om606 no start, vacuum in fuel lines? - PeachParts Mercedes-Benz Forum

NY300SD · #1 10-30-2008, 01:26 AM

Hi All,

I got about a block from my house and it quit.

I cranked and cranked and it was firing intermittently, but couldn't keep it going.

Here's the weird part: When I took off the filter I noticed a brief sucking sound when it came loose. Didn't think anything of it at first and proceeded put a new one on and filled it with atf. Cranked again and it started only briefly. I decided to have a look at the pre-filter and as I took it off I heard the sucking sound even louder this time.

And it was totally dry.

It seems I have a blockage upstream right? I doubt it's the tank screen because it has been running great, and I have yet to see a speck of anything in the pre-filters.

I have a full tank of pump B99 mixed with a couple gallons of regular diesel, and the temps haven't gotten to freezing yet.

By the way, this same exact thing happend a couple of weeks ago. I didn't look at the filters because I was too busy. My wife got it started while I was away and it's been running great till now.

Anybody know what's going on?

Thanks

pimpernell · #2 10-30-2008, 07:49 AM

Quote:

Originally Posted by NY300SD

Hi All,

I got about a block from my house and it quit.

I cranked and cranked and it was firing intermittently, but couldn't keep it going.

Here's the weird part: When I took off the filter I noticed a brief sucking sound when it came loose. Didn't think anything of it at first and proceeded put a new one on and filled it with atf. Cranked again and it started only briefly. I decided to have a look at the pre-filter and as I took it off I heard the sucking sound even louder this time.

And it was totally dry.

It seems I have a blockage upstream right? I doubt it's the tank screen because it has been running great, and I have yet to see a speck of anything in the pre-filters.

I have a full tank of pump B99 mixed with a couple gallons of regular diesel, and the temps haven't gotten to freezing yet.

By the way, this same exact thing happend a couple of weeks ago. I didn't look at the filters because I was too busy. My wife got it started while I was away and it's been running great till now.

Anybody know what's going on?

Thanks

Living in upstate New York, the temps have to be going into the 30s, I would suggest that you try putting some diesel anti gel in to keep the fuel from gelling up. I run straight diesel in my car, so I don't know the properties of putting in B99 and regular diesel....good luck...

dieseldan44 · #3 10-30-2008, 09:44 AM

I think you may have a fuel gel problem. the temp at which B100 gels is dependent on what it is made from. most b100 is made from soy in the US, which shouldnt gel until 32 deg F, but maybe your bio cam from a different source and has a small percentage of something else that gels higher. wvo soy also gels higher, or so i am told.

the fuel pump is pulling on the lines for fuel, which are blocked upstream due to gel, and thats where the vacuum is coming from.

dd

nhdoc · #4 10-30-2008, 09:49 AM

You should be able to test the gel theory by trying to start it later in the day when it is warmer out. If you are able to pump fuel them without starving it then I would conclude you do have a problem with the B99 gelling. Try adding some power service (white bottle) to it which should help too.

pmari · #5 10-30-2008, 10:23 AM

How many miles on the car, how many tanks of 90% or greater Bio-D run through the fuel system?

Sounds like shes fuel starved from the tank. If she's running off a fuel filter filled with trannie fluid.

Depending on the amount of varnish, asphaltenes,and various other crud that is/was in/on your tank could now be free floating due to the solvent nature of Bio-D run at percentages above 90%. So the tank strainer (assuming there is still one in there) could be the culprit. It has been cold the last few days, so gelling could be a problem also, if.... Mr. Murphy is not hassling you

.
Power Service Rescue 911 poured into the fuel filter a few times should free up the gelling in the lines and IP. Otherwise you may have to drain the tank ETC.....

NY300SD · #6 10-30-2008, 10:52 AM

Thanks for the replys. I was certain that gelling wasn't the problem because it was 5pm and the temps were in the 40s. Plus I had a couple of gallons of regular diesel mixed it just to prevent this sort of thing.

The car has 197k on it and I've put about 4k miles on it since I got it, most of it on B99.

