Fuel filter light flickers for a few minutes when switching back to diesel. - Diesel Forum

SLO_TAO · 12-12-2005, 09:46 PM

Hello everyone.. so far I've logged nearly 800 miles on WVO in my 1995 PSD. It's been running great so far but I think I may be approaching a clogged filter. I have a two tank setup with two separate spin on filters for WVO and diesel.. The front/rear tank switch acts as a switch for both the tanks and filters. I still utilize the stock fuel filter/bowl. I noticed the past couple evenings when switching back to diesel for purging that the "fuel filter" light flickers for a few minutes and gets brighter depending on how heavy I lay on the pedal. It seems that after only 800 miles I shouldn't have clogged the diesel spin on filter.. Could it be just the diesel side has a little veggie in it that's still too thick? I does go away after driving on diesel for a little bit. I bought some new filters today but I'm concerned that it shouldn't be clogging already. Any thoughts?

Rich

h2odrx · 12-12-2005, 10:12 PM

how do you process the WVO? is it clean? ie.. no water?

SLO_TAO · 12-12-2005, 10:18 PM

I filter to 3 microns, dewater with heating, then settle. I only experienced the problem on the diesel side when purging.

Rich

h2odrx · 12-12-2005, 10:28 PM

what temp is the WVO and or the fuel, it may not have any effect but the temp change may have some thing to do with it?

350 long rod · 12-12-2005, 11:13 PM

My truck does the same thing some times. I take it that you are returning veggi to your diesel tank when you switch back.I have thought about adding a 3 port to loop on swicth back it will increase purge times but it the cold weather may be needed.It seem to not be as bad after I have filled up the diesel tank and it dilutes the veggi mix.You could heat up youp diesel filter to see if it will clean out.

Charlie_M · 12-12-2005, 11:15 PM

Do you have a schematic of your setup? If you have one handy that may help people to think about it.

Veggiesurf · 12-13-2005, 03:55 PM

My truck did the same thing about 800 miles into my conversion, only when I was on VO. I changed the diesel filter even though it had recently been done and the problem has not returned. Currently at 2300+ veggie miles. I think what might be happening is when you first use oil in the stock tank it loosens up crud in the botom of the tank and gets it into the fuel supply lines. I have a simple system with some mild cross contamitation of vo and diesel(not that problematic so far in my climate and with the IDI engine's ablity to take it) so that is what I attribute my problem to.

JOAT · 12-13-2005, 11:42 PM

[ QUOTE ]
what temp is the WVO and or the fuel, it may not have any effect but the temp change may have some thing to do with it?

[/ QUOTE ]

My suspicion too. Cold diesel hitting the veggie and causing a temporary congealing that plugs the filter?

JOAT · 12-13-2005, 11:53 PM

[ QUOTE ]
Do you have a schematic of your setup? If you have one handy that may help people to think about it.

[/ QUOTE ]

As I recall he's running a traditional system, switched near the tanks and using the stock pump and filter for both fuels, thus the mixing.

I'm wondering does the diesel side get heated as well? If it's cold diesel mixing with the veg that could be causing it to thicken as mentioned above.

Charlie_M · 12-14-2005, 12:51 AM

[ QUOTE ]
[ QUOTE ]
Do you have a schematic of your setup? If you have one handy that may help people to think about it.

[/ QUOTE ]

As I recall he's running a traditional system, switched near the tanks and using the stock pump and filter for both fuels, thus the mixing.

I'm wondering does the diesel side get heated as well? If it's cold diesel mixing with the veg that could be causing it to thicken as mentioned above.

[/ QUOTE ]

Interesting. I guess if you had both fuels in the stock filter, the question would be whether the #2 cools the vo enough that it gains vistocity via cooling faster than it thins due to mixing. I'm sure some smart guy can ratio the heat capacities and look at the curve of viscosity vs. temp and say if that's the answer(but that wouldn't be me!). Certainly that explanation would fit with the problem going away after a while of driving on #2. At some point the thinning has got to win out (as you approach 100% #2 in the system). Interesting stuff.

Charlie

SLO_TAO · 12-14-2005, 10:32 PM

[ QUOTE ]
[ QUOTE ]
Do you have a schematic of your setup? If you have one handy that may help people to think about it.

[/ QUOTE ]

As I recall he's running a traditional system, switched near the tanks and using the stock pump and filter for both fuels, thus the mixing.

I'm wondering does the diesel side get heated as well? If it's cold diesel mixing with the veg that could be causing it to thicken as mentioned above.

[/ QUOTE ]

It's sort of like that but there's another 3-port switch in the engine bay for switching between two add-on filters.. one for diesel, one for veggie. It may be just crud getting cleaned out of the tanks too.. I did add some powerservice diesel kleen to both tanks prior to filling a few days ago.

Rich

SLO_TAO · 12-15-2005, 09:05 PM

Well I changed the diesel spin on filter.. It was pretty sludgy in there. I'm hoping it was just crud from the tank and fuel lines.

Rich

JOAT · 12-15-2005, 09:22 PM

If you get a chance go to biodiesel infopop forums and do a search on "veggie snot". There are some pics of sludgy stuff that seems to build up in the filter housing for some who blend. Maybe just some similar residue separating out of the diesel or WVO [img]/ubbthreads/images/graemlins/shrug.gif[/img]
When the b100 broke loose the stuff from my tanks it was dark and sorta chunky