Put the engine back in after removing it to repair the trunk hinges and finished hooking everything up yesterday. After a couple turns of the key to purge the fuel lines of air, I hit the key to start it.

After a few turns it started and when the AFR gauge finished its 20 sec countdown, I was looking at 16.0 on the AFR gauge.... way too lean.

That is the upper limit I have set to display on the Autometer Wideband AFR so I really don't know what it was, I just know its too lean. I won't idle, just shuts off, but will start right back up again.

Double checked all the vacuum hoses and everything is connected correctly. and if there was a vacuum leak the idle would be waay up. I know that from experience.

One of the things I did while I "was in there" was switch out the 037 ECU for a 044 ECU I had purchased. The 037 being used on both the 1.7 and 2.0 in 1973 and the 044 being used on the 1974 2.0

Also set the valves and changed the oil.


When I built a 2056 I set the MPS as per Anders. I found I had to futz with it beyond that test drive futz test drive futz. My car ran better when leaner but too hot. Perhaps because I bumped the compression. I have it set pretty rich at the moment. One problem is there is no way to alter the slope of the curve. You can set idle and you can set the point where the second diaphragm cuts in and you can set the max. And that is it.
Good luck!
I left the MPS as I had it set using the 037 ECU and it was richened considerable to get it to run good. I really had expected it to be to rich for the 044 ECU also.

These are the MPS specs from P Anders site.

Click to view attachment

For comparison this is what mine was set at.

0 Hg 1.51
4 Hg 1.34
15 Hg 0.85

Richer than the chart but worked for my engine mods.

2056 w/ Raby 9590 cam and HAM RS+ heads D-jet 2.0 FI system 123 Ignition.

Looks like my next step will be to put the 037 ECU back on and see what that gives me.

I had unplugged the O2 sensor when I removed the engine and it would probably register a failure if the wire wasn't plugged back in right. I had changed the 123 dizzy setting from 1 to 2 which was the recommended setting for the 044 ECU but that would not / should not affect the mixture.

I thought that the ECUs usually did not fail and the engine did run but I wonder if I got a bad one??

What else would cause this.

Well down to the garage to switch out the ECUs , I'll report back later.

Valves may be too tight, that would cause lean.
Timing also, but at idle you would see less impact.

Then, back to the other ECU.

Those heads will flow better than a set of stock heads, so that will also cause lean.

Are you SURE the sensor is calibrated correctly?

Is it cold where you are?

I'd just put the 037 back in.

Did the idle mixture adjustment have any effect? These ECUs are pretty bullet proof.

I did try the idle mixture on the 044 ECU to no effect that I could see.

Again the top range of the AFR gauge is set at 16.0 I may have been able to notice a difference if I had adjusted the top AFR setting to something like 20.0 or whatever the top of the range is.

as it was, revving the engine in the driveway it remained solid above 16.0 and I didn't want to venture down the street not knowing how lean it was and risk cooking something.

The heads flow better, so it will run more lean than stock.
The 037 always ran rich, so you may have a decent setup.