usoff89

iTrader: (2)

Thanks cowboy, I kinda figured thats what it was. Hopefully I'll get ahold of my buddy at work and have him solder the new caps in. I'm still considering doing it myself.

IF I try it myself, I'll practice on a old computer board or something first. A question though.... Do the original caps have it written on them as to which way the go in? I want to make sure the new ones go in the right way. How do you tell which side goes where?

LScowboyLS

there is a stripe on the negative (-) side of the cap, and also a minus sign on the board, and all caps on a board will face the same directions, in other words, all negative sides will be on, for example, the North and West sides of a board (or North and East)

however, if you had read my post #1 thoroughly in this ECU caps thread, you would have learned that you need to make a full diagram the cap locations and values and polarities before you remove anything and also take some cell phone pics in case you lose your way on re-assembly - you also use this diagram to check anyone else work!

Personally - I would say that the LS400 ECU is far too tricky of a job to "learn on" - pro solderers only on this one!

usoff89

iTrader: (2)

Before I or someone else do anything, I will be re-reading everything to make sure I cover all basis. Thank you for your concern. I've soldered before just never on a curcuit board. I'm pretty sure I can do it with some practice, but I do understand that there is a good chance that I could screw it up too. Thanks again for the help cowboy. If I do end up doing it myself I will take lots of pics, and maybe a video. If anything when I'm done, it will be very helpful to others or a "what NOