Stock Harness to Holley Adapter?

[TireFryer]

Hear me out. Couldn’t one create an adapter for our cars to run a Holley ECU in our cars similar to the ms3 PNP? Some of us like the ability to plug in a ms3 and have tons of tune ability, but the i/o is very limited. I know the ECU Gn is also a good alternative, but a lot like Holley. Isn’t all that the Casper’s or Cruz harness is? Takes the stock ecu sensors and pins them to the Holley pinout and adds all the new wiring and relays? Couldn’t you just make a small harness to convert the stock ecu plugs, and make a harness to pin them to a Holley style? So you could keep all the stock harness and just plug in a Holley, tune it and go? Surprised this hasn’t been done yet.. I may take this on as a project to see if it can be done for us younger Buick enthusiasts that don’t have 6 grand to spend on a complete overhaul..

 

[THensley]

you should have enough worms in that can to fish for the rest of your young life.
If your doing it on the cheep buy a universal harness from Holley, don't try to fix a 40 year old GM harness
Just my 2 cents, My harness was junk and repaired two many times to even think about a ECUGN . I was ordering a OE from Caspers but went Holley instead of OE. If my harness was good I would consider ECUGN. Im very happy with my Caspers harness for Holley and Im too old to build my own.

 

[GNVenom]

The main problem with using an adapter is that the original wiring on our turbo cars commonly fails due to deteriorating connections, oxidized copper, unsealed connector failure, etc. And the Holley has many extra inputs and outputs that won't interface with the basically simple stock turbo harness. Power feeds, O2 wideband connections, etc. add to the complexity of trying to interface to the factory wiring. Much better to rip up and replace at this point.

 

[BEATAV8]

I’ve not seen a Holley connected to a stock ignition module? Always seem to be set up with coil on plug. You’d really need to butcher a stock harness for that. Not to mention the missing items like the wideband that would need to be added.

It would be a mess of unnecessary connections at the stock ECU connector, and a bunch of added items going around that. Better off just eliminating the stock ECU connector and replacing it with Holley ECU connectors.

For example on the ECUGN, the wideband and the coil on plug harness come in through their own harnesses and plug into the side of the ECU. They don’t go through the stock connector

 

[Chuck Leeper]

I Have been involved with several Holley installs on other cars.
Buying a "complete system" is the least expensive.
However, "ala carte" is more user/installer friendly..
Were we doing the last system again, we would bite the bullet with these choices.
ECU, unterminated main harness, handheld unit.
Modifying a specific harness is a total PITA. The unterm harness is plenty long enough to put the ECU
where you want it.