Yamae

Toyota has stopped using infamous electrolytic capacitors that contained “quaternaty ammonium salt" for your 2003 ES300. Newer series of electrolytic capacitors have been already in use at that time. So you must have correct capacitors in the ECU. If you want to try to replace them, select the same capacitors currently used. But I don't think the capacitors change of your car is as effective as a LS400.

GoKeez

Oh wow, then I guess it is another issue altogether. The symptoms are very similar to what others here have posted. Right now the car starts up fine but just shuts off. If I start it and immediately start driving it runs perfect until put in park. It won't idle without shutting down. Prior to this the engine light would come on sometimes. The AC stopped blowing cold and other lights like trac flashed occasionally for about a week. Should I just replace the ECU? If so, what is a reasonable amount to expect to pay for this service so that I am not burned by opportunistic mechanic. Need the car to run asap and money is super short

Yamae

Why don't you read the code first? That's the important first step before you speculate and consider that the capacitors are the problem.

CMDSlick

So after some prompting of some members here, I replaced the capacitors on my '93. What a difference. I have noticeable power throughout acceleration and feels like I get exactly how much I am putting into it. It could be in my head, but I believe it fixed the issues I was experiencing with sluggishness after the car warmed up. Super stoked. Thanks LSCowboy and Yamae.

Yamae

I want to ask you one question, CMDSlick.
Did you see any evidence of the leaking liquid?

CMDSlick

I'm honestly not sure. There was a glossy look on most of the bottom of the caps. The pic below shows the glossy on one side of the cap where the rest looks more matte. This could be a leakage, or it could be some sort of glaze covering that didn't get this cap fully. The other capacitors had some level of gloss as well. There was no sign of leakage on the board at all.

BUT OMG!!! It's like a whole new car.

Just to recap. My symptoms were sluggish performance after the car warmed up. When I first started the car I had quite a bit of pep and intermittently didn't have much of any get up and go once the car was warmed up. I had no noticeable misses, and felt almost like it was in a very high gear when I was going slower.

Changing the capacitors caused my car to perform like it did when it was first started now all the time. I have V8 and I can tell. I'm more in love with this machine every time I drive it.

CMDSlick

Capacitor glaze?

evoltap

Yamae and LScowboyLS, you guys are AWESOME for hosting this thread and imparting your wisdom-- thank you!

Ok, here's my story: I just bought a 93 LS400 from a mechanic. He had changed out the "original" ECU because he said he wasn't getting spark on one bank. The original ECU has rebuilt stickers on it dating 2013. Inside, I can see visible corrosion through some copper traces, and shotty work, so I think that one is toast (car won't start with it). The one he put in was from a wreck and has rebuilt stickers from 2011. This one seemed to run ok when I bought the car (not as much power as my 92 had), but then the car started doing some weird shifting after 2nd gear and just stalls. It will usually start once, but then the next time I accelerate and go through the gears, it dies and will not start. I've been able to start it by disconnecting and reconnecting the neg battery cable. This led me to believe it was ECU related, which led me to read this whole thread and replace the caps on this ECU. I used the recommended caps from post #1 and experienced no change-- same symptoms.

I'm at a loss as these symptoms seemed to be the caps. I am also having the erratic tach and speedo issue where they work sometimes and not others, as well as weird gas light behavior. I'm off to a pick-a-part to grab another ECU and see if it's good enough to recap, but would love to hear you guy's thoughts!

IBGREEZY

I replaced all my caps and I think I may have damaged the ECU, not sure. I need to know the areas involved for the ignition sequence, as my car is not starting. It starts fine every morning for 2 secs and then dies and doesn't restart. I am at the end of my rope here and hoping Yamae-san can please help resolve this nightmare. I have fuel and spark and no vacuum leaks so I'm suspecting an electrical issue or ECU. I don't want to hijack this thread, just would love a little more insight on the areas of the ECU responsible for the ignition sequence so I can verify if I installed all the caps accordingly.

Yamae

Thanks for the detailed report with a clear photo, CMDSlick. The moisture protector was sprayed to the board and it usually looks glossy. So, there was no leak at all.

As you did, it is smarter to change capacitors before the leak starts. The leaked liquid is a very strong alkali and it damages traces, nearby parts and the board itself. The invaded liquid to the layers of the board cannot be removed easily. They say, "It's no use crying over spilt milk and victory goes to the one who makes the first move". Smart guys change capacitors before the leak starts. This also let them notice that the car has bigger power than before.

Yamae

I worry about the board was already damaged as you wrote above. As I wrote in the post #925, the leaked liquid damages not only the traces, but also the board itself invading inside of layers. I suggest you to find some used ECU on ebay or somewhere and to use it after replacing original capacitors to the recommended ones.

Yamae

It is hard for me to tell without seeing your ECU but the symptom "It starts fine every morning for 2 secs and then dies and doesn't restart" sounds like the result of the safety shut down function.

I have 3 questions to ask you.
Did you check every trace around capacitors carefully with an ohm meter?
Did you check nearby parts not be damaged by the liquid?
Is there any point where the liquid is invading to the internal layers?

t2d2

iTrader: (8)

Is there any way to tell if internal layers have been leaked into? My ECU required repairing of some traces. The tech was fairly confident in that portion of his work but said it would be very difficult to determine if any damage was done between layers, let alone fix it.

With the 15-25 year age of these cars, and 10-12 year shelf life of the original capacitors, the odds don't seem good of finding replacement ECUs that don't have some leakage themselves. In my case, the leakage wasn't even visible until removing a couple of the capacitors.

Yamae

The way I check is to insert 2 sharp metal pins to the board and measure the resistance. Of course the surface of the board should be well cleaned prior to the measurement.

Depending on the depth and the distance of each pin, reading value varies or ∞, but if there exists any resistance, it simply means that the liquid is already inside and you can't expect a lot.

t2d2

iTrader: (8)

Thanks. I'll pass that along to the guy who did my repair work and see if he tried that method.