Failed 3FE ECUs (1 Viewer)

[Spook50]

This is for anyone who's had a known 3FE ECU (89661-60020) failure; what symptoms did you have that led you to check that the ECU had failed?

Long story short, I'm looking into a refurb potential for these units which would involve essentially replacement of the capacitors in them (of which there are quite a few), along with testing and replacing any failed transistors and diodes. This would be a large undertaking, and as a consequence, expensive. Because of that I'm hoping to have something of a "symptom list" that can be used for anyone who suspects their ECU is needing refurb or replacement, rather than situations of "I think it might be bad so I'll have it done" and then have the problem NOT be solved.

Image shamelessly stolen from another post here on Mud, just to give an idea of the internals

 

[cruisermatt]

is there a market for that? I've never heard of a an issue with one. would be interesting to hear if someone like @cruiserdan recalls ever selling replacments back in the day when FJ62/FJ80 were newer

 

[cruiserdan]

I do not recall ever selling one (between 1990 and 2016). If I did, it would have been one-only and very early on.

 

[Spook50]

is there a market for that? I've never heard of a an issue with one. would be interesting to hear if someone like @cruiserdan recalls ever selling replacments back in the day when FJ62/FJ80 were newer

I think the failure rates when they were new would've been incredibly low (at least I wouldn't be surprised if they were). They are very robust units, which has contributed greatly to their longevity. The biggest issue at this point in their age is capacitors reaching end of life (especially the electrolytics). 30+ years is a long time for a capacitor to last, so I have a suspicion that failures are going to increase at least a small amount as time goes on. I don't think it's necessary to keep a huge stock of replacement parts, but perhaps having one ready on standby if someone knows they need a replacement is my thought.

I'd love to get my hands on a known failed unit and see where the failure occurred (and if I could get it operating again).

 

[3_puppies]

1988 aprox 14 years ago I had a crank no start after running a while and parking it for 30-40 minutes, cranked well and wouldn't fire
after much troubleshooting, decided to change out the ecu with another I had, that solved the issue, never had the problem again.
If I didn't shut the rig off, it would run with no problems, it only happened when it was shut off warm/hot for an extended period. after it cooled off or the next day, it would start and run without a problem
still don't understand what the issue was, I think I still have the "bad" ecu

 

[Godwin]

Not worth it. I don't recall hearing of any failures in either 60s or FJ80s here on Mud or when the 3FE list was active. The number of 3FE'd Cruisers diminishes each year so the potential market for a repaired ECU is going to be negligible, plus if you do need one finding a used one in good condition is more likely.

 

[Spook50]

1988 aprox 14 years ago I had a crank no start after running a while and parking it for 30-40 minutes, cranked well and wouldn't fire
after much troubleshooting, decided to change out the ecu with another I had, that solved the issue, never had the problem again.
If I didn't shut the rig off, it would run with no problems, it only happened when it was shut off warm/hot for an extended period. after it cooled off or the next day, it would start and run without a problem
still don't understand what the issue was, I think I still have the "bad" ecu

Sounds like it might've been a transistor not switching when it needed to until a cap was completely drained of its residual charge after shutdown. That's just a spitball of a first guess, but if you still have the old one and have no desire to keep it, I'd gladly pay for the ride to take it off your hands and mess around with it.

@Godwin You may very well be right. I hadn't considered how many still-good units are swapped out each year due to engine conversions that keeps the supply of used parts healthy.

 

[3_puppies]

let me check if I still have it and I'll let you know

 

[MWM1]

Following
From a learning perspective, I would be interested in your findings and potential solutions. Please keep us posted.
Ty!

 

[Roonie]

Mine was misfiring and so the the ECU was replaced among a bunch of other things. Not sure if it was the problem. Torfab did it. I haven't had the problem since and it runs great.

 

[Spook50]

Following
From a learning perspective, I would be interested in your findings and potential solutions. Please keep us posted.
Ty!

I think @Godwin pretty much nailed in that it wouldn't really be worth offering as a service (unless it's a one-off type deal where I could occasionally help someone out who's hard up and can't get or afford a replacement ECU).

I think the most likely avenue will be I'll get my hands on a failed unit to play with it and see if I can even find the cause of the failure, then detail what I do to fix it (IF a fix can be performed) for the benefit of the community and for anyone who's just curious about it. Hopefully @3_puppies still has his and can find it when he has a chance. I haven't badgered him since I'm not in a big hurry myself either.

I do have a couple engineer buddies here at my work who might be able to help me reverse engineer it and see if there's any shenanigans we could do with one

I've actually gotten curious if mine is starting to show some deterioration itself. My high idle that I detailed here An interesting high idle issue - https://forum.ih8mud.com/threads/an-interesting-high-idle-issue.1340479/ hasn't changed one bit after almost a year of driving, but recently if I shut down my engine just after warmup (say a grocery store stop) and go back out, it'll very quickly race and then drop to about 600 RPM for less than a quarter second, as if the ECU is trying to get a handle on the engine speed. It hasn't been consistently happening though so it was one of those "I'll investigate when the weather gets better" things. This last weekend I had my battery out for a maintenance charge inside on my NOCO, and yesterday when I would pull up on a red light and sit waiting, it would continually do those quick dips in idle and then recover. No racing those times though, and this is something it never did any of the times I would reset the ECU in the past. Today, didn't do it at all. Just high idle.

 

[MWM1]

It would be interesting to swap your ECU to see if there is any change? Keep after it!
Ty!

 

[Spook50]

It would be interesting to swap your ECU to see if there is any change? Keep after it!
Ty!

As far as troubleshooting my rig, I'd like to borrow a known good one if I can track one down locally and see if these things actually ARE being caused by my ECU or if I need to keep looking elsewhere.

 

[3_puppies]

which ECU # are you looking for a test?
I think I found the questionable one

 

[Spook50]

which ECU # are you looking for a test?
I think I found the questionable one

89661-60020

 

[White Stripe]

You could possibly use a gm ecu instead.

 

[Spook50]

You could possibly use a gm ecu instead.

I'm not sure how feasible that would be for someone in need of a 3FE unit. The Toyota EFI system from this era, from what I understand, is very similar to Bosch systems. So I would assume finding a Bosch ECU from an engine as close in similarities to a 3FE would be more feasible if someone wanted to go to the effort of making one work. That I really don't think would be worthwhile at all, to be honest.

 

[cruiserdan]

My memory and research seem to match up. Originally there were 4 applications. 2 for California and 2 for the United States...(Get it? CA versus the US/ )

The early California supersedes to the later and the early federal supersedes to the later. The California and federal variants appear to not be interchangeable.
therefore you would be looking for a 60020 or preferably a 60021 as obviously something was improved in the latter.

 

[Spook50]

My memory and research seem to match up. Originally there were 4 applications. 2 for California and 2 for the United States...(Get it? CA versus the US/ )

The early California supersedes to the later and the early federal supersedes to the later. The California and federal variants appear to not be interchangeable.
therefore you would be looking for a 60020 or preferably a 60021 as obviously something was improved in the latter.

View attachment 3842165

Perfect! Plus from my understanding the FJ62 and FJ80 variants are also not interchangeable.

It makes me wonder what was changed between the 20 and the 21. Be interesting to see if the programming is the same between the two, or if it was just hardware/component revisions. Now I can't find the thread I stole that pic from to verify if that's a 20 or a 21

Also just for giggles; if memory serves, the CA "compliant" ECU has a provision and programming for an EGR temp sensor, and if it doesn't see a signal from one, will not run properly at all.

 

[3_puppies]

correct on 62 and 80 series ECU being different, the plugs don't match