First breakdown..not really broken...but HELP!
 

Driving down road at 50, I feel car lurch down like its in a really big headwind. Hmm, I floor it, just a lot of noise, no response. I shift down, revvs pretty high. Finally, car conks out. And refuses to start, but does putter a lot.

I take my Swiss army knife, and use handle to smack the fuel filter a lot. The primer pump wasn't doing anything, just hissing. I continue to crank and crank, manipulating the accelerator and idle adjustment knob, and finally it comes to life. I drive it home.

Prognosis: Clogged fuel pref filter or main filter..

What do you guys think?

I hope it's nothing major...IP or something. Oh, and oil was fine, antifreeze was up to snuff as well. I figured it was either starved of air or fuel.

I hope its something this simple..

The primer pump hissing is the telltale sign. Is the the style with the white handle that you have to screw down? Or is it the black handle you just push. If white, just replace it.

There could be some air leaking into the fuel system as well. Track down that hiss.

KylePavao,

Was it hissing when you were not running the engine? And not while you were actively pumping on the handle?

Sounds like you may also have a clogged vent to the tank. Was the fuel level indicator (generous term for many of these things) showing normal or expected values?

The hissing might have let air back into the system so you could draw more fuel out of the tank. My father in law had exactly what you describe happen to him, and if he didn't have gorilla hands he might have been stranded. He thought he ran out of fuel as the reserve light came on while the indicator showed he had more than half a tank. When he went to open the filler cap it was stuck pretty good. He clamped onto it and forced it open, with a big rush of air going inside, and then the car ran fine for another hour or two.

If it the vent, do a search. They are in the trunk and the rubber joining parts of the lines get goey and soft with exposure to fuel and heat and time. If they touch on the inside they kind of weld together. Cheap fix though. Good luck, Jim

Hey
 

When pumping it was hissing, yes. I opened the fuel cap, and it opened easily. It never hissed when not pumping, and it screws down fine. The fuel gauge was reading as normal. I am going to change both filters.

I'm going to risk getting in trouble with P. E. Haiges and say again change the pump. It's probably cheaper than you think. You say the pump was doing nothing but hissing when you pumped it, which really sounds like the pump itself is leaking. And that pump, which is the old style, is well documented to be a leaker.

Something fishy is going on
 

I went to Fastlane to search for the primer pump. They show it as "not available", but you can buy a "primer pump assembly" for something like $150! That is not what I'm talking about. I searched for primer pump and found an old thread where TXBill quoted the price at around $15. Indeed, PartsShop shows the primer pump at $15, and even lists the "old style primer pump" at $12.

I like the old style pump because using it, it possible to tell whether the primary filter (in line) is plugged or the secondary (spin on) filter is plugged.

This is determined by the feel of the pump handle while pumping. If the primer handle pulls up hard, the primary filter is plugged. But if the handle pulls up easily and pushes down hard, the secondary filter is plugged.

It ia a rare occasion that both filters need to be replaced at the same time.

I miss the primer pump on my 300SDL.

P E H

I'm going to very, very respectfully disagree with putting the new style pump on. PEH has it exactly right, in my opinion; why not let the pump tell you which filter is at fault (especially on the road)? I think it's worth the drill to find the o-rings and possibly a junkyard pump to practice on.

Kyle, you may also want to consider a tow rope for the trunk, in addition to spare fuel filters. Pull starts are easy on a diesel and a lot easier on the battery. And someday you might be a hero to a young damsel in distress.

The new primer pump is soooooo much more civilized. It actually pumps, and doesn't spill fuel all over the place.

the hissing you hear is from the fuel pushing the check ball off its seat in the return fuel fitting in the rack of the injection pump. this is normal.