22RE to 3RZ swap
- Thread starter Kevin B.
- Start date
TJDukit
I.Y.A.A.Y.A.S.
- Location
- Clearfield
Yay for your smelly toyota.
- Location
- Stinkwater
Two different computers now, and I can't get either to work. Pretty sure one of them fried my distributor/ignition coil, putting me further over budget. With no funds for a new computer and no inclination to trust another junkyard ECU, we've decided to grab a Megasquirt off my buddy's shelf and do that instead.
Splicing the factory dash harness into the 3RZ ECU was deep water, but this wiring is utterly beyond me. Mike will be doing most of the brainwork, although I'll have him show me what he's doing and why so that I know what's going on in my wiring if I have to troubleshoot down the road. I'm more concerned with the practical implications - I know I won't have OBDII like I was hoping, and obviously going this far away from stock can be trouble if it's not done right (I trust Mike and I to do it right), are there any other reasons this might be a bad idea for a truck that still needs to function as a daily driver? I won't need to be changing my fuel ratio and such like that away from stock for quite some time (although having the ability to makes forced induction a very tempting probability, later) - can the Megasquirt do a reasonable impression of a factory ECU while I need it to, or is this a bad idea and I should run away screaming?
Splicing the factory dash harness into the 3RZ ECU was deep water, but this wiring is utterly beyond me. Mike will be doing most of the brainwork, although I'll have him show me what he's doing and why so that I know what's going on in my wiring if I have to troubleshoot down the road. I'm more concerned with the practical implications - I know I won't have OBDII like I was hoping, and obviously going this far away from stock can be trouble if it's not done right (I trust Mike and I to do it right), are there any other reasons this might be a bad idea for a truck that still needs to function as a daily driver? I won't need to be changing my fuel ratio and such like that away from stock for quite some time (although having the ability to makes forced induction a very tempting probability, later) - can the Megasquirt do a reasonable impression of a factory ECU while I need it to, or is this a bad idea and I should run away screaming?
sixstringsteve
Well-Known Member
- Location
- UT
the only advice I have is to not make any compromises. Build it exactly the way you want, even if that means waiting another 6 months for the funds.
I don't know much about the megasquirt other than what I just read from my google search. Are you worried about reliability? Cutting up more harness, changing stuff from factory adding what I assume will be more stuff to go wrong. If needed will you be able to return to factory easily? Will it be emission compliant? You know way more about what's going on than I do obviously but I would be hesitant to get away from factory, as that is what makes Toyota's so reliable.
Are you 100% sure ECU is bad? Distributor? Anyone known good ones you could try, or vehicles you could try yours in?
I'm of no help, and wish I could be of more help. Wiring is voodoo to me and I sure hope my 3.4 stays running in the 4 runner or I might be breaking out the incense to fix it.
Are you 100% sure ECU is bad? Distributor? Anyone known good ones you could try, or vehicles you could try yours in?
I'm of no help, and wish I could be of more help. Wiring is voodoo to me and I sure hope my 3.4 stays running in the 4 runner or I might be breaking out the incense to fix it.
- Location
- Stinkwater
Yeah, big changes in the wiring introduces a lot more points of failure. We can minimize that by soldering shrinkwrapping and stabilizing the splices. And I don't know if "back to stock" has much meaning for this truck anymore 
, but it would take new harnesses. It could be done if I had to. I was more worried about the reliability of the computer itself, but now that I've had time to Google around it a bit, I see lots of guys putting the Megasquirt in off-road vehicles without complaints of the thing failing, so I think we'll forge ahead. Gonna move the truck down to his shop some time this week and get busy.
, but it would take new harnesses. It could be done if I had to. I was more worried about the reliability of the computer itself, but now that I've had time to Google around it a bit, I see lots of guys putting the Megasquirt in off-road vehicles without complaints of the thing failing, so I think we'll forge ahead. Gonna move the truck down to his shop some time this week and get busy.
sixstringsteve
Well-Known Member
- Location
- UT
I'm guessing you're not worried about resale value. I know nothing about megasquirt (apart from miata applications). If I were buying a truck with a 3rz motor swap, I'd want it to be as close to a factory 3rz as possible. A megasquirt would be a deal-breaker for me.
Megasquirt may be the best answer, I just don't know much about them. I can't imagine going into an autozone in the field and trying to remember which injectors, plugs, wiring etc I have.
