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Hookecho
08-25-2011, 01:46 AM
I've had an ongoing issue with the ECU retarded timing. This happened above 4200rpm. When I ran a TMIC I figured this was due to hot intake temps and it happened all of the time. Even at stock boost pressure. When I installed the FMIC this issue went away and I was happy. Too bad it only lasted a couple of weeks.

I guess the FMIC only masked a different problem.

I do have the LED Knock detection mod and every time I take the motor past 4000rpms I can feel the ECU retard timing and my LED's indicate that the TVSV has acuated low boost mode.

This issue had me to a point where I was just ready to sell the car and buy a Vette. Seriously. I have tons of time and money in this car and it is pretty much in new car condition.

I mean, I love my car but a man can handle so much BS. I had gotten quite frustrated with having spent so much time trying to track down this gremlin.

I couldn't figure out what was going on. All of the ignition components are new(well, 4000 miles on them). The cylinder compression is spot on. Ignition and mechanical timing is right on. The fueling system is new and injectors are clean. I've swapped ignitors, AFM's, knock sensors...the works. I took the boost pressure down to 7psi and retarded ignition timing to 7*btdc. There was nothing rattling on my car to cause false knock. Nothing made a difference.

I did everything possible to figure out what the hell was going on. Poor Luni listened to me piss and moan about it for the longest and between the two of us I figured it could be sorted out.

Then Lunikins throws a hail mary and tells me to go down to the shop and pull the ECU. Take it apart and look for a bad capacitor.

This is what I find.

http://www.celicatech.com/gallery/files/4/1/4/3/100_0884.jpg

http://www.celicatech.com/gallery/files/4/1/4/3/100_0885.jpg

I hope I can fix this myself and solve my issues. I hope this IS the problem. I'm sure it is. If I can't fix it then I'll get another ECU.

Luni, I think I'll keep you another week!

UtahSleeper
08-25-2011, 02:46 AM
Nice find!!!!! Hate it when that shit happens. And it should be an easy fix. Did it on a DSM once.

Car_Barn_Bandit
08-25-2011, 02:48 AM
'Sploded cap win!

Tecker184
08-25-2011, 03:12 AM
I think there's something wrong with my st215 ecu. Mine keeps throwing a knock sensor code but both the knock sensor and the wiring are fine. I cant see anything wrong with it i wish mine was this obvious.

DudeMan
08-25-2011, 04:18 AM
Yeah that would be a nasty little gremlin to track down.. Shit like that will bring people to the breaking point.

Mafix
08-25-2011, 01:38 PM
do not try and fix that. get another ecu. that's a double layer board and a simple soldering iron won't due the trick.

Hookecho
08-25-2011, 03:09 PM
So how would I have to do it?

I do have another ECU on the way but fixing this problem would be beneficial to me if it happened again. These things aren't getting any easier to find.

Mafix
08-25-2011, 04:47 PM
well if you get the boost bug you won't have to worry because you'll go stand alone soon enough.

Hookecho
08-25-2011, 05:31 PM
I would upgrade to gen3 electronics before fooling with a stand alone ems. I don't want the headache of having to tune one. I just don't have high power goals for this motor.

I'm looking at this circuit board on the ecu and it looks like a simple desoldering of the old capacitor and soldering the new one on. I don't understand what a double layer board has to do with anything.

Funkycheeze
08-25-2011, 05:49 PM
If the cap is thru-hole mounted (you can see the wires poking out from the other side, soldered down) then carefully use some solder wick to remove all the old solder and replace the capacitor with a new one by removing it from the holes in the board. Then solder the new cap into place making sure you heat the cap leads and the solder flows down thru the holes in the board

Mafix
08-25-2011, 05:55 PM
what he said

Hookecho
08-25-2011, 06:13 PM
Cool. That I can do.

ChrisD
08-25-2011, 07:10 PM
wow. hail mary for sure. very nice find.

wonder how common this is?

Hookecho
08-25-2011, 07:14 PM
Not sure.

It definitely changes the way I will troubleshoot in the future.

Luni
08-25-2011, 07:17 PM
Chris, its common enough that I thought of having him do it.

Guys we covered EVERYTHING. I preached and threw out all sorts of shit for him to try. Check your ignition components, plugs, cap, wires, rotor, ignition timing, coil, igniter, get some octane booster, reset your ECU, this is what causes you to be in bad gas mode, blah blah blah, maybe your ECU temp sensor is bad, replace that, fuel pump not flowing high enough so youre running lean, try my other AFM, blah blah blah. Then finally I said, you know what, go open the ECU and maybe you have a bad capacitor. It WAS a hail mary, I honestly didnt expect to be right. But sure as shit he calls me back a few hours later and told me I was right, and that was it.

