MPS #037 w/ ECU #043/044? Calling PBanders (BRAD) Options

[detoxcowboy]

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

[pbanders]

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.