W123 239E fuel pump

Slat4090

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Joined
Feb 13, 2012
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Location
Blandford Forum, Dorset, England
Your Mercedes
230E/1985/2300
Morning all,
Having a few problems with the old girl. Started out with a rough idle, which i put down to it actually being used, and hoped that it would sort itself out once all the gunk had gone through the system. Idle started to get worse, so started investigating. Changed plugs, leads, dissy and ran a top end fuel system cleaner through. This did nothing. Hoped that taking it for a 200 mile drive may improve things, but as yet nothing seems to have improved.
The ony extra bonus I now have is that the fuel pump has started to squeal when the engine is running, and it splutters a lot on idle. It cuts out occasionally when pulling away, and the car feels as though there is no fuel going in, so it wants to stall. When this happens, it takes a good 5 seconds of pumping the gas pedal before we get moving (at quite a rate of knots!)
Would this be the pump or could it be something else? I have another 500 miles to cover before I get home, and dont fancy relying on te RAC for a tow home.:confused:
 

MechPhil

Senior Member
Joined
Feb 8, 2012
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Location
Brandfort, South Africa
Your Mercedes
'87 260E
I think you may have an air leak somewhere. Open the bonnet and work the trottle by hand with the engine running, just enough to get it to run steadily enough to be able to see whats going on. Now listen for a sucking sound. Check the vacuum line that goes from the intake manifold to the brake booster. Also check that large, short rubber hose between the intake manifold and the throtle body, they tend to perish and crack. Also check all the small vac hoses that connect to the intake manifold.

If there are no air leaks, change the fuel pump anyway, a squealing fuel pump is bound to get you in trouble sooner or later!

In future, place technical questions in the technical section of the forum, you will be helped much more quickly!

Phil
 

MechPhil

Senior Member
Joined
Feb 8, 2012
Messages
488
Reaction score
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Location
Brandfort, South Africa
Your Mercedes
'87 260E
I just want to add that fuel pumps normally first cause trouble at hogher revs with wide throttle openings, and then progress to the idle level of fuel demand, so my first guess is that the pump is still working OK.
 

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