w124lk

hi. Could someone please shed some light as to why I cant hear my fuel pump engage when I try to turn on the engine? I cant start the vehicle it just cranks. New fuel pump too... any advice would be much appreciated.

w124lk

had a look at what I believe is the OVP relay. the fuse appeared to be fine.



then i started to look at the wiring that runs to the adapter and it appeared as though one wire had melted and stuck to another wire??







separated and insulated the bare wire(s) to test if the vehicle starts and unfortunately it still does not fire.
any ideas folks?

w124lk

update: pulled out the OVP relay. had a look internally to find a failure. i think this may be the culprit. will solder up and see if it fixes the problem

optimusprime m1

And did it fix your prolem ?.
If still the same join no 7 and no 8 conntacts in the base of fuel relay .It sits in the same location as the ovp relay ..Only to see if it is the fuel relay at fault .MOST Important to remove wire link after you try this task .Doing this fires up the pump none stop ,and will fill the inlet manifold with fuel if left in place

w124lk

hi yes it fixed the problem and the fuel pump is now working. vehicle starts and drive but i will not drive the vehicle as the cause of this in the first place is the wiring harness. it is completely destroyed im afraid

optimusprime m1

w124 so sorry to hear that .Can you get it fixed ? How much of the wiring loom is burnt out ?.

w124lk

hi optimus. i believe it is quite severe in areas near the intake manifold, injectors, etc... MAF sensor wire is the worst!

w124lk

not a pleasant sight at all

optimusprime m1

I know of a lot of members that have had this problem over here in england .And have rewired the engine compartment loom with one from the pick and pull yard .The engine loom works out about £500 for a new new one in the uk ..Good luck hope you fix it soon.

w124lk

have been making a few calls in recent hours optimus
if only you could use your transformer powers and bring this loom back to its former glory

optimusprime m1

If i could my friend i would .These things are sent to try us .Like my 260e i have had one thing after another, but only small items . But you find one problem , only to end up with two more . Like door straps going off like a gun as you open the door replaced all 4 of them .You name it i have had my hands in to it . But thats the joy of owning an old benz .I dont look at it so bad after i go to the car shows and people just want to look ,and ask questions about it .My car is not a show stopper by a long way .But 100% original and all the bits and bobs that came with it new , i have them with the car .Down to a box of Imperial Mints that still sit in the cubby hole ..And original number plates sit on the front and rear.

w124lk

thats the spirit

optimusprime m1

124 you keep your chin up , and get stuck in to the mercedes wires . Do you have a scrap yard by you ? Pick a loom up from the yard .You will see how its removed getting it out of the engine yourself. But main thing is to take a camera, and a roll of masking tape, to stick on the end of the wire . You mark it with the marker, or a felt pen as you remove it.

w124lk

Yes i was about to remove the harness yesterday evening however i wasnt sure where the harness runs after it exits the plastic casing near the power steering reservoir?? I can see the casing which sits on top of the inlet manifold. Just cant see whats underneath the manifold and where the loom runs underneath it? engine is the M111

optimusprime m1

It wants removing and fitting at the same time so all the leads line up with the right part .

w124lk

do i have to take the inlet manifold off? i was hoping not to

optimusprime m1

I dont think so .

w124lk

removed the old harness (what was left of it really). Bit the bullet and ordered a new one from MB and coil loom too

optimusprime m1

Good one ,now get cracking and install it . Hope the problem is fixed after .

w124lk

Transplant complete, car drives beautifully. Very happy

optimusprime m1

Nice to hear that the job was worth it after the work you put in . Now its time to enjoy it ..Thanks for letting us know. Did you open any of the loom up to see the damaged area ? .

w124lk

Hi optimus. Upon inspecting the loom i found that the worst deterioration was on the injector wires and the wire which goes to the MAF sensor. Its a very messy job and when you're moving the wires around it will only do more damage and leave bits of insulation everywhere. Some wires were completely bare. When you're taking out the old harness you will slightly move the ignition coil harness connector. Mine was very brittle and the insulation started to flake off. I ordered a genuine one with the main loom, its a fraction of the engine loom price . This took most of the time as the ignition coils on this engine were located under the inlet manifold. Not the easiest place! Hands had to suffer some pain as you have to get under the inlet manifold. I preferred not to remove the manifold. I had the throttle body removed so it made it a little easier to see from above. The coil harness would cop quite some heat i'd imagine as it sits beneath the inlet manifold. MAF sensor would not be too far as the standard wiring runs along the valve cover. Great place to get cooked. I can say that replacing the harness will put many things right on these cars.

optimusprime m1

What engine do you have in the car .As i see w124 in your forum name i though it was a w124 . But its not a W124 is it.

w124lk

its a w124 E220 (M111)

optimusprime m1

Good to hear you up and away .