300SD dies at idle and has NO POWER!!! - PeachParts Mercedes-Benz Forum

disbo100 · #1 02-03-2009, 01:03 PM

Hello Folks,

I looked through the DITY pages and the other helpful links but Im not sure what my problem is..

Got kind of a weird one. I have an 83 300SD (300K miles) been running on VO for about 2 years now. No real problems with it until recently. I have an inline heater and 3 filters. I replaced all filters and I'm running on 50 WVO and 50% diesel.
About 2 weeks ago the power was getting really low. Not much acceleration at all. Then it just died.. I got it restarted but wouldn’t hold an idle. I had to bump it from N to Drive to get it home while giving it some gas.
It still had the original hand pump to prime the system. When I was working it leaked all over.
Thinking this lack of fuel meant it had an air leak. I replaced the pump, checked all fuel lines for any possible leaks and none could be found. Started it up and seemed to be OK.. Drive it around the block and it still had NO BALLS at all. Then Id died on me again... I had to do the bump and grind to get it home.. Again.
I did notice that it would shutter a bit in the tranny and wouldn’t downshift on good acceleration
-My guess is a vacuum/air leak of some kind? But where....
-what places can I check to ensure all the right hoses are connected?
-Any suggestions are apprenticed.

Thanks Chris in FL.

LUVMBDiesels · #2 02-03-2009, 01:08 PM

1) Change the primer pump -- Air is getting in.

2) Try running the car on Diesel from a bottle bypassing the tanks. The tank screen could be plugged or the VO might have gunked the hard lines.

If it still does not idle correctly:
As you are running the car, try pulling the vacuum line from the shut off valve on the IP and see if it will idle.

Good Luck!

jross · #3 02-03-2009, 02:02 PM

Sounds like VO claims another injection pump.

Have you tried running your car on straight VO? Bypass the heaters and run straight VO. If that solves your idle problem, your IP is shot.

mplafleur · #4 02-03-2009, 02:53 PM

Quote:

Originally Posted by jross

Sounds like VO claims another injection pump.

Have you tried running your car on straight VO? Bypass the heaters and run straight VO. If that solves your idle problem, your IP is shot.

When has VO claimed any injection pump?

disbo100 · #5 02-03-2009, 03:48 PM

Hi,

I did replace the primer pump with OEM.. Same story.

All three filters are clear and I can see that fuel has no problems getting to the IP.

Ill pull the vacuum line off of the IP and see what happens.. Im assuming it SHOULD die.. if not what does that mean??

Ive done the diesel purge on this and my 4 other converted cars.. Ill give it a shot and see what happens..

If the IP is dead.. It should not work at all...RIGHT? or it may be so degraded it its only working at 20-30% power?? I dont know I havent ever messed with the IP.s

Ill keep ya posted.

Chris

mobetta · #6 02-03-2009, 04:17 PM

I posted in bold

Quote:

Originally Posted by disbo100

Hi,

I did replace the primer pump with OEM.. Same story.

All three filters are clear and I can see that fuel has no problems getting to the IP.

Are you just using 3 plastic inline filters? I hope not. can you see air bubbles?

Ill pull the vacuum line off of the IP and see what happens.. Im assuming it SHOULD die.. if not what does that mean??

No, it should not. I am unsure of what the op is getting at, it may be this- it could be getting a bit of vacuum thru the switch and partially closing the fuel supply.

Ive done the diesel purge on this and my 4 other converted cars.. Ill give it a shot and see what happens..

If the IP is dead.. It should not work at all...RIGHT? or it may be so degraded it its only working at 20-30% power?? I dont know I havent ever messed with the IP.s

if it is not sealing well, the thicker wvo could increase pressure. and this failure mode would be somewhat gradual, getting worse as time progress's. caused by wet and or dirty oil. what is your processing technique?

Ill keep ya posted.

Chris

mplafleur · #7 02-03-2009, 05:36 PM

My guess is that you are not getting enough fuel when power is needed. Maybe the tank strainer. My was plugged with black sticky stuff.

Astroman · #8 02-03-2009, 10:25 PM

coked injectors.

If it runs worse or won't start on straight diesel, then it's worn/worn out IP

disbo100 · #9 02-04-2009, 12:13 PM

All good points Gents..

-the first in line Filter (from the gas tank is always full) so Im not sure the strainer is clogged. Actually, all the filters are full with no bubbles.

-Ill run stright diesel in it and see what happens.

-Could someone post a picture of which vacuum line I should pull/check?

I let the WVO sit for a few weeks, pump it in to my 5 micron filers. It sit again for a few weeks then pour it in with 20-50% diesel..

thanks chris

jross · #10 02-04-2009, 02:46 PM

Quote:

Originally Posted by mplafleur

When has VO claimed any injection pump?

It claimed the IP in my (new to me) 300 just after I bought it, and I've seen it a couple times now on local cars. Typically it's because of problems on the install (though one was because of lack of filtration...)

veggiejoe · #11 05-01-2009, 08:23 PM

Hey guys,
I have the exact same problem as described in this thread and wondering if my ip is toast. However I run a two tank system & after running diesel purge through the system, it runs fine again on diesel. When I switch to vo, it lacks power. Also I have an inline heater for my vo fuel line just prior to the lift pump.

Any thoughts / ideas?

pottzie · #12 05-01-2009, 09:16 PM

You said you replaced all filters. If that includes the big secondary, then this is no help.
But you keep referring to three clear filters, without mentioning the "big daddy" fat filter that's by the power steering pump. That's the one that would clog up.

Alastair · #13 05-02-2009, 01:32 PM

Quote:

Originally Posted by disbo100

All good points Gents..

I let the WVO sit for a few weeks, pump it in to my 5 micron filers. It sit again for a few weeks then pour it in with 20-50% diesel..

thanks chris

Hmm, I think this could well be the demise of your IP's....

The oil will contain Moisture. Not all will settle out. WVO/UVO HAS to be DRIED PROPERLY of moisture.

The suspended/entrained moisture from food cooked/bad storage/condensation will become ACIDIC due to the FFA (Free-Fatty-Acid) content Always found in Used Veggy oils.

BTW, FFA Cannot be Filtered out. Its an oil just like the VO its dissolved in, ands will make any moisture acidic, --Just right for the mega-precision pumping-elements found in an IP....

....

Thats why I gave up with WVO, TOO much effort to PROPERLY dry and filter to prepare it, and only a little more work to make a PROPER fuel, ie--BioDiesel

Diesel911 · #14 05-02-2009, 11:37 PM

Quote:

Originally Posted by disbo100

Hi,

I did replace the primer pump with OEM.. Same story.

All three filters are clear and I can see that fuel has no problems getting to the IP.

Ill pull the vacuum line off of the IP and see what happens.. Im assuming it SHOULD die.. if not what does that mean??

Ive done the diesel purge on this and my 4 other converted cars.. Ill give it a shot and see what happens..

If the IP is dead.. It should not work at all...RIGHT? or it may be so degraded it its only working at 20-30% power?? I dont know I havent ever messed with the IP.s

Ill keep ya posted.

Chris

If you pull the Vacuum Tubing off of the Shutoff Vlave (and plug the Tubing) it will not die; in fact you will not be able to shut it off by turning the key off.

Also take a look at all of your Throttle Linkage and see if any thing has come loose or fallen apart.