Megasquirt may be the best answer, I just don't know much about them. I can't imagine going into an autozone in the field and trying to remember which injectors, plugs, wiring etc I have.
- Location
- Stinkwater
Not in the slightest. Watching you and others try to move your modded rigs has convinced me that if I ever do decide to move on, this truck will get sold in pieces.
I could be wrong, but I think the Megasquirt comes with it's own pigtail harness, and all the connectors on the engine to the various sensors and injectors and such are factory, obviously. I've got a toasted motor harness that came with the motor that we'll take apart and splice into the Megasquirt pigtail. I know if we do those splices right that they'll be reliable.
Programming the thing will be an adventure, for sure. I doubt anybody out there has a writeup for programming a Megasquirt to manage a stock motor! It'll be good though - the possibility of a shiny snail under the hood has been floating around the back of my mind, and going to the Megasquirt brings that a little closer to reality.
You'd be amazed. I know a couple guys on the board with 3RZ motors, but none with the early distributor setup like mine. And the local junkyards and classifieds are empty - most of the extra parts I've had to scrounge have come mailorder from yards in Colorado and California. The 4cyl Tacomas and 4Runners just didn't sell well here.
I have zero electronics troubleshooting knowledge. I'd love to just pop open the computer and swap out a little thingy, but I wouldn't even know how to determine what if anything was blown, let alone possess the skill to replace it.
Last edited:
sixstringsteve
Well-Known Member
- Location
- UT
Watching you and others try to move your modded rigs has convinced me that if I ever do decide to move on, this truck will get sold in pieces.
Tell me about it. I can make $5k more parting out my truck and putting it back to stock vs selling it modified.
- Location
- Stinkwater
Got it down to Mike's shop a couple weeks ago (thanks for the assist Ric!), and we both had time to play today so we got busy. Took out the stock harness, cleaned everything unnecessary off the motor and capped several vacuum ports, hacked up the old burnt harness for connectors to build the new one, and got to splicing and soldering.
My new wireless engine bay. How cool would it be to stick bluetooth transmitters on all the sensors? I wonder how long they'd last before the heat and vibration killed them.
When you are discombobulating a harness, strict and accurate labeling of the plugs is essential.
Scavenged plugs.
Used to be a harness...
The new harness will be about 26 wires, plus or minus. That's all of them, though we're going to make the connections on the Megasquirt and be sure that everything is happy before we tidy everything up. This is going to be a much cleaner engine bay, I'm stoked for that if nothing else.
The aftermath of a wiring party...
And we finished my flatbelly mod while we were in there.
Here's the rest of what's hiding in that shop on a Sunday afternoon - lots and lots of Rich People Cars, and this is only one side of the entire garage. The Bastard was certainly out of place.
My new wireless engine bay. How cool would it be to stick bluetooth transmitters on all the sensors? I wonder how long they'd last before the heat and vibration killed them.
When you are discombobulating a harness, strict and accurate labeling of the plugs is essential.
Scavenged plugs.
Used to be a harness...
The new harness will be about 26 wires, plus or minus. That's all of them, though we're going to make the connections on the Megasquirt and be sure that everything is happy before we tidy everything up. This is going to be a much cleaner engine bay, I'm stoked for that if nothing else.
The aftermath of a wiring party...
And we finished my flatbelly mod while we were in there.
Here's the rest of what's hiding in that shop on a Sunday afternoon - lots and lots of Rich People Cars, and this is only one side of the entire garage. The Bastard was certainly out of place.
sixstringsteve
Well-Known Member
- Location
- UT
Progress!
- Location
- Stinkwater
Still working on that harness - it's kinda slow going, because I'm triplechecking everything before I solder and heatshrink, but it's actually sorta fun. This morning I mapped out all the wire colors coming off the individual sensors and such, and got a preliminary routing and dressing done. I've had to repair lots of the factory wiring due to cracks in the insulation, so I think I'll get my hands on a bunch of heat reflective tape to wrap the loom in once I've got the routing finalized. Next step is to sit down with Mike and a box of crayons and make sure we know what goes where on the Megasquirt pigtail before we finalize those connections. Then we can plug the computer in and maybe start programming.
Stashing this here for my own reference:
Stashing this here for my own reference:
sixstringsteve
Well-Known Member
- Location
- UT
will the megasquirt still allow you to have OBD2?