Confirmation of problem: Tii/Turbo electric fuel pump

[www.bmw2002.co.uk]

My Turbo won't start, checked the fuel pipe feeding into the injection pump & with ignition on (can hear the pump "buzzing") no fuel coming out. So I have worked my way back through the system. New Fuel tank & pick-up unit. Last night I removed the Fuel pump & cannister from under the car as there is nothing coming out of the pump. Made sure it was all clear (gauze), reassembled it all but still nothing coming out the pump although it sounds ok (they always seem noisy). Do they need bleeding or something stupid like that? Or is the pump shagged? Second opinions please. Otherwise I'll go for the Bosch replacement as mentioned on Keith's superb 2002 Tii site. Argh Old cars, old owners ;o)

[jetboy]

if i were you id pop open the tank and stick a hose in there direct(or jsut use a gas can) , hook it to your pump and see if it pumps. you might have a cracked hose between the pump and the tank-- since thats the low pressure side it would not be shooting gas all over, just sucking air not gas------

or it could be your sending unit got a rock stuck in it or something i suppose--

it will take a while, use a short piece of clear hose so you can see it come and yo don't run the pump too long dry- if its still good now, running it while dry is gonna ruin it eventually.

[BillWilliams]

into consideration.

1. Is the wiring straight? I am not sure if that can be reversed and cause the pump to run backwards. Maybe a long shot.

2. John Weese says he has to prime his tii pumps to get them to work so he may chime in with that process.

3. As the above post describes, find a safe way to see if the pump will pump fuel through another hose and container.

4. If you loosen the feed hose, (from the tank to the pump) at the pump, do you see fuel dripple out?

[www.bmw2002.co.uk]

The Tank & Pick up unit are new, but yes the hose from the Pick up unit to pump is the original. Could very well be sucking in air thinking about it.

Cheers.

Richard.

[peteinjp]

I had the exact same problem. hose clamp on the inlet side needed a couple of turns then it was fine. It happened after an extended period of no use.

[BillWilliams]

from the tank to the pump. If that is original, replace it, they get brittle.

They are a pain to replace with the tank in place. Maybe someone has a trick to make that process easier.

I use two people, one to pull from the underside of the car and one to push from the top of the car, apply rubber friendly lube liberally. I pull with a pair of pliers leaving enough length on the hose to cut what I damage on the pull.

With the tank in place, you only have about two inches to push the hose through from the take side.

I tried pushing from the underside of the car and pulling from the tank side, but I failed miserably doing that.

[peteinjp]

Not the factory way but... The fuel line that I ended up with (from BMW) seemed (was) impossible to fit thu the existing passage. I used a section of metal tubing (8mm??? same as the rest of the metal tubing to the front valence) thru the said passage with the rubber fuel line on either side. The metal tubing was bushed with rubber tubing that it into the passage and sealed the trunk. This created a permenent hard line from the trunk interior to the rear subframe area.

[02fanatic]

A couple follow-up comments:

1. When I installed Hugo's pump it ran but wouldn't pump fuel, so I actually sucked on the inlet hose from the tank to make sure there was fuel in the line, then it pumped fine...it was not primed. The pump will run, but it won't pump fuel unless it's well primed.

2. As for as the fuel line hose between the tank and the pump (8mm?) it was indeed a real pain to install....lubricate liberally as Bill said, and it "will" come through the hole in the rear panel. I think the wall thickness on the replacement line from BMW is "thicker" than it was back in '72...thus the dilemma pulling it through.

It's a good idea to replace "all" of the rubber fuel lines underneath the car while you're under there.

Good Luck,

John

[jetboy]

priming can be a real pain if there is no gas left in your pump. id give it a shot and see if it works as it might still have enough residue inside-

if you don't feel like sucking on the tube, you can get a cheap little plastic pump at most auto stores (also good for changing differential oil etc.) this is really much better than sucking because you can put it inline before your electric pump and force the gas into the pump to prime it. just make sure the high pressure side is clear so that air can escape and it should prime right up.

you may need some little adapters to make the pump fit with your line-- but its a lot better than trying to suck on that shit-

[jetboy]

oh yeah, they switched the tube thickness in 74 - so BMW just sends you the new type-

its probably for the best really--

[www.bmw2002.co.uk]

I did take the pump apart last night & carefully reassembled it. I have asked some other people hear & they said you don't have to prime the pump.

But basically I think it certainly won't hurt to try. Also I will test & replace the hose between pickup unit & pump. So thanks for all the useful tips - I will report back as soon as sorted with my findings. Oh the joy of old cars. ;o) Or is it old owners. ?

[jgerry2002]

I don't see a reason to prime the pump.

On my '74tii, I replaced EVERY bit of fuel line in the car, even had the tank rebuilt.

All I did was turn the key, waited a couple of seconds and it was fully pressurized. I had one leak after the kfish, but that was it. The system is supposed to be self bleeding (I believe its in the manual). I turned the key and in three cranks the motor started right up after sitting for 1 year.

If you need to "prime" it, I'd say the pump is weak. Get a rebuild from Mesa, and pick up a used one for a spare.

[jetboy]

if you didnt replace the pump, there was probably still gas in it - the pump will stay full unless you run it dry- pump air through. so no need to prime.

but i agree, usally you dont need to prime them-

[ingraham]

Check the wires to the pump. Try reversing them.

I never had any trouble priming the pump by running it.

I don't recall any problem installing new fuel hoses. The larger hose is 12mm ID and 18 mm OD. Part number is 16-12-1-469-787, and it's about $13 per meter.

If you don't know the age of the fuel hoses and any of them look old, replace them all. The smaller hose is part number 13-53-1-469-783, about $30 per meter, 8x13 mm.

[DAK]

It might seem like a silly question but... is the NEW tank full? A full tank will self prime easier than a tank with only a few gallons in the bottom.

Back when I was into VW's I often ran into the dry fuel line issue for various reasons and often had to prime the system from the tank to the motor. I found that the easiest way to do this was with a compressed air hose! I would turn the air pressure regulator down to 20 PSI and loosely wrap a shop rag around a blow nozzle. Pull off the gas cap and insert the blow nozzle into the fill tube using the shop rag to partially plug up the fill tube and squeeze the trigger on the blow nozzle. this pressurizes the tank sending fuel all the way through the pump to the motor.

On a carbed car you can fill the entire line, pump, and float bowls in just a few seconds. On an EFI car I have used higher air pressures and primed all the way through the return line. You can also use low pressures if you have an assistant to watch for fuel on an open fuel line at the front of the car.

Hope this helps. Good luck.

BTW ONLY USE A COMPRESSED AIR LINE FROM AN AIR COMPRESSOR OR AN INERT GAS WELDING TANK. DO NOT USE AN ELECTRIC LEAF BLOWER OR AN OXYGEN TANK THESE COULD LEAD TO VERY DANGEROUS CONDITIONS. I also suggest only using this method in a well ventilated area as the pressure created in the tank will also push gasoline vapors out of the tank ventilation tube.