I want to make a harness to run a 727 ECM to convert my 85 V8 carb'd Firebird to fuel injection. Since I want to run underhood only, with minimal non-engine functions, could I modify a V6 Lumina/GP harness and add the extra fuel injector plugs into the harness? Repinning the ECM plug if necessary... Is there just too much different, or are they fairly close, sensor wise? I'd probably be pulling the sensors from the same car as well.

Thanks

 

This is do-able. Only better harness would be a 90-91 Corvette. I am not familiar enough with the Lumina harness to say which connectors/sensors do/don't work. I think the FWD '727 vehicle were DIS, so that area will need to be changed a little.

Get all the sensors and see what else needs to be changed. A friend of mine is doing this exact thing. He is going to a single plane MPFI setup and an under hood '727.

After stripping the covering from the harness he mounted the ECM and laid out the harness over the engine. Then changed wire lengths and pin-outs as required. Got the extra injector plugs from a couple of different vehicles along with miscellaneous connector ends and sensors.

There are '727 Corvette wiring diagrams over on the diy-efi site.

RBob.

 

Watch the computer connectors. The non corvette connectors are missing pin holes and will not work properly.

 

You brought this up once before but never followed up with which pin opening is missing. Do you recall which pin(s) is was?

RBob.

 

Well, The first is black "A" connector, It is missing pin 19 EAC Sol. The orange "A" connector appears to be ok. Next is white "B" connector, it is missing pin 6 vats sig (I know not a problem), pin 11 Serial data, pin 15 AC Req. Grey "C" connector appears ok, And the blue "D" connector appears ok. These are the only connectors I had from other cars. Some other combinations could be ok, I'm not sure.

 

I can see where this can be a problem. My buddy asked about the ALDL data and it was a simple change to use pin B5 instead (ALDL serial is on both pins). He doesn't have A/C, VATS or air pump. So it all worked out for him.

I wonder what the possibility of drilling a hole(s) for the missing openings would be. Next time I'm over there I am going to take a better look at the connector to pin interface.

Thanks for the info.

RBob.

 

As I recall Ludis posted some GM part no. for the 727 empty shells and bits to wire them up as needed, at DIY-EFI.

 

I have the part #s and where to get the correct connectors. These have all 22 pin holes for all four connectors. Also have GM Part # for the pins. Email or PM for info.