I recently got an 81 rabbit pickup truck. It ran flawlessly off the first tank of bio-diesel(blend 85% bio) but now it has some issues. I replaced the fuel filter. The truck will crank up and idle after some work. If you are standing at the front of the rabbit and you pull the throttle you can see what looks like bubbles coming through the fuel line. The engine basically revs up until the fuel line is empty and then it shuts off. If you wait a minute and let it fill back up it will idle again with no problem. I was wondering how to "bleed" the fuel or if this is even the issue. The fueld filter does have a little knob on it to release pressure. I have been told there may be another fuel filter or screen like device inside the tank. Any heads up would be greatly appreciated. Many thanks if someone can help with this.
nobody has any experience with this issue?
I'm considering going to Bio-Diesel with my '84 Rabbit, and I haven't heard of any issues like this. Did you make the bio diesel yourself or buy it from somebody? I know there's a certain amount of time that you're supposed to let everything seperate once you add the lye and crap like that, so if you didn't do it yourself, somebody may have screwed something up in the process of making their bio-diesel. Anyways, sorry I can't help more, but let me know for sure if you figure out what the problem was. I don't want to convert over if it's gonna cripple my car.
There is a bleed screw on the top of the filter mount, and it may be leaking, also there is a drain plug on the bottom of the filters that may bee leaking but I suspect that the rubber hoses from the tank to the rigid fuel lines are the cause of your problem.
IF the fuel line empties I'd be wary of the strength of your fuel pump, if it will refill the fuel line given time(as in just sitting at idle?) then it definately could be it.... i think no promises.
When all else fails, shoot someone.
If the pump is weakened, then he can place a 85-93 cabby in-tank pump to augment the flow. You simply connect it up to the fuel shut-off circuit. That was the fix back in the day from a dealer I knew.
Also check the crush washers on both sides of all the banjo fittings, I have see those get a burr and allow air into the system.
Yes there is a filter (screne) in the tank of your caddy that is on the fuel pickup tube and they do plug up especially runnig biomix. But it does sound like your pulling air thru your main fuel supply line. The quick way to check your fuel line is to put a hose in the tank, seal around it with a rag at the tank and put very low pressure into the tank, i have a small pump that i bought at harbor freight for transfering liquids , i pump it a few times then squeez the hose to hold pressure, if you have no pump you can blow on it itll work fine.this takes two people , one to pressurize and one to watch for leaks under the truck, youll see any leaks real quick,, this is also a great way to prime your lines ,filter and injector pump if you ever run it out of fuel.Make sure you do this outside or put cardboard under your truck to catch the fuel,,. dont used compressed air because of rupturing the tank.The caddy fuel tank isn't designed for a intank pump, and the lines are suction design not pressure, do you still have the oem lines on your truck. let us know.. haulin-hare
Thanks for your input, yes it has all OEM fuel lines/fittings....I have heard alot of people have to replace the older fuel lines with newer synthetic hoses. I am gonna be able to work on it some this weekend with the holiday. The truck ran great when I first bought it using petrol diesel. And to answer your question about the bio, I make it myself and its ran in one of our tractors flawlessly...the tractor is a 30 year old wonder now. I get great power when I am using the bush hog. The fuel injector does look like it is leaking slightly, there is a round piece that the filter screws in and on both sides of it there are these big fittings where the lines come in and they look like they may have a slight leak. I think the problem is definitely fixable. My question is where do you think I should start on troubleshooting it? I think I should take the fuel tank off and clean out the screen and make sure all the fittings are tight. ****edit**** These Banjo screws on the fuel pump...are they what I use to bleed the fuel lines? there is also a little screw on top of the pump as well. I didn't try really hard to turn it but it seemed very tight. Many thanks to those who replied, your input is greatly appreciated!!!!!
Last edited by stuartnc84; 07-02-2008 at 05:30 AM. Reason: more info
Check you're not getting air from the fuel filter you changed. Just a thought.
now that iv'e given it some thought the rabbit pickup dosent have a intank pickup and strainer just the cars,
What i would do first is pressurize the system like i described earlier and check for leaks, repair any leaks and tighten all clamps and fittings from the tank to filter and pump, i would then repressurize the system and open the bleeder screw on top of the fuel filter mount until all air stops coming out (fuel only) and retighten bleeder screw , then crack open the injector line on #4 injector at injector and crank the engine a little until fuel is observed, retighten line and your ready to start. You may still want to pull your tank and remove the fuel gauge sending unit to look into the tank for crud , look towards front bottom of tank where lines hook up, this is where they start to plug up. Pay special attention to the metals lines in front of the tank by the leaf spring mount( i had a pinhole rust into one of these lines before and it took me two days to find),i finally found it by pressurizing the fuel tank, Let us know