Well, biodiesel DOES gel. I don't know the exact temp, buty it was butter-ized so I stopped using it for now. Ultra Low Sulpher Diesel (15ppm) I already know about WVO, it's not a big concern to me at this point, neither is a valve adjustment until after the engine wants to run. My car retained all of it's stock metal lines, I only changed the rubber ones with vinyl (wrong material I know, but it works) Would the transfer pump be that thing with the black plastic purge valve on it?
OK I went and got my hands dirty and learned a bit about how the fuel system is supposed to work. I now know that: Fuel is supposed to come from the tank, flow through an inline filter, then go somewhere at the bottom of the injection pump, get pumped back up into the canister filter and go back to the tank. Right? I'm still clueless as to what the red plastic line on top of the injection pump does.
What my car was actually doing: Well, nothing unless you pumped the purge valve very quickly, then fuel very slowly came up from the tank and barely made it into the inline filter. It would run if I kept the canister filter full, which had to be done by pouring it in through the top.
What I did: I bypassed the inline filter and red plastic line that makes the fuel go to the pump and back. I connected the line from the tank straight to the reciever underneath the purge valve and used the valve to pump fuel (which was much easier now with the shorter trip) directly into the canister filter.
What happened: The car ran continuously as long as I frequently pumped the purge valve. The idle would get rough as if running out of fuel if I didn't. A foamy mixture of air and fuel ( I could see it was now a B99/ULSD mix) flowed of the line at the top of the purge valve. This was the fuel feeding the engine, correct?
What else I learned: The nuts and possibly seals on the purge valve assembly seem too easy to loosen which causes fuel to slowly drip out. Perhaps running bio ate some rubber seals which are now letting in air?
My conclusion: The fuel pump is not doing it's job. I should have seals in the purge valve replaced with OEM/better quality parts, along with lots of other seals and hoses under the hood. Please correct me if I'm wrong. And if you've made it this far, THANK YOU THANK YOU THANK YOU. I would be permenantly up poo creek w/no paddle without the internet and the people who use it.
The first video shows what happens when I throttle up the engine. The line coming from the lower side of the injection pump spurts some fuel, mostly air.
In the second video you can see me pump the purge valve, which will fill the line from the tank to the canister filter. Shortly after I stop, the line empties, and you can see fuel and air coming out of the filter on it's way to...? I can't remember, but it goes back to where ever it was designed to, I didn't change it. I think it goes to the pump because as long as I used the purge valve to fill the canister it kept running.
The third video is a longer, poorly lit version of the Second. I threw it in there just in case.
Finially got to the mechanic while he was still open and he told me that it's probably just a clogged screen blocking the fuel pickup in the tank. Now I gotta get that huge ass hex bolt out and have fun with downpouring diesel. Anybody know what size it is? 19mm?
I think you're right it's 19mm or 22mm. I have never remembered to check it while it's on the lift. It's best to run the tank down first if possible or use a container to catch the fuel before removing the strainer.
Definately not compression, I'd just sell it for parts if that were the case. I used a pump siphon to empty out as much of the tank as I could into a new diesel can today but I only got about 1 gallon (there's at least 10 more in there) and the stuff I sucked out was real dirty with lots of flakes, supporting the mechanic's idea of a clogged screen. Went to Harbor Freight but they didn't have any big hex keys. Any idea where else I should look? Working on a diesel is a real pain when it won't QUIT RAINING! Oh well, I'll be back out there tomorrow if I have time after work.
Are they black flakes or rust flakes? I get chunks of rust in my 300D fuel system which settle out in the prefilter. It was a San Diego car as far as I can tell so it probably got a fair share of salt spray.
The bolt on the bottom of the W114/115 tank? Try 24mm. I bought "the right tool" from the benz dealer in manhattan way back when. They gave me a slight discount since it was a used tool right off a work bench.
When I saw, it I just started laughing. It was a big bolt with a 24mm head and two nuts jammed together. It worked like a charm. No clue where that tool is these days. That was like 12 years ago.
Oh, snap! I didn't even think of that! A couple of minutes with a drill and a few dollars for a huge bolt would be way better than paying $19 or so for a "special" tool I'm only going to use once or twice! Thanks!
VICTORY! Well almost. I finished plugging the fuel lines back together the way they're supposed to be - still using clear vinyl so I can see what's flowing - and the car ran for about 45 minutes. I let it get nice and warm and I even drove it a couple miles. A few times at idle it got rough so I pumped the purge valve a few times to fill the tank > inline filter hose and it smoothed back out. Strangely, the line from the injector pump to the canister filter isn't full, it's just spitting small amounts of fuel up the line, as is the return line. Stranger yet is that the car idled for 20 minutes after I drove it (then stalled) without me doing anything. The tank to filter line has some fuel pooled in it but no flow. Does the injector pump hold a certain amount of fuel in it? I did not yet get to the screen in the tank but when I do I'm not going to clean it - I'm going to chuck it in the trash.
I am also leaking fuel from all the looped return lines at the injectors, (that can't be good - time for repleacement) and this, which I never noticed before. I hope some metal rings will fix it.
Last edited by SakoTGrimes : 01-06-2007 at 05:04 PM.
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