Alternator? Battery? Fuel Filter? [With Pictures] - PeachParts Mercedes-Benz Forum

Dynotoaqrimp · #1 09-30-2009, 10:59 AM

I've been driving my 75 300D 115 for a couple of days, and noticed a serious problem. When my car is accelerating whether after a red light, on an on-ramp, over hills and bridges, my car struggles. Over hills and bridges it starts decelerating until it sputters out, and no amount of pressure on the gas pedal prevents it.

I suspected a bad fuel filter that was clogged up and needed to be replaced, I replaced it and the symptoms remain. On that note, when I went to the parts stores they mentioned a primary and secondary fuel filter, however when I looked I only found 1 fuel filter, a cartridge fuel filter. Is there another fuel filter hidden? [Pictured below]

I'm also worried it may be the alternator or the battery. I noticed the belt on the alternator was looser than it should be, and I want to tighten it up, but I can't figure out how to do it. It is unlike any pulley tensioner I have seen [Pictured below]. It has some forks on it that I assume you use to tighten the pulley, but I can't successfully move them to tighten it.

Can anyone help me solve these issues?

Thanks,
Will

Necrosavant · #2 09-30-2009, 11:10 AM

theres a filter in the tank, i dont think the 115 comes stock with a pre filter/ at least mine didnt i added the filter when i got the car..
as for the alternator as long as your battery lights not coming on and its not squealing you should be fine....but to adjust you need to loosen the bottom bolt of alternator and loosen the bolt behind the adjustment screw, then turn the adjustment screw clockwise to tighten and then retighten the bottom bolt then top again

Dynotoaqrimp · #3 09-30-2009, 11:19 AM

Was your filter in your tank plastic?

And thanks for the info on the alternator adjustment, I have noticed some squeaking though. I had to tighten my AC belt as well.

Necrosavant · #4 09-30-2009, 11:26 AM

filter in the tank is actually just a strainer like cast metal and about 10 micron plastic element, the prefilter should be a clear plastic inline filter that sits in engine compartment next to injection pump, once again mine didnt have one i had to cut the rubber line and add one

Dynotoaqrimp · #5 09-30-2009, 11:33 AM

Yea my car does not have one, did you add it immediately? Or were you driving with just the strainer and cartridge filter for awhile? And did you notice any of these symptoms while driving yours before adding the second plastic filter?

Necrosavant · #6 09-30-2009, 12:10 PM

Quote:

Originally Posted by Dynotoaqrimp

Yea my car does not have one, did you add it immediately? Or were you driving with just the strainer and cartridge filter for awhile? And did you notice any of these symptoms while driving yours before adding the second plastic filter?

i added it immediatly because when i got the car i knew it had been sitting for a long while, the diesel was dark yellow and tank looked rusty...i ran through about 3 tanks of diesel then i had to change it and since then ive been only getting really clean diesel in my prefilter

Dynotoaqrimp · #7 09-30-2009, 12:13 PM

Thanks this sounds exactly like what I'm experiencing at the moment with my fuel. So before the fuel gets to the cartridge filter you added the plastic filter? And you said you had to cut the fuel line and mount it somehow?

Necrosavant · #8 09-30-2009, 12:22 PM

dont mind the dust just got it back from paint shop

Dynotoaqrimp · #9 09-30-2009, 12:28 PM

Thanks so much for the pics

. That helps a lot!

meltedpanda · #10 10-01-2009, 09:26 AM

the real fix if you suspect the filter in the tank is to remove it and replace , while in there blow out ( with compressed air) the lines both outgoing and return , diconnect and clean out sludge around filter. It is a very messy job. Close it back up Then place clean gas in the tank swish it about and empty it again , do this several times. Then you should be good to go.

Dynotoaqrimp · #11 10-01-2009, 10:56 PM

The primary and secondary filters? Or the screener in the tank?

Necrosavant · #12 10-02-2009, 08:37 AM

Quote:

Originally Posted by Dynotoaqrimp

The primary and secondary filters? Or the screener in the tank?

hes saying to fix the prob that you have with hesitation you must also clean the filter in the tank or better yet, replace it...because adding an extra filter is just for extra protection

meltedpanda · #13 10-02-2009, 08:44 AM

took the words right out of my mouth

Dynotoaqrimp · #14 10-02-2009, 12:29 PM

Thanks for clearing it up, the only way to get the screener is to drop the tank no?

Mike D · #15 10-02-2009, 12:38 PM

The '75 has a large allen head plug in the bottom center of the tank. Invert a spark plug socket and use it as the allen wrench. This removes the strainer assembly.