New guy; pulling hair out

Otto · Post by **Otto** » Wed Jan 12, 2011 10:43 pm

Hello everyone,
Just found this forum a couple of days ago, lots of knowledge here. I'm hoping I can borrow just a little. My 81 Rabbit has refused to start for the last week and a half. I've owned this car for the last 17 years and know the car intimately and have been successful at repairing it until now.
I drove the car to run some errands and it ran normally as it has during my entire ownership, parked it and went to start it the next day- no fire. So I pushed it into the shop and went throught the usual motions of checking glow plugs (it was 22F that day, which is cold for here). Until now that has been all I've ever had to do- not now. All glow plugs tested good (test light w/bus disconnected+ taking out the easy ones to run 10A through). 50A fuse- good. Power to bus- good. Checked power to stop solenoid- good w/clicking when power applied. Switched out stop solenoid w/spare- no change. Checked for water in fuel- none. Went through relay testing procedure in Bently book- tested OK. I loosened an injector union and cranked the engine- got fuel, not sure how much to expect but got fuel. Replaced glow plug relay w/new one- no change. This car has not made a sound in a week and a half, but the starter is getting quite a workout. I'm stumped. What have I missed?
Thanks

Post by **Fatmobile** » Wed Jan 12, 2011 10:52 pm

Do you have clear fuel lines?

Otto · Post by **Otto** » Wed Jan 12, 2011 11:03 pm

No, I swapped out the clear one from the filter to the pump some time ago. It was getting brittle and looked like it might fail. Replaced w/black hose.

Quantum TD · Post by **Quantum TD** » Thu Jan 13, 2011 1:04 am

My trusty truck failed to start the other day with temps in the teens. I made the mistake of trying some starting fluid: bad idea. I had to pull all the injectors to blast it out of the cylinders.

Anyways, I found that my pump had been sucking air. Well, I knew that all along, but I just found out where. A broken fuel return nipple on an injector, and a sweating fuel return hose to the tank.

If I were you, I' do the following:

1) Replace the return hoses (the small braided hose)

2) Unscrew the OUT bolt from the top of your pump. You should have fuel all the way to the top of that bolt hole. If not, get a squirt bottle and CLEAN diesel fuel, ATF, Injector cleaner whatever, and fill it to the top.

3) Take a jumper wire from the battery to the stop solenoid and make sure it clicks. It could be possible that it had a touch of water in it and it's sticking.

4) Glow your plugs about 3-4 times. Each cycle will be about 8-10 seconds if you have fast glow plugs.

5) crank it over. I'd be willing to bet it will start.

If that doesn't solve it, get a new fuel filter and repeat the process (but fill the filter with fuel before repeating the process).

Otto · Post by **Otto** » Thu Jan 13, 2011 10:29 pm

Thanks for the suggestions. Quantum- if you're talking about the little hoses that jump from one injector to another, I gave them a looking over. I trimmed some ends that might have been loose, but nothing was seen to be leaking from them. Replacements will have to wait until tomorrow. I removed the OUT bolt and found the fuel level to be about 1/4" below the top. Filled w/ATF. Jumper wire to the stop solenoid yielded an audible click. Also noticed this lit up my test light connected to the bus. Is this proper?
Anyway, cycled the glow plugs 3 times...and nothing.

I spun the stop solenoid out and pulled up on the plunger, I thought just maybe it could've been stuck. This did not work either. The fuel filter will have to wait until tomorrow as well.
I'm completely baffled as to what could have laid my trusty bunny so low, so quickly.
Otto

coke · Post by **coke** » Thu Jan 13, 2011 10:42 pm

Loosen all 4 unions above the injectors and have someone crank while you watch for fuel at all of them. Then tighten them and try.

I had a TDI that refused to start despite a pump full of fuel until I did this. I know its not the same bird, but it might work for you.

82vdub · Post by **82vdub** » Fri Jan 14, 2011 12:16 am

Did you pull the glow plugs and verify that they glow nice and orange in the 7 seconds the relay would energize them? I've found some that would just start to glow when the relay kicks off, leading to hard starts.

Post by **Fatmobile** » Fri Jan 14, 2011 12:51 am

Swap a clear fuel line just before the pump.
Without it you are blind.

Swing by a motorcycle shop and grab minimum 2ft of 1/4" urethane.

Get a piece of 3/8" rubber fuel line too.
Slide a half inch piece of that 3/8" rubber line over the urethene, then slide the urethane onto the barb and slide the rubber down over it like a hose clamp. That should keep it from leaking, if not you can put a hose clamp over the rubber hose,.. a clamp on urethene can make it leak worse.

