metalman

Sounds good, I'm liking what I keep hearing on this result. Now that I got my charging issue solved........Ended up getting a NEW alternator again. Let me rephrase that, a new rebuilt one. FACT, the other one did not come with a new voltage regulator....no-way, it was all pitted with age. I mentioned this to Rock Auto, and the new one has a brand new regulator in it. I think I should feel relieved now. Next is the wheel bearing, some new rims and get this computer upgraded. I love this car, but would like opinions, I might sell it in the future to try more Lexus cars out. Preferably the GS400or GS430. I love the V8's and don't want anything else. That's why I just bought a Tundra. (my Nissan truck club might not like me anymore)

TaffyK20si

Do you have to follow exact voltage? If I'm ordering 100uF-35v and you have listed 100uF-10v. Or 220uF-50v and the list says 220uF-16v.
Thanks.

LScowboyLS

higher voltage on the replacements is fine, but don't get too crazy.

the lists I provided (as opposed to the links) are the capacitors that came on the car stock

why not just use the links I have provided in post #1, I have listed all of the capacitors that will work, that are of this very rare type, and the sources I have linked to are about the only place to find them that are not counterfeit!

if you deviate from the exact capacitors and sources I link to, I cannot have confidence that the repair will work, these capacitors are not available locally, or on amazon, ebay, or at radio shack, etc.

TaffyK20si

Cool thanks! Yeah I was following the links provided.

qha_vn

I replaced all recommeded caps. works great. just wondering how to lift up fuel gauge needle. I filled full needle reaches just a little above 3rd bar.

I inspected the gauge, there are couple of caps there too. should I replace them? specs?

LScowboyLS

yes, search on here, there are quite a lot of caps to replace on the instrument cluster, and a couple of them are surface-mount - which means they are about half the size of a grain of rice!

TNice94

Alright the caps I ordered came in. I'm pretty confident the car will run great. here's some pics of the ecu from phone.No caps leaking from what I can see.

LScowboyLS

please practice on some old computer motherboards with some standard capacitors from radio shack or wherever, before diving into this project unless you are a seasoned old pro at soldering and capacitor removal and hole making - this is not for the faint of heart and is not for someone new to soldering delicate electronics

practice, practice, practice - before screwing around with your expensive ECU!

also, to do it right, you will need a narrow tip for your soldering gun, as the soldering on the top side connections is very tight!

I personally leave out the 10uF that sits below the 220uF on the first set of soldering, otherwise you have boxed yourself in and cannot get to the 220uF's top side leads as the 10uF and other components blocks it completely!

TNice94

Great tip.. I feel like there so much helpful tips on this forum.. Someone from work will be doing the rebuild and Ive takin pics and drew a diagram incase. I CANT WAIT TO GET HERE ON THE ROAD. Oh and Ive noticed a lot of folks from FL on here and the pics of there ecu look bad. The moisture. Mine looks new and its clean inside out. I'm from cali and the car has been Garage kept most of its life...

TNice94

Happy to say car is running great . Had buddy at work solder it. Was a little nervous though. We'll see if clearly all problems fixed once I go on long distance trip and drive for a week or 2. Drove it for 25 min around neighborhood then freeway. Car ran pretty strong prior so not sure the responce is better. but I'll get here out agian and keep updating.I can also take some photos of old caps that now look like they just started to poop..I could not see this before as you can see in pics taken earlier.

TNice94

Good news car ran great for a long distance drive 2 1/2 round trip. Very responsive, Like a sports car . were as before it ran strong like a luxury sedan. Now Cowboy or Yamae I have a question after reading through again some of your tips in thread. Were we suppose to solder both sides of board , cuz my coworker only worked from the backside. And when looking on front side at CAPS. The solder didn't come all the way through?

Yamae

Your coworker should had soldered that those legs of the capacitors not to be seen at the mounted side. I mean that the bottom side of the capacitor should be attaching to the board surface and you couldn't see those legs at all. So you'd have no idea to solder there.

When capacitors are away from the board, there will two problems. One is the mechanical stress to legs when the car is running a rough road and the other is the increased impedance caused by long legs.

One of the reasons why the ECU causes poor engine running is the increased internal impedance of capacitors and it fails to reduce ripples and the noise enough at the Vcc line for processors and sensors. Those unwanted ripples and noise are sent to sensors and also the processors cause malfunctions resulting the poor engine running.

Longer legs cause the additional external impedance and those would be better as shorter as possible. In your case, capacitors are very new and the internal impedance is quite low and some additional impedance can be disregarded judging from your current good engine running. But when capacitors are aged in the future, you might be noticing the difference.

TNice94

Ok cool thanks. I was surprised on how low He got to the board so I believe I'm ok. we are all really blessed seriously for all of the information and hard work you guys do and for sharing it!.

Yamae

You are mostly welcomed, TNice94. My intention is just let those nice cars to be lived longer. It's not a hard work for me. The hard worker is him LScowboyLS who documented well investigating the availability of capacitors in the USA as well as preparing drawings and others. I only have informed him the basics.

One of the most serious problems on these cars is the ECU problem which can't be diagnosed and fixed inexpensively by most mechanics. The new ECU costs more than $2000 and also many of used ones from junkyards are not in a good condition.

As a guy who knows the ECU and electronics controlled circuits some, it is just my pleasure to aid those people who are not happy with their ECUs and fix it by himself / herself. It is just sad to give up keeping the car only because of the failed ECU which is mostly caused by aged capacitors.

Now there comes a happy guy like you next to next and it also means that his / her LS400 is saved and can be lived more. I must say thanks to you reviving it.

LScowboyLS

OK, everyone gather around, because this will be a very rare sight - me disagreeing with Yamae, because I agree with him on technical things about 99.9999% of the time, however on this lead length issue, Nippon Denso has the electrolytic capacitors up off of the board approximately 3mm or so, on every model of LS400 ECU and every electrolytic cap within those ECU's except for the single exception of the large 330uf Matsushi-ta cap on the 98-00 models, which is flush mounted. You can see that in the "before" pics above.

and as my tests have proved, when resoldering one of these boards, it is nearly impossible to get a nice solder joint on the top side of the board when soldering only from the back, and with the caps all the way down on the board, you have no way to know if the top joints are soldered nice once you have the new cap soldered in.

you need a very narrow long tip for your soldering station to go back on the top side with some flux and solder and touch up the leads under those caps, it has to be super long and lean in order to not touch something with your hot iron that you shouldn't, you "snake" it in there!- if you flush-mount them Yamae's way, all the way down, you have no way of knowing if the top side joints are good after the new caps are soldered in, and you also have not done it the way that the Nippon Denso robots did it from the factory.

and 3mm is not going to make an appreciable difference in ESR, and even if it did, the caps we are installing today are already considerably lower ESR than the original Nichicon PF(M) caps

otherwise, keep listening to Yamae, he is still the deepest technical expert on the LS400 we know of, and he has over 100 U.S. patents, which is frankly just mind-blowing!