Lumix

Mrskylighter
This could also be an issue with dodgy capacitors in the ecu. A guy in Qld will replace all your capacitors and check the ecu over for $129 including postage back to you.

I found faulty capacitors in my gen3 3sgte ecu and have ordered replacements. Will attempt to change them out myself on my spare ecu. If it's too hard I'm going to pay for the service I mentioned.

This could describe your problem as when the caps are failing you get inconsistent issues. Even if the caps have not spewed their guts out and look fine they can still be bad.

Would you mind sending me a PM with his information?

Me too please Nick.

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I don't want to hijack your thread or anything but here is what I have been reading about the caps and a guy that changes them out.
 
Thread on MR2OC talking about it. Lots of good info. Think they are fixing a gen 2 3sgte ecu.
http://www.mr2oc.com/6-mkii-90-99-na-turbo/559625-ecu-capacitor-replacement-how-guide.html
 
Another handy thread specifically for the Gen 3 3sgte ecu. Shows the caps needed for that particular ecu. I actually ordered all these for my 2 ecus and they should arrive tomorrow. I de-soldered two blown caps today which were the exact same ones as the poster Luni had fail.
http://www.mr2oc.com/61-3sgte-turbo/658722-gen3-engine-loss-power-cel.html
 
The guy that fixes the ecu caps can be found below on Gumtree and Ebay. 
$129
https://www.gumtree.com.au/s-ad/kenmore/engine-engine-parts-transmission/toyota-soarer-ecu-capacitor-replacement-repair/1180256244
 
$129 but Ebay has 10% off at the moment.
https://www.ebay.com.au/itm/Toyota-Soarer-Supra-Camry-Aristo-MR2-ECU-capacitor-replacement-service/253391439375?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649
 
My message to him asking for more info:
 
Hi Michael,
I have an SW20 MR2 Generation 3 3sgte stock ECU that is doing some weird rough/rich idling. I opened the ECU and found a bad cap. My spare ecu is doing the same thing now also. Ignition components all new and the car drives fine under boost etc.
The ecu seems to have 8 capacitors in total. For the $129 service you provide will you replace all 8 capacitors regardless of their condition? I'm guessing these ecu caps are starting to die now. Mine is 1994 era.
Cheers,
Nick
 
Hi Nick,
The ECU reconditioning service I provide includes replacing all the electrolytic capacitors with quality Panasonic capacitors. I also check the circuit board and repair any tracks that have become corroded due to the failed capacitors and also use a special circuit board cleaner to ensure there is no corrosive liquids which will slowly ruin the ECU over time. I then use a special "conformal coating" which seals the PCB and components to protect against dust and moisture. The process takes a full day with 2 cleaning / drying stages and once completed means you never have to worry about the ECU again.
If you are interesting in having the work done, message me back and we can arrange a time to suit.
Kind Regards,
Michael Edwards
 
 
Hope that helps all. I would definitely use this service but like to try and fix things myself. If I can't change the caps for whatever reason or my repair doesn't work I think I'd try this guy. I'll post up the results once I'm done with mine.
 
There is also a heap of info online if you search especially for Soarer ECU caps.
 
Most peoples niggling issues these days are probably due to these caps. Apparently they have about a 10-15 year life span. My gen 3 ecu which failed is likely around 24 years old.

I have no affiliation with that guy by the way. I stumbled across him two days ago when researching the cap issue. Im sure there are many more providing this service that you could try.

Thank you for the information, Nick. I will begin doing some research into the caps. Keep us updated on the ECU repair.
 
I would like to get a second ECU for testing and see if that has any affect on the first start up but before I do that I want to cross off fuel pressure reg and vacuum lines.

Lumix
Roger confirmed his Bathurst only has 1 VSV... 
 
Can anyone else confirm the VSV and vacuum layout on their Bathurst?
 
 

This is how my 99 Bathurst is connected, exactly as your two pictures above.

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Cheers Mike for checking your car.
 
I found a few threads of other Toyota vehicles where Toyota has the FPR vacuum line connected in between the airbox and throttle body where there will almost never be any vacuum.

I received my package from Digi-key this morning. Ended up being 3 day postage from the US. Very nicely packed in clear labelled bags.
 
I spent AUD$36 total and bought two full sets of capacitors to do 2 x Gen3 3sgte ECUs, roll of desoldering wick and some 1mm solder as well. This price also includes the awesome UPS 3 day shipping (over the weekend)
 
I de-soldered only the caps that were visibly faulty and soldered in the new ones from Digi-Key. I didn't do the other 6 caps though.
 
Took the car for a drive and it has never been smoother. Ever since I have owned it I have been trying to solve a hesitation issue going from cruise/vacuum to boost. It now transitions very smoothly. The rich/rough idling is also gone.
 
It has honestly transformed the car. It feels so nice now. I guess over the years I had forgotten or lowered my expectations of how smooth the engine should be. I will drive it around more now to confirm the above. 
 
Would I bother buying these parts and mucking around trying to get the old caps of the circuit board? I wouldn't, I'd just pay someone like that guy I mentioned a few posts above. It really was fiddly, took hours and I only attempted it myself as I have a spare ecu.
 

 
I received the Blox fuel gauge adapters today and the spare was sent to Carmikey. I should receive the gauge tomorrow so will be good to see if my pressures are within spec. 
 

"Most peoples niggling issues these days are probably due to these caps. Apparently they have about a 10-15 year life span. My gen 3 ecu which failed is likely around 24 years old.
Took the car for a drive and it has never been smoother. Ever since I have owned it I have been trying to solve a hesitation issue going from cruise/vacuum to boost. It now transitions very smoothly. The rich/rough idling is also gone.
It has honestly transformed the car. It feels so nice now. I guess over the years I had forgotten or lowered my expectations of how smooth the engine should be. I will drive it around more now to confirm the above."
 
Wow. How bout that. After what you have just done with the new capacitors it sure is a strong indication that they are at the heart of quite a few of our various niggling problems. Many thanks for writing it up.
I would be very keen to hear more on this as you drive over the next weeks.
 

Thanks! I'm going to pull apart the ECU in my ST205 this weekend!

Admin
Thanks! I'm going to pull apart the ECU in my ST205 this weekend!

Have a look at the two brown Caps. One on the daughter-board C895 = 50v10uf and one directly below it on the main board C816 = 50v10uf. They were the ones visibly leaking on mine and the only ones I replaced.
 
Drove the car again late last night and it is still smooth going from vacuum to boost. Has heaps more power now also. The caps must have been impacting not only the idle circuit but overall air/fuel ratio as it is less stinky rich now (which is why it has more power)

Great post, Joel. I hope you find the solution to your rough start issues.
Thanks for the link to repairer, Nick. Esp. handy as he's only 5 minutes away from where I live.
I'll get in touch with him to see if he can do a repair to the ABS unit in my BMW wagon (the engine bay heat tends to cook the electronics in the ABS control unit).
cheers
Steve