'75 EFI: Upgrade or not?

[markandson]

Originally Posted by Wolfman3002 Mark, Thanks, I've gone thru most of your 2.2 engine build thread, and it's a good, informative thread. Is the IAC in your pictures the module sitting next to the fuel regulator, on what looks like a custom aluminum plate? Randy

Randy, you have it correct. That module is the IAC from the Jeep bolted to the small square block that is the manifold that I got from DIYautotune. The aluminum plate you see is the custom adapter plate that I made to be able to use the Marren injectors. It is bolted to the manifold with the 6 screws that held the original Opel injector assemblies. Since the center of the piece was available for mounting stuff I used the area to mount the regulator and the IAC. Take note that I had to grind the top of the regulator adjusting screw down and saw a slot into it for adjustment. It was originally lower but I had to move it higher in order to make room for the fitting that comes out the bottom of the regulator. The adjusting screw hit the hood and had to be cut down. It was a little nicer looking with the allen key socket in it but I had no choice. Everything is very tight. If you don't go nuts like I did and build a manifold from a 6 cyl. intake you might not have the same issues.

[Wolfman3002]

Originally Posted by markandson The adjusting screw hit the hood and had to be cut down. It was a little nicer looking with the allen key socket in it but I had no choice. Everything is very tight. If you don't go nuts like I did and build a manifold from a 6 cyl. intake you might not have the same issues.

Hopefully, I won't have this issue. My original plan was to build the 2.0 motor w/ the EFI, then install it into the GT, but the more I think about it, I think I may want to build the EFI system and install it onto the 1.9 that's currently in the GT to get the fitment right, then swap it onto the 2.0 when it's finished. Or is that going to cause problems w/ tuning (at the very least I assume I'll have to tune the system twice, once w/ the 1.9 then again w/ the built 2.0). Or is this going to require more than just a retune? Will the circuits on the Megasquirt have to be changed at all (assuming I keep all the sensors and such in the EFI system the same)?

[markandson]

Originally Posted by Wolfman3002 Hopefully, I won't have this issue. My original plan was to build the 2.0 motor w/ the EFI, then install it into the GT, but the more I think about it, I think I may want to build the EFI system and install it onto the 1.9 that's currently in the GT to get the fitment right, then swap it onto the 2.0 when it's finished. Or is that going to cause problems w/ tuning (at the very least I assume I'll have to tune the system twice, once w/ the 1.9 then again w/ the built 2.0). Or is this going to require more than just a retune? Will the circuits on the Megasquirt have to be changed at all (assuming I keep all the sensors and such in the EFI system the same)?

No change in sensors that I can think of, re-tune for sure. The only time you have to change jumpers and/or add/remove parts on the board is if you change ignition types. If you read the portion of the MegaManual that is the build instructions (44 pages I believe) for MS-II you will get a good handle on the decisions you have to make when building the MS-II. The ones I remember are Wide Band vs. Narrow Band O2, Coil or EDIS or Points or VR or ..... for ignition, Bias resistor change for Non-GM IAT or CLT sensor, Stepper vs. Non-Stepper idle control, High Impedance vs. Low Impedance injectors. There may be more, do some reading.