MAF elimination project W210 606 turbo - PeachParts Mercedes-Benz Forum

mdisav · #1 10-21-2009, 10:05 PM

I am wanting to eliminate the MAF on my modified 606 turbo. So far I have gotten close but no cigar.

I took the output wire from the map sensor and spliced it into the maf wire going to the computer. The voltage curve must be similar because I get no CEL in any driving conditions...

except when sitting at idle.

If when I come to a stop I apply slight pedal pressure so that my idle is 900 or 1000rpms I can drive without ever getting a check engine light.

The maf sees a little over 2 volts at idle. The map sensor sees about 1.5 volts at idle.

So that tells me that 1.5 volts is not enough from the map at idle. I need a signal with a little over 2 volts at idle to not trip the check engine light.

Does anyone know how to do that? Evan? I have been trying with a 5 volt diode and a potentiometer with no luck so far.

Does anyone know what the output voltage from the throttle position sensor is and what wire color and pin it is at the computer?

KarTek · #2 10-22-2009, 11:36 AM

So, you have the MAF out completely and you're just running a splice from the MAP to the MAF signal wire?

Also, if you're running the EGR elimination circuit, you may have to change the resistor to a higher value so the circuit isn't dragging the voltage too low.

compu_85 · #3 10-22-2009, 12:14 PM

Can't you just get the computer reprogrammed to ignore the MAF? I have such a setup on my TDI... it works great. It uses the MAF when its plugged in, but if I unplug it it defaults to max airflow giving more off the line power... and a little more smoke. No CEL is tripped, though it does store a code.

A better question is why are you trying to ditch the MAF in the first place?

-Jason

mdisav · #4 10-22-2009, 02:02 PM

Yes Evan, The maf in just sitting in the corner plugged in but not piped in. I have the egr elimination in there but need a way to get a little over 2 volts incoming from the maf.

mdisav · #5 10-22-2009, 04:26 PM

I do not think that program is available. I have asked Oliver at speedtuning and he said it is probably not possible.

Also I do not think our cars set codes without the cel.

I put a series of 5v zener diodes together from the 5volt signal from the maf to get roughly 2.5volts. It seems to idle without a code now. I will drive it and see if the coast is clear and if I get a code under any other driving conditions.

The egr bypass is in its modified state. In other words I did nothing to it with this mod.

KarTek · #6 10-22-2009, 07:12 PM

Here's a couple documents that might be of interest/help to you...

http://apps.bosch.com.au/motorsport/downloads/sensors_mappressure.pdf

http://apps.bosch.com.au/motorsport/downloads/sensors_throttleposition.pdf

http://apps.bosch.com.au/motorsport/downloads/sensors_airmass.pdf

mdisav · #7 10-22-2009, 08:02 PM

No codes so far and I have driven it around town about 10 miles or so. Right now I have a series or 5 volt diodes in a row bringing the 5 volts reference down to 2.2 volts. So the computer is seeing exactly what it saw before at idle.

Apparently the map curve is adequate for the computer through the maf wire and the egr mod is happy too.

I will report back after a couple of days with varied driving. It just may be licked!

Thanks for the documents Evan!

auspumpen · #8 10-24-2009, 11:43 AM

Is the MAF used on the 606 just for the purposes of EGR management, similarly to the AFM used on the 603?

mdisav · #9 10-24-2009, 01:04 PM

I think it is like the afm for the 603. It may offer some off the line part throttle enrichment but I am not sure how much if any.

I have driven my car for the past two days in hwy and city and no check engine light. I believe it is a success!

aklim · #10 10-24-2009, 02:39 PM

Quote:

Originally Posted by mdisav

I am wanting to eliminate the MAF on my modified 606 turbo. So far I have gotten close but no cigar.

I'll bite. Why?

aklim · #11 10-24-2009, 02:41 PM

Quote:

Originally Posted by mdisav

The egr bypass is in its modified state. In other words I did nothing to it with this mod.

Another question. Why? Isn't it simpler to reprogram the ECM to NOT use the EGR?

mdisav · #12 10-24-2009, 06:00 PM

It probably is simpler. A lot of guys do not want to do it because of the legalities.

aklim · #13 10-24-2009, 10:30 PM

Quote:

Originally Posted by mdisav

It probably is simpler. A lot of guys do not want to do it because of the legalities.

Which question were you answering? EGR or MAF?

compu_85 · #14 10-24-2009, 10:36 PM

The 606 uses Bosch EDC12 right? Or is it EDC15? In any event the MAF is used to see that the EGR is working, and to limit smoke.

If they are EDC 15 you should be able to tune out the EGR and get MAF delete if you so choose. If your tuner can't do that I'd suggest finding another one.

-J

aklim · #15 10-24-2009, 10:41 PM

Quote:

Originally Posted by compu_85

The 606 uses Bosch EDC12 right? Or is it EDC15? In any event the MAF is used to see that the EGR is working, and to limit smoke.

If they are EDC 15 you should be able to tune out the EGR and get MAF delete if you so choose. If your tuner can't do that I'd suggest finding another one.

-J

I would think that a competent tuner can take out the EGR. Mine did. If you remove the MAF, aren't you also removing something that the ECM can use to sense how much air is coming in and adjusting fuel and trim, etc, etc?