1992 Mercedes 300D, 272K miles, I've owned car since Dec 07, it is my first Mercedes and first diesel vehicle. I have installed waste veggie oil conversion kit from frybrid.com.

Car will not start on diesel (never mind on veggie oil. NO veggie oil has been added to the car, BTW). I crank engine (20-30 seconds) but it doesn't fire. Done this maybe 10 times, waiting a few minutes between each attempt to start car. Diesel tank is about 1/4 full. Vehicle parked on level ground. Air temp in the low 50s F.

I've opened each (one at a time) of the hard fuel lines at the injectors, cranked engine, but see no diesel there. I opened fuel line between lift pump and injector, cranked engine, and see fuel there (conclude that lift pump is working OK). Return line has fuel in it. Mityvac hand held vacuum has been used to remove air from all rubber fuel lines. Is the fuel injection pump the problem? What else can be done to test fuel injection pump? Could screen on fuel line pickup in tank be partly/fully clogged? I'm stuck here. Thanks.

Kevin
Baltimore

As I understand your problem, car ran ok, you installed a veggie kit, and now car won't re-start?

If that's the case, it's got to be air in the fuel lines. Is this a 2 tank system?

How are the fuel selector valves hooked between tanks and IP?

May be try forcing compressed air into your diesel tank (be carefull not to blow it up!... not more than 5psi I would say). I did that on mine to help "pushing" diesel fuel into the system after doing a 2 tank conversion. I have put a rag into the fuel tank openning and stuffed through it the compressor hose... We were two people, one checking air pressure in the fuel tank, the other cranking car.

Are all glow plugs confirmed ok?

Hope this helps.

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BigBen

'98 E300 Turbodiesel 244 000km
RIP '92 300D 2,5 Turbo 632 859,4km due to engine failure

>As I understand your problem, car ran ok, you installed a veggie kit, and now car won't re-start?

Yes.

It is 2 tank system.

>How are the fuel selector valves hooked between tanks and IP?

Page 4 of this PDF has great diagram of how diesel and veggie fuel lines connect to valves and then to IP. I followed this PDF carefully.

http://frybrid.com/additional2.6.pdf

I haven't tried forcing small amt of compressed air into diesel tank but I may! Thanks for idea.

>Are all glow plugs confirmed ok?

I think so. They worked fine on Feb 11 before I started frybrid install.

Kevin

Call or Email frybrid and explain what is happening. I bet it has happen to someone else and they have an answer.

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84 300D, 82 Volvo 244Gl Diesel

I am not familiar with the arrangement of hoses on your car as I have 84 300D. If your situation was happening on my car I would disconnect the hose that goes from the little primary filter to the fuel inlet tubing that goes back to the fuel tank. I would stick the hose into a 1qt can or jar filled with diesel fuel and open up all of the hard lines at the injector and have some one crank the engine and see if it gets fuel that way. If you are getting fuel to the injectors from the fuel in the can it means the problem is somewhere to the rear towards the tank.

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84 300D, 82 Volvo 244Gl Diesel

Chris from Frybrid.com replied to msg I posted on his site and said that his 3 way valves aren't as air tight as one might think. Apparently, a small amount of air was being passed from empty veggie oil (VO) fuel lines through the 3 way valve and into diesel lines. Chris suggested putting few gals of diesel into VO tank and priming the VO fuel lines. I did this last night and almost got engine to start. There's still air in some of the fuel lines because engine won't stay running. The Mityvac pump has been invaluable for removing air from the fuel lines. There's now plenty of fuel at the injectors... they "hiss" when I crack one open. I must still have air leak in diesel and possibly VO fuel lines. I don't see any fuel leaks from these lines, though. If air can get into fuel lines, wouldn't I see a fuel leak somewhere? All hose clamps seem tight. I keep battery charger connected to battery at all times since I'm cranking starter so often.

I'm getting closer....

Thanks,

Kevin

D'OH! How I wish I had followed Frybrid directions MORE CAREFULLY!

Frybrid instructions clearly say to plug the banjo bolt (picture a threaded bolt with 1/4 inch hole in threaded section) on the fuel return line. This bolt is on side of diesel filter housing and (as configured by MB) allows some of the diesel in return lines to pass back into diesel filter and then to injector pump (and the remaining fuel is returned to diesel tank). The opening in bolt MUST be plugged when frybrid kit is installed otherwise VO could possibly be sent back to diesel tank. A big No No.

I hadn't yet plugged banjo bolt thinking this wasn't really needed until I added veg oil to VO tank. So, hole in bolt allows air in the return line to be drawn back into diesel filter and then the injector pump. The car will never run properly (on either diesel or wvo) until this bolt is plugged. (I even have JB Weld for this).

Hats off to Chris Goodwin at Frybrid for spending time this morning replying to my postings on his msg boards. He takes a LOT of heat for not replying to email, phone msgs, etc. but today he really helped me out (and QUICKLY!)

Unfortunatly air can get in at places that fuel will not leak from. Can your mity vac help? Pull a vaccum and see if it holds? You might have to isolate parts of your system but if it's intaking air the vaccum should not hold up in a constant fashion.
At the present time I might make the engine run on wd40 until it purges all it's air out. This will only work of course if the system is tight.

Update: I spent quite a while removing air from diesel fuel lines and finally got car to start today. Life is good again. The Mityvac vacuum/pump was essential in this process. I cracked each of the injectors and repeatedly started the car (resting 30+ seconds between attempts). It takes a long time to purge air out of fuel system. Also used battery charger to keep battery from discharging. Thanks for the feedback. Kevin

Hi Kevin,

I'd encourage you to replace the banjo bolt with a regular bolt rather than filling it with Epoxy (JB Weld). Epoxy doesn't have very good fuel resistance and might degrade over time. JB Weld has fillers in it like silica (sand) and/or metal particles to increase the strength of the epoxy. If a little epoxy dissolves, these particle will be released into your fuel stream, and (depending upon where your filter is) might be delivered to your injection pump. The bolt is kind of an odd thread pitch, but I was able to find one in my local autoparts store packaged in the "random, generic parts section" (red packages branded HELP!).

Be sure to use the metal seal washers with the new bolt.

Good luck with your conversion!

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1998 E300D 1-tank Elsbett Veggie system
1986 190D 2-tank Veggie system -Sold