Racor Gauge in the red - Plugged Fuel Line?

[JoeCich]

I purchased my '85 FC 31 in March 2012, and since then the Racor vacuum gauge has been halfway in the red zone. I have replaced the filter four times. The first 3 changes the filter was completely black when changed, after only 300 mile intervals, suggesting sludge in the fuel tank. I treated the fuel with Technol 246 Super Sludge Dispersant. At the last filter change, after 220 miles, the filter was now still white. However, after installing the new filter, the Racor gauge immediately went halfway into the red zone above 40 mph. I called Parker, and they said even with dirty fuel a filter wouldn't plug up that fast, and that the problem was more likely in the fuel line. I think originally the problem was sludge in both the tank and in the lines. From the white filter I think the dispersant has worked on the fuel in the tank, but the gauge immediately going into the red indicates there is still restriction in the fuel line. The question I have been working up to is, is there any way to clean sludge out of fuel lines?

[dmurdock]

Did you change the secondary filter? My guage reads from both (its right at the injector pump).

[Rick]

What filter did you use. 2 or 10 micron? I would think the 2 would clog very fast under the conditions you described.

[Spike45]

Originally Posted by JoeCich

I purchased my '85 FC 31 in March 2012, and since then the Racor vacuum gauge has been halfway in the red zone. I have replaced the filter four times. The first 3 changes the filter was completely black when changed, after only 300 mile intervals, suggesting sludge in the fuel tank. I treated the fuel with Technol 246 Super Sludge Dispersant. At the last filter change, after 220 miles, the filter was now still white. However, after installing the new filter, the Racor gauge immediately went halfway into the red zone above 40 mph. I called Parker, and they said even with dirty fuel a filter wouldn't plug up that fast, and that the problem was more likely in the fuel line. I think originally the problem was sludge in both the tank and in the lines. From the white filter I think the dispersant has worked on the fuel in the tank, but the gauge immediately going into the red indicates there is still restriction in the fuel line. The question I have been working up to is, is there any way to clean sludge out of fuel lines?

WHat is the part number of your Racor filter? Was this Racor added by a previous owner or the factory? Pardon my ignorance but what engine is this? Do you have a specification on maximum fuel flow including any return to tank fuel flow? How many 90 degree elbows are in the fuel line from tank to filter to the transfer pump? Is the Racor gauge connected at the transfer pump on the suction side?

The black sludge is actually microbes (bugs) that live in the water in the fuel tank and feed on the fuel. I am not familiar with your product you used. Is it a biocide to kill the bugs? The filter system has to remove the bugs, living or dead. At some point you need to remove the fuel tank and get it cleaned out and dried out before reinstalling. As for clearing the fuel lines, you will need to remove sections of it and try to blow them out (reverse of fuel flow direction) using air pressure. Judging from the age of your coach, it can be that there is a rubber hose that has the liner separating from the hose structure. Replace that hose. Better yet, replace all fuel line hoses. Check steel lines for dents, sharp bends that flatten the line.

[Mike Hohnstein]

Electric pusher pump working??

[JoeCich]

The engine is a Cat 3208T, the final fuel filter on the engine is a CAT 1R-0750, which I think is 2 micron. The Racor unit is a Model 900FG, with filter 2040PM-OR 30 micron. It looks as if the Racor was original equipment. Mike, you bring up an excellent point, I completely forgot about the pusher pump. I can hear the pusher pump operating when the ignition is turned on, but I suppose that doesn't necessarily mean it's pumping. The fuel lines that connect to the Racor unit appear to be 3/4" rubber. Should I be using the Racor 10 micron 2040TM instead?

[Randy Dupree]

There has been issues with Racor filter housings clogging up with black gunk (technical term),you have to take the filter off and take it apart to get it clean.

[JoeCich]

Mike,
I live in Gurnee, 8 miles south of the Illinois-Wisconsin border along I-94. I drove my coach around the lake to Holland Motor Homes for repairs this Spring. Are there any former Wanderlodge dealers in the Milwaukee area? Or in Wisconsin? Where do you go for service? Thanks, Joe

[Frank W.]

If the RACOR and engine filter are new and you do not get 0 or + pressure at the RACOR gauge your suffering from fuel flow issues based on my typical readings and experience in a similar coach.

I would think that an effort to: clean the RACOR unit well, and blowing out the fuel lines from the RACOR to the fuel tank would be worth it. You can disconnect the fuel supply at the RACOR inlet fitting, disconnect at the FACET fuel pump outlet and blow air back. I did this once and got a good bit of crud out. I would then blow out the line that runs from the FACET to the tank. Then I would also flush and clean out the FACET pump. Reassemble and prime....and test and see what readings you got.

I think your current selection of filters is ok...a RACOR in the range of 10-30 and the OEM 2 micron at the engine.

[JoeCich]

Finally found the root problem causing my Racor vacuum gauge to read in the red - the hard way. Started west on I-90 on our way to Wyoming, got as far as South Dakota. The vacuum gauge started going up, until it reached 16 inches of vacuum, and I could only make 45 mph on I-90. By a phenomenal stroke of luck the next exit, Kimball S.D., had a great garage, Overweg Repair. Dan, the owner, said he had just fixed the same problem on a truck, and was familiar on how to track down the problem. The root cause turned out to be the final length of rubber hose in the engine compartment connected to the fuel filter. From the heat of the confined space the rubber was hard as a rock, and cracked apart as they bent it to remove it. The hose liner had separated from the outer rubber, and was collapsing from the vacuum, which is exactly what Parker had predicted. In retrospect it seems obvious, the hose in the engine compartment would deteriorate first from the heat. On flat ground the gauge now reads zero.