The thing that was odd about it was he said it pretty much happened on a fuel fillup. It worked fine, then he got gas, and it never worked right again. Nukkin Futz. But as our ECUs get more age on them and use, its going to be more and more common for this sort of thing to happen. So yeah, keep this one in the spank bank everyone. It happens.

Funkycheeze
08-25-2011, 09:27 PM
the 1JZ-GTE ECUs are notorious for this. They blow caps on the injector drivers and then the injectors stick open and the car goes waaaay rich.

KoreanJoey
08-25-2011, 09:44 PM
the 1JZ-GTE ECUs are notorious for this. They blow caps on the injector drivers and then the injectors stick open and the car goes waaaay rich.

Is this with the factory injectors?

I know guys w/ standalones and big low impedance injectors that burned out the injector drivers since they didn't run a resistor pack.

Facime
08-25-2011, 10:51 PM
"lets not start suckin each others dicks just yet gentlemen"


It COULD be the problem, but Ive learned long ago that its never fixed until its fixed. Just trying to ward off and bad juju here caused by counting chickens.



and yes its very common in the 1JZ's for whatever reason.

Funkycheeze
08-25-2011, 11:23 PM
Yes, with stock injectors. Stock everything. It is bad caps, once they are replaced (unless the goop damaged the board) everything works great again.

KoreanJoey
08-25-2011, 11:34 PM
That is weird, wonder if it was just a batch of bad caps that made it into the 1jz ecus.

Tecker184
08-26-2011, 12:28 AM
A computer place should be able to do that for you cheap.

Funkycheeze
08-26-2011, 04:51 AM
I guess Toyota used cheap caps. It's not an issue with USDM or JDM 2JZ engines, or the later 1JZ-GTE with the big single and VVTI.

Luni
08-26-2011, 06:05 AM
Not yet guys. All capacators have a life rating in hours. They eventually die.

underscore
08-26-2011, 06:14 AM
All caps eventually die, they're one of the few things that can die with electronics that aren't abused. If you've got it apart you may as well swap them all cause it's easy.

Terracar
08-26-2011, 04:14 PM
Well F a duck... I wonder if this is the issue with mine... hmm, I already replaced the ECU and it 'sploded hardcore. Maybe the replacement has a bad cap... hmm. Thanks for posting this up.

-Terracar

Hookecho
08-26-2011, 04:19 PM
Let us know.

klapa
08-26-2011, 07:52 PM
I have two spare ST-185 USDM ECU for troubleshooting.

I have access to any electronic parts you may need, especially electrolytic capacitors, in many values of capacitance and voltage as well as temperature ratings.

I can send you the parts anytime you ask, Bruce.

Aside from all that - the capacitor in the picture does not seem bad to me - generally an electrolytic capacitor such as that will have a "bulge" on the top to indicate a problem.

Note that electrolytic capacitors are rated not only for capacitance value, but more importantly for hours of operation at a specific temperature.

Let me know if I can help - you have my phone #.

Facime
08-26-2011, 08:31 PM
Aside from all that - the capacitor in the picture does not seem bad to me - generally an electrolytic capacitor such as that will have a "bulge" on the top to indicate a problem.


This

Hookecho
08-26-2011, 08:59 PM
So what's it leaking for?

I googled it yesterday and saw pictures of them leaking from the bottom. I've read that while they do more commonly leak from the top they can leak from the bottom.

klapa
08-26-2011, 09:27 PM
So what's it leaking for?

I googled it yesterday and saw pictures of them leaking from the bottom. I've read that while they do more commonly leak from the top they can leak from the bottom.

Hookecho,

When a capacitor "leaks" - it does not do such from the bottom or the top - it leaks between the "plates" internal to the capacitor.

Surely - the leakage current will go to the "bottom" where the leads are - but - generally speaking - if the cap has been leaking for some time the top will "bulge" due to the stress on the internal electrolyte expanding due to change in composition and also due to heat. To put this in simple terms - if an electrolytic capacitor is breaking down you will generally see this is a "bulge" on the top - or even a bulging of the body of the cap.

The one I see in your pic shows no such symptoms - I don't really think that cap is bad.

As said - I have two extra 3SGTE USDM ECU here - neither has been tested - but I could test them in my car and then send to you as a loaner for troubleshooting purposes.

Just a thought - but if I could just go buy a Vette maybe I would do that too...... just sayin'.

Actually - my first choice would be to just go buy a 4WS Ferrari or possibly a Lotus but all that is out of my "pocketbook" range so I'm just stuck.