I will try power service today. I certainly hope it is that simple.

TMAllison · #7 10-30-2008, 12:41 PM

Check for any bubbles present in the plastic fuel lines.

When was the last time the orings on the kill switch on top of the fuel filter were changed? How about the pre-filter oring?

Put a jar of B99 outside where you can see it so you know at what temp it gels.

pimpernell · #8 10-30-2008, 12:54 PM

Quote:

Originally Posted by NY300SD

Thanks for the replys. I was certain that gelling wasn't the problem because it was 5pm and the temps were in the 40s. Plus I had a couple of gallons of regular diesel mixed it just to prevent this sort of thing.

The car has 197k on it and I've put about 4k miles on it since I got it, most of it on B99.

I will try power service today. I certainly hope it is that simple.

Cold Weather Management
Unlike gasoline, both petroleum diesel and biodiesel can gel at cold temperatures. If the fuel begins to gel, it can cause increased stress on fuel pumps and fuel injection systems. It can also clog filters or eventually become too thick to pump from the fuel tank to the engine. B99 gels at a higher temperature than conventional diesel fuel. Most B99 begins to thicken (cloud) at around 35°F. To prevent cold flow issues, some users switch from B99 to a blend of B50 in cold weather (below 35°F). B50 provides adequate dilution to prevent cold weather gelling. Other options for using B99 in cold weather include keeping vehicles in a heated garage, using fuel system heaters, or using winterized biodiesel (biodiesel with cold flow additives).

pmari · #9 10-30-2008, 12:55 PM

You'll have to have more than a couple of gallons #2 when winter sets in.
http://www.enertechlabs.com/Biofuels_Additives.htm

http://www.duffscience.com/bd_calculators.htm

I'm starting to think either the fuel is poor or your cleaning the fuel system and clogging up. Unless she's sucking air as already suggested.

NY300SD · #10 10-30-2008, 01:06 PM

all the orings are new, and aparently sealing really well, or the filters wouldn't be vacuum stuck every time I remove them.

I tried power service and got it running roughly for a few minutes at a time, refilling the filter when it quit. Did that several times. Almost got it up to operating temperature, but then it stopped working. I'm shocked that the battery has shown no sign of quitting yet.

Alas, it is still not sucking up any fuel. And the tank is so full that when I went to add power service I only got a few ounces in before it overflowed.

Crap. I could really use the car today.

pmari · #11 10-30-2008, 01:12 PM

If you disconnect the fuel supply line coming from the tank does fuel flow from it? If not, a shot of compressed air may clear the tank pick up but that's a temporary fix and would confirm crap in the tank.

NY300SD · #12 10-30-2008, 01:25 PM

pmari,

I am not totally familiar with the fuel system on this car. Mainly because it's so hard to find without taking the intake pipes off which I haven't done yet. Which line comes from the tank? I think it is the one going strait to the pre-filter, but I see it is connected to something else that I can't reach.

Also, how do you disconnect the plastic lines?

Thanks

Oh right, just disconnect the pre-filter.

pmari · #13 10-30-2008, 01:52 PM

That is where I would go first. If it's flowing out of the tank you know you'll have to trouble shoot from there (the prefilter). If you do give it a shot of compressed air, be sure to siphon some fuel out and leave the tank cap off

Quote:

Originally Posted by NY300SD

\Oh right, just disconnect the pre-filter.

NY300SD · #14 10-30-2008, 02:01 PM

I got it running on power service again for a few minutes. Took a look at the line going to pre-filter and it is empty. Tried blowing on it to no avail. Will have to take the tank cap off next time and use compressed air. I don't have access to a compressor today. Maybe tomorrow.

TMAllison · #15 10-30-2008, 03:08 PM

You'd do much better applying vacuum to the prefilter line or better yet to the hard line on the right(?) firewall and "pulling" the fuel up to the engine same as the lift pump does.

Using comp air, about the time you get fuel to move out of the tank is "about" the same time the tank ballons out and deforms from the pressure being pumped into it.