Left turn power loss! 78 300 cd - Page 2 - PeachParts Mercedes-Benz Forum

Phillytwotank · #16 03-04-2013, 11:03 AM

Update:

Bypassed the supply side "pollock" valve by re routing the fuel lines to the original configuration... no joy

Pressurized a part of the fuel lines with air to look for leaks. Started small and pumped up everything from the end of the hard line on the inside fender through the filters and valves to the lift pump with about 40psi. Noticed a small bubbling coming from the output point of the spin on filter. Said "AH HA" "got you now you dang air leak". swapped out the crush washers. torqued it down. pumped it up again and the bubbling was gone... Went for a Drive. NO JOY!!

Inclement weather on saturday and prior commitments on sunday kept me from going any further into searching for leaks with pressurized air on this weekend. so, i'll have to keep driving on the two tank until at least next weekend.

Still have this feeling that the source of the problem is somewhere in the spin on filter and connections. has been modified during the greasecar conversion and if it could have developed a leak there at the output with out having taken that apart since i did the conversion 5years ago, there could very well be other leaks there that i could not see.

Also, when i spin off the filter its only half full of fuel. isn't it s'posed to be FULL of fuel there? Could that explain the left turn power loss scenario? if fuel was sloshing to a side in there during a turn.

Question:

Is there s'posed to be a washer seal on the main center bolt for the spin on? What about the o rings on the bolt itself? i've switched out that bolt with another one that looked slightly better that the one i had but that didn't change anything. Can i get new orings or a new bolt?

Phil

vstech · #17 03-04-2013, 11:36 AM

certainly need new o-rings on the spin on bolt.
and yes, it should be full of fuel.

chasinthesun · #18 03-04-2013, 11:56 AM

Is your air cleaner attached properly to the assembly? A 190d I drive had loss of power due to an opened up air cleaner hose ,it was pulling straight air from the engine bay to one cylinder.The cars are very different in this area, yours could be the air cleaner itself but since its not feeding one cylinder but all I dont know if its a possible scenario with the 617 motor to interupt combustion.The car lossing power on turns would be right if it was somehow jerry rigged.

Phillytwotank · #19 03-04-2013, 12:25 PM

Any leads on finding appropriate o rings for that application? I have a set but none really match.

I'll check the air cleaner but at this point I'm almost entire convinced that this is an air I'n fuel problem.

Thanks

Govert · #20 03-05-2013, 06:38 AM

There is a small air hole where the spin-on filter connects to the filter housing. This air hole is there to bleed the filter. It connects to the return line. Make sure this hole is not damaged or blocked.

barry12345 · #21 03-05-2013, 10:29 AM

[QUOTE=Govert;3109484]There is a small air hole where the spin-on filter connects to the filter housing. This air hole is there to bleed the filter. It connects to the return line. Make sure this hole is not damaged or blocked.[/QUOTE

Personally I like this suggestion. The air pocket or acumulated presence of it seems to have been located. Take it a step further though if you find that bleeder hole is open.Make sure the path to the return system is both present and not modified plus actually open back to the return system.

If you do this and it all checks out. Make sure that the return line to the tank is reasonably open. I have no ideal of the effects of a closed up return system but my thoughts are retained or even new air air might collect at the highest point.

Your original description indicated to me from my limited experiece that a pocket of air was possible. When I had the issue it was somewhat hard to decide what it might be and required some thinking to decide where it might be once I had. This was not on a mercedes diesel.

Phillytwotank · #22 03-05-2013, 11:35 AM

Ok ok. Y'all talking about the banjo bolt on top the filter housing(injector overflow and IP overflow to cigar hose)? There to bleed air? or to return the return fuel to the supply side?

barry12345 · #23 03-05-2013, 12:31 PM

Suspect to dump air but some manufactures recycled the return fuel back into the filter to preheat it a little .This function was usually thermastatically controlled so it is not a consideration. Plus the setup to enable it is differant. The actual bleeder hole should be very small as it takes fuel pressure to make it work and wasting that pressure is not desirable.

The contents of the secondary spin on filter are seeing whatever the full pressure of the lift pump is. So the only way air could not leave by that bleeder was if the return was obstructed or at the same pressure as the lift pump supplies.

I suspect an obstruction somewhere is allowing the air to accumulate. The air volume in the filter might also be present if the system was back bleeding its fuel as well though. Normally I would not suspect that but with a two tank system possibilities might be increased. Depends a lot on how it is set up from a plumbing perspective.

Phillytwotank · #24 03-05-2013, 01:28 PM

definitely going to have to investigate that further.

looking at the EPC i'm seeing something interesting.

looks like there is a "seal ring" and "spring washer" that is sposed to be a part of the "hollow screw" assembly on the spin on filter housing. Never had those two pieces before.

Phillytwotank · #25 03-05-2013, 01:33 PM

40 and 41

probably go ahead and get a new 38 while im at it.

Phillytwotank · #26 03-10-2013, 08:37 PM

Like to report back. Problem solved!

Cause: air leak in filter housing fuel output causing an air pocket to form in top of the spin on filter. Left turn would cause the air to shift and be sucked in and chug a bit. Also, it would eventually cause a hard start after sitting for about two days.

Critical oversight in failing to realize "off the rack"copper washers are not the same as MB sealing rings.

I replaced the original sealing rings five years ago when I did the GC conversion. It took me all this fiddling to find out the hard way that... Those things are picky. One tight down and no adjustments are about all they can take and they have to be the perfect size to work right.

So, all the Time I was working out this air leak problem I was under the assumption that the seals on the input, output and return line fittings on the filter housings were good. Not so. Replaced the old copper washers with new used MB sealing rings and, after a week of driving, all is well. Left turn chug is GONE.

feel confident at this point that this problem has been solved.

whunter · #27 03-11-2013, 12:48 AM

Quote:

Originally Posted by Phillytwotank

Like to report back. Problem solved!

Cause: air leak in filter housing fuel output causing an air pocket to form in top of the spin on filter. Left turn would cause the air to shift and be sucked in and chug a bit. Also, it would eventually cause a hard start after sitting for about two days.

Critical oversight in failing to realize "off the rack"copper washers are not the same as MB sealing rings.

I replaced the original sealing rings five years ago when I did the GC conversion. It took me all this fiddling to find out the hard way that... Those things are picky. One tight down and no adjustments are about all they can take and they have to be the perfect size to work right.

So, all the Time I was working out this air leak problem I was under the assumption that the seals on the input, output and return line fittings on the filter housings were good. Not so. Replaced the old copper washers with new used MB sealing rings and, after a week of driving, all is well. Left turn chug is GONE.

feel confident at this point that this problem has been solved.

I am glad it was an easy fix.

I assume you will be stocking up on the MB seal rings, for future need.

.

Phillytwotank · #28 03-11-2013, 06:59 AM

Hopefully will NEVER need to take apart the line fittings again. Seems to me that the sealing rings are more reuseable so surley I won't need to worry about the seal for future filter changes. Right?

Thanks for your help Roy and everyone who responded.

whunter · #29 03-11-2013, 03:02 PM

Quote:

Originally Posted by Phillytwotank

Hopefully will NEVER need to take apart the line fittings again. Seems to me that the sealing rings are more reusable so surely I won't need to worry about the seal for future filter changes. Right?

Thanks for your help Roy and everyone who responded.

Glad to help.

As an FYI to others who find this thread.

Most WVO contains some degree of acid, the content is wildly variable. This does not take into consideration industrial cleaners that may have been dumped in.

De-watering and Titration-Test of WVO are critical for fuel system durability.
How to test pH level in WVO

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