an adj fuel pressure reg will do u no good what so ever. if u need more fuel flow for an NA setup, then u need to mess abt with the EHA it has a tiny screw which will result in more or less fuel flow.

if u need to up the system pressure to counter the boost pressure, then u need to know what ur doing and u need a fuel press reader and it is complicated to do.

I saw this post and I think you would be able to help. I have a W124 M103, and it starts fine when cold, but when warm has problems starting, when I check timing with a light it looks a bit retarded (while idling).

Anyways, when the engine is warm and I trick the ECU to think the engine is cold (by connecting the green/red wire from coolant temp sensor to a 10k ohm resistor, which makes it seem as if the engine is -10degree C), then it starts up fine and idles up to 1500, since it thinks its cold.

What could the problem be? It starts fine when tricking the ECU, I'm guessing this is injection side. It is the 2 wire coolant temp sensor.

BTW, I've done all the basic diagnosis and checked fuel pres. and leak down and all have checked within spec.

thanks

OK, I Finally had a chance to take Benzer 1 to the track this past week-end and with NO OTHER CHANGES from the previous time I had Benzer 1 at the track, except for the substitution of the ECU bearing part number 002 545 97 32 and the removal of the resonator and muffler, Benser 1 went a full second quicker in the quarter mile in much worse conditions than what we had the last time we were there! We are talking an uncorrected 15.95 @ 87.27 (15.487 @ 89.939 MPH corrected) where last time we couldn't do better than a 16.95! Mind boggling! We repeatedly spanked a Bimmer 525i in the process too! (Well, actually, slaughtered the Bimmer.) I honestly think that I was more thrilled to get that 15.95 out of Benzer 1 than I was when I got that 14.348 out of Benzer 3!

So now we have some "real world" numbers to back up all of the theories we have discussed here in this thread. It turns out I was on the right track, I just needed to finish the job by freeing up the exhaust and trying that older, Non-California ECU! Sometimes we are just looking in the wrong places! We have to take care of the basics first. Now this car might be more responsive to some of the other tricks discussed here in this thread!
Regards, Eric

ECU bearing? Please tell us more! Or did you remove them muffler bearings and install them on the ECU...? (sorry, I couldn't resist, lol...)

:stuart: :stuart:

fresh headlight fluid makes an extra 20HP last I read on the interwebs!

Congrats Eric:)

Yeah, and adding a wing on the back will reduce your E/T by a half second!
Regards, Eric

The thought occurs that if you want to try tuning the CIS the best start would be a junk yard for an EHA valve thing. Then you can adjust and fiddle with it to your heart's content, knowing that your factory-set one is safe there ready to refit if you screw everything up :)

The very next thing that I'm gonna try is my dummy CTS trick. It did provide me a documented, repeatable gain at the track with my M119 and I fully expect it to do the same for my M103 since CIS-E M103s are even easier to fool than LH M119s are. The neat thing about the CTS trick is that it also gives you additional ignition timing and is by far the quickest, cleanest, easiest mod of them all to do and undo! Just unplug the plug from the stock one and plug in the dummy! When you leave the track, do the reverse! I've obtained TWO EHAs from the P-n-P but I'm hesitant to mess with the EHA on the car because I don't want to jeopardize my street fuel economy. My dummy CTS mod allows me to switch back to "street mode" far easier than switching out EHAs would.
Regards, Eric

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

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.

:detective:

Now you are making the same mistake I was. When you said "CTS" you meant "ETC", correct?

The pre-90 CIS-E cars didn't have IATs so that isn't an option for manipulating and fooling the ECU/EZL in my case.

Dave, are the ETCs the same between the 2 systems? I know for a fact that the IATs are different between the post-90 CIS-E cars and the M119 cars, with different part numbers, and slightly different behaviors (Remember? In my thread my tests showed the IAT from the CIS-E cars is more "rangy".) even though they physically interchange. I'm now wondering if the ETCs might be different between the 2 systems too.
Regards, Eric

The four pin CTS / ECT (not ETC) is the same on all LH cars, but I'm not sure if it's used on any CIS models. And you are right (again!), the official MB acronym is ECT - resistance data (for M119 ECT sensor) is here:

http://www.w124performance.com/docs/mb/M119/LH_temp_sensor_values.pdf

If that doc is to be believed, it says that yes it's for both CFI (CIS) and LH, including M103/M104. Then again it says the IAT values are the same and you found they were not, so... all bets are off again...

:stuart:

Yeah, just one post earlier I was calling it by it's correct name, ECT.
How and why did I suddenly start calling it ETC? :o:confused:

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

OK, I've just read all 12 pages of this thread again and I'm still not clear about how to substitute the 1,200 ohm resistor in place of the ECT sensor to bump only the timing, not the fuel. I understand that 2 of the wires from the ECT are for the CIS ECU and the other 2 wires are for the EZL, but which ones are which? I read the post were Jay says to just do a continuity test but my multi-meter is missing again. Besides I'm thinking that since Jay has already done this mod to a M103 car, he can just tell me which wires to solder the resistor to! Come-on Jay, help me out! We've got another track day coming up in a few days and I'm ready to try your mod at the track!! Some pictures would be really helpful too! Please help!
Regards, Eric

I too would also like a better picture of what this looks like. :):D:cool: