Turbo/waste gate issues - Low Power

[rostapher16]

I have a turbo problem and probably more specifically a waste gate actuator problem. For the first bit of driving, the turbo spools like it always has, after that it does not spool and the engines stops accelerating once it gets over 2200-2300 rpms. Occasionally, i still hear the turbo a bit, but not like normal. I took a look at the turbo itself and it spins fine, no play and it's not stuck. I actually have a shop manual, but its for the D24, so it does not have the turbo section in it. (anyone know of a link to that part of the shop manual?) How do I check/replace the waste gate actuator? How does it attach? can I get to it without removing the turbo itself? etc? Alternately, does anyone have other ideas for why I'm losing power @ higher rpms? Any knowledge would be helpful, thanks!

[Jason]

I don't think its going to be the waste gate, it is boost controlled. It cant open up and dump boost unless you are making 8 to 10lbs. If it was hung/stuck open, you would never make any boost in the first place. When its warm and lacking power, do you get a bunch of black smoke while trying to accelerate? Have you checked for a clogged muffler? I think I read in your intro that you have had the pump rebuilt, so that should not be a area of concern. What about injectors? Have they been rebuilt or pop tested? Did you also say it had a bad head gasket? Is that fixed? It wont run correctly if its drowning in coolant.

Jason

[rostapher16]

I have not checked for a clogged muffler. (I'm not sure how I would do that...) and the injectors haven't been tested either, since I'm trying to do most of the work myself. I don't think it is the injectors since this happened rather suddenly one day, but I suppose it could be anything. There is not lots of black smoke. The head gasket is not repaired. I was going to try that head repair mix you add to the coolant this weekend. Does anyone have any experience with that stuff? Basically, I'm trying to gather more information before I go replacing/repairing things that don't need it. Thanks for any and all ideas

[Jason]

An injectors are more of a wear out over time thing, unless one gets clogged in some way. Have you replaced your fuel filter recently? As for the muffler thing, just cut them off, these engines sound great opened up. No black smoke with no boost means no fuel. If the injection system is working correctly and the turbo was faulty, you would have black smoke because the turbo isn't supplying the extra air to clean it up. Have you checked to see if the hose has come off/torn from the manifold to the AFC housing on the injection pump? That refrence hose allows the injection pump to supply more fuel under boost, and if not connected you will be limited on fuel flow, though I don't know if it would be to the extent you are experiencing.

Above all (this should probably have been listed first) don't waste your time with the "head gasket in a bottle" crap. It will clog your cooling system and wont work on the gasket. A diesel engine has WAY too much compression for that kind of a repair to do anything. Maybe on a half worn out old 350 v-8 with no compression and a slight hg leak it would work, but not on a diesel. Before you waste much time troubleshooting anything on the engine the head gasket needs to be repaired. These engines depend on compression to run correctly, and a blown headgasket screws everything up. You should think about using the updated stainless headgasket, or the stocker with headstuds to help keep it sealed up if you are going for performance. If staying stock, make sure to use new bolts anyway.

Jason

[rostapher16]

Thanks for your responses again, Jason.

The hg will be a project one day. However you mentioned a clogged muffler. After I read that, I later went outside and whacked the muffler several times with my hand while it was running, then I covered up the pipe a couple times just to put some back pressure on the system. Then I got in and it ran great! I drove it about 20 mins that night and drove it again the next day with no problems, so... it's fixed. :D I guess it really was just a clog somewhere. Thanks again! I never thought to look at something at the back that seemed to a problem in the engine.

[Jason]

You need to replace or just cut off that muffler. Its probably still restricting flow which is bad for performance, mileage and making your EGTs high.

Easy fix though!

Jason

[rostapher16]

Well,

Turns out it wasn't the muffler either. I ended up taking off the fuel filter and it was completely clogged with sediment. All it needed was a new one and its back to running great again...

That was a lot of frustration for something so simple.

~ross

[v8volvo]

I was about to say, new fuel filter is the fix. Classic symptoms, same problem we see every day. Once the revs rise and the vane pump is drawing fuel through the filter media at a high rate of speed, a restricted filter will begin to pull power down since the effective timing and injected quantity get held back. The fact that the car can still make good power at low RPMs and idles and starts fine often confuses people and makes them think of everything else except the filter, but the filter is the cause nine times out of ten.