wont rev past past around 2500
 

85 740 Turbo Diesel sat for 18 years. changed oil, and fresh fuel in a can to the IP as the PO cut the fuel line to the filter. the car starts right up. idles and drives ok but wont rev past about 2500 rpm. free reving or in gear. pulls right to the same spot and starts misfiring. almost like rev limit in a gas car. i have a rebuilt IP, rebuilt 32mm head and n/a cam and intake manifold on the way.

bubbles in the return line?, stuck turbo? or restricted exhaust?
I hope you've changed the timing belt.

Timing belts as well as other belts and fluids will be changed as soon as parts arrive this weekend. Car isn't being run again till all that is done. I just needed it to run so I could move it so its out of the way.

Sounds like a fuel delivery issue. Could be air restriction too, on inlet or exhaust side as 745 said, but I think you would notice a lot of black and gray smoke if that were the case. Enough of a restriction to hold the engine at 2500 rpm when it's getting full fuel delivery should mean a big smoke show.

Do you have your fuel can running direct to the IP inlet, or through the old fuel filter? If the old filter is in the system that could be the issue. Generally good to try avoiding running with no filter in the line since even a little bit of dirt can hurt IP and injectors.

"In" and "out" banjo fittings in the right places on the injection pump? Return line not blocked? The banjo bolt for the return fitting at the IP also has a little screen inside it, if the pump had something get dislodged and then get stuck in that screen and plug it, can cause strange issues. Might take that off and see if it is clear.

Could have some injectors doing weird things too if they were sitting forever with old fuel in them. E.g. leaking compression in above certain engine speeds, etc.

Could even be a timing issue -- like if the advance piston in the IP is stuck in place and is not giving any dynamic advance as engine speed increases, it might get to a point where it doesn't have enough timing to run faster. If it sat for a really long time with the same fuel in it, I'd wouldn't make any bets on the pump and injectors being 100% happy.

You might try running it and letting it fill the pump and injectors full of biodiesel or Diesel Purge or ATF or whatever you like as a detergent/solvent and let it sit for a few days, then see if something frees up.

That last bit is so true, I have had a couple cars slowly get better for months, often with an overnight sitting of new fluid being the biggest single day.

So you are saying let it suck up a bottle of atf and let it sit a few days?

Or fire it off every so often to stir things around.
installing your rebuilt pump will be the most likely cure though.

Yea ill probly just leave it alone till the parts arrive And eventually rebuild my old pump. I forgot to answer one question tho. at idle there is alittle Grayish smoke but under throttle there is a lot of grayish white smoke.

I figured an update was due. Turbo is Indeed seized. Looking to upgrade. Holset HX or HY? Im not sure of the differences.