Hello,

So I've had this 1987 300SDL for a few months now. It hadn't been driven for a few months prior to my buying it, and the day after I bought it I drove it a few hundred miles. After 3 hours or so, it suddenly lost power (terrifying feeling, driving on the highway, the gas pedal does nothing, slowly losing speed). We survived, got to the side of the road, and I, not knowing diesels, ascribed it to vapor lock (it happened that it took me a few minutes to go open the gas cap, and since then, waiting has seemed to be the primary fix for the problem). On the way home, however, it did it every 45 minutes or so (waiting longer each time before it would start again). I called the previous owner, and he suggested fuel filters, so I changed the primary filter, but finally had to call AAA to get a tow to the mechanic.

The mechanic said "Yep, they do that when the filters get dirty," but the primary and secondary filters were too clean to change (still seem to be, though I think I'm going to change the secondary filter today). So he suggested the tank screen, and I was ready to have them take out the tank and clean it to replace the screen when they turned it on and one of the injector lines burst and spewed diesel everywhere. They got that fixed and replaced and suggested I try out the car for a while before taking the tank out, just in case the injector line had been the issue.

I bought a thing of diesel treatment and dumped that in the tank, and the car seemed to run fine. I drove a hundred miles (hung out for a while) and then drove back. Driving around town worked fine too.

But yesterday it lost power on that same hundred mile trip, and on the way back, waiting half an hour wasn't enough to get it to go again, and so I got to sit with a loquacious tow operator of 11 years and hear about his hitchhiking travails. The stories were pretty great, but I'm not sure where to go from here.

I've got another bottle of diesel kleen, as it seems possible to me that the previous bottle is what allowed me to drive those hundred miles and back and that I have run through a couple of tanks since then. I finally changed the air filter, even though I really don't think it was causing it, because it was really dirty. I looked at the primary and secondary filters and they're full of diesel and if they're dirty or clogged in any way, I can't tell it.

That's really why I'm posting here. Is there any chance I'm going down the wrong alley with the diesel filters? Is dirty diesel visible? I keep wondering if there's any way the gas pedal linkage could be the problem, or something else.

I was told by several folks that biodiesel would "clean out the fuel system" though I'd need to be ready to replace the fuel filters a bunch of times. If the tank screen's what clogged, though, would biodiesel clean that out, or would it just further clog that screen? Should I just bite the bullet and go have the tank screen replaced? (The mechanic talked about several hours worth of cleaning out the tank).

Thanks for any thoughts you all have.

Definitely replace the secondary fuel filter before you get too carried away, especially if it's been sitting a long time. I would suggest that you also carry at least one primary and secondary filter with you (and the tools to install them) for the time being.

The screen in the tank is also a definite possibility.

Keep in mind that running a product like Diesel Kleen or even biodiesel through the system will dislodge whatever gunk is in the system and foul your filters and even tank screen. Point being that you shouldn't rule out filters/screen just yet even if you've just replaced them.

The other thing that comes to mind as a possibility is air entering the fuel lines somehow or possibly the fuel pump being on the fritz. Air in the lines may cause extremely rough idle once you get it fired back up after an "episode" and may explain why you can get it started again after a lot of cranking.

Not familiar with the fuel pump on this car yet as that is one o the few areas of the car I haven't had problems with...yet.

Sounds like a fuel problem to me. Certainly worth at least cleaning if not replacing the screen. Cleaning the tank will depend on how dirty the screen is.

I'd hold off on the fuel system cleaners until after the screen and possibly tank are cleaned. Otherwise you're just loosening more sediment and sending it through the fuel system.

Sixto
87 300D

sounds like the problem I had with the low mileage car I bought in Florida some years ago. It was algae in the tank and both filters clogged up. Also got stranded a couple of times. Can only recommed you change both filters and have spares in the trunk. Also would drain fuel completed and remove the strainer (filter) in the tank and the fuel level sending unit and change/clean them. It also could be that the cleaning additive is loosing the
algae from the tank walls and clogging the filter in the tank. Algae shows up as a fine dark brown substance. Best is to remove the tank and clean it
properly. For the r&r of the strainer and sending unit you will a 46 mm socket.
Cheers

So today we replaced the secondary (screw in) fuel filter and, because they were all on the fritz, all the glow plugs. Whoever designed this engine really hates the idea of people replacing glow plugs without pulling off the intake manifold, which just looked impossible, but in the end, with a very long ratchet set, a u-bend, an extra long 12mm socket, several extenders, and half a dozen angles, we got to them all.

The car starts up and runs fine now. Unfortunately I don't have time to test whether we fixed the fuel starvation or not because it takes so long to happen or not. Will have to take another road trip, but with more preparation so we can change fuel filters on the road if need be.

Thanks everybody.

Hey diesel friend, is removal and cleaning of the tank something I can do without a lift? How do I get to it?

Thanks!

If it ever does this again. Remove the fuel tank cap and check for a whooshing sound. The tank vent may be obstructed. Actually a comm0n issue to some degree.

Sitting around the tank vacuum that has accumulated decreases slowly and the engine can get fuel again.

It is just one possibility that has been suffered by many people with these cars. Of course power will decrease as the fuel pump is fighting to supply fuel in a loosing situation.

I actually picked up a good 300d one time that had this issue. The owner gave up and purchased another car to continue his journey. Leaving the car behind at a garage.

Besides a little trouble getting a title release all went well.The garage involved had told him they thought he needed a new injection pump.

Sounnds exactly like what was happening with my 81 300SD. Finally got around to the tank screen after looking at every other possibility and it was totally clogged with algae. Now 100% fixed.

__________________
Greg

Current
2005 E320 CDI (50k) W211 with OM648
1999 E300D Turbo (133k) W210 with OM606.962
1997 E300D NA (170k) W210 with OM606.912
1991 300D 2.5 Turbo (199k) W124 with OM602
1990 300D 2.5 Turbo (170k) W124 with OM602

My 85SD had the same problem. Filters & a shot of Startron diesel Additive fixed it.

http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?productId=109361&catalogId=10001&langId=-1&storeId=11151&storeNum=10106&subdeptNum=10434&classNum=10437

I eventually had to replace rear hoses because they were leaking and discovered the tank screen to be clean. I had seen Startron discussed here & thought perhaps it was snake oil but now am a believer - for growth in the tank.

__________________
85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

You might want to rule-out this probable cause, by trying a "local tank" of clean diesel, piped right into your IP under the hood. Take a large plastic pop bottle (cleaned and dried of course) full of diesel with two hoses from the neck one hose to your pump on the side of the IP and the other hose catches the returns from the IP back into the bottle. Bypassing all filters on the car. (Plug the ends of the removed hoses on the car with golf tees or something).

Go for a drive up a steep hill see if you still have a power issue.

Add a can of diesel purge to your pop bottle and drive that through the system... see if things change. Try a second can. You can run this stuff straight instead of diesel.

__________________
Cheers!
Scott McPhee

1987 300D

I had/have the same problem. My car has been sitting for a couple of months. I went to clean the tank screen. Did not have the 45mm socket. The outside of the strainer looked like new. I removed the fuel line and shined a flashlight down the hole for the fuel sender. The screen was clear and shiny. By the way the car was running I expected to see the strainer very clogged. Moved to the primary filter, it was clogged with algae. Replaced both filters and will add some Biocide. My fuel gap does whoosh a little, I will check the vent. Years ago I had an 83 300SD, it did the same thing, but always ran great. I'll let you know if it is cured after replacing oil, oil filter, flushing cooling system, installing new t-stat and new G-05 coolant.