A 2 inch piece of that rubber hose slid over the urethane can protect it from any spots where it rubs.

I use silicone grease to slick the tubing up so the rubber hose will slide.

Otto · Post by **Otto** » Sun Jan 16, 2011 4:15 pm

So this is what I've tried lately:
Replaced fuel filter; actually cut the old one open to see what was inside. Just a trace of sediment and no water. Replaced the fuel hose from filter to pump w/Tygon hose (yellow, but still see-through). Cleaned all battery connections and grounds. Disconnected all four injector unions and cranked the engine repeatedly.
There appears to be a big bubble in the fuel line down at the pump inlet that I can't seem to get rid of. I know I brought this on by all of the hose and filter disruptions. In the past when fuel filters have been changed, it wasn't a big deal getting the engine running. I've run the car out of fuel and got it going again just by adding fuel to the tank. Also tried applying compressed air to the tank filler w/filter bleed screw open, and then the pump OUT fitting removed. I expected fuel to come out, but didn't. The bubble remains.
Are there any additional troubleshooting tricks I can try? I'm stubborn enough to keep at this if you'll stick with me.
Otto

TylerDurden · Post by **TylerDurden** » Sun Jan 16, 2011 5:00 pm

I would try running the engine from a bottle of clean fuel, instead of the tank. Hang the bottle higher than the pump to give it gravity feed.

If the engine runs, you know the supply is blocked somewhere between the pump and the tank.

Otto · Post by **Otto** » Sun Jan 16, 2011 8:02 pm

An update from today's events:
I investigated the filter in the fuel tank. The Bentley book says there should be one, but I didn't see anything that looked like a filter. Tank looked like new inside; no rust or crud. So with no filter to deal with, I blew compressed air from the filter/water seperator in the engine comp back into the tank. I'm satisfied there is no obstruction in that line.
I hooked a Mighty Vac to the return barb on the OUT fitting and pulled fuel back through the water seperator and the pump until solid fuel came through. Feeling optimistic, I tried to start the car but nothing. There is a large bubble that still forms down in the clear supply line closest to the pump.

I have a spare pump, but its a leaker. As a hail mary move it may get installed, but I'd rather do some more troubleshooting on the one installed. Question: does the stop solenoid plunger come out without disassembly of the pump?
Otto

coke · Post by **coke** » Sun Jan 16, 2011 8:11 pm

Yes. The stop solenoid is an item thats screwed into the high pressure head of the pump. It unscrews, plunger and all. Once its out you can take the plunger and spring and set it to the side. If the solenoid is keeping it from starting, it should start when you reinstall the solenoid w/out the plunger.

82vdub · Post by **82vdub** » Sun Jan 16, 2011 11:32 pm

If you have fuel coming out at the injectors when you crank over the engine, it almost points to timing or glow plugs. You checked glow plugs, but did you verify that they glow fully in the 7 seconds they get power? If your car has a block heater, plugging it in for a couple hours will point you towards glow plugs (if the car starts) or timing if it doesn't start.

Post by **Fatmobile** » Tue Jan 18, 2011 1:00 am

Sounds like you did a good job of checking the fuel system for restrictions.
No screen in the tank?
Backflushing the line was a great idea but air might not move crap stuck in the line.
I used a fuel pump and a long hose, drew fuel out of the tank,
through the fuel level sender hole,
up to the front where I pumped fuel backwards down the line, back to the tank. The car used to be a gasser that sat untilt he fuel dried up.
It took 7 hours of backflushing to clear the line, I couldn't believe how much crap was in the fuel line,.. no tank screen to stop it.

A piece of clear line before the filter would help you see if crap is damming up against the fuel filter barb.

tylernt · Post by **tylernt** » Tue Jan 18, 2011 11:22 am

I just had this issue on my Rabbit when temps fell below freezing. One time it took a lot of cranking to start; the next time, I ran the battery down trying to start. The pump was totally empty of fuel and no amount of cranking could get fuel into it.

My problem was twofold. One, my fuel tank vent line was clogged with ice. This allowed a vacuum to form in the tank. Two, I had a leak in a fuel line somewhere, which allowed air to be sucked into the system (thanks to the vacuum). As a result, my injection pump was dry inside when I took off the OUT bolt on top.

The get-me-home solution was to fill the pump with fuel via the OUT bolt. The long-term solution was replacing the fuel lines, and drilling a 1/16" vent hole in my (aftermarket) fuel cap in a manner that wouldn't allow rainwater to get into my tank.

For the OP, if a bubble is forming near the inlet with a primed pump, your pump mainseal may be bad, allowing air to be sucked in instead of fuel.