Rev4 NA to rev2 Turbo - wiring problem

This section is for technical Q & A
Please try the search function before starting a new thread.
Forum rules
Many subjects will have been discussed before. Please try the search function before starting a new thread.
Check in the Know Your 2 as the information you need may already be there.
Important ! - Please make your topic title as descriptive as possible . titles with just "help" generally dont get as many answers as a title that points to the problem
Post Reply

Topic author
Hubcio
Posts: 6
Joined: 28/05/17 20:02

Rev4 NA to rev2 Turbo - wiring problem

Post by Hubcio » 08/02/20 17:57

Hi all, I am in the process of putting a rev2 turbo engine into my 1997 NA mr2 that I've had for a bunch of years. I'm really excited for this but I'm struggling to find a thread that would explain in detail what changes need to be done to the ECU and fusebox pins..

Most people swap their old engines for rev3+ engines so maybe that's why.. either way if there is someone who's done it in the past and doesn't mind explaining what to do, that would be grand! So far the engine cranks and there is spark but the fuel pump doesn't seem to be working for any longer than 1-2 seconds. (NA pump) I'm also missing pump relay and resistors if that is the potential reason for this? :confused1: Haven't done anything to the waiting pins so far so definitely some changes need to be done. I'm using the original rev4 body harness.




Topic author
Hubcio
Posts: 6
Joined: 28/05/17 20:02

Re: Rev4 NA to rev2 Turbo - wiring problem

Post by Hubcio » 10/02/20 10:55

Anyone please??

I'm guessing I'll have to re-pin the 22-pin connector from body harness that goes into the ECU, but I'm not very good at wiring at all.. I'm trying to match connectors to pins in the rev2 turbo ECU but there is a whole bunch missing, can some have a look and tell whether I'm making the right assumptions?
https://imgshare.io/image/capture.Lp0wP

User avatar

peteV6R5
Full Member
Full Member
Posts: 2729
Joined: 13/08/07 13:06
Gender: Male
Years of MR2 Ownership: 12
MR2's Owned: 2
Real Name: Pete
Location: Stratford upon Avon
Has thanked: 1 time
Been thanked: 3 times

Re: Rev4 NA to rev2 Turbo - wiring problem

Post by peteV6R5 » 10/02/20 12:58

1st things 1st.
you trying to use the NA ECU?
the best way would be to use the wiring harness and ecu off the rev2 turbo.
AFAIK the turbo engine wont work with an NA ECU even with pinout changes.
you could try linking the batt to fp1 in the diagnostic port, this will keep the fuel pump running and see if the engine runs like that, just to see not for full running.
sounds like not activating the COR relay to keep pump running after initial start (again prob ECU / harness related).
Image
Highland Drive 13/14/15/17/18/19
JAE 07/09/10/11/12/13/14/15/16/17
Japfest 09/11/12/13/16/19
Wales runs 14/15/16/17/18


Topic author
Hubcio
Posts: 6
Joined: 28/05/17 20:02

Re: Rev4 NA to rev2 Turbo - wiring problem

Post by Hubcio » 10/02/20 16:23

Thanks for replying and apologies if I made things unclear.. I am using the rev2 turbo ECU and engine harness but keeping the rev4 NA body harness. Question is whether changing pins in 22-pin ECU connector would be enough for the pump to work or would I still need to fiddle with the fusebox? I don't have the fuel pump relay or pump resistor but apparently it is not essential?

Cheers

User avatar

abovetherim
Full Member
Full Member
Posts: 825
Joined: 29/01/11 18:53
Gender: Male
Years of MR2 Ownership: 9
MR2's Owned: 1
Real Name: Jan Olsson
Location: Leicester

Re: Rev4 NA to rev2 Turbo - wiring problem

Post by abovetherim » 11/02/20 21:29

First off you need to make sure you have all the required connections in the fuse box in the engine bay.
As for the 22 pin plug for the body loom to ECU the best way to sort out what goes where is to open up each ECU and draw a pin out like the pic you posted. Inside the ECU the pins are labelled on the board.

Also rev4 n/a pin out is slightly different from the rev3 n/a pin out.

You may also find that there is a wire that needs to move from the body loom plug to the engine loom plug .

When I did R1 to r4 na swap I missed the ign (I think iirc) and the car would start and idle for a few seconds until fuel pressure dropped. It may have been white wire with red stripe. But I had r4 engine loom with R3 ecu

Hope that helps
1991 rev 1 T Bar n/a 3sge import. A work in progress!!!


Topic author
Hubcio
Posts: 6
Joined: 28/05/17 20:02

Re: Rev4 NA to rev2 Turbo - wiring problem

Post by Hubcio » 13/02/20 17:17

Thanks a lot for replying!

I did just what you suggested with the pins.
However, I thought that rev4 and 3 had the same pins.. I've changed my 22pin plug pins around to match the ECU but now I have a problem where the engine starts cranking with the key in position 1.. which means I can't turn the ignition on without the engine engaging🀔 annoying as I can't check whether there is power going to the pump now. The problem persists but I was made aware the the missing injectors resistor might be the culprit.

Could this ignition problem be because I've put one of the pins in the wrong location? I'm pretty sure it's matching rev3 correctly but now I know I might be different for rev4.

Does anyone have a pinout for rev4 3sge??

Thanks

User avatar

abovetherim
Full Member
Full Member
Posts: 825
Joined: 29/01/11 18:53
Gender: Male
Years of MR2 Ownership: 9
MR2's Owned: 1
Real Name: Jan Olsson
Location: Leicester

Re: Rev4 NA to rev2 Turbo - wiring problem

Post by abovetherim » 14/02/20 19:16

Connections in the fuse box will be different!

I will have a look in my garage in the morning to see if I still have the pin outs for R3 and r4 n/a ECUs.
I wrote them out on a bit of paper.
PM me your email and I will send a pic over.
1991 rev 1 T Bar n/a 3sge import. A work in progress!!!


Topic author
Hubcio
Posts: 6
Joined: 28/05/17 20:02

Re: Rev4 NA to rev2 Turbo - wiring problem

Post by Hubcio » 17/02/20 13:57

Ok I managed to pull an additional wire from the fusebox to the correct pin in the ECU as recommended. The pumps seems now to be working but I believe the engine is running too rich and is choking at lower revs due to spark plugs getting wet? Has anyone had a similar issue?? I'm using the stock NA pump and stock turbo injectors.

Post Reply

Return to “MK2”