Tuning with CIS - PeachParts Mercedes-Benz Forum

400Eric · #1 06-27-2011, 07:47 AM

Well, first of all, I've been doing you all a disservice by referring to my dummy CTS mod as the dummy CTS mod when I should have been calling it my dummy ECT mod. (The CTS is the one that tells the cooling fans and temp gauge what the engine temp is while the ECT is the one that tells the ECU what the engine temp is.) While I'm confident that most of you still knew what I really meant, I still need to be more accurate, especially because some of the newer members of this board may not know the difference.

Well, the results this time were a wash. No gain. (No loss either.) I don't know if it's because the ECT that I used was actually from an M119 car (It is in fact the very same exact one that I used when I tried this mod on my M119. I thought they were the same!), or if it's because I couldn't put the dummy ECT in a location where it could stay as cool as I was able to do on the M119 (the ECT is on the back of the M103 while it is on the front of the M119), or if it was something else. Who knows. There is no doubt though that since this mod did work so well before (as documented in back to back testing at the track on my M119), that it would work well on this car too since, again, M103 CIS-E cars are easier to fool than M119 LH cars are. (If only I could figure out what the problem is.) I would like to have this mod as an option because I really do love to have that "plug and play" ability.
Regards, Eric

gsxr · #2 06-27-2011, 12:21 PM

Quote:

Originally Posted by 400Eric

since, again, M103 CIS-E cars are easier to fool than M119 LH cars are. (If only I could figure out what the problem is.)

I suspect that the fuel & ignition maps on the M119 LH and EZL do not vary the mixture/spark as much as the CIS-E does, given different inputs. It's not that the M119 is harder to fool, it's that the M119 doesn't reduce output as much during "less than optimal" conditions.

FYI, the FSM (more specifically, the Diagnostic Manual) specifies that when dyno testing the M119 engine, a fixed IAT of 20°C and fixed CTS of 80°C should be installed. I've tried 60°C vs 80°C and found basically zero difference in power output between those two points.

400Eric · #3 06-29-2011, 02:55 AM

Yeah, just one post earlier I was calling it by it's correct name, ECT.

Quote:

Originally Posted by 400Eric

Well, first of all, I've been doing you all a disservice by referring to my dummy CTS mod as the dummy CTS mod when I should have been calling it my dummy ECT mod. (The CTS is the one that tells the cooling fans and temp gauge what the engine temp is while the ECT is the one that tells the ECU what the engine temp is.) While I'm confident that most of you still knew what I really meant, I still need to be more accurate, especially because some of the newer members of this board may not know the difference.

Well, the results this time were a wash. No gain. (No loss either.) I don't know if it's because the ECT that I used was actually from an M119 car (It is in fact the very same exact one that I used when I tried this mod on my M119. I thought they were the same!), or if it's because I couldn't put the dummy ECT in a location where it could stay as cool as I was able to do on the M119 (the ECT is on the back of the M103 while it is on the front of the M119), or if it was something else. Who knows. There is no doubt though that since this mod did work so well before (as documented in back to back testing at the track on my M119), that it would work well on this car too since, again, M103 CIS-E cars are easier to fool than M119 LH cars are. (If only I could figure out what the problem is.) I would like to have this mod as an option because I really do love to have that "plug and play" ability.
Regards, Eric

How and why did I suddenly start calling it ETC?

The reason why I am thinking the CIS-E cars use a different ECT is because the plug in the harness on my 300E has a flat spot in it to line up with a corresponding flat spot inside the ECT so that they will go together only one correct way. The ECT I pulled from the JY M119 doesn't have that flat spot leading me to suspect that the CIS-E cars used a different ECT. (I was forced to line up pin numbers to insure that I installed it correctly. Maybe I messed up and that explains why I got no gain this time? Maybe the #"1" pin on the M119 ECT isn't the same as the #"1" pin on a M103 ECT is?) I of course didn't know about these issues until I was at the track and unplugged my M103's ECT for the first time. The part number on this JY M119 CTS is 008 542 32 17 BTW. I can't see what the number is on my M103 ECT without removing it.

Regarding the IATs, the part number for the one for CIS-E cars starts with a "007" and the one for the LH cars starts with a "009". I can't remember what the HFM M104s use though.
Regards, Eric