Hookecho
08-26-2011, 09:56 PM
So what do you think that stuff is under the capacitor? I imagine it's conductive and causing a short.

klapa
08-26-2011, 10:04 PM
So what do you think that stuff is under the capacitor? I imagine it's conductive and causing a short.

I didn't notice anything under the capacitor - I will take a second and more careful look at the pic.

CollapsedNut
08-26-2011, 11:15 PM
So what do you think that stuff is under the capacitor? I imagine it's conductive and causing a short.

Its a surprise I left for you to find... <3

underscore
08-27-2011, 05:56 AM
I've seen caps poop out the bottom before. Like I said, may as well change'em all just to be safe.

klapa
08-27-2011, 07:03 PM
Yea - I certainly should have looked better - as thee is def some stuff under that cap.

It's sort of funny though - as it is black - normally an electrolyte leak will be white - but I must keep in mind that these are from the early 90's.

Didi you remove the cap yet? Can you desolder it with no problems? Do you need help to do this?

What is the reference designator for the cap (i.e. C?)?

I'll get one of my ECU and open it up to compare.

Luni
08-27-2011, 07:19 PM
Klapa I was about to do an across the internet slap across the back of your head. Faulty cap in the pick is plain as day.

klapa
08-27-2011, 07:42 PM
Yea - that is clear - but the BLACK goo - that might be indicative of more than just a cap that failed due to age - like something in the load.

As we speak I have both my ECU here and have opened one of them up - as the other is old and I can't get the screws off the covers.

I need to backtrack a little here - as I just noticed that while both my ECU are labelled "3S-GT" they have different connectors. The one I have open I bought from Shadow a year or so ago as a spare - and it looks nearly brand new. The other came with the 3SGE engine "turbo project" I bought from a guy awhile back.

The better one has 26p, 16p, and 22p connectors on the back. The other one has a 10p, 18p, and 24p connectors (in the same order - left to right) and each set of connectors have a different keying arrangement. The newer one has a label very easy to read and the P/N is 89661-20761, while the other has a partially obliterated label and the P/N seems to be 89661-20760.

I'm going to look up some P/N and will post pics soon.

klapa
08-27-2011, 08:29 PM
OK - so a quick check of P/N revealed nothing - but looking at that Aussie guy's site I see I have a ST-185 ECU (the better one that I got from Shadow) and an ST-165 ECU (the old one that came with the "project engine").

So - I will post up pics of the ST-185 ECU - but just really need to know the ref des of the bad cap to help - I will also look back at the pic to see if I can tell for myself.

Hookecho
08-27-2011, 08:39 PM
The cap is labeled 10uF 50v on one side and 105*c on the other. I learned that both have the same meaning and that the "c" means +/- .25pf. Is that right?

klapa
08-27-2011, 08:51 PM
So - my pics are pretty bad as my camera is not capable of close-ups. It is so old maybe my cell phone would do better, lol.

Anyway - here they are - see if this matches your ECU.

http://www.nashdom.com/GeneralPics/ECU1-1%20%28640%20x%20480%29.jpg

Another view:

http://www.nashdom.com/GeneralPics/ECU1-2%20%28640%20x%20480%29.jpg

This is the P/N label - note the 5th gen ECU cover with the label is sitting on top of the 4th gen ECU which has the yellow connectors.

http://www.nashdom.com/GeneralPics/ECU1-Label%20%28640%20x%20480%29.jpg

klapa
08-27-2011, 09:08 PM
The 105C means the thing is rated to a temperature of 105 degree centigrade - which is as good as an electrolytic cap gets.

Just for general information - the lectrolytic capacitor is essentially the part that defines the life of an electronic device. Semiconductors and ceramic type capacitors are rated for operation at up to 125 C for nearly continuous operation, but electrolytic capacitors degrade over time and "dry out".

A 10 uF electrolytic would never have a tolerance such as +/- -.25 pF - now would it ever need to have such a tolerance. A capacitor such as this is used just for filtering - smoothing the DC voltage - and might vary +/- 30% and still perform adequately. The primay spec for an electrolytic - especially in an automotive application - if the temperature rating.

First - for expediancy - I will tell you what yu need:

ANY electrolytic of at least 10 uF and at least 50V that will fit will do the job. You can go higher on the capacitance or the voltage with no ill effect - but you should not go lower - especially on the voltage rating. Just get what will fit within the mechanical form factor you have available (height and lead pitch). If you want - I can choose one for you - but I need the reference designator - i.e. C101 or whatever.

Don't get one from Radio Shack! They don't sell the caps rated for extended operation at higher temperatures - and actually Radio Shack components are all "factory seconds" that failed the basic ratings for one reason or the other.

klapa
08-27-2011, 09:23 PM
I just took a cursory look at my ECU and found two 10uF 50V caps - C101 and C402.

