I ran into a couple of self imposed snags but am now 100% in the CLEAR!!! I was running into a really weird thing after I installed the shift solenoids. I was getting an O2 heater code even after I reverted the O2 system back to stock. I was also getting a lean condition at WOT and misfire codes. I toiled over it a bit, double checked wiring etc. Keep in mind that I had been data logging with the SPD only and couldn't see anything out of the ordinary. I then decided to hook up my laptop and log with the piggyback as well and see if I could see anything there and BAM. Early on I was playing with the MAF clamp and had it set to 3.75 volts
This means I got a good fuel reading up to there and pow, the thing would fall on its face.
The funny thing is, I changed the 3.75 to a 0 to null it out. Then I took her for a test drive and she was bogging on light throttle. Look over at the AEM gauges and the MAF output voltage was indeed "0"
Kind of funny actually. So then I had to bump the MAF clamp up to 5.26 so it wouldn't come into play. The neat thing about this accidental experiment is that she was still maintaining a 13.1:1 AFR at WOT with no MAF signal. The only difference was a stumbling on slow starts. Very interesting the play between MAF and MAP on this car..
Once I fixed this, the o2 heater code also disappeared. So the MAF voltage being off in conjunction with TPS and other factors was making the car think there were other problems. Kind of weird that last one, but oh well. I'll have to make a note of that one in case it crops up again.
Other than that, I have been working on the electronics and getting some nice good long logs of beating on the car in stock form. Later, I can use these logs to compare and see what I might need to do with the AEM to help fool the stock ECU into not thinking it has a SC.
I also ordered a Motorola MAP sensor that works with the SPD. This last step will free me from the AEM logging 100% and allow me to tune strictly from the SPD. I've calibrated the AEM maps accordingly and everything is set to match 100%. This is a real treat and is going to make things SO much easier.
So, I've been thinking about next steps and I'm set on installing the SRT injectors next and adjusting the AEM to compensate and getting the otherwise stock car back to perfect. Once I achieve that next milestone, I can then finally start bolting on the go fast parts
This will make it easier to peel back the layers if troubleshooting future problems gets "complicated".
Note: Shift solenoids. I don't think it is my imagination and it makes perfect sense. The tranny seems a bit easier all the way around by putting it in winter mode. In "standard" mode it is excellent for hitting it hard but the downshifts to a stoplight can be annoying. So, S for spirited driving and W for taking the wife to dinner. I'll prove this out a bit more and touch base when I have some more miles with it under my belt.
Note: I was also playing around with tapping the stock MAP sensor and using it to match the AEM maps. It appears that the stock limited MAP is a 1.5 bar sensor for those that may be interested later. It was at 3.7v with the car off or an absolute pressure of 14.7 so that doesn't leave much room!
Note: AFR. I mentioned it before but I had to say something again because I was impressed. Most OEMS shy away from a beautiful 13.1:1 AFR. However, mercedes did right by us as far as the AF goes as she is exactly where she needs to be. So many cars run rich and power can be found simply by leaning them out at WOT. Too bad I can't advance timing with the AEM to see if there is anything left on the table in the form of spark.
Oh well, the next update will come after the injector install. Looking further ahead, we finally enter the Rotrex zone!