W124 Lack of performance and noisey with it

[belugablack]

Have had a triumph today with my 1991 260E, many thanks to the chap who pointed me towards the over voltage thing on my posting a week ago. Once I had finally located the OVR thing - hidden under a black cover - - lo and behold the 10a fuse was blown... thinking I was on the brink of a Eureka moment, I replaced it, and not only did the engine start on the button, but it also idled perfectly at a healthy 650rpm rather than shuddering about to die at 350rpm and the major bonus was that the ABS light promptly extinguished too for the 1st time since I have had the car -- I am not usually so jammy and am so chuffed that I didn't buy a new ignition module at £200 - or a new cap and rotor like I was going to before I decided to scrap the car... this has been the cheapest fix ever!

Anyway, after resolving to scrap the car last night - - with this morning's good fortune and realising there is actually no ABS issue I have viewed the car in a new light. My main niggle is that the engine is very sluggish and really "bogs down" when pulling out of junctions for instance - I have had a decent 260E before so know exactly how one should perform. It's not like a misfire as the engine revs smoothly and there's no stuttering or faltering - I just doesn't pick up speed at all.

The gearbox changes are very late, going from 3rd to 4th rather reluctantly over 4000rpm, but even when holding gears manually the performance doesn't improve, the revs shoot round but I don't go any faster -- so although I probably need some gearbox work at some point, I doubt this is linked to my problem.

I have taken the airfilter housing off and lubricated the throttle linkages, checked the ATF fluid so far... at the moment I am thinking fuel related - - maybe injectors, fuel check valve, fuel pump relay???

Also when I finally reach 60mph cruising, I find the engine is noisey, really quite intrusive and harsh, revs are at about 3000rpm -- but it should be much more refined than this... the 300CE I has was always noisey once at 60mph so I got rid of it quickly... has anyone experienced this, and more importantly cured it please?

 

[Ian B Walker]

I would have a compression test done on it first. I would think that you may be short of a few pounds pressure on either number 6 or 2 cylinder.

 

[Karl]

Check that the vacuum advance on the distributer is working by attaching a pipe to the vacuum unit and sucking the pipe with your mouth.
You should notice a restriction if not the diaphragm is holed and you will have not enough advance when pulling away or when under load.
Had this on my 1990 230E, it was an easy fix.

Good Luck

Karl

 

[belugablack]

Thanks for those pointers. Now that the car starts fine, I've been using it all day today and its performing a lot better, albeit still needing a manual knock back from 4th to 3rd its reluctant to change down when slowing into a sweeping corner to power back out - leaving you stabbing the accelerator with no gearchange in response...

Does anyone have any ideas about it being noisy? It's not any untoward noise like exhaust blowing or engine in distress, just that at 60mph+ it makes a constant noise like it should have another gear to shift up into, i.e. it's over-revving at 3000rpm at 60mph? As I mentioned I had exactly this on a 300CE - am wondering whether it might be a gearbox issue?