603 Drivers. Can you hear your Injection Pump? - PeachParts Mercedes-Benz Forum

777funk · #1 11-28-2007, 03:51 PM

I have noticed that when I press the stop button on my om603 engine that I hear a noise every time. Kindof a ehhhhh sound that lasts for about 5 seconds. If I turn the key off, I never hear the noise. It's only when I have the key on and manually press the STOP button on the pump that I get the noise.

Anybody else heard this noise or do I have a weird IP?

ALSO, I can hear the IP making some sort of similar sound (maybe the idle control electronics) when I'm at idle when the engine is warm... Weird. But every stop sign I can hear it once the engine is warmed up.

Any clue as to what this is?

Brian Carlton · #2 11-28-2007, 04:27 PM

Quote:

Originally Posted by 777funk

Any clue as to what this is?

........operator problem........

777funk · #3 11-28-2007, 05:30 PM

Quote:

Originally Posted by Brian Carlton

........operator problem........

Hey Man, go easy on a brother!

The car did this when I bought it so if it's operator error, it's the operator before me

Ha ha

Hatterasguy · #4 11-28-2007, 05:54 PM

Don't know never noticed it. Shut the car off with the key like your supposed to.

777funk · #5 11-28-2007, 06:24 PM

So No Sound when you press STOP?

Hatterasguy · #6 11-28-2007, 07:24 PM

Nope, not that I remember.

2.5Turbo · #7 11-28-2007, 07:30 PM

When I replaced my shut off valve on my 602 I noticed that pressing on the stop lever pushed the diaphragm on the valve up which created a little pressure in the line to the key switch if the key was not in the off position. Perhaps the noise you are hearing is that pressure bleeding off. It also could be some electrically operated vacuum devices (switchover valves, transducers, etc) continuing to operate (since the key is still in the on position) off the residual vacuum

greasybenz · #8 11-28-2007, 07:58 PM

Yep i hear a sound when i press the stop tab on the engine. I think 2.5T pretty much explained what it could be. To me it doenst really sound electronic but more vacuum related.

777funk · #9 11-29-2007, 04:57 PM

It seems like when I'm at a stop sign, I can hear the injection pump trying to regulate idle speed and it seems like for a second or two after stopping the IP is getting it's bearing. It slightly speeds up, slows down, speeds up, and stabilizes. That's all after I stop and within a second or two.
But I can hear this stuff that 2.5 described doing it's thing. I wonder if it's all ok. If I can't figure it out, I'm not worried, I'll drive it till it dies no matter what but wondering if it's changeable components that are doing this.

777funk · #10 07-14-2008, 01:27 PM

Ok to finish the thread. I feel dumb even admitting what the sound was, but Brian's post was right, "operator error" lol

. It was the shock on the idler pulley. The bushing to bolt wasn't tight and it'd rattle a bit while coming down to idle or at times while idling. I put a rubber washer on the bolt between the shock and engine block and it's silent. So it wasn't the IP, just a rattle of an old car. The stop button still makes it's sound when pressed but I'm guessing that's normal.

On another note... I was at a diesel injection shop a few weeks ago having my injectors pop tested and they had some pump on a bench and they were spinning it on a machine. That you could hear. Without the engine noise the IP spinning for a bench test at different RPMs sounded just like the engine. I think it was a 4 cyl box truck IP because it was a quieter version that was resemblent of a small Isuzu or Mitsubishi type engine running. Sounded pretty cool actually! Wouldn't mind an IP in a case somewhere on display in my garage. Cool souding little thing! Pretty neat.