Turbo Noise on 603 - PeachParts Mercedes-Benz Forum

justinperkins · #1 06-14-2007, 05:06 PM

I know this has been talked about several times, but I just want to make sure I'm OK. I was looking at this thread already: Should I be able to hear the turbo spooling?

Just recently I've started to hear my turbo spool up when I get to around 3k rpms. It's really noticable, not something I could have missed before. Nothing has really changed with the engine, except I installed a new air filter about a month ago. I only started noticing the turbo noise about a week ago though.

I was reading in that other thread that maybe a rubber grommet between the airbox and the air snorkel could have came loose, is that a possible scenario?

There is no noticable loss in engine power, nor does it feel like anything is really wrong, but still, as much as I like hearing the turbo (loved my TDI's whistle), it's not normal and makes me scared.

#2 06-14-2007, 07:16 PM

The IDI engines with the stock air filter assembly and no intercooler should not be able to hear the turbo.

justinperkins · #3 06-15-2007, 01:11 AM

I've also noticed a little amount of oil residue build-up around the aluminum tube that the egr (I have the block plate installed) connects to. I'm referring to the piece that goes up and then the crossover pipe connects to it.

I probably just have an exhaust leak somewhere that I haven't located yet. The small flexpipe is tight and does not appear to be leaking.

Hit Man X · #4 06-15-2007, 01:18 AM

Junk the AFM like I did, you'll hear it then. Just use a 617 intake tube to bypass it like so:

justinperkins · #5 06-15-2007, 01:22 AM

wait a sec, what's going on there?

did you cut that hole in your airbox for the 617 intake tube or did you just flip the airbox around 180 degrees?

where does that tube go, did you just stuff it between the headlight and the radiator?

afm?

Hit Man X · #6 06-15-2007, 01:42 AM

Quote:

Originally Posted by justinperkins

wait a sec, what's going on there?

did you cut that hole in your airbox for the 617 intake tube or did you just flip the airbox around 180 degrees?

where does that tube go, did you just stuff it between the headlight and the radiator?

afm?

Just shows all the emissions stuff removed for off road use.

Nope, fit right in there. Just toss that Air Flow Meter (AFM) away and put the 617 intake tube in between the two tubes.

Nothing was flipped. It was a simple toss of the AFM and put the hose in place.

justinperkins · #7 06-15-2007, 01:49 AM

sweet, will do. thx

Hit Man X · #8 06-15-2007, 01:51 AM

I hope it makes sense.

I have all that crap removed now, vac lines, EGR, etc. Also block heater cord installed and a 150A alt.

Also, may as well punch out your cat... I did.

retmil46 · #9 06-15-2007, 01:57 AM

Is that all the AFM is there for, just emissions controls, nothing really to do with injection or engine control?

Hit Man X · #10 06-15-2007, 02:00 AM

Quote:

Originally Posted by retmil46

Is that all the AFM is there for, just emissions controls, nothing really to do with injection or engine control?

Yes, it's of no use. Mine has been gone for years.

retmil46 · #11 06-15-2007, 02:04 AM

Well, deja vue!

We recently figured out the same on the Jeep CRD's - unplug the MAF sensor on the airbox, and the computer shuts off the EGR valve and the butterfly valve on the intake, kicked that 4300 lb breadbox up a good 2 mpg at least.

#12 06-15-2007, 02:06 AM

Quote:

Originally Posted by retmil46

Well, deja vue!

We recently figured out the same on the Jeep CRD's - unplug the MAF sensor on the airbox, and the computer shuts off the EGR valve and the butterfly valve on the intake, kicked that 4300 lb breadbox up a good 2 mpg at least.

What about the evil check engine light?

retmil46 · #13 06-15-2007, 02:17 AM

Constantly on. I've renamed it the "High MPG Mode" indicator light.

Goes away if you plug the sensor back in after 3 cycles, or can clear immediately with scangauge or OBD scantool.

Gent over on one of the Jeep forums has actually made a circuit board you can splice in - tricks the computer into thinking it's still connected, keeps the CEL off as well as the EGR, and with a flick of the switch can be put back to stock mode for the vehicle inspector.

I'd rather not go to the trouble of hacking wires - I'll just plug the sensor back in and clear the codes/CEL before i take it in for inspection.

Besides, I'd rather not take the chance that some nosy inspector might actually know what he's looking for and find that box spliced in.

With the sensor harness - "Oh, I missed that connector when I changed the air filter".

Unplugging the MAF sensor on the Jeep is the equivalent of the "BB in the Vacuum Line" on the MB - does the job, and is easily reversible back to stock.