Power loss... I'm at a loss?
 

Over this past winter, I noticed that my 1997 twelve valve doesn't have the torque it used to. I attributed it to needing a valve adjustment, but I checked them, and they are all at .010 intake, and .020 exhaust.

My turbo seems ok, no funny noises, spooles up fine, and with the top of the air box off at idle there is plenty suction going into the turbo.

What else should I look for? It does act like the turbo is not 100%, from 2K rpm to 3K takes a long time. Before, you give her pedal at 2K, and be ready to shift at 3K, and it pulled HARD all the way. Now just kinda rev's up, and doesn't pull or rev as fast as it did.

This is a stock engine, only have a drop in replacement K&N air filter, and the exhaust is staight piped 4inch. Also I only have 130,000 miles (just turned 130 about 60 miles ago).

What am I missing here? Truck runs fine otherwise, just kinda gutless.
Thanks for any advise.
T.B.

have you changed the fuel filter yet if not do that first. then i would look for boost leaks and then slipped timing

Pull the intake hose off and feel for turbo play or see if there's oil around the turbines. It would help to get a boost and fuel pressure gauge on there. Any smoke?

I don't know much about these issues, but haven't I heard about the throttle cable or linkage? If it's too loose, won't it do that? Because you wouldn't be actually at WOT?
Ditto on the fuel filter. I need to check mine, too.

What is slipped timing? Could you educate me on this? I do know I had a heck of a time finding TDC when checking the valves. #6 seemed to be opened more than what was described when #1 was TDC. How does one time a diesel, no distributer to get a pulse from?

Yes fuel filter is new, and the turbine is clean (no oil) spins free, and has no lateral slop.

timing is done mechanicaly no pulses. snap-on sells a timing kit $300 or you could take it to a diesel shop and they can do it for aroung $100. the timing gear is on shaft of the timing pump and it isn't keyed or anything tapered. so it can slip a little and retard the timing. take it to a shop and have them advance the timing to around 16.5*. if you search you will find all kinds of links on timing and the procedures

The diesel shop I called quoted me $400. Another said probably about $150 but he'd have to look at it first...

Is transmission slipping? or clutch going? Fill out signature.
Does it start fine? Maybe check to see if you are getting full movement from the fuel solenoid/lever.
But I'd maybe change the pre-filter as well.

No, the engine is having a hard time revving, or revving slower than normal. The clutch is not slipping, and revving up.

Where's the pre filter?

It starts a little harder than it did... maybe? But just doesn't rev, or pull as hard as it did. If some one diddn't know better, they would never think there is a problem. But, it definatly is slower than it was.

Also is it possible that in 130,000 miles the valves are still in adjustment? They seemed fine to me, but I find it odd they diddn't loosen up.

Thanks a lot for all the help, gonna check the intercooler for leaks, as well as the fuel shut off soleniod for proper opening.

i hope your kidding. The best pump place in the whole country Columbus Diesel Supply only charges like $75.
your truck isn't making a ticking noise is it. it could possibly be the overflow valve on the pump.

my truck is doing the same thing i cleaned my prefilter, fuelfilter is good turbo is good its boosting 34psi and my egts are running good but there is a lose in power and mine does tick loudly when it has a load on higher rpm but wont do it in neutral. btw cleaning the prefilter gave a night and day difference

There are actually 4 filters on our trucks. The regular one at the engine, a prefilter in the fuel heater unit, a mesh one on the pick up in the tank and another mesh type inside the pickup assembly in the tank.You have to drop the tank to get at the last 2. A few guys have found that the mesh inside the pick up/float assembly has been really plugged with crap which really restricts fuel flow.You have to pull the float assembly apart to get at it once you have it out of the tank.Not an overly hard job just a pain in the donkey to get too.

I had this problem too and it turned out to be the fuel filter. How "new" is it? mine pluged up after 3000 miles. So I never thought that was the problem. I had checked my timeing, all the other filters, replaced my lift pump and yada yada. Another thing I Dont think was mentioned yet was your overflow valve. Its on the injection pump, top, motor side, front. If you do a search here you should be able to find the methods to check to see if its any good with the use of a fuel pressure gauge. Someone had also told me to check the fuel shut off selonoid to make sure it was opening completely.

I did put a new sending unit in last summer, so the in tank filters hopefully are good. I'll have to check the pre filter, gonna be a busy weekend, hopefully I get time to check all this stuff.

I haven't noticed any ticking?

Thanks again for all the advise.

How does one remove, and clean the pre-filter?

I have noticed a chirping sound while under load. Kinda sounds like the nightime frogs (or peepers as they are commonly reffered to up here) chirping around ponds.

Would that be an indicator of the overflow valve, how do I test it?

Now I do have some up, and down play in the turbo impeller, It doesn't hit the housing, but don't think it had any before. Is there a spec on the movement? It spins nice and free, but I can get a little movement from the impeller shaft.