There is plent of room (mechanical space) for substitution there - so you should easily be able to find a replacement.

Note that you mst be careful when you replace the capacitor. These boards (PCB) have conformal coating on them to keep out moisture. What this means is that when you would attempt to desolder the component you might overheat the PCB and lift a pad by the time you melted through the coating to actually desolder the thing. You should first scrape the connection with an exacto knife to remove that coating - and then use solder-wick to remove the solder. I would suggest that you first cut out the cap as at least on my PCB the thing is mounted above the top surface of the PCB.

CollapsedNut
08-27-2011, 11:09 PM
Hooks gonna ruin his ECU. Thats all there is too it. I've seen him at work. Precision is not his game. He couldnt even hit the hole, if you know what I mean.

Hookecho
08-27-2011, 11:35 PM
Yeah, I believe I'll let a pro handle it.

And Matt, I may not can hit the hole but at least I don't cross thread it.....

klapa
08-27-2011, 11:45 PM
Hooks gonna ruin his ECU. Thats all there is too it. I've seen him at work. Precision is not his game. He couldnt even hit the hole, if you know what I mean.

I don't know if you are joking or not there.

To replace that is not exactly easy because of all that gunk on the PCB - it may be that actually the thing has had a high current and the traces re burnt, based on the black stuff. The first thing that needs to be done is to remove the cap and clean the PSB area of the black stuff to access the damage (if any).

Just clip out the cap, and use a toothbrush with alcohol to carefully remove all the gunk and then we can see if the thing is repairable. It probably is - as even if pads have lifted it is still possible to place small jumper on the copper - I do it all the time.

klapa
08-27-2011, 11:51 PM
Bruce,

I'll send you my ECU if you want to try and see that that is the problem - and change that cap for you too.

It is no problem for me to do it.

While I am not thrilled to part with my spare ecu it is just that - a spare - so if you need it just say the word. I'm not sure it works either - though it looks nearly brand new.

Luni
08-28-2011, 12:21 AM
Bruce just send your ecu to klapa see if he can fix it. Klapa what year is your spare ecu? Is it a usdm or jdm one? It matters.

klapa
08-28-2011, 12:56 AM
It is USDM - I bought it from ShadowLife about a year and a half ago. It came with an email from the guy Mario bought it from.

I say it is USDM based on the P/N on the label (89661-20761) - and this site:

http://gt4.mwp.id.au/Electrical/All%203SGTE%20ECU%20Diagram.png

The Denso P/N is:

175000-3920 12V.

Actually - after looking into things a little deeper - my other ECU is also for an ST-185 - not a ST-165 like I thought - it is just for an early 89-90 ST-185 that apparently had different connectors like the older ST-165.

As I said - this later model unit I have looks like brand new - both outside and inside. I'll post more pics if you all need them.

Luni
08-28-2011, 01:18 AM
Won't work for Bruce. He needs a jdm ecu. You can run a usdm car on a jdm ecu but not vice versa. The jdm cars have a single wire O2 sensor and usdm ones have a heated 4 wire circuit. The usdm ecu is looking for the heater circuit and if it isn't present will pull an O2 sensor CEL.

klapa
08-28-2011, 01:32 AM
Yea - I checked - I managed to get the cover off the older model ECU - and neither are like the pics Bruce posted.

I can fix that problem with the PCB or provide both instructions and equipment for Bruce to fix it himself - but can't replace the ECU.

Still I might add that if the thing is "looking for a heater circuit" that is something easily faked.

If it is a JDM ECU then I would think the P/N on the label would be 89661-20750 for 89-90 or 89661-20751 for 91-UP.

This has piqued my interest to actually find out what ECU I have in my own car - that supposedly has a JDM engine.

I will do that tomorrow just for fun.

Luni
08-28-2011, 01:43 AM
It is easily faked. You're right.

CollapsedNut
08-28-2011, 02:30 AM
Yeah, I believe I'll let a pro handle it.

And Matt, I may not can hit the hole but at least I don't cross thread it.....

Hey that stupid fucking line was a douche and got what it had coming.

Luni
08-28-2011, 03:25 AM
Yeah Matt, you really showed that line what was what... LOLZ.

Klapa, as for repairing the ECU, Id do it but youre closer, so shipping and turnaround to you would be quicker, thats why I suggested he send it to you instead of me.

Ive already sent him a revision 1 JDM ECU, but to use it hes gonna have to repin his harness. I think if he could be without his car for a few and send his ECU to you for repair it would prolly be a better fix IMO.

