I just bought my first Diesel. Its a 91' F250 7.3L 4x4 manual tran. Man this engine sounds AWESOME but, after it warms up it stalls if I take foot off accelerator. The Guy I bought it from changed the injectors and the fuel pump. Some blue smoke at start up but it clears up after she is warm(I figure thats normal). Any sugestions? Seems to me pump might need adjusting but not really sure. Thanks

 

Air in lines possibly. Look around your injectors for wet spots. Also the fuel/water separator can be bad.

 

If you slowly take your foot off, how low are the rpms going before it flat dies? Does it run smoothly until it dies or does it surge or otherwise seem barely to run.

I believe the spec is somewhere around 700 or 750rpm curb idle for a manual transmission. It should say it on a sticker on one of the valve covers.

 

It runs smooth, I did turn idle up to about 750. Its not stalling now. I've change fuel filter/seperator. It is hard starting. If I put a rag w/ some gas at intake she starts but without that help she wont start. Once its started, and warmed it sounds good. She smokes alot. A blueish smoke, and alot of it but she's not burning oil and no blow by. I was leaning to fuel pump timing, the lines on pump are almost 1/8" off, when I lined up/timed it ran worse and smoked more. I see no wet or damp fuel lines where it might get air. I Appreciate any thoughts.

 

When my truck was leaking it was right at the injector at the plastic caps, you'd see it get wet around them.

Hard starting could be glow plugs.

Is it smoking the entire time? Or just when it's cold? IDI motors tend to smoke on cold starts, and that's what I assume from the first post.

When you say it smoked a lot more when you messed with the timing, you mean black smoke?

Something else to look at is your lift pump, the low pressure mechanical fuel pump mounted to the engine.