W123 300D problems

Single Tank WVO systems and blending SVO WVO to thin it.

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W123 300D problems

Postby pietbez » Tue Mar 09, 2010 4:48 pm

hi, i am new to the whole veg oil revolution and very eager to learn.

i have a 1978 W123 300D. i have had it for about 1 month now and i love the car.
yesterday i decided to try my first blend but i think i did it wrong :(

i drove my last tank of diesel till the reserve light came on. then i mixed a small 4litre blend of 1.5litre brand new veg oil and 2.5litre diesel.

yesterday was a hot day, about 42 degrees. yes, i live in a very hot area.

usually with diesel, i have to swing a few times before she takes. but now for the first time on the blend, she takes with the first swing, and she sounds great.

i tested the blend for about 30 mins. driving, idling, reving, stopping, starting (started first time every time)

but then the trouble started. the engine started shaking, bouncing, missing and just not sounding right. especially at low revs or idle and when i turn the car off it gives a few wild shakes before it dies.

this obviously freaked me out so i filled the tank with straight diesel again but the problem is still there

i have little knowledge of diesel motors but it sounds to me like she is running on only 4 cylinders. could this be?

could one of the jets be blocked? what am i to do? did i kill my car?

please help
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Joined: Tue Mar 09, 2010 3:51 pm

Postby coachgeo » Tue Mar 09, 2010 10:02 pm

Doubt you killed the car. It's just baffled cause you changed its diet.

Look at your inline fuel filter. If looks yucky. change it and the cannister filter as described below. If not.....

First do an Italian tune up on diesel ( google search should tell you what that is)

Then change your fuel filter(s). Veg has a tendency to clean things and junk pulls loose and clogs the filter. change both the inline filter and the canister filter. Fill Cannister filter with Lubramolly Diesel Purge before you put it back on.

Repeat Italian Tune up.

when you try some Blend again it may loosen more stuff so it could happen several times as it cleans the system.

Also you might notice some hesitation as the IP's mechanical system adapts to the change in viscosity. The 300d's Injection Pump is a pretty remarkable design that does adapt some to viscosities. One reason why it is such a veg loving engine. Once it gets a few minutes of flow of the changed viscosity it pokes along rather normally.

There is also the chance that you had an air leak that your fuel filter's auto air bleed system could take care of just fine. That is until a higher vacuum was needed to pull a slightly thicker fuel. This may have increased the size of the path of leak. Tighten all your fuel clamps... not over tight over course. Replace any fuel lines that looks old and cracked at the ends.
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