Hookecho
08-28-2011, 03:53 AM
I'll send it to you Jacob. That would much appreciated. Be looking for it next week. If it can be fixed I'd rather try that. I already repinned my 91 engine harness to work with my rev2 ecu. So not having to repin it again would be nice. Not that it's difficult anyway. If it still gives me problems afterward I'll use the one Luni gave me.

klapa
08-28-2011, 04:22 AM
I can turn that thing around quick and will put a priority on it - you have my address.

I will look at it - remove the offending cap - take pictures - and if all it needs is cleanup and a cap you would have it shipped back in a couple of days - else I will advise as to what the problems are.

*edit*
Next weekend is Labor Day - I am planning to go see my Mom - so get the thing to me by Wednesday I can repair it and have it out to you by Friday. I will make sure to have the 10uF 50V 5000 hour 105C cap by Tuesday - I know the component size from looking at my own ECU and I need to order some next day parts anyway so I will just throw that one in.

Hookecho
08-28-2011, 05:02 AM
Great. Thanks man. I'll get it to you Monday.

klapa
08-28-2011, 05:16 AM
I will order the parts tomorrow.

In the meantime - look the thing over carefully - especially focusing on the electrolytic capacitors - let me know if you see any other "weaklings".

Look over the PCB - it should be "green" - if there are any areas that are brown or where the material seems to be dried out or delaminated - that would also point to problems.

You probably won't find any such problems on the PCB, but it never hurts to check.

As I said - I deal with this all the time in a different way - designing LED lighting products with warranties. The electrolytic capacitor IS the "weak knee" of any hardware design - especially when elevated temperatures are concerned.

I will take care of you as best I can and as quick as I can dude.

Hookecho
08-28-2011, 06:36 AM
Cool. I'll look it over. If for some reason you find other problems then that's fine too. I don't want you to feel rushed to complete it. Just let me know what the costs are.

I'll post up some pictures tomorrow so you can have a better look at everything.

I really appreciate you.

Hookecho
08-28-2011, 04:03 PM
I don't see any other problem areas. Just that one capacitor looks to be it.

http://www.celicatech.com/gallery/files/4/1/4/3/100_0892.jpg
http://www.celicatech.com/gallery/files/4/1/4/3/100_0893.jpg
http://www.celicatech.com/gallery/files/4/1/4/3/100_0894.jpg
http://www.celicatech.com/gallery/files/4/1/4/3/100_0897.jpg
http://www.celicatech.com/gallery/files/4/1/4/3/100_0884.jpg
http://www.celicatech.com/gallery/files/4/1/4/3/100_0885.jpg
http://www.celicatech.com/gallery/files/4/1/4/3/100_0898.jpg
http://www.celicatech.com/gallery/files/4/1/4/3/100_0910.jpg
http://www.celicatech.com/gallery/files/4/1/4/3/100_0909.jpg
http://www.celicatech.com/gallery/files/4/1/4/3/100_0908.jpg
http://www.celicatech.com/gallery/files/4/1/4/3/100_0907.jpg
http://www.celicatech.com/gallery/files/4/1/4/3/100_0906.jpg

klapa
08-28-2011, 08:04 PM
Wow - that thing is really clean! Should be no probs to change out that cap - and I can even re-apply conformal coating on it as we use that on all our boards that go on exterior products (like street lights).

That ECU is def nothing like the two I have - neither of mine have that "daughter board" that connects through the flexible PCB trace cables. These are those white cables which appear to be copper traces - as opposed to simply wires. These are normally used to route high speed signals short distances to other boards. Care needs to be taken with these - they are not meant to be moved around (flexed) much and also tend to get brittle with time potentially causing the traces (conductors) to crack when moved, which could cause allot of grief.

The idea that these are flexible traces is bolstered by the fact that the two large IC (64 pin DIP) on that board each have a crystal (the little metal can) - indicating that they are micro-controllers. I looked up those chips and found they are DENSO. (http://www.kexu-icerp.com/Stock.asp?Page=205).

Anyway - I'll get the parts (capacitor) and have it ready by the time I get the unit - the repair will take no more than 30 minutes. I should have it back in the box and shipped the same day I get it.

As it is I'm sure I already have a 10uF 50V cap - I'm just not sure if I have a 5000hr./105C rated.

klapa
08-28-2011, 09:05 PM
Just for info - this is the usual indicator of electrolytic capacitor failure (or imminent failure):

http://www.avforums.com/forums/attachments/lcd-led-lcd-tvs/165280d1266962088-bad-capacitors-samsung-lcd-tv-le40r73bd-bad-caps.jpg

Note the bulging at the top - also note the little "cross hatch" on each cap. This is a vent intentionally made to be the weak point and vent internal gases. You will note in the photo that one cap has completely failed, and all but one of the others are severely degraded.

