Boost / Power question.

[ACoyle]

The truck is a 99 3500 auto 4. 10 gears.



1) On the highway starting to pass someone.

2) Floored the sucker.

3) Starts to speed up. boost coming up nicely.

4) Boost suddenly and immediately drops off to 0#.

5) Got off it. Tried several times most boost I can make is about 8#, without EGT's climbing faster that I would like.

6) I don't think that I am in limp mode, the truck will try to accelerate.

7) Took out all the intake plumbing, no loose clamps, nothing disconnected. No help with the problem.

8) Truck ran like that all weekend.

9) This morning, boost and poers seem to be back.

10 ) Never got a check Engine light.



What do you think? Stuck waste gate?

 

[LSMITH]

Even with the wastegate wide open you should be able to make more than 8 PSI. You have the HX 35 turbo, so only the rear 3 cylinders are wastegated anyway, the front three never open. If you get under the truck you can look right up at the wastegate rod, see if you can move it toward the front of the truck. If you can it is sticking open. You should be able to move it to the rear and then it will spring return back toward the front of the truck.



If the EGT went up quickly and the boost did not then it is likely not a fuel issue, I would think it has to be in the boost tubing connections, possibly the intercooler itself. If you want to know how to pressurize the boost side of the intake let me know.

 

[lizzyhermit]

if you have an exhaust brake, it may have been stuck closed. this happens to PACBRAKEs that have a clogged filter element. and boy, does the truck run awful !

 

[Gary - K7GLD]

LCSMITH =



"Only the REAR 3 cylinders are wastegated anyway... "



HOWINHELL is THAT accomplished without some sort of split manifold?

 

[Ethdee]

My truck's got a split manifold...



Jim

 

[LSMITH]

Gary, pull your turbo off, it will cost you about $15 in gaskets and about a half hour. Look into the manifold and the turbo. You will believe it then. The HY turbo is wastegated on all cylinders, the HX is rear 3 only.