the boost does the same thing.

[charliepeterson]

PatrickM is onto something. The solenoid will get cranky with heat and time. On the back side of the waste gate solenoid is a clip and screen. This is the vent circut I believe. I don't think just cleaning this will cure the issue but looking at it might tell you what the "blood pressure" is for the circut.

[Kennedy]

I've had good results rejuvenating the solenoids by spraying a bit of WD-40 into the wastegate hose from the canister end.

Drifting boost sounds like a sticking solenoid. Good thing you had a gauge to see it before it quit altogether! If you only knew how many people I argue with about the need for gauges...

That and cooling upgrades. The "I don't ever tow" thing just is not a good excuse or reasoning...