When the capacitor ages the electrolyte begins to dry out and leak more over hours of operation at elevated temperature - and this causes an increase in the caps ESR (equivalent series resistance) - which in turn causes it to get hotter, which then causes the electrolyte to dry out more....

The electrolytic capacitor essentially defines the "life" of an electronic product, because it is the "weak knee". None of them are rated above an operating temperature of 105C, while ceramic and film type capacitors go up to 125C operating temperatures. Yet a ceramic capacitor of 10uF 50V (if you could find it) might cost $5 while the electrolytic would be more like $0.05. All capacitors are not created equal - especially electrolytics. They are not only rated for capacitance and voltage and tolerance of the capacitance value - but they are also rated for hours of operation at a maximum temperature. This last rating defines the "life" of the capacitor. The best of them (and most expensive) are rated 5000-10000 hours at 105C. This means the thing can operate at that temp for that many hours before certain specifications (ESR) degrade to a specified point. There are curves that one may use to determine the expected life at lower than those max temperatures.

Panasonic is a great source of information and design guidelines for many passive components - capacitors and batteries being two of the bigger sectors they operate in.

If any are interested - check out this document - I use it all the time:

http://industrial.panasonic.com/www-data/pdf/ABA0000/ABA0000TE6.pdf

I only mention these technical things to let everybody know that "all capacitors are not created equal" - especially electrolytic types. I can get a 10uF 50V cap in many "flavors" - but for use in the electronically hostile environment of an automobile I would need to carefully select my replacement component. This means a component rated for extended operation at elevated temperatures. I would also need to carefully select the vendor I would buy such a component from - this means NOT Radio Shack.



That's the way they make them these days - gone are the "good old days" when you could plug a cap in the wall-socket and have a "KABOOM" for a couple of yuks!

Galcobar
08-28-2011, 11:27 PM
Just for info - this is the usual indicator of electrolytic capacitor failure (or imminent failure):
...
I only mention these technical things to let everybody know that "all capacitors are not created equal" - especially electrolytic types.
...
That's the way they make them these days - gone are the "good old days" when you could plug a cap in the wall-socket and have a "KABOOM" for a couple of yuks!

Bad capacitors are responsible for the gigantic rash of failed computers during the early 2000s. It was also known as the capacitor plague, affecting Intel, Apple, Dell and HP most notably (volumes). The primary cause were incomplete formulae for the electrolyte, causing the electrolytes to break down and produce hydrogen gas. This causes the capacitor to bulge and eventually pop its top vents; without the vents, the capacitor is basically an overfilled rigid ballon and explodes. It may alternatively cause the rubber plug on the bottom of the capacitor to pop out, leaking electrolyte down.

Most of these faulty capacitors originated from Taiwan, either under Taiwanese brands or as counterfeit Japanese capacitors, which is why you'll see Japanese capacitors still advertised as a claim of greater reliability.

That said, is it just me or are the vent lines on the larger capacitor in Hook's ECU (fourth picture down on his detailed pics, bottom right) extra visible? If it were me, since the ECU's being opened up anyway, I'd probably replace all the capacitors. They're all the same age.

ChrisD
08-29-2011, 05:54 PM
FYI that daughter board style was introduced in the post-facelift models from '92 and newer. 90-91's have the old style (as does st165).

klapa
08-29-2011, 11:48 PM
It may alternatively cause the rubber plug on the bottom of the capacitor to pop out, leaking electrolyte down.

They are not supposed to fail that way - at least not these days. The plug at the bottom is to seal the thing after the manufacturing process - the vent hole is on top.


Most of these faulty capacitors originated from Taiwan, either under Taiwanese brands or as counterfeit Japanese capacitors, which is why you'll see Japanese capacitors still advertised as a claim of greater reliability.

They all come from China anyway - you may notice on your Intel or other chips that they may say "Malaysia" or something like that - very few foundry's left in US or Japan and very few capacitors made there either - why? - China and those other Aisian countries don't have OSHA and environmental laws like other places, and the almighty dollar will always rule.

Aside from the above - it is not WHERE they are made so much as what quality process the parent company imposes on the plant that makes them. Plenty of good caps (particularly Tantalum) come out of Taiwan.


That said, is it just me or are the vent lines on the larger capacitor in Hook's ECU (fourth picture down on his detailed pics, bottom right) extra visible? If it were me, since the ECU's being opened up anyway, I'd probably replace all the capacitors. They're all the same age.

