Author Topic: 1.9 Diesel Fuel Delivery/Starting Problems (Read 5066 times)

prancer00 · « **on:** January 29, 2006, 01:28:15 pm »

I'm having a starting problem on my '82 VW Rabbit Pickup. It has a new 1.9L n/a diesel engine in it (maybe 2000 miles), and I usually use biodiesel, or lately, a 50/50 blend with diesel to help with colder viscosity.

Here's my trouble: my truck won't start, and I don't think it's getting fuel to the injector.

The history: My fuel gauge doesn't work, and I accidentially ran it out of gas last week; now I can't start it. I added 5 gallons of biodiesel that I had at home. I have a small inline fuel filter right before the regular filter, just to give me a better visual on my fuel delivery. This hasn't caused a problem in the past. I replaced that filter, just in case. I removed the supply hose off the fuel tank, and blew through the hose on the other side to make sure that it wasn't clogged. There seemed to be no obstructions. Also, fuel flowed freely from the tank when this hose was removed, so I assumed no blockages there either. I put the hoses back and it still wouldn't start. In fact, no fuel was coming down the line to the injector pump. I cracked the fuel lines on top of the injectors, and turned over the engine with both the air screw on the fuel filter housing open and closed, and still, not a drop of fuel in the line. I attached a hose to the outlet on the fuel filter housing, and siphoned to see if there was a blockage, but the fuel came out without any problems. Just in case, I then changed the fuel filter, and filled the new one with ATF. This morning, I cranked through a fully charged Optima battery, and still no fuel flowed down to the injector, and the lines were dry.

I'm at a loss on what I should do to get this thing going. It ran great before I ran it dry, never any starting problems or anything. Thanks for any advice!

zyewdall · « **Reply #1 on:** January 30, 2006, 09:32:22 am »

Hah. I did this to my rabbit yesterday (ran it out of fuel and airlocked the injectors and the filter). What you have to do it get fuel back to the injector pump inlet (if there is air in other parts of the system) before cranking it with the injector lines loose to get the air of the injector lines. The injection pump doesn't seem to be able to suck air through the rest of the lines to prime itself. And if it's not primed, it can't force the air out of the injector lines. I have a small electric pump in line to do this (generic one from a cabureated gas car). Once you have fuel at the inlet of the injector pump, then you can loosen the injector lines on all of the injectors just a little bit, then turn it over till fuel seeps out of those nuts. Didn't take more than 5 or 10 seconds on mine. Then I tightened the nuts back down, and it started right up.

prancer00 · « **Reply #2 on:** January 30, 2006, 11:52:06 am »

Where inline did you put your fuel pump? That sounds like a nice insurance to rig up. I don't have one around to throw in; I called my mechanic, and he said I should use air pressure a little to push the fuel up the line. I'd rather use a fuel pump, seems way safer.
Does your pump self-prime, and do you have a switch on it?

zyewdall · « **Reply #3 on:** January 30, 2006, 01:19:00 pm »

Right now I've got the pump in the engine compartment just before the filter. It will self prime and draw fuel from the tank. However, I'm getting vacuum leaks from the line going back to the tank (I have a micky mouse connection between a rubber hose and the plastic OEM fuel line in one spot under the car), and it's sucking air into the system. I think I'm going to move it to the back, right where the line comes out of the tank. Right now it's just got a wire that I touch to the postive battery terminal to turn it on, but I was planning to wire it up to a switch to use for priming. Fuel will flow through the pump fine when it's off, so it doesn't necessarily have to be on when the ignition's on. Although I've heard that helps the power at higher rpms.

prancer00 · « **Reply #4 on:** January 30, 2006, 07:54:04 pm »

I wound up trying to prime the injector pump by siphoning the fuel.

Luckily, I had an extra banjo bolt, so I rigged up a little siphon on the out port of the injection pump that bolted right in, no hose removal needed. After some serious inhalations (glad I use biodiesel!), I got fuel in my new line. I put the old banjo and hoses back on, cracked the injector nuts, and it fired up. It took a bit, and was bumpy, but once the air cleared out and everything was tightened back down, it ran like a champ.

I plan on keeping that little siphon unit and a 17mm wrench in the truck, in case I ever run it dry again. Of course, I really need to get the fuel gauge to read accurately to prevent that... but I'll save that topic for another thread.

I think a fuel pump would be nice, but I don't know if I'll get there yet.

zyewdall, thanks for your help.

zyewdall · « **Reply #5 on:** January 31, 2006, 06:08:19 am »

Yeah, I hear you on using biodiesel. I filled mine with B100 for the fuel system plumbing/troubleshooting, because knowing me, I was going to get fuel all over, and I hate smelling like diesel for days afterwards...