bad caps of the 1990's played havoc with car ECU's

[image079]

Hi. I have a 1993 Camry. It has done over 300 000kms. In the last year it has developed a bad idle on start up but improves when warm. Engine is very good, excellent compressions, excellent sparks. I have spent many hours probing all the sensors and have found no problems. I have also replaced coolant sensor, oxygen sensor, MAP sensor, ignition coil.
Checked plugs, checked leads, cleaned idle control motor, checked throttle position switch, cleaned EGR valve, cleaned all terminals.
As a last straw I was about to fork out the money for ECU.
Anyway, I found this site and so decided to pull out the ECU out to check the Capacitors, and what do you know... it looks just like the photo above. Leaking caps galore. I will post pictures soon after I have a go at the repair.

[stj]

did you check the idle-air bypass on the throttle body is not clogged with crap?
it's common on honda's

[image079]

Yes. Throttle body cleaned, Idle air control cleaned and probed.
Anyway I removed the ecu and have taken photos of the leaky capacitors.

[stj]

you got lucky, that looks like some of the late 90's honda ecu's
those leak and go up in flames!!

[kc8adu]

i have fixed a cubic shitload of those.
looks like you caught it before it got real bad.
watch for eaten traces and ones with black under the coating.

[image079]

I went ahead and changed out the two leaky capacitors and I can confirm that IT IS FIXED!!!!
Idles perfect from start up, NO Hesitation and NO Flat spot on acceleration.
I can feel a noticeable gain in low end torque.
In the last year it has gotten very sluggish, which I just put down to engine getting old. Now, it is back to how it was when I first bought it.

I am hoping that fuel economy will also improve, because lately I have needed to fill up, way too often.

I only changed out the 2 leaky capacitors. These were Michicon (PF) 47uF 63v (Brown) Capacitors. I read on another site that these (PF) series caps are the ones that always go bad. The other 4 on the circuit board look to be of a different brand and show no leakage. I don't know much about capacitors and my soldering skills are limited, so I decided to leave these for now. There was one trace which was almost eaten all the way through, so I decided to solder in a small length of wire. I made sure to solder both sides of the board where the capacitors are, because the PCB looks to be a double sided board.

The car is a 1993 Toyota Camry 2.2 CSi Manual Gearbox.

I took a few pictures of the capacitors installed.

[theOracle]

hello from Club Lexus! - it's me, LSCowboyLS who wrote the original thread

[momaka]

Nice work image079!
However, I can't help but mention that your new green "LOW ESR" caps appear to be of very questionable quality (probably cheap Chinese caps). Be prepared to do this again sometime soon, especially if the ECU is in a spot that gets hot. And keep in mind they may not necessarily bulge like the old ones did. They can just go bad without any visual signs whatsoever. So if the car starts acting up again, change those caps again.

And for next time, get good genuine Japanese caps (see theOracle's sig right above my post). Avoid eBay! There's only very few good sellers on there. Most just sell junk. Try Digikey, Mouser, Farnel, RScomponents, or even this place (badcaps.net).

[theOracle]

an even more important reason to avoid ebay, is that it is not just enough to get one of the 4 high-end brands of caps listed in my sig, but you must have chain of custody due to there being so many counterfeits out there.

I decide on a brand of capacitor that meets the spec I am seeking in order to fix an ECU, then I go to the manufacturer's website and look at their list of authorized distributors and only source from those sources - you would not believe the good fakes I have seen on ebay, even from sellers with 100% feedback, (they don't even realize they are fakes!) - even your local mom & pop electronics store could have fakes and not know, they are that good!

[pc7fan]

^^Could not agree more! Always use quality capacitors, especially in critical applications like this. These crappy caps should be only used on non critical equipment and on hobby projects.