1JZ ECU leaking capacitors.

[Ribfeast]

I used a 4.7µF and a 10µF in parallel to replace my 15µF capacitor, works fine. I tried Farnell at the time and they didn't have a 15µF capacitor.
I replaced all the electrolytic capacitors in the ECU with Jaycar ones. Car runs great

Just check the tracks for damage while you have the capacitors off, as the stuff that leaks out tends to corrode the tracks.
Also be careful removing the capacitors, as you can lift the tracks in the process (some are soldered to tracks above AND below. I would favour just chopping them off at the body and re-using the old legs.

[Slim]

I was googling some info on capacitors today (I searched for "what happens when a capacitor leaks ecu") and found my own thread at the top of the results.
I can't believe i was asking about capacitor replacement back in 2007 and it's taken until late 2009 for me to actually go and replace them.

Anyhow... this is what i found.




Thanks again to everyone that responded to my initial question though... and thanks to "urantia" for orangising a set of capacitors for me.

[Z2TT]

Hello.

On another forum somebody mentioned that even if you get the same capacitance and temperature rating on your replacement caps as the one you are replacing, that you just cant buy any caps, but need a certain grade in order to work correctly.

I don't quite understand this, can somebody here explain more about the grades, and which grade capacitors need to be used in 1jz ECU's.

Also this Capacitor problem seems to be more common in 1jz's from the amount of threads I see, or does this happen as much to all Toyota ECU's ?

Thanks.

[cambelt]

I was just going to add that the older toyota ecu,s pre 88 dont seem to have any cap problems , maybe because of there simplicity im not sure .\
Ive never had a yellow plug ecu cause any problems whatsoever .
Dave

[TERRA Operative]

The difference is in the ripple rejection (resilience to AC voltage), lower impedance (acting like an inductor) and their general longevity. Also the better caps have a rated temperature of 105deg, rather than 85deg of the cheaper ones.
Basically in a motherboard/sensor situation you want the best caps so the input/output is as accurate as possible, and the caps will last longer too.

There's not *that* much difference in the price of the better caps, and it's well worth using them.

I can provide part numbers to source these from RS components (although you need to purchase them in multiples of 5), or just provide you with the caps needed individually (I do so many cap replacements in Toyota ECU's that I keep a stock of parts....), alternatively, I can do the whole lot for you for a nominal fee if you can send me the ECU.

[petergoudie]

Heat is one of the big killers of capacitors as they dry out. On the cressida the ecu is directly under the front black coloured dashboard and it gets cooked in the sun.

[Mr_Flawless]

so these capacitors are the 33 micro farrad capacitors?

[Z2TT]

I believe there is about 4 or 5 different capacitors in the 1jz ECU. Then again wouldn't there be differences between JZA70, JZX81, JZZ30, JZX90, JZX100 etc etc?

But one Question, How can we get specifications for the Ripple Current Rating and ESR for the factory 1jz caps so we know which ones to replace with?

[TERRA Operative]

Using Rubycon ZL or YXF series, Nichicon HE, or Panasonic FC series will work fine. Preference basically in that order.
The actual ripple and ESR values aren't that important, just choose caps with the highest ratings you can get.

[Z2TT]

Highest ratings, as in just Temperature rating? or Highest Ripple and ESR?

From what I read if Ripple ratings are not same as the original capacitors, the capacitor will heat up and fail prematurely.

[TERRA Operative]

Using the ones I specified above will guarantee the ripple rejection is greater than those used OEM in the ECU.