Year 2000 MR2 roadster, UK version

Treboeth · August 27, 2017, 12:54

You definitely didn't come across as shunning any help offered s:D

s:D

tperry2x · August 27, 2017, 14:03

Ok, thanks everyone. I'll try getting to the ECU this evening. Too hot out there right now. Will update this post when I've got some pics.

Shnazzle, I'm using 3 separate resistors, 1 for each sensor.
Carolyn, I've got 2 buttons on the key fob. One is Lock and the other Unlock. There's no red light flashing for an immobiliser, although there is what looks like a panel and a LED, but it's either not working or disconnected? Not sure.

Carolyn · August 27, 2017, 14:24

It does sound as though you have a JDM ECU in a euro car. That should be ok.... What O2 sensors do you have?

tperry2x · August 27, 2017, 14:43

I have three as pictured in the schematic in my above post but I did notice that bank 1 sensor 1 and bank 2 sensor 1 look like different makes as the ends were different. I know there are official Toyota ones and other manufacturers (Denso?), but not bothered as long as they work. Not taken the 3rd bottom sensor out yet to see what that looks like.

Carolyn · August 27, 2017, 15:11

Toyota originals are Denso. The cumulative experience is that Denso is the only way to go and other makes lack the reliability. Yes the Densos are more expensive, but (like Persil) 'they really work out cheaper'!
I do recall someone else having a problem with a JDM ECU in a Euro car -

tperry2x · August 27, 2017, 16:41

This is all brilliant info, thank you.

Well, the award for the most hidden ECU goes to...
Perhaps, would've never known where to find that. Here's some photos. Is it a Euro ECU or Japanese one?

Carolyn · August 27, 2017, 16:59

The label isn't in Japanese. All the labels on my JDM car are. Curiouser and curiouser..

Did you take that screw out that holds the bracket to the bulkhead? If not, it's an indication that it's not the original ECU.

It might be that, with that information on the label, you can get it identified by Toyota?

Next time I have that bin out, I'll look at the label on mine.

tperry2x · August 27, 2017, 17:06

Yes, I did take the screws out of the bracket, just to have a look at the numbers properly

shnazzle · August 27, 2017, 17:07

Yup that's definitely a jdm ecu part number.

So someone has put an MR-S ecu in your car.
Also, judging by the rust on the bolt hole for the security plate... There was no security plate.
Further confirming that the ecu has been changed for a jdm one.

There has to be some dodgy wiring for that 3rd o2 sensor then

Carolyn · August 27, 2017, 17:34

Quote from: "shnazzle"Yup that's definitely a jdm ecu part number.

There has to be some dodgy wiring for that 3rd o2 sensor then

Not if the engine has a Euro loom. It's just that the ECU won't see the third sensor.

So an ECU with a set of locks and keys from your favourite breaker.

If you do swap your ECU, I'd be interested in your old one as a spare.....

Just to be absolutely sure about your car, which side of the column is your indicator stalk on?

shnazzle · August 27, 2017, 17:39

But why would the car freak out if the 3rd o2 sensor was disconnected?
That's what puzzles me about this

jonbill · August 27, 2017, 17:59

There's not a lot of difference between sensor disconnected and 0v reading is there? I wonder if something else coincidentally caused the noise.

Carolyn · August 27, 2017, 18:02

Dean at Rutland MR2 told me that JDM ECUs are not happy on Euro cars... don't know why not. I know a JDM ecu will run a Euro engine and loom in a JDM car, but there is something dark and murky about putting the ECU in a Euro car. Could be very slight wiring and voltage differences....

shnazzle · August 27, 2017, 18:06

So I think the long/short of it is that you'd be best off getting yourself a replacement UK spec ECU and set of adjoining keys. This means you'll probably regain the immobilizer you've lost (and probably your insurance thinks you have), and you'll be able to use a normal OBD2 reader s:D

s:D
Also, the 3rd o2 sensor will do it's job. Which is a good and a bad thing depending on what side of the tree-hugger line you're on s:)

s:)

Carolyn · August 27, 2017, 18:26

That's my take. Just make sure you get the transponder loop with the set and you should be fine.

actually, the loop will probably be there... just check.

tperry2x · August 27, 2017, 19:13

You'd be welcome to my old ECU once I know my replacement one is working fine of course s:D

s:D
So, this will sound like a really obvious question to a lot of people. Can't I just plug a new box in – I need new keys, as in car ignition keys? Are they coded to the ECU? What is a transponder loop? Dumb questions, no doubt.

