Is the swapped vehicles ecu even needed anymore?

So i have been reading through the links at the top of this page trying to find out if the ecu in my 1992 toyota cab and chassis is even needed anymore. I mean can anything related to the old engine be traced back to the ecu and eliminated?

I have the dash out and I'm gonna pull the hvac stuff out and give it a cleaning and take care of any other issues like new foam for vents and blend doors and thought it would be great to pull out unnecessary wiring at least in the engine bay and while i have easy access to the harness.

No, ECU is not needed but be careful you don't rip out any wires needed that are not part on the engine management.

Cause i imagine lights, hvac and dash stuff is ran by switches and relays.

I will have to look at my wiring diagrams for the toyota and see if anything of importance goes to the ecu such as the toyota cluster. There is as many wires going to the back of the instrument cluster as there is to the toyota ecu.

No. You do not need the toyota ecu. I removed mine and all my gauges work except the tach (coming)

Btw, everything else works too. Radio, ac controls, fan , turn signals, etc......

Get rid of it and hide the vw ecu u get the kick panwl

Had a friend print out the all data on the wiring diagrams tonight and it makes so much more sense. Just about everything excluding the engine sensors and etc have their own relays, fuses and power and ground source.

The only few things going into the ecu that are not engine related main power and some other outside parameters that i can work around. The little fuse box under the ds dash may only have 9 fuses but it sure provides fused power for a lot of things

Lews930, how much of the wiring did you remove?

Forgot there was a lot of good info in your build too Rockwell. Did you ever add in the cruise control?

papasmurf said:

Forgot there was a lot of good info in your build too Rockwell. Did you ever add in the cruise control?

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My project has been on hold but will start up on it soon now that work is slowing down. I just need a speed signal, doesn't have to be accurate since it's only for cruise, and I found a universal control switch if I can't get the VW switch to mount nicely. I never really use cruise but it might bother me if it's not working.

So basically some of you removed the ecu but left the toyota harness in place and tapped into it where needed? Did you trace every wire from the engine sensors back to the ecu?

My '87 had few wires that went to the engine, I removed what I could easily do in the engine compartment and taped the rest into its wire bundle, can't even tell. I'm laying the new harness and it's completely standalone. The ECU wasn't much bigger than a deck of cards, I tossed it and the connector is tucked up under the dash, I didn't touch any of the other wiring in the cab. The only wires I can think of at the moment that I spliced into was the brake light wire. Other than that I have just one ground wire, one keyed ignition and one battery hot to hook up. I even wired all the swap related wiring directly to my cluster to bypass the Toyota wiring.

I only removed wires from the engine bay. Mostly fuel injection wires for the v6.

I removed the Toyota ECU completely in my 2003 Tacoma Swap. I unplugged it first and left the wires, then made sure everything still worked (ignition, 4wd, HVAC, horn, speedo, etc.)

Once I was satisfied I pulled all the unneeded and unused wiring from the plenum and engine bay.

Awesome. Gives me a better understanding. Rockwell i like the back of that cluster. Looks easy and simple and when you plug in the connectors everything else will work as factory

Literally took me all of 2 minutes to take out. Will have to double check the 2 big connectors that i had to unplug above the ecu but i don't think it will be a problem

Yep - it's basically just a standalone EFI set-up.