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The mkiv Supra Owners Club

Warning Engine ecu failure


Twin turbo

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Just a pointer to anyone thinking of doing this themselves or trusting it to a ecu repair agent, make sure the replacement capacitors have a decent ESR rating. Capacitor technology has come on a long way in 20 years and ESR wasn't such a consideration then as it is now, but even so many caps advertised and sold even with the correct farad and voltage rating won't last long in the ECU. Good to hear you are using a ESR tester Chris.

 

A couple of years ago I sent some VERY expensive broadcast standard COFDM multiplexers off for repair, they all had SMPSU issues due to dead electrolytics. Came back and worked fine for a few months but failed again due to the same caps failing. The repair place had used bog standard replacements and had lousy esr qualities.

 

https://www.avnet.com/wps/portal/abacus/resources/engineers-insight/article/understanding-esr-in-electrolytic-capacitors

Edited by Shane (see edit history)
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The board needs cleaning, gently and carefully with 99 or 100% isopropyl alcohol (IPA) to see if the electrolyte has already burnt through the tiny tracks on the surface. that's a BAD leak and the electrolyte may well already be in inner layers of the board, doing damage. Once it gets into sub layers cleaning doesn't really get it out, it just carries on doing its damage :( Clean it up and look with a good light and magnifying glass to see if the tracks you can see are still intact. That looks like its been leaking for ages! I have a couple of good ECU's here, I'll have a look inside to see what the caps are like and perhaps have a play at swapping them out, but I am mad busy right now.

 

ive just taken it back from ECU repair guy ,hes told me can do it for £75 with no guarantee i can get a 2nd hand one for £100,what about these pcb sliver repair pens anyone used them .

ive cleaned up the damaged area with IPA and got it all off ,theres 3 tracks affected about 10 mm,will have a look through the mag glass tomorrow .where can i get the capacitor from, maplin? ,these are the numbers on the cap [ 105-c--h9350 --pfm ].

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How do you know the secondhand ECU is not faulty? My first ECU had this problem, ended up scrapping it as the board was junked, then I got a replacement which had slightly different issues, but funky behaviour as well (and thats the problem, it can cause such a wide range of issues). Now I finally have a good one, but may still replace the caps in it anyway to be safe.

It is the age of the ECUs (and other electronic parts) that is going to show more and more stuff like this occurring I reckon.

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To those asking . Yes, you could get a Syvecs S6 plus which for install and mapping I was quoted £3.5-4 grand for. That takes care of all functions on the car inc auto box.

 

As i understood pro efi also have a very good standalone ecm made for supra that fully control the automatic and have advaced failsafe modes.anyone tried this with automatic?

Edited by Twin turbo (see edit history)
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ive just taken it back from ECU repair guy ,hes told me can do it for £75 with no guarantee i can get a 2nd hand one for £100,what about these pcb sliver repair pens anyone used them .

ive cleaned up the damaged area with IPA and got it all off ,theres 3 tracks affected about 10 mm,will have a look through the mag glass tomorrow .where can i get the capacitor from, maplin? ,these are the numbers on the cap [ 105-c--h9350 --pfm ].

 

As Chris said, these are multi layer boards, this means there are tracks that you cant see in between the layers. However, in my experience you would be exceptionally unlucky at this stage if it had penetrated between the laminated layers via the plated through holes. Personally, I would be on the lookout for a second hand one that is working and if the car is a keeper send it to someone with a decent SMT/de-soldering work station and get them replaced. I have a GTE ecu on my desk here that gave issues with my gear changes, I was getting the OD light flashing and MANU was disabled when it happened, exactly the same symptoms as an overheated box, I simply took a chance on a second hand ecu from the for sale section and so far so good.

 

I do know a guy with all the kit to work on this type of PCB, but sadly he wouldnt be able to test it on a car afterwards due to being a TVR nut.

 

RS components or CPC would be your best bet for the caps, but keep an eye on the ESR rating.

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I recently replaced about 20 caps on my old game gear, was able to buy a cap replacement kit off eBay for a few quid. Has anyone made a note of all the caps in the ECU with there ratings? I would recommend keeping to well known brands of caps and paying that little bit more for a better quality item.

 

 

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  • 2 years later...

Just posting here hoping to spark some news of any progress with this issue. My N/A Auto ECU has been deemed beyond repair, so I am looking for a replacement that is either fully functioning or repairable.

Any remotely economic alternative replacement ECUs become available in the past couple of years?

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