Carolyn · August 27, 2017, 19:21

The loop is a wire that goes around your ignition barrel and enables the ECU to read the key,.
Yes a new ECU will plug in.
Yes the keys are coded to the ECU.
I know Rutland MR2 will sell an ECU with keys and locks as a kit. Bit of a faff, but all very do-able.
Not one dumb question.
I'll be happy to pay for the ECU. If you have a JDM car, it's got value.

tperry2x · August 27, 2017, 20:12

Hmmm, but if I'm changing keys, I'll have to change all other locks too. Both door locks. A real faff.
The car is running fine with whatever ECU that is, just the lights I'm trying to extinguish. Didn't really want to pull apart the whole car to be honest and it's sounding more and more complicated.
I'll have a think, but think I've got a solution. It's a 2 seconds timer, wired to the engine light bulb in the back of the instrument cluster. (turns off engine light after 2 seconds).
MOT tester is happy, I'm happy because it's an easier fix and all the time the car is running ok, then jobs-a-good-un!

Not ideal, I'll grant you, but a lot easier than changing everything else.

shnazzle · August 27, 2017, 20:13

It's not as hard as you think. You take the "guts" from the key of the new ecu and put it in the fob of your existing key. So it opens your doors and unlocks the immobiliser and doors... And starts the car obviously..

Been done many times

The idea is to resolve problems, not work around them.
And if you have a buyer already for your ecu, you're in for a winner s:)

s:) Basically free fix!

Carolyn · August 27, 2017, 20:51

Shnazzle is correct. I mislead you with that response. You only need the locks if you've lost your key.... My apologies.

tperry2x · August 27, 2017, 21:26

Ok, I'll have a think and do some more research. Thanks for everyone's help so far.

Essex2Visuvesi · August 28, 2017, 09:19

The other solution would be the Apexi PFC.... plug and play solution and you get to tinker with stuff s:)

s:)

shnazzle · August 28, 2017, 09:28

Haha. Let's not go there E2V!

tperry2x · August 28, 2017, 10:53

The cheapest I can find a replacement ECU kit is around £60. Or, can raid all the bits of another roadster off eBay for £45, plus postage or going to pick it up comes close to £60 again.
I read up on the Apexi PFC, it's got a ton of possibilities but at over £450 (used) it's out of my price range. It's definitely overkill for what I need, Plus my hex editing on a computer is a bit rusty.

The wiring diagram I proposed above uses 4 wires and a modified bulb. I know it's a workaround and not a 'proper fix', but I'm old skool and stubborn.
Don't care what the ECU particularly thinks, as long as the car is running and not about to eat it's engine. It can be throwing all the advisory codes it wants, I can still always read them if I want, so that side is still there.
It's just there's no glaring orange engine light on the dashboard to annoy me constantly. Worked out that if I just modify the wires on the bulb itself, it means no changes need to be made to the back of the instrument cluster board, so it's an un-doable fix if I change my mind.
The timer relay costs £2.85. It also has the benefit of no more light staying on ever again if another fault invariably appears.
(The whole thing seems needlessly complicated to be honest. I'm used to working on 1990's stuff and much older), so at least this way the light comes on and mimics what you should see before it goes out. The timer relay board is quite small - less than the height of a 50 pence piece. I can store it behind the dash, and nobody need know it's there. It's a lot less work to install and as far as I can see, means the light won't bother me again as I've had enough of it by this stage.
Again, I don't recommend anyone take my lead, but I've just had enough of what I see as an annoying system and this is a permanent fix until I decide to take it out.

Call the midlife! · August 28, 2017, 10:56

Quote from: "tperry2x"The cheapest I can find a replacement ECU kit is around £60. Or, can raid all the bits of another roadster off eBay for £45, plus postage or going to pick it up comes close to £60 again.
I read up on the Apexi PFC, it's got a ton of possibilities but at over £450 (used) it's out of my price range. It's definitely overkill for what I need, Plus my hex editing on a computer is a bit rusty.

The wiring diagram I proposed above uses 4 wires and a modified bulb. I know it's a workaround and not a 'proper fix', but I'm old skool and stubborn.
Don't care what the ECU particularly thinks, as long as the car is running and not about to eat it's engine. It can be throwing all the advisory codes it wants, I can still always read them if I want, so that side is still there.
It's just there's no glaring orange engine light on the dashboard to annoy me constantly. Worked out that if I just modify the wires on the bulb itself, it means no changes need to be made to the back of the instrument cluster board, so it's an un-doable fix if I change my mind.
The timer relay costs £2.85. It also has the benefit of no more light staying on ever again if another fault invariably appears.
(The whole thing seems needlessly complicated to be honest. I'm used to working on 1990's stuff and much older), so at least this way the light comes on and mimics what you should see before it goes out. The timer relay board is quite small - less than the height of a 50 pence piece. I can store it behind the dash, and nobody need know it's there. It's a lot less work to install and as far as I can see, means the light won't bother me again as I've had enough of it by this stage.
Again, I don't recommend anyone take my lead, but I've just had enough of what I see as an annoying system and this is a permanent fix until I decide to take it out.

You could always just take the bulb out and periodically check for codes, as long as you replace it if you should sell it. It wouldn't be the first time someone has sold a car with the bulb out or in al least one case, covered with blu tack...

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