This car has almost no throttle response until the peddle has reached the half way point then it just takes off. At first I thought the linkage was way out of adjustment, but it wasn't. I can manually move the throttle arm on the injector pump and the engine will only increase the idle just slightly until it reaches the half way point then the engine will suddenly jump to near full RPMs. I adjusted the ALDA out nearly all the way and that seems to help only slightly. Now, it seems to have some response to gradual movement of the throttle, but still it is just very little improvement. I have cleaned the boost sensor and lines to make sure it is sensing turbo boost. I would greatly appreciate any input on this problem.

I know it seems silly, but when I changed both of my fuel filters, it seemed to help my off-idle response. Might try it and see, can't hurt.

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Dave

1982 300D
352,000 miles

Already replaced fuel filters, checked injection timing, boost pressure, and adjusted the ALDA. So far every thing points at the injector pump, but I want to be totally sure before pulling this one.

How does the car shift from a standstill? I'm thinking its the trans pressure control cable, but the "...suddenly jump to near full RPMs.." part is puzzling.

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2001 Dodge Ram 2500 Cummins Turbo Diesel - 4x4, auto, 3.54 gears, long bed
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'92 300D 2.5 Turbodiesel - sold
'83 300D Turbodiesel - 4 speed manual/2.88 diff - sold
'87 300D Turbodiesel - sold
'82 300D Turbodiesel - sold

It has flat response in "park". Just grab the throttle lever and slowly advance the throttle and the RPMs will only increase about 100RPMs until mid-range. Then the RPMs will exponentially increase to full throttle. When it is in drive, you press the peddle until half to the floor and then it accelerates almost normally except it is difficult to maintain a constant speed.

David:

So sorry, but this sounds like a governor problem. You can try some Marvel Mystery Oil or SeaFoam in the oil on the off-chance that the difficulty is only a buildup of varnish, but I suspect you will need to have the IP rebuilt. Do check that you actually have oil in the IP (bottom part, supplied by a small line from the block, it drains back via the mounting flange). If the line is plugged, you may just be short on oil, and fixing the supply with fix the problem.

All diesels have a speed governor, and it sounds like yours isn't working -- you get a speed increase when you exceed the governor's range and manually move the injection control rack with the throttle. It is still drivable, but a big pain.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!