Hi,

Didnt know I've got this problem until I started driving my 1983 W126 (280SEL) harder than normal. Basically I'm a very mild driver, maxxing at 3000RPM. So one day I wanted to test my car's capability at higher RPMs, but once I reached 3500RPM, the exhaust starts spoofing-spoofing, as if it'd ran out of breadth. At this point in time, the power surge flattens out and if I held on at more than 3500RPM, I'm sure the power will fall. It has happened everytime I had a go at the pedal, so it is not an isolated case.

Is this a case of rev limiter problem? I'm entirely lost.

Any help is appreciated, thanks!

Mervyn
:)

QUick possibilites... Check your Air Filter. Also check your fuel filter (rough idle too?)..

Drive it harder
 

Sorry Mervyn, but couldn't resist... it's a Mercedes, not a china doll... drive it harder; you and your car will be happier. Doesn't mean you have to rip down the interstate at 130 mph - try gearing down on hills or manually shifting at the stoplight.

Spoof-spoof-sputter sounds like ignition breakup. Check plugs, wiring, distributor cap and rotor.

I have seen many times where the fuel pump would cause this. Just a blind guess though.

I would have thought it was a fuel pump problem. My dad's car had the same thing too, until the fuel pump was changed and it was fine since then.

Would be keen to learn whats happening, Merv.

By your side with support.

:)


Ps. Richard - Driver harder?? :D

Had my air filter,plugs,distributor cap and rotor,ignition control module, idle air valve just replaced 2 weeks ago. Ok, will go check on my fuel filter and fuel pump.Do you guys think that the fuel pump relay could be a suspect?

Well, I've began to find the joys of driving my car harder, and phew, it's still not too late. :)

And does someone else here experience the same problem?
Thanks for sharing.

Mervyn

PS.YMsin: will update you on the progress

Do you have Catalytic converters on your car that could be clogged?

I ought to know my car better, but really, I have no clues to whether there are any Catalytic converters on my car.

YMsin, do we have catalytic converters and idle control relays?

Nevertheless, John, I will go check on the cat converters to see if they exist. Thanks!

Mervyn

C.C. on W126
 

I dont think you'd find a c. c. on your model, Merv. Its optional in the Japanese version. Not Singaporean and Malaysian, i.e. Asia-Pacific version.

As to the idle control relay, it is located in the middle of the 300se firewall - red coloured. Sometimes its called an overload relay.

For 280SEL, is your fuel injection KE version or L-Electronic version.

If KE - it should be the same place. If its L-tronice, its likely they dont come with it.

Let me know?

:)

YMsin, I have checked, and my 280SEL is the KE-Jetronic version. As for the idle control relay (aka Overload relay), I'm still looking for it! :(

Do you think that my idling characteristics will improve upon replacing this overload relay?

Thanks!
Mervyn

It should, Merv.

Best wishes .. :)

To Benzmac and YMsin,

Just made a trip to my mechanic today. He test-drove my car, and as usual, the spoof-spoof phenomenon happened again.I asked if it was the fuel pump working its "magic", and he said impossible. In his words, "if the fuel pump is faulty, you cannot even drive the car!" Well, makes sense, unless someone here can tell me that there is such a thing as partial-faulty-ness, meaning the fuel pump operates fine until 3500RPM and above, where it starts to fail. Guys, any comment on this?

Maybe I'll post a separate thread on this.......

YMsin, I checked with him too, and he said that my car does not have a idle control relay (aka OVP-Overload Voltage Protection Relay).

Thanks again, will let everyone know the progress.

Mervyn

PS.YMsin, you mentioned your dad's car had the same problem. Does the spoof-spoof set in only at 3500RPM and above? And works perfectly fine under 3500?

Hi Merv - your symptoms, I meant the MB :), (yes) was like my dad's before he had the fuel pump changed. The mechanic said something about the fuel pump not functioning as efficiently as it should, i.e. not delivering the kick when more fuel is needed - thus he changed the fuel pump. All was well after that. Then again, dad drives a 260E W124 which might have some difference, though I dont think so.

Do let us know, Merv.

Am surprised your MB does not come with a idle control relay. Am gonna replace mine soon and see if there's any marked difference. Will post you on this in due course ... like next week?

YMsin, thanks for sharing.

Now I'm beginning to think that there might be a chance that the fuel pump is playing tricks. Perhaps its not fair to call it faulty, but rather more like what you mentioned - "the fuel pump not functioning as efficiently as it should, i.e. not delivering the kick when more fuel is needed ". Makes quite a lot of sense to me. Perhaps at higher loading, the fuel pump does lose some kick, and there goes the spoof-spoof.

And I also feel that this problem could be independent regardless whether its a 124 or 126.

Great! I'm waiting to hear your update next week! If you can do me a favour, could you ask your mechanic if my 1983 280SEL has an idle control relay? Thanks!

I'm not giving up yet!

:)

Mervyn