Hi,

I have two ECU's
One is 0 280 100 037 the 1973 ECU for 2.0 liter
the other is 0 280 000 044 which is for the 1974 2.0 liter.

Assuming I am using a new TPS, a new CHT, and any MPS I can find/tune...
Does it matter which ECU I use?

I know that the ECU and MPS must match in the 037 case, but If I cant find the proper MPS, I will have to tune one anyways.

I am hoping to find a 2.0 liter MPS that holds vacuum, and just go with that...but I may need to tune it anyways.

Rich

The ECU needs to match the correct parts. Help here:
http://www.icbm.org/erkson/ttt/engine/fuel...on/fi_parts.jpg

From the "914 Tech Tips 700" book on pressure sensors:
Early '73 2.0L: 0 280 100 037
Late '73-'76 2.0L: 0 280 100 043

Go to my web site here:
http://www.icbm.org/erkson/personal/Porsch...20Injection.pdf
for the 914 factory manual on fuel injection. See [Adobe] pages 27-29

Aw heck, I forgot about this GREAT web site!
http://members.rennlist.com/pbanders/DJetParts.htm

The top section of the page has all the tasty numbers you'll need

Your MPS has to match the ECU. Especially if you use the 037 versions. And if you use the 037 version, you have to get the 017 CHT sensor which might be NLA. Also, do you have a harness? There are some differences in harnesses. I would probably try to use the 74 stuff, I think its more available. The 73/037 setup is definitely unique.

ECU's usually are quite similar and in many cases you can use a "wrong" ECU in a pinch. The 037 ECU was originally used with the 1.7L engine, so it has a different speed mixture compensation than the 044, which was designed for the 2.0. The use of the 037 ECU on the '73 2.0L appears to have been somewhat of a kludge - perhaps the 044 ECU wasn't ready yet and they used the different CHT, ballast resistor and differently adjusted MPS (the 037) instead.