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Our other truck is also a 88 superliner 350 e6. It doesn't have the same speed as it used to and doesn't seem as powerful as before. It's been rebuilt once about 3 years ago. It just started acting up. Idles fine just doesn't seem to have power on acell or at top end. I've searched but haven't really found anything. Any ideas?

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Theres a air line that runs to the puff limiter on the injector pump. When you release the parking brake it will apply air pressure to the puffer to keep the rack from opening until theres boost. Take off the airline and unscrew the puffer out of the injector pump. Pinch off the airline so it wont leak when you release the parking brake. Go for a drive.

The air line on the puffer comes from the reversing relay which is on the intake manifold on the other side of the engine. When your engine starts to build boost the reversing relay takes air pressure off of the puff limiter. The relay or puff limiter can be bad. I usually replace both.

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Look for simple things first ... Replace fuel filter, check that the throttle lever has not slipped around the pump shaft, make sure it has full travel...if that's good check for good boost pressure. inspect turbo for broken fins. After that you will need to start looking at the pump and compression levels...

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Look for simple things first ... Replace fuel filter, check that the throttle lever has not slipped around the pump shaft, make sure it has full travel...if that's good check for good boost pressure. inspect turbo for broken fins. After that you will need to start looking at the pump and compression levels...

My '89 had no power, ran up to about 1750 RPM slowly, and no boost. As he said, check the throttle linkage. The splines on the shaft going into the injector pump are gone on mine. Put the linkage back in the correct spot, ran a 1/4" bolt through it, and whammo... Mechanic wanted to send the pump out and that would have been $4,000

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So here is a picture of my pump. (Dirty, I know) On the back of the pump, there is what looks to be a make spade electrical connector with a nut under it, with nothing attached to the connector. And to the left of the throttle arm, there is a set screw with a locking nut, is that the fuel delivery adjustment screw? And that is a picture with my throttle to the floor in the cab....is that about the angle they are when wide open usually? I can push it a bit further, but not much.

This engine is an EM6 300.

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scott, look at the picture that full floater posted, you see the throttle arm where the throttle linkage attaches? then look about 2 inches below the connection, do you see the cresent shaped rectangular slot with the metal tab in the center of it. now have some one mash the throttle pedal all the way to the stop bolt under the pedal,now did you see any movement in that cresent shaped slot? if not you need to adjust your linkage. either at the pedal or on the pump splines. that sloted opening allows for overtravel of the throttle pedal once the rail has reached its internal stop in the pump. when properly set the tab inside the cresent should move slightly as full throttle is reached at the pedal stop. hope this helps. Rob

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