Am I cursed? - PeachParts Mercedes-Benz Forum

bgkast · #1 07-28-2006, 02:43 PM

You may have seen my recent saga of buying a $400 240D that would turn over, cough, sputter, and shake, but not start, then seized while I was trying to diagnose the problem. Well today I tried driving my other 240D and the same thing is happening!

The trouble seems to have started a while back when I changed the fuel system configuration from pushing through the spin on filter, to pulling through it due to a change in my veg oil system. Doing this forced me to plug the air-venting orifice on the top of the spin on filter using a solid bolt in place of the banjo bolt. I had noticed that a minute or so after starting the car would loose power for a second or two, then go back to normal. I figured that this was due to an air bubble in the system that would normally have vented through the stock setup.

Before starting the car today, it had been sitting about a week, verses overnight the other times the loss of power had occurred. The car started fine, warmed up for a minute then died when I started to back out of the drive way. I tried priming it, but the primer pump seems much less effective with the new fuel system routing and I could not get the car to re-start.

I guess I will just cap off the oil system for now and change the fuel system routing back to stock and see if it works any better. If it does I guess I will add a electric fuel pump to the oil system and stop sharing the lift pump between the two fuel systems. Does anybody know if the air vent orifice will provide enough flow to prevent “dead-heading” the lift pump when the car is running on oil?

Thanks for reading my rant. -Bryan

biopete · #2 07-28-2006, 07:29 PM

Did you by chance put a new style primer pump on when you installed your veggie system. I did and it cost me days. That cheap thing from ********AZ would not prime in veggie configuration where it hand to suck it through a filter. Finally, i put the old one back on that came with the car and it primes great. Man, talk about frustrating. So note to veggie users, the new primer pumps are not for you. If yours breaks, get one from a junk yard.

What is your normal system for letting air bleed off? Let fuel go back to the fuel tank?

good luck.

bgkast · #3 07-28-2006, 07:42 PM

My car came with the new style pump. Because I no longer can use the air bleed I just let the fuel return line send the air back to the tank.

biopete · #4 07-28-2006, 07:55 PM

Quote:

Originally Posted by bgkast

My car came with the new style pump. Because I no longer can use the air bleed I just let the fuel return line send the air back to the tank.

Well there is your priming problem. Throw it away. Or use in on a car with stock configuration. Mine can prime in regular configuration . I have my return going through that bleeder bolt thing and switching valve after it. I've thought of plugging this up since it dumps a little veggie oil in the stock filter. But i dont think it can be that much since the stock filter is full and not getting .... REVELATIon ... maybe. I was going to say the stock filter is not getting fuel sucked out of it. However, If i have my return line running through that and to a switching valve that loops the fuel back to IP then, the IP could be sucking fuel from the stock filter and this could explain why my startup tank seems to drain faster than it should. I was blaming the pollak valve. I'm going to plug that thing up. cheers

bgkast · #5 07-28-2006, 08:10 PM

If you are pulling through the stock spin on filter and don't cap the air bleed port the return line can allow fuel to bypass the filter. Does that 300CD in your sig. have a good turbo engine?

Old300D · #6 07-31-2006, 01:03 PM

Quote:

Originally Posted by biopete

Did you by chance put a new style primer pump on when you installed your veggie system. I did and it cost me days. That cheap thing from ********AZ would not prime in veggie configuration where it hand to suck it through a filter. Finally, i put the old one back on that came with the car and it primes great. Man, talk about frustrating. So note to veggie users, the new primer pumps are not for you. If yours breaks, get one from a junk yard.

What is your normal system for letting air bleed off? Let fuel go back to the fuel tank?

good luck.

I never had a problem with the new style primer pump running vegetable oil. I've found that pump to be superior to the old style in every way. It even works well with biodiesel.

bgkast · #7 07-31-2006, 01:31 PM

I bought a 12V fuel pump, but just had an idea to try before I put it in and revamp the whole system again. Is it possible that if I had a small air leak on the diesel side of the system could air fill the system as the car sits?

Lostyankee · #8 07-31-2006, 02:52 PM

I use the new style prime pump with 25% RUG + WVO. My old one failed and I had lots of air in the lines. I believe the air came from the old pump.
Please do not take this as flaming your WVO process.
I would keep a standby temporary fuel system handy (like the diesel purge system) and use this to make a base line of what works. If you can run the engine on a quart of diesel, then look at your fuel or fuel dilivery system.
How are you dewatering?

This is how I use WVO and it may fail tonight and or ruin everyone else's engines, cause divorces, male disfunction, children ... (disclaimer). I decided to forego a two tank system or common WVO conversion. To KISS, I blend fuel to the climate (20-30% RUG) and use store bought diesel in the cold. I realize this hugs a few less trees, but I have an uncomplicated system. As for the $ for conversion, I looked at the $ vs the $ of a few gallons of diesel and RUG per year and I would have to drive 20k miles to breakeven. I do have a insulated pad style heater on the IP lines and made a cheapo viscometer to gauge my blend against a constant (diesel).
Good luck and please post your results.