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81 Mercedes 240D 164,000 on the clock (clock was broken "awhile..") That's been fixed-- with instructions found elsewhere.. I highly recommend doing that!

Had it since February-- has some blowby, but starts and runs reasonably.. Not a powerhouse, but will cruise down the expressway 70+ without issue.

..except sometimes.

Twice now since I've owned it, it's 'lost power' and kinda slowed to a stop. Acted like a plugged fuel filter/fuel starvation situation..

Air and fuel filters have been changed since purchase. The primary looks fine...

Both times, I was near half a tank of fuel.. I added about 4 gallons, and it would start.. Wether this actually had any bearing on the real problem, or it was something else, that corrected itself, while I added fuel-- dunno..

Both times also, the engine was 'hot' (as in had been running for some time-- temp gauge consistently reads ~90C) and it was 85F or better outside. Again-- not overheating, but not just started in the driveway, and leaving home.. I'd say both times, I would have driven around 10 miles when it acted up..

I've since installed a pyrometer, and on the expressway, my temps are right ~900-1000F. Obviously higher, while I'm trying to merge-- and briefly to the 1250F range..

Idles good, starts easily.. And again, after BOTH episodes-- I drove the wherever I needed to, without further issues..

I'm wondering if I've got "alge" "fungus" "diesel bug" whatever..

I bought http://www.westmarine.com/webapp/wcs...9&classNum=764 (Starbrite Star Tron Diesel additive) which is supposed to kill and enzymatically dissolve the funk in your fuel-- so it can be filtered or burned.. (Sounds hopeful to me-- but unrealistic).. For $12, though, I thought I'd give that a shot, before I drained and dropped the fuel tank.. (anyone who's done that understands why, right??)

Yes, I DO carry spare primary and spin on filters-- and tools to change both..

I put an two ounces in the tank-- 1 oz is supposed to treat 16 gallons.. I didn't know if the tank was 20, or 25.. It looks like the first "dose" is supposed to be twice the 'maintenence' dose-- so I figured a little more is what it's looking for.. I filled my tank, drove it home, and am "planning" to let it sit the weekend-- to let it do what it's going to.. (Supposed to be 95F tomorrow)..

Just wondered if anyone had used a biocide before-- or if anyone had another idea what my 240D's issue is.. The last time it put me a smidge late for work-- and it wasn't an issue, but I don't want it to be a problem for my g/f, or when I need to get somewhere in a more timely fashion..

Anything else I should be looking at??[/align]

 

I don't have any answers for you, but I do have the same problem. This only occurs when I get on the highway, going about 65-75. It only started shortly after I replaced the fuel filters, which was late winter. The first time it happened was summer, I was on the return trip, and three quarters of the way home. So, I had driven 250 miles without problem, then two days later, drove about 175 miles fine, and then started losing response in the accelerator and eventually dying altogether, forcing me to pull off about a half dozen times. I just tried the highway again, and the problem occurred right away, after about 15 miles of highway driving. Throughout this whole stretch of time, I can drive around town completely fine, with no indication of any problems.

The vehicle in question is a 1991 350SD with about 115K miles. Please, I am already dreading my rods bending, so don't rub in my impending doom. Any advice beyond fuel additives?

 

Well--

I've only driven the 240 about 30 miles since I dumped in the starton..

I did some "around town" stuff, then took it out on the expressway.. Stopped home, dropped off some stuff, then got about 3 blocks from my place, before I had a similar fuel starvation issue.. (shrug)

I did nothing-- hoping that the filter screen is plugged.. My hand pump (injection primer) was leaking, and I'd temporarily installed a facet electric pump.. I ran that, while I drove to the grocery store (about a mile away) and let it continue running while I was in the store about 10 minutes, and continue running on the drive home. No issues..

I think my goal is to try to run the tank down as far as I can-- pump out whatever I can, and pull tank strainer screen. (and replace it)

While I've got the tank "mostly empty" hit it with a BIG load of biocide and rinse it with kerosene or vege oil.. As rusty as the 240 is, I'm honestly spooked to drop the fuel tank.. I'm hoping that maybe-- if it's not diesel bug, that it's just a partially plugged tank screen.. My gut tells me-- this is ugly-- and gets a 'fatal' plug occasionally.. Time will see..

I may hit the tank with a second dose... Dunno... I'm not sure if this stuff needs "time" or "dose" or both to be effective.. It does list a "double" dose for the first tankful.. To me that's saying they want to get a 'lethal' level-- then use a lower dose to keep it down..

I remember reading on one of the VW diesel sites, that a guy had a piece of 'foil' (like the seals under a bottle cap) that he found in his tank.. He'd stall when his tank was under 1/2 full, taking left turns.. Upon removing it, he theorized it normally sloshed around in the tank "harmlessly" but the lower tank volume, allowed it to get sucked to the fuel line..

What I don't get-- is why the return and intake don't enter the tank thru the screen.. Seems like the fuel return could create a constant "flush off" for the screen...