ROM Ecu Remapping

[SuperRedMR2]

Has anyone had their standard ecu modified using the ROM procedure?

[toxo]

Define "the ROM procedure"?

Do you mean having a daughterboard soldered in to replace the standard chips with writeable ones?

[Lauren]

My AE86 came over with a modified ECU. Basically has a daughter board soldered on to it.

What does it do? Who knows really, no real way of finding out.

It has jumper switches on it, presumably to change timing, fueling etc. Trouble is there is no way of identifying it convincingly, so you'd likely have to take it apart to work out what does what.

But yes, it's possible.

[elbon50]

My AE86 came over with a modified ECU. Basically has a daughter board soldered on to it.

What does it do? Who knows really, no real way of finding out.

It has jumper switches on it, presumably to change timing, fueling etc. Trouble is there is no way of identifying it convincingly, so you'd likely have to take it apart to work out what does what.

But yes, it's possible.

Needs someone capable of reverse engineering it

I think there is at least one such person on IMOC

[Lauren]

Would involve taking it apart.

It's just not worth it as it's not really going to offer enough of a gain to warrant doing it.

I tried the modified ECU on the rolling road against a standard one and the tuner reckoned it was massively over fuelling. It also would always develop a misfire after a few hundred kms at 3000ish rpm. You could reset it, which would cure it, but it always returned.

[kherseth]

Doing a reverse engineering on a ECU like that would be just out of personal interest. It simply takes way to much time to make it worthwhile other than as a academic exercise.

Honestly, for a engineering service like that, 100£/hr would be typical, one would need about 30 hours to get a good overview on such a system from reverse engineering, then t here would still be holes to cover, stuff you never knew how it really works etc... Better just pay for a aftermarket ECU and get done with it.

On the other hand, the daughter board might be as simple as a ROM interface to allow a more modern memory chip to talk to the old fashioned one that is in the ECU

[3S Service Centre]

We do chip tuning on Honda's its very popular and I always wondered why this was never followed through on the Toyotas. Techtom were a state side company who worked quite a bit with the supra and were actually very successfull but my emails with them lead to nothing, if theres no money in it who's going to waste their time.
Last year we developed a honda based ecu to run 3sgte's and it worked well, there are several of them driving around, the main issue is the combination of labour and time to have this work moved into standalone brackets so now we simply upgrade out customers to standalone.
James

[toxo]

Doing a reverse engineering on a ECU like that would be just out of personal interest. It simply takes way to much time to make it worthwhile other than as a academic exercise.

Honestly, for a engineering service like that, 100£/hr would be typical, one would need about 30 hours to get a good overview on such a system from reverse engineering, then t here would still be holes to cover, stuff you never knew how it really works etc... Better just pay for a aftermarket ECU and get done with it.

On the other hand, the daughter board might be as simple as a ROM interface to allow a more modern memory chip to talk to the old fashioned one that is in the ECU

IIRC you ground a pin on the Toyota CPU and it reads from an external memory chip rather than its internal memory chip. You'd still have to do the reverse engineering to know what to put in the chip, but it has been done, and people are driving around with cars with these ECUs in. They are for all intents and purposes writeable stock ECUs.

[SuperRedMR2]

I thought a chap called Jeremy did this?

Only wondered about it as apparently you can change the TVIS kick in and limiter, very basic adjustments.

[toxo]

From what I remember Jeremy had a look at it first and then vanished. Jon Sole was looking at it most recently. I sent him some of the ST205 ECUs I had before they went into my car, so he could compare and help work out some values. There's a thread about it on TwoB somewhere.

[elbon50]

If I understand correctly Jeremy Ross developed a very much in depth understanding of the ECU software

I read that he then suffered a very serious accident which would explain why he vanished from the scene

Don't know how well he is now

[Lauren]

I thought a chap called Jeremy did this?

Only wondered about it as apparently you can change the TVIS kick in and limiter, very basic adjustments.

Trouble is, changing either of these is not going to gain you anything really.

Jeremy does have a great knowledge of the ECU, that is true.

[elbon50]

I have some of the papers that Jeremy published entitled "Lifting the Lid on the Mk1 MR2 ECU"

I think the web site that hosted them no longer exists

[Fab4MR2]

I think they were working on some of this over on 2brutal, in particular for the 4agz, but got sidetracked on a discussion about the Aussies having done the work already, and the discussion was eventually dropped. However, I recall the Aussies only having worked on the 4age. But maybe this was a different group than others are talking about.

Yes, Techtom did this, and would customize a daughterboard for your ecu at great expense. I contacted them, but the guy who did the work was mostly in Japan and rarely came back over state side. Even so, they gave me a rough quote on just the unprogrammed board, and it was incredibly expensive by itself, let alone the extra costs for programming and dyno work.

[elbon50]

Probably better to go Megasquirt than mess with daughterboards on stock ECUs

[LimeyMk1]

Probably better to go Megasquirt than mess with daughterboards on stock ECUs

That's pretty much what it boils down to, the newest megasquirt is a pretty capable ECU and more than adequate for the old 4AGE.

An old member on here did start doing ECUs which would plug into the MR2 Loom (Mk1 and Mk2 tubby), dunno if he still has/does any. He moved onto Clios but now has an MX5 and a 200SX.

[3S Service Centre]

We have developed a Aem plug and play option for 3sgte which we can easily adapt as a plug and play for the 4a if required.
James