Saving WVO orphan! Input? - PeachParts Mercedes-Benz Forum

Cadin · #1 06-14-2015, 01:52 PM

Hey Gang,

I just recently picked up an '85 300TD that suffers from the classic ailment of Portlandia Grease Conversion (PGC).

The story from the PO: The car will fire if it had sat for a day or so, and run great for a moment; but will smoke, smoke and not fire if tried to start sooner.

-Valves have been adjusted; local Merc. mechanic thinks a problem with fuel delivery.

-Had been run on veggie oil for who knows how many miles, PO disconnected WVO and went back to just petrodiesel, new filters. Said he found a lot of red gunk in the WVO tank (didn't sound like rust, but could it be IP rust? Red Algae?

-Funny thing, car has all service records, as well as the original dealer window paper; beautiful interior, strait body, faded hood.

Sooo, Where would you say I go from here? I have a known good IP and rebuilt injectors. Should I just swap IP's (I have the MB locking pin, and have used it successfully), injectors, filters (oil and fuel), shoot the ohms on the glow plugs?

Any and all input welcome!

vstech · #2 06-14-2015, 02:06 PM

I would drop the fuel tank, pull the screen, and have it and both fuel lines and the air vent steam cleaned... Seriously, STEAM cleaned. Don't bother with anything else until that is done.

If you want to rule out the IP as a problem, unhook the fuel lines, and get a bottle of fresh diesel connected directly to the supply and return lines under the hood, and see how it runs like that. If it STILL runs poorly from a direct bottle of fuel, you need a new IP also...

I guess the FIRST thing I'd do is a compression test.

Report back after that.

Cadin · #3 06-14-2015, 02:58 PM

The fellow's mechanic said the compression was good, but I will confirm the actual numbers. (I have an unused HF diesel compression tester around here somewhere...)

The factory tank was never used for WVO as far as I know, it was all on a separate tank out of the trunk with a switching valve (6-way?).

I will put a container of fresh fuel on the fender and give her a whirl.

As far as the steam cleaning is concerned, I have a pressure washer and hot water tank, do you think that is sufficient if I crank it up (temp)?

Cadin · #4 06-14-2015, 03:00 PM

Oh, and should I perhaps diesel purge and replace the fuel filters? (Provided compression is good.)

cooljjay · #5 06-14-2015, 06:00 PM

Run...RUN...RUNNNNN away!!

Its a nightmare, use the money you are going to be spending on all the replacement parts to buy a TD not ran on WVO...

Here's my first hand experience...

My new 300D...plus headache.... - Mercedes-Benz Forum

I would also count on the tank and lines needing cleaning....sure its never been done and also when it was switched to diesel from wvo...I am sure some back flowed into the tank...mine a was a single tank and this is what the stuff turns into...

This is what the fuel filter looks like..

Drago · #6 06-14-2015, 06:17 PM

I was just never keen on running anything on WVO from all the horror stories. I used home made bioD which created some of it's own problems. The best results I've seen was virgin VO mixed with either kero, gasoline, or diesel. I would just replace the tank with a junkyard pull or even put a boat tank in. Replace all the filters, replace all the rubber fuel lined flush all the hard lined and flush the IP with liqu moly. first I would try to do the IP flush and see if the IP still worked. My 300D is more of daily driver/hobby car. I have two other cars to get to work with.

Cadin · #7 06-15-2015, 01:09 AM

Well, I don't think that the stock tank was used for the WVO, it was all through a plastic separate tank in the back with a switching valve. Hopefully she is not lost!

Cooljjay, I just read your thread, and it seems promising since I have the parts in the shop. (Was it supposed to discourage me?

) I don't get to start wrenching on the beast until Tuesday, but I will share my joy when I know just what I'm dealing with!

It like a dimestore mystery! I think I'll try gathering the clues to save this old pearl.

cooljjay · #8 06-15-2015, 02:14 AM

I suppose not to discourage but to show what may be involved...I don't want to ever do it again...

I would have to change and adjust valves at least every thousand miles for years. This was the in the hopes of getting the gunk out of the engine and carbon build up. You see when you burn wvo you burn something with that produces more carbon then diesel and people don't increase maintenance...pretty much the car I bought and the car you bought are what these cars turn into after so many years of wvo use...

Even now I burn a quart of oil every 300 miles...sometimes two....I cannot use synthetic as it burns it like gas...its crazy...I love that car but it was honestly a nightmare...

Cadin · #9 06-15-2015, 02:35 AM

Well I Certainly appreciate your candor, and you do speak as one who has walked this path!

I'll get some more clues and share the fun, or chagrin!

Stretch · #10 06-15-2015, 06:12 AM

With the pictures cooljjay posted I recommend some whole grain bread and a big knife for spreading - yum yum!

(To be honest with you I'd do the cheapest things first and see if it runs before investing loads of time and cash)

Maxbumpo · #11 06-15-2015, 10:25 AM

Straight biodiesel (or B99) will do wonders for cleaning out the entire fuel system, be prepared with new filters and the tools for changing them on the road side.

Phillytwotank · #12 06-15-2015, 10:33 AM

You've got a spare IP and rebuilt injectors... I say go for it!
Would probably use and auxiliary fuel tank set up at first to avoid the potential to foul up the spare IP and injectors with tank crap.

Cadin · #13 06-15-2015, 03:56 PM

Quote:

Originally Posted by Stretch

With the pictures cooljjay posted I recommend some whole grain bread and a big knife for spreading - yum yum!

(To be honest with you I'd do the cheapest things first and see if it runs before investing loads of time and cash)

Mmm, Delicious!

(I was thinking the same thing, that's why I figure I'll do the compression when I swap the injectors, and run some diesel purge through the open lines. Get her going with a tank on the fender, and spare filters, tools, AAA, and a good book on hand. Hope for the best, expect the worst!)

llensart · #14 06-15-2015, 04:02 PM

Why do People think that you can run these vehicles on "Veggie oil" (when selling them ) and think that's a virtue

Ceristimo · #15 06-15-2015, 04:13 PM

Why?

Because "bomb proof" and "million mile engine" and "best car evah!" and "these W123's will run forever" and "old diesels will run on anything" and "diesels were designed to run on peanut oil!".

Sure, but Mercedes intended this one to run on diesel...