Hopefully one of you all can shed some light on whats going on for me. I recently did a diesel purge, where I disconnected the fuel lines and ran totally off of Lubromolly Diesel purge to clean the injectors. So, after I was done I changed the main filter and changed the inline filter. After doing this the car does this really weird thing that it will start and run really rough for a while. I have to keep my foot on the gas pedal or it will cut out on me. Most times I have to press the pedal all the way to the floor and it seems like it is struggling to get fuel. Eventually the engine will get the fuel it needs and rev really high. After doing this a couple times it seems to clear up and run fine.

The car never had this weird thing before I did the diesel purge.

I have since replaced the injectors and injector return lines, still doing the same thing.

Any ideas? Should I replace the fuel filter again, maybe replace all the fuel lines? Does it sound like my injection pump is starting to fail?

How are your glow plugs?

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83 SD

84 CD

Either glow plugs or an air leak in one oh the fuel lines. Do you see air bubbles passing through the filter?

Sounds like you have a very small air leak that is allowing the IP to drain down while the engine is not running. Try using the hand primer before you try to start the engine and that would give you a clue where your troubles lie.

Anytime I have done anything to the fuel delivery system it runs like crap for about 200 miles.

I just replaced my glow plugs and in the process I had to remove the injector lines.

I reinstalled them, ran it for a while, cracked the line at the injector one at a time for a minute each while running to let all the air out and it still ran like crap for 200 miles.

It did that when I ran out of fuel before, when I replaced the delivery valve seals and o-rings and pretty much any time I have even sneezed on the fuel delivery system.

I suggest you bleed the air from the injector lines and drive it for a while.

I used to get unnerved by the resultant performance but it sorts itself out after about 200 miles, every time.

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1993 W124 300D
-297K on the clock as I type this.

Mmmm, I don't think it would be the glow plugs, I just replaced them this past January. As for the fuel filter, I can't see into my filter because I have a cleanable metal inline filter instead of one of those plastic ones.

Good idea. I think I might also just go ahead and replace all the rubber fuel lines just to rule those out as a culprit.

Thanks for letting me know about that. I will try bleeding the air from the lines and see what that does.