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The aftermarket fuel pump on my car has been noisy since I got it back in August. Usually, it just has a smooth but annoying high-pitched buzz, but recently it has sounded rough at times, like it's cavitating. My car still starts and runs fine, but does feel a little sluggish up hills. Today, I started my car hot and it sounded like I had a beehive in my trunk. Both pumps, I assume, were moaning atonally. I drove 15 miles or so this way with no ill-effects. By the time I got home the extra moan was gone. I think it's time that I finally check the in tank pump out.
My question: What do I do about the 2 hard fuel lines going to the pump? They're hard plastic, really, and look like they cannot be removed without cutting. I'd have no problem with that and then just splice it all back together with some 3/8" fuel line that I already have. I just want to make sure that there's not some trick that I don't know.
Fuel pressure checks out fine, fuel filter replaced 500 miles ago. I plan on looking for a used Bosch pump the next time I'm up in Waco at the PNP.
Thanks BB,
Charlie
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1985 244DL B230 M46 170k
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I pulled the in tank today. The fitting above the axle broke free w/o too much trouble. Disconnecting the send line to the main pump was more difficult. Everything looked fine. I bench tested the pump and it worked. Looks like it has been replaced at one point because there is an AC unit in it now, and I think the stock ones are VDO. Sock filter wasn't unusually dirty, but I blew it out with some compressed air. Rubber hose has definitely been replaced. So, everything checked out there. I put it all back together and started it. Main pump (aftermarket) is still noisy. I think that it's the nature of it or something. The car starts quick and runs great. I'm going to get a used Bosch pump if I can find one at the PNP next time I go and see if that doesn't fix anything.
Strange findings: pulling fuses 4 and 6 doesn't cut off power to the pumps. The wire colors match and I'm getting voltage everywhere that I should be, though. Also, neither pump gets voltage in the II position, only when it's running. What to make of this?
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Strange findings: pulling fuses 4 and 6 doesn't cut off power to the pumps. The wire colors match and I'm getting voltage everywhere that I should be, though. Also, neither pump gets voltage in the II position, only when it's running. What to make of this?
Fuse 4 should kill the tank pump. Fuse 6 isn't wired to anything till '91 models in U.S. 240s. Pump run in KP II didn't come until LH2.4 in '89 for 240s.
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Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
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Interesting. Pulling #4 definitely did not cut power to the tank pump: I even had a multimeter on it when doing so. Car continued to run fine. So, 12V goes from 25A fuse to relay, relay to main pump, right? Tank pump should be 12V from relay to fuse 4, #4 to tank pump, right?
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Right.
Relay to fuse 4 input is a junction: From there to Main pump and thru fuse to Tank pump. Pulling fuse 4 should kill the Tank pump but probably won't stop engine.
See Bentley page 390-28, bottom of grid K5.
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Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
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This post was very timely since I was just preparing to replace the sending unit.
I have a 1992 240 that spent most of its life in CT. The wires to the top of the old unit had completely corroded and when I was removing the hoses I found that the fuel lines were easily bent because of the corrosion. The replacement unit (from FCP) is made in Estonia. The only complaint I have with it is that the wires are reversed at the plug - easy enough to fix but something to be aware of.
Thanks to Art's posting the job was made much easier.
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Two nylon lines??
In The Tank
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Art Benstein near Baltimore
What's the definition of a will? It's a dead giveaway.
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Maybe I'm remembering it wrong. Last I saw it was in August when I tried to pull it troubleshooting right after I got the car, but stopped when I saw the nylon line. Your page answered my question, though. I'll just cut the nylon line and splice it with some fuel hose.
Thanks, Art.
Charlie
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1985 244DL B230 M46 170k
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Art, your the man.... I wish I had your skills.
As always learning from you is an true asset.
Charlie,
I found it easier and wiser to disconnect the left line
where it connects under car above the rear axel to the
metal line. This way you don't have to slice and
dice, patch and check for leaks at your new connection.
The fuel line on the right just has a clamp
at the sending unit.
Joseph
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Joseph,
Believe me - if you survive owning 10 of these cars in 10 years, and read this forum, you'll add any skills I have to your own.
I agree with trying the axle connection first, especially in Ari...., er, the Southwest. I need to add some more to that page after last month's new tank pump experience. Had an "out of box" experience with an aftermarket tank pump.
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Art Benstein near Baltimore
She had a boyfriend with a wooden leg, but she broke it off.
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Can the pump be replaced without taking the hoses off/apart? Maybe just raise the unit a bit and change it out.
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"Can the pump be replaced without taking the hoses off/apart? Maybe just raise the unit a bit and change it out" That's not possible--the unit can't be lifted very far with the hoses attached--and even if you could lift it, the little fiddly bits that have to get disassembled to change the pump would be uncomfortable to deaL with in tight quarters. As to the question of the hard return line--splcing (5/16 or 8mm fuel hose) will work and makes wiggling the unit out of the trunk floor a little easier--but if the undercarriage connection will come loose it makes for a neater job. Be sure to use a fresh piece of hose from the pump to the unit. -- Dave
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By the looks of those pictures, that Maryland road salt is pretty unforgiving. I'm glad to not be in Minneapolis anymore spending hours breaking rusty nuts and bolts loose.
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1985 244DL B230 M46 170k
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Yes, that's right, and I dare not complain, as my friends to the North have the far greater challenge.
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Art Benstein near Baltimore
With her marriage she got a new name and a dress.
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