Hey Everybody,

I`m getting ready to replace my main fuel pump. Seems like a straightforward job. The main issue is safety. Working with gasoline present is a little intimidating. I`m aware of the `depressurization procedure`.I just need a little of assurance that the gas doesn`t keep running whilst I replace the pump and filter.
Testing diagnoses suggested by the members here have been invaluable to someone not very familiar with electronics but generally easy to do.
I`ve posted a couple of times earlier this month about the latest adventures of 240 ownership (I still love her!).
There are some lousy grounding and wiring in this car as we all know, but I`m thinking main fuel pump. She quit while driving home from work.
The car has a healthy spark. I checked the timing belt-Crankshaft pulley mark on 0TDC, camshaft pulley mark matches cover mark, rotor points to no. 1 cylinder. Jumped #4 to #6 fuses. I can hear the in tank pump whirr. Its very faint, you can barely hear it. The relay clicks when the key is turned on and off a few times. Removed relay and jumped #30 and #87/2 in relay plug. Again heard the in tank pump but with the key off if this makes any difference. I don`t hear anything by just turning the ignition switch.
I bought a new Bosch pump (#69593 and filter#71039)from the auto parts place I work at-$102/all.
Any tips/opinions welcome. Hope to do the job this weekend.

Jim S. `86 245 ...want my baby back!

Main fuel pumps are loud as they near end of life, normally when the car quites it will restart when the pump cools down or sets a few min's. Also if you tape it lightly it will probably run again for a while. Main pumps also are more finicky as the tank gets lower as they have to work harder - that said .. there is many times a problem with the in tank pump not delivering fuel which makes the main pumps job harder leading to early failure. In tank pump may be running but the fuel line between it and the pickup is in bad shape.. oxi fuel is said to be hard on the orrigional bellow type hose. Second problem I found by accident on friends 240... the wire feeding the in tank pump has a cold solder joint at the intersection with the lug if you will that fastens under the fuel pump terminal. This cold solder joint looks ok but only detected when you have every thing apart and wiggle the wire at the solder joint. Can be intermitant and will cause you to loose hair.. friend had 3 new pumps installed over time befor I found that problem by accident. ... lastly the main pump will get you home if you run a wire directly to it as there is some loose of current at the relay .. etc. My trick was to lift rear seat and drop a wire from the overhead dome light to the connection under the rear seat. With less voltage drop the pump will manage to run longer ... by the way main pumps really run slow when they are on last legs.

the line from the fuel tank into the main pump leaks the most gas.
as you undo it, you might have a 3/8ths extension, or a similiar diameter bolt, or a wood dowel on hand to stick in the line so you don't have gas all over the place as you continue with the replacement procedure.

as with anytime fooling with open gas, have a garden hose with a sprayer nozzle at hand. If you spill, wash it down, be safe.
--
-------Robert, '93 940t, '90 240 wagon, '84 240 diesel (she's sick) , '80 245 diesel, '86 740 GLE turbo diesel, '92 Ford F350 diesel dually

"I`m aware of the `depressurization procedure"

If you mean the "pull fuel pump fuse and run engine till it dies", I'm afraid that's a wide-spread fallacy, at least with Bosch FI. There is no "pump" fuse as such, only the 25A fuse under the hood (pull that and the engine won't start) and the 4A Tank pump fuse (which won't prevent engine running).
As for Fuse 6 (mislabeled as Main Pump), it connects to nothing on U.S. market cars. Consider it merely a spare.
Just have a rag handy to wrap around any loosened fittings.


Tony says there will be no siphoning, but with the pump lower than the tank, I'd put a hose-pincher on the pump inlet hose. I recall doing that the last time I disconnected a pump. Not sure if I had to though.
There will be some drain-back from the front too. Not a lot but be prepared for it.
--
Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

It's straight forward. You may want to drop the Filter/Pump bracket down, and run a Ground and +12V wire from the battery to the pump. There should be a "+" and "-" sign right on the plastic by the terminals. It would assure you that the pump is the real issue. If it doesn't spin with voltage direct from the battery...it's toast.


Put a pan under the pump. disconnecting the hoses will not cause a siphon affect. You will get some gas that you don't want in your driveway or in your eyes. Plan on getting sticky fingers as the gas drips on the undercoating causing it to soften.
--
'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me