I'll look all that over when I get it - and if I think something else needs to be replaced I will replace it. I agree - all those caps are the same age - in years - and that does matter somewhat. But the primary "age factor" for an electrolytic capacitor is hours of operation at a particular temperature. Look at that Panasonic PDF file I linked above:

Note, as an example, that for a 5000 hr./105C cap operated at or below 85C the life expectancy would be ~20,000 hours of OPERATION. This would equate to ~6 years if operated 8 hours per day, every day, for 6 years.

Note that if a car has 150,000 miles on it and during this time has averaged 30 MPH then this would only total up to 5000 hours.

Yes - it might be a good idea to "shotgun" the thing and just replace every cap - but for now Hook has a problem and he just needs to know if this might be it. Making gross changes might muddle up the situation. Add to the above that he only has _one_ of these things - there are no spares for substitution or comparison. So caution is paramount.

It could be the cap just failed because it was it's "time" - it could also be that something in the load is placing extra stress on the cap. We will see.

klapa
08-29-2011, 11:56 PM
I will also mention - those little blue caps are tantalum - also polarized - and also famous for getting leaky over time.

alltracman78
09-07-2011, 01:10 AM
Good info guys, it's great to see this stuff up. :)

As far as that double board, my guess is that's for the added diagnostic capability for the post revision cars.

klapa
09-07-2011, 07:15 PM
I looked at the differences on that one compared to my two when I got it here for repair. All the processors are on the little daughter board on Hook's - while on my other two everything is on a single board.

I already changed out the cap and sent it back yesterday - changing the cap is nothing - but getting that old gunk off and cleaning the board off without damaging the copper was not easy. In the interest of troubleshooting I only changed that one single cap - but included a complete set of the other electrolytics in case want to change them later after checking if that was the problem (it certainly was "a" problem). The values of the caps are the same in my two ECU. I also was able to get the values for all the tantalums so will get some of those next time I make an order at work (to save on the shipping).

I took pics - but they are all no good - my camera is just no good at close ups.

Hookecho
09-09-2011, 06:49 PM
Well, I plugged up the ECU and did some driving. The ECU is still pulling timing. It's not near as bad as it was though but it still did it a few times during hard pulls. I still had the base timing set at 8*btdc from when I was troubleshooting before. It did seem to idle much smoother and wasn't stalling out at idle.

So my test drive was at a base timing of 8*btdc, 14lbs of boost, it's 70 degrees outside and with a fmic I know my intake temps are chill. There is absolutely no reason why the ECU should pull timing

I think this ECU is just toasted. Maybe that capacitor goo messed up the board, idk.

I'm just going to repin my harness and run the ECU I got from Luni.

Facime
09-09-2011, 08:14 PM
you dont happen to have a wideband do you?
Also, when was the last time you did a compression check? is it possible you have a large build up of carbon deposits? You might try rigging up a water injector system into your intake to steam clean your cylinders.

Luni
09-09-2011, 08:38 PM
I doubt his issue is mechanical. It happened literally overnight.

Facime
09-09-2011, 09:14 PM
ahhh...I see.
A wideband would still be useful to see if there is a lean condition under boost. That would at least let you stop chasing those geese.
What about the wiring between the KS and the EC? Is that all stock? maybe there is something interfering or cross talking there?

I guess what Im getting at here is there are three options. It really is detecting a knock, its giving a false positive, or the ECU is interpretting the signal incorrectly.


Im unfamiliar with the knock detector LED mod. Is it reading pre ECU info or post ECU reaction?

Luni
09-09-2011, 09:58 PM
Post ECU reaction.

Facime
09-10-2011, 12:21 AM
good then that means you should be able to monitor the KS signal real time and determine what its doing in relation to the ECU pulling timing. Might be useful diagnostically.

klapa
09-10-2011, 03:48 AM
Well, I plugged up the ECU and did some driving. The ECU is still pulling timing. It's not near as bad as it was though but it still did it a few times during hard pulls. I still had the base timing set at 8*btdc from when I was troubleshooting before. It did seem to idle much smoother and wasn't stalling out at idle.

So my test drive was at a base timing of 8*btdc, 14lbs of boost, it's 70 degrees outside and with a fmic I know my intake temps are chill. There is absolutely no reason why the ECU should pull timing

I think this ECU is just toasted. Maybe that capacitor goo messed up the board, idk.

I'm just going to repin my harness and run the ECU I got from Luni.

Sorry to hear that man - I will continue to look at my ECU's to try and determine what that circuit the cap is connected to effects - it it not easy - as that circuit does not go to any one single pin either directly or indirectly.

I agree with Luni - if the problem happened "overnight" - it is a good bet it is an EFI or timing control problem of some sort.

