1St Post: W250 lacks power . Suggestions?

[Ramonathe1stGen]

Hi everyone. I hope everyone is safe and I am glad to be part of the forum. I am looking for some suggestions if possible.


Got a 93 W250 automatic extended cab and it’s very slow, lacks power. Transmission was not shifting to Over drive and after changing TPS sensor, computer and another used transmission with (what the shop told me was a new torque converter) truck still lacks power as if my rear brakes are always on.


Truck is completely stock. Wondering if the issue is turbo, inter cooler boots, intercooler clogged, bad torque/ transmission or need to put a bigger fuel pin. It has new diesel Filter.


My father in law’s D250 feels much better quicker and faster(also stock) Any ideas where to start ? All help would be greatly appreciated.

 

[Bob4x4]

Start with the basics.Test fuel pressure.Check for boost leaks.Check injection pump timing.Air filter clean?

 

[Mark31]

As if the rear brakes were on? Get up to 30 and put it in neutral and net it roll to a stop and see if you have any drag. Infrared heat gun will help find a hot brake or bearing

 

[Buffalo]

I have a '91-1/2 W-250 which I bought new in Aug. of 1991. Still have it. At the time, they were calling them the "dog diesel's" because they were so slow. I took mine to the dealership and they put it on the dyno and it had 1 horsepower over the limit that would have caused them to do something about it. So, they did nothing!!! I was walking my dog, one day and ran across a man with a truck like mine & shared my complaint of low power. He said he had the same problem and took the truck to a diesel fuel injection pump shop in the Phoenix area and they fixed it up so well that the truck was too fast and he took it back to have them lower the power. I took mine there and they said that they would re-balance the pump but, would not tell me what that meant. It did work, though. Mine wasn't too fast but, there was a definite improvement. Downside was that it now smoked like a freight train. Then, I ran across an engineer that was working on turbo's and he said that I had a 21 square centimeter housing and the '89 & '90's & '93's had an 18 sq. cm. housing to fix the problem. He said that I'd be better going to a 16 sq. cm. housing and that would work even better. The '91's & '92's went to the 21 sq. cm. to meet emissions standards but, people hated the performance so much that they went back to the 18's. My 16 sq. cm. really woke the truck up, especially with the balancing of the injection pump. Changed the trucks performance completely. I still don't know what the balancing entailed and when I asked a number of times the owner of the company started getting mad and mentioned that he didn't want to divulge any of his secrets. The other thing is that the 4 speed transmission (auto) left a lot to be desired, especially the torque convertor. I finally got a new trans with a lock-up TQ convertor which, the stock convertor was not a lock-up. I even had the stock one rebuilt so it would grab at a lower RPM. That helped a little but, nowhere near enough. The explanation was that the trans. that they put in those trucks was originally designed for a larger gas engine that produced much higher rpm's and the TQ conv. got enough rpm's to actually grab. Mine was always slipping. I had an ATS Trans. with a Triple-Lock torque Convertor put in and that really allowed the power to get to the rear wheels, for the first time. Towing my trailer was a much nicer experience. Finally, my truck was working the way I expected it to the day I bought it from the factory. The trans. was quite expensive and I had it done in '2002. I hope this information helps you out. Took awhile to figure it out and get it done. It made the truck much more pleasant to use.

 

[Fastback67]

My 90 was less than impressive when I first got it, so I made a few changes. The two items that made the biggest difference for me. First was swapping out the original turbo for the 16mm job, but the biggest gain came when I got rid of the old diaphragm style fuel pump, and installed a piston style HVLP pump kit from Dieseltuff.... HUGE night and day difference there.