Member
Fuel pump doesn't appear to be actually pumping fuel... Putting a multimeter on each of the plugs coming in, shows ~9.5V on both of them when I turn the key, but if I put a clear tube on the output, no fuel is coming out. Pump has been idle for ~3.5 years while work on other components went on. I partially lifted the pump assembly out of it's cradle earlier to put a siphon tube down in the tank to remove bad fuel (assembly cradle did not ''want' to come out, but pulled out enough to get the tube in). I have since put about 10 gallons of fresh gas in, and when I tried to remove the pump cradle just now, lots of fuel started gushing out, so evidently the fill level in that half is above the pump cradle hole. I replaced the pump cradle, as I don't want to fill the back seat with gas. Any suggestions?
shade tree mechanic
Moderator
Probably the pumps are stuck from the old fuel, have seen many of them in the parked cars in our wrenching group warehouse. The old fuel get's red and disintegrates and then the fuel pumps, filter and even fuel injectors get plugged with a gum like stuff from the old fuel.
We have tried to revitalize them, sometimes it works, mostly not. Remove the fuel pumps from the tank and then use a separate battery with 2 wires and give to plus/minus short shocks with the cables, forwards and backwards, sometimes it works.
Of course, 9.5V is very low. Basically a dead battery. Also check both fusible links.
Shogun tricks and tips for the E32 series are HERE!
BMW CCA Member
You might try soaking the fuel pumps in Sea Foam Motor Treatment. I poured two cans into empty fuel tank in my car and let it sit for several days and then I was able to reach inside tank and wipe it clean of the tar and residue.
Member
Pumps are most likely toast - when I pulled mine after 2 years of sitting all the rubber mounts were completely gone like they'd never existed, the screen/filter was in pieces and everything so corroded it looked like something found in a shipwreck at the bottom of the ocean.
Siphon off the extra gas, pop in a new pump assembly and then don't worry about things for another 10-15 years.
BMW CCA Member
I thought I could rebuild pump assembly using the Walbro pumps but my assembly looked like it had also been on the ocean floor for 50 years so I just bought a new pump carrier from scorebmwparts.com for around $525.Originally Posted by rockytt
Member
$525??
Dang, I paid under $300 a few months back - ouch!
Member
What seriously? How was it so cheap? I paid $500 new in box. I thought $500 is about the price for these pumps?
Member
Siphon , how? Pulling the pump floods the back seat, and siphoning doesn't work from the filler neck. Can I just siphon through the currently non-working pump? Would that damage a working pump in case that's not the issue?
Member
How long is the tube you inserted in the filler neck? I have recently worked on the fuel pump assembly on two BMWs (including the 8) so it's still fresh in my mind. If you are attempting to siphon from the filler neck, make sure your tube reaches all the way into the tank itself. The siphon tube will have to be submerged in the fuel in the tank for the siphoning affect to start. The neck does go into the tank. You just need a strong enough motor to pick(siphon) up the gas.
Last edited by ChrisFuture8; 03-08-2018 at 01:02 PM.
Member
Tube was probably 6 feet long? It encountered a blockage of some kind before being fully inserted, and never got submerged
Member
If you look at the diagram here and item #1, there's a bend so could that be your obstruction? Did you measure the length of the tube at the point of obstruction? Was the siphon tube you used soft? Maybe try something a little more rigid but still pliable to see if you can get it passed that obstruction area. Take note of the length of the tube that got obstructed with each tube you try.
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