I checked the two transistors associated with the circuit that cap was in - they were fine with a static junction check. The failed capacitor was a filter on the emitter circuit of two transistors - the collectors of these transistors fed a pair of rectifier diodes - which checked good.

This circuit seems to be a voltage supply of some sorts - it had some continuity to a number of pins - I don't have my notes handy here but all the IG pins had some continuity to those rectifier diodes.

Maybe if you drive it some more - perhaps it is is a "mode" running some default profile and it will "heal itself".

Th PCB is fine - the capacitor goo did not do anything but eat off the solder mask and conformal coating - this has no effect at all on the copper and thus the connectivity of the PCB - and the control (presumably from a processor) is on the base of the transistors - completely isolated from that failure. I did not change any of the other caps because they do not look bad - and none of them measured shorted (I checked all the electrolytics).

Hookecho
09-13-2011, 12:15 AM
Ok guys, the jury is in on this one.

I decided I was going to give this ECU Jacob worked on another chance. I filled up the gas take and went for a short drive. Then came back to my shop and set the timing back to 10*btdc. I did have it at 7*btdc when I was troubleshooting a couple of weeks ago before sending the ECU off.

I then just went for a casual drive through the country side for about an hour. Not boosting hard at all. All was good so far.

On the way back I gave her hell though. Kept pulling timing as it was before. Just not as frequently. I lowered the boost and it didn't help. So I'm kind of mad that the ECU is still giving me fits. I get back to my shop and check the timing again. It was spot on at 10*. So I said enough was enough and repined the harness for the JDM ECU that Luni gave me. Which is actually the correct ECU for my Rev1 motor anyway. I was using a Rev2 ECU that came with my Rev1 motor.

Anyway, I get the new ECU plugged up and crank the motor. I take it for a drive and notice that it is lacking serious power. I go back to the shop and check the timing. It was at 1*btdc. So I instantly knew that I had found the problem. The other ECU was not controlling the ignition timing properly and it was over advanced. So when I had the base timing set at 10* it was actually at 19*. Which makes perfect sense as to why that ECU was constantly pulling timing. There must have be some kind of overload in that circuit and fixing the cap didn't fix it.

So now that I have the other ECU hooked up I'm having no problems. Yet, lol.

CollapsedNut
09-13-2011, 01:51 AM
You found the surprise I left you, a F'ed up ECU!

Facime
09-13-2011, 02:01 AM
so switch back the original ECU and base time to 0. ;)


but seriously, thats kind of wierd. I know you were shorting the diag connector when setting timing right? Im trying to imagine how there might be a short or a pin config issue there with the other ECU (so when you short the connector, the ECU isnt actually seeing it ?)

Hookecho
09-13-2011, 02:05 AM
Nah, repining a harness is the suck.

Facime
09-13-2011, 02:39 AM
lol, agreed. What if any is the drawback of this ECU anyway? You just didnt want to repin for it in the first place?

(sorry, sometimes I realize Im just playing catch up here)

Luni
09-13-2011, 05:47 AM
The only real drawback performance wise is the lower fuel cut. Other than that, same diff. Im sure his car runs great now like it used to. Right Brucie?

If so, youve got some of my MR2 up in ya.

Hookecho
09-13-2011, 06:33 AM
I am so fucking fed up right now.

Luni
09-13-2011, 06:17 PM
Whats wrong now?

Facime
09-13-2011, 06:17 PM
Im guessing by that comment your problem is back.

You need to rig up an in cabin monitor for what your knock sensor is actually doing.

Hookecho
09-25-2011, 06:54 PM
The car is running fine.

I was pissed because on my way to work that night one of my JDM clear corners flew off the car. Then my alternator went out. I have spares so that didn't bother me much. I was more pissed about the clear corner than anything else. Go figure..

Why am I obsessed with this damn car? It's a sickness I tell ya!

CollapsedNut
09-25-2011, 07:39 PM
FAIL

shreddr69
10-16-2011, 07:36 PM
I'm having cold start and rich fuel issues with my st165 with a st185 motor using the st165 ECU, sensors, intake manifold but the st185 injector rail.The car just doesn't want to high idle cold and is running to rich but no engine codes are on. I'm confused.

Luni
10-16-2011, 09:25 PM
I'm having cold start and rich fuel issues with my st165 with a st185 motor using the st165 ECU, sensors, intake manifold but the st185 injector rail.The car just doesn't want to high idle cold and is running to rich but no engine codes are on. I'm confused.

You should start a thread. We don't want the info on Bruces and yours getting fuddled.

donteatbugs
10-21-2011, 07:24 PM
You broke one of my corner lights....FU.......Go to toyota and order another one for like $30

Hookecho
10-21-2011, 08:14 PM
Will do.