82 300D Runs then dies, Wait, Runs then dies

[Rock-n-Roll]

Hi, I've got a buddy who has an 82 300D. I've searched the web, this board, etc. and haven't found what to do to fix his problem.

First, he's got all new gloplugs, replaced the fuel filters and a leaky fuel line.

He says that it was starting up without a problem then he'd drive some number of miles, it would die and couldn't get it started. He'd let it sit for a while it would start right up then die several miles later, sit, start up, etc.

The last time he drove it he only got about a mile from his house when it died.

Does it sound like the fuel system? Dying pump? Fuel line with stuff settling when not running and then building back up and clogging an orifice once the fuel system is repressurized? If so, where would I tell him to look? Injectors, maybe?

By the way, it's his only transportation, he hasn't got much money, he's about 50 miles away from me, and I, a non-mechanic, have tried to diagnose it purely over the phone. So it may take me a while to talk with him and then get back to the board to post results. And I'd appreciate knowing if there's a "right way" and way that works fine but is not as costly, e.g. kind of like substituting a VW part for a Porsche part.

Need anymore clues?

Thanks for the help!

[talonlover]

I have seen a lot of these 123 diesel cars have that problem. First step is to change both filters and blow out the fuel line back to the tank(use a air hose connected to the rubber pre-filter line and blow it out. If the problem continues(which it probably will) I would say there is a strong chance of rust or other contaminants in your fuel tank. It's not a easy fix, the tank must be dropped and flushed out completely. Sometimes this works, sometimes the rust is just too bad and the only way to fix the problem is to replace the tank.

[talonlover]

PS, I don't wan't to say for sure that the problem is the tank, I've just seen that a lot. A faulty injection pump or even a leaking diesel line or something as simple as a broken vacum line could be the problem.

[Rock-n-Roll]

Thanks, talonlover! I'll relay that to him and see what happens.

[j_hef]

i agree, do the blow back to the tank, if that helps it run better theres a clog, but not necessarily the tank rusting. The fuel strainer could very well be clogged. Also I've only seen it once but take the line off at the tank and at the prefilter and see if there still seems to be a blockage in the line. 5 inches of crap blew out on the one that I had, how it got past the strainer is beyond me. theres also a product called "diesel purge" by lubro-moly for the injectors that works well-
performanceproducts.com sells it. good luck

[j_hef]

just another thought but, crankcase pressures can shut the car off too and make it act like a fuel problem. take the air filter housing off, leave the blowby tube and the housing drain tube open. If pressure from the blowby tube is somehow going directly to the crankcase, it will shut the engine off after a minute or depending on the pressure.

one last idea, unplug the brown vacuum line from the rear of the injection pump and see if it stays running then- thats the shutoff valve.

[Rock-n-Roll]

I appreciate the advice, j_hef!

[j_hef]

sorry, yet another came to mind, have him drive it with the fuel cap off, see what happens...

[talonlover]

Originally Posted by j_hef

sorry, yet another came to mind, have him drive it with the fuel cap off, see what happens...

Are you thinking maybe the tank cannot purge and the pump is pulling a vacum?

[Rock-n-Roll]

Certainly no "sorrys" needed, j_hef. I'm thankful you're putting the extra thought into it.

Hopefully one of these will resolve issue.

Thanks again, guys!

[Rock-n-Roll]

Originally Posted by talonlover

Are you thinking maybe the tank cannot purge and the pump is pulling a vacum?

This maybe nothing, but it sure sounds like a good clue to narrow it down a bit:

I just relayed the info to him and he said that during the last fill-up he got either a pressure or sucking sound when removing the fuel cap. And that it never happened before.

By the way, he's 76ish years old, so it may take him a while to try everything you guys have suggested. Unfortunately, he's about an hour & half away from me so I can't just drop by and help him after work. But with your help I think we'll get this done one way or another.

[j_hef]

yeah thats what I had in mind. i've got a handful of these old dogs here and at one point or another one of these things has happened to all of them... I've almost seen it all ;-)