I'm investigating in putting a stand alone or piggy back ECU on my LT1. I'm curious has anyone done this without hacking up the existing wiring? I'd like to use some sort of adapter harness to work with the existing wiring to give me the availability to go back to the stock setup/PCM.

I'd rather try to pin a custom or mating harness to attach to the stock wiring and then modify that harness to adapt to the new ECU. Does anyone make a female plug/harness to mate with the stock wiring? I've seen the kits to adapt LSX style computers but would prefer the versatility of an aftermarket ECU.

Thanks.

 

I've never seen a harness like that, but I wasn't looking for one.

There are recipes on the web (or at least used to be) for benchtop programming harnesses. That would give you part numbers for the harness-side connectors and then you can see if there is a mating connector available.

Most of the GM electrical connectors I've encountered used a standard pitch that can be mated, electrically but not always mechanically, with some Molex connector. You could find a suitable Molex and jury rig it, but that might not be the most elegant or reliable solution.

If it's a "switch back before I sell" situation rather than a "switch back more than once" situation I'd just get a spare engine harness and modify one for the aftermarket ECU.

 

There seems to be a few questions that need to be answered . One of them is A/C. if you have A/C and want it to work properly, the ECU needs to know. The other is EVAP. If you don't plan on using it, ok, but if you do plan on using it there must be a connection to the purge valve system from the ECU. And then there is the starting system, VSS and your check engine warning light. So a completely stand alone system for your LT1 doesn't seem to be feasible.

I haven't seen anyone that makes a piggy back wiring that just pugs into a current electrical system. Not enough demand I would guess. Now, many hot rodders that run LT1s in there rods can buy a wiring harness to run the LT1, but they don't need to integrate into a current system. I would suggest you contact some of the wiring companies like "Painless" to see if they can fab one for you. I don't know exactly what your project is but if it involves putting a LT1 into an older car, why would you want to switch back to the original motor?

I'm still working on mine.

 

Aftermarket stand alone ECU's can handle those type of inputs/outputs. I don't see a problem there.

This is for my Camaro that currently has an LT1 in it. I'd prefer not to put a whole new harness in or hack up the stock one. I would like to make/find an adapter harness to connect to the stock harness so that the car is more easily converted back to stock.

 

I think I understand. Your Camaro already has a LT1 in it (1996). Why do you need a harness? Is there a problem with yours?

 

I think what he is wanting is, a direct plug and play adapter harness, to fit the factory original harness.(Not hack up his factory harness) and be able to install and aftermarket ECU with no rewiring, just plugging in these "adapters"

 

See above.