[Mk2] [NA] Swapping ecus?

[Nivek4209]

Hi all ive just bought a sw20 auto and na it has the 3sge engine
I bought with a fault thst will start for a few seconds and stall
Sometimes you will get 10mins runtime but mostly start to stall with in a few seconds
Upon some google trawling it seems it may be a dodgy igf voltage from the ecu that could be the culprit that cuts injection if no confirmed spark signal hense the stall
Now i have another mr2 auto broken so i thought swapping the ecu id be on a winner but i dont even fire up if i do this
Are there other parts id need to swap over with the ecu
Is there a fix for my current ecu ?
I think my breaker is sw20 rev 1 and the new one is a rev 2 but both are na and both auto

[Pauln]

I don't think rev1 and rev2 ECUs are interchangeable.

Have you opened up the rev2 ecu to check for leaking capacitors and any damage to the tracks if they have leaked?

It's a pretty common fault.

Paul

[Nivek4209]

I don't think rev1 and rev2 ECUs are interchangeable.

Have you opened up the rev2 ecu to check for leaking capacitors and any damage to the tracks if they have leaked?

It's a pretty common fault.

Paul

Had it open and all looks good in there no burst capacitors or burned or damaged circuits

[Pauln]

That's a shame, provided the damage isn't too serious, you can usually repair an ECU with leaking capacitors. I had a couple suffer with that issue.

I also had a rev2 manual NA a few years ago which kept cutting out and there were no signs of damage in the ECU. Unable to get to the bottom of the problem, I took it to a friend of mine who runs a garage and as you mentioned it turned out that the ECU was cutting the injectors after the engine had been running for a while. Once you let it cool down, you could start it again, but it would again cut out after a while. It made me wonder whether something in the ECU was breaking down through heating up or just current passing through.

But as I couldn't see any physical signs of a problem in the ECU, I bit the bullet and replaced the ECU, and the issue went away.

Unfortunately the hardest part was finding a replacement Rev 2 ECU, there were plenty of Rev 1 and Rev 3+, but Rev 2s seemed quite rare. Which also meant they often carry a fairly heavy price tag.

MR MR2 is selling a rev 2 automatic ECU on ebay at the moment at £85, but you need to check that the part number corresponds to that on your faulty rev2 ECU. He's quite a useful source for parts, but not the cheapest.

There's no guarantee that changing the ECU will fix your problem, but it does seem very similar to the issue I had. Good luck

Paul

[wilkie senior]

https://www.ebay.co.uk/itm/Toyota-MR2-M ... SwZVpcyWcN

this the one, as above no guarantee t wll be this i bought fresh ECU for rev 5 amongst several other OEM parts £££££s it was something else n the end with my issue

you could ask steph if he would consider a reduction n price, can only say no? wont be a massive discount but always worth asking

[Pauln]

Oops, I was going to include the link but forgot

Paul

[Juliuswws]

I don't think rev1 and rev2 ECUs are interchangeable.

Have you opened up the rev2 ecu to check for leaking capacitors and any damage to the tracks if they have leaked?

It's a pretty common fault.

Paul

Had it open and all looks good in there no burst capacitors or burned or damaged circuits

A capacitor can dry out, shorted or opened without any signs on the outside. Over time their internal resistance (ESR) rises which could also cause problems in a given circuit.
I would just change them all.

If you suspect IGF signal, you might also have code 14 stored in the ECU.
Worth checking.

If that, make sure that the ignitor is well grounded to its bracket and the bracket makes good connection with the body.

I would also check all connectors for oxidation. Igniter, coil, ECU, distributor etc

Cheers