I am having a similar problem. I also have a GC kit.
The difference is that my Suburban runs in oil but the performance is terrible.
The vehicle runs as if the required amount of fuel does not get on time to the IP (it runs with subtle jerks.) On top of that the vehicle does not pass of 65MPH even with the gas pedal all the way in. And in an uphill it completely looses all the power forcing me to switch to diesel. As soon as I switch to diesel (milliseconds) it is like if I had a bottle of nitro connected to it, it takes off and recovers all the power.
Let me explain chronologically the set of events that I think may have something to do with this situation.
1.- I have been using soybean oil from a Chinese restaurant. And in the last few weeks to a month filtering the oil has gotten really difficult with the beginning of the winter. I have no means to heat the oil, so the only thing I do is let the oil settle and attempt to filter it to 20-10micros before putting it in my veggie tank.
2.- I have added a veggietherm that heats up the oil a extra 60 to 100 degrees right after the veggie filter and before the oil pass through the solenoid valve (obviously.) So in the last month or so I have felt confident to start the car and turn the veggietherm on, which it only heats up the oil in the line between the veggie filter and the solenoid valve, and switch to veggie just 2 or 3 minutes after starting the car. I am thinking that this may have caused a clogging of the veggie filter which it has just 1500 miles.
3.- So after I started loosing power (thinking that it had to do with the injectors,) I decided to run a fuel injection cleaner straight into the veggie filter. So I remove the veggie filter and filled it up with fuel injection cleaner. It took me a lot of tries to get the car started in veggie and when it finally did the problem was still there and the jerking started to happen.
4.- Today I am planning to replace the veggie filter all together and see if that solves the problem. But I am still worry about the jerking because it is more probable that it is caused by an air leak in the system.
I have tried to contact GC support but they have not been able to get back to me yet.
I would really appreciate any help you can provide me.
My similarity is with the issue in topic:
Sorry about the confussion
Sounds a lot likea clogged filter - what ahppened when you changed it?
If it is not a clogged filter, it could be an air leak. Since the vehicle runs great on diesel, it would be a leak on the veggie only side. Is the filter tight, are all the hoses really tight? Can you puta second hose clamp on some of them?
You should filter better than 10 microns. I go all the way down to 1 micron absolute rated. Then your 10 micron spin on filter won't clog that often. Definitely replace that thing. It is probably gummed up pretty good. Have you replaced the plastic T-fitting with a brass one? That is a good idea to eliminate the possibility of an air leak.
To test to see if it's the veg or air, unhook the veg intake line from the fitting and put it in a can of diesel fuel. Run the car. If you have severe stuttering, you've got yourself an air problem. If not, you've got a veg problem (heating, filtering, etc.).
Replace your filter first- that could clear it up
When your ride starts to stumble on Veg switch to diesel, if the power returns almost immediatly it is probably a lack of fuel flow. If the stumbling continues for a little while it is probably air in the lines. Note that if your filter is clogged it may worsen or even cause air leaks.
1500 miles represents quite a lot of fuel through your filter when compared to a VW with the same miles traveled. Also filters can clog with solid fats that will melt at higher temperatures, if the problem improves after a few more minutes of driving (longer as the temperature gets colder) this could be part of the problem.
Government is the PROBLEM not the solution.
'81 300D - Greasecar system installed Oct 2005
-- Stoneage 2000 Jetta TDI Greasecar kit installed 2008
1981 300D Greasecar kit installed Fall 2005 - sold after transmission cracked 2008
Thanks to all for your replies.
It ended up being the filter. I did though a check in all the hoses to make sure there was not air leak.
Nearly identical to the issues I had with my Cummins. Summer was awesome, winter has been trying, but I'm getting it nailed. Mass insulate every hose you can. Shield Vegtherm from air flow but don't insulate it. Shim with thin aluminum the GC filter for a tight fit. This is a major factor, as a loose filter will not get nearly as hot! Cover front of truck and greatly increase amount of time you heat the oil to be filtered. I now filter it to a second barrel and circulate that oil for several minutes through a Racor commercial unit. OIL IS CLEAN, and so far so good. Bucked a 50 knot wind yesterday at 70 mph with no stumbling. I also have increased my warm up time to 15 minutes. We shall see.
If you cut open your filter I bet you'll see brown silty sludge and saturated paper.
95 Cummins 4x4 pushing 400k miles and running like new.
I've got experience with the burbs, add a fuel pump to your veggie lines if you have not done so. Insulate the coolant lines with the pipe insulation for 3/4 inch copper pipes then cover them with a two inch loom for protection from road debris ( Del City.com) you can cover part of your radiator (like the big rigs do) to limit the amount of bone cold air through your radiator. and fiter to AT LEAST 5 microns, and use non hydrogenated oil your engine and veggie kit will thank you.
KEEP ON GREASIN' 1997 F350 7.3L TD PS
1998 VW Jetta 1.9 TDI
1989 VW Jetta wolfsberg 1.6 L NA
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