Brad,

Regarding my Stock 1974 2.0

I have read your DJet Parts Compatibily, and notice your logging/trying/testing MPS and ECU combinations but have not seen and would like your opinion of the MPS #037 in conjuntion w/ #043/044 ECU.. I am currently using this combination (no ballast resistor) and both units are NEW/NOS. I have not noticed a functional change in performance since switching from Used but funtional combination units of #043 MPS and #052 ECU. Everything else in my system is NEW/NOS certainly everything but the AAR, PCVvalve and Fuel Pump , so the djet playground is "clean". Not Certain as to which CHT but it has not changed when I changed mps and ecu nor has a ballast resistor in conjunction ( I have a very very early 74, 9th one by engine #'s and ordered the cht by that #)




I seemed to have learned more about it after putting together than when I was purchasing to do so,.. Confused?

Wondering if I should be using a specific CHT and no where have I found information on why the 037 MPS is different on that it is " specially adjusted" ( I am drivng around close to sea level so. cal.). Seems to be more info about the 037ECU's affect than the 037MPS's?

Thanks PBanders ahead of time for any input will assist understanding more of the Djet.. Joe

037 MPS needs 037 ECU and 270 ohm resistor. 043 does not need resistor

I knew that config. Sixer but thank you for putting it out there cause I did not state it thinking he already knew that, he unwittingly has taught me much , but there are other variation combo's not all of which have been tested by PBanders(Brad) and in his docment he leaves it to further research...

my input restated is that I am currently using an 037 mps w/ 043 ecu and runs great (unshop tested w/computers but daily driver and a few 600 - 1000 mile trips in just 6 mo. period same 3 0r 4 trips I did the 5 months before that when I was using the generally recommended 043 mps and 052 ecu>)
so this leaves me as to ask why exactly is the 037 mps special? adjust yes but what effects is it doing when it stands alone without the 037 ecu and the 270 resistor.

OK, so here's my "quick" reply (maybe more later if I have time). From what I've seen from doing bench characterization on many NOS MPS's, including 049's, 043's, and 037's, is that there is a LOT of variation in their adjustment from unit to unit, often, enough so that they're overlapping. It's not surprising to me that an 037 MPS works fine in your application, as they're all tuned to the same part-load adjustement. Only the full-load settings seem to vary, and as I said, not very consistently.

The issue with the ballast resistor is that it has to be used when you've got the 037 ECU and the 017 CHT sensor. If you've just got the 037 MPS I wouldn't use it unless measurements showed your mixture was way off.

If you really want to get all this stuff right, you've got to check it out on a dyno. Fully warmed up, you want to see a CO of 2.5 to 3.0% at part load (constant throttle angle, light load, 2500 to 3000 rpm), and a CO of 4.0 to 4.5% under full-load conditions (WOT, heavy load, 4500 rpm). Idle CO should be 3.0%. If your part-load and/or full-load are off from those values, you'll have to either adjust your MPS (see my page) or get a different MPS that's closer to ideal.

BTW, I may talk a good story here, but I'm just as guilty of not having the exact numbers on my own car. I need to go to a dyno shop myself, and am hoping to do so in the next couple of months.

Thanks!! I have been waiting for an answer to that question in my head for 6 months, and everytime I put it out there I would get the same reply. 037 037 017 resistor.. I will need to try more exteneded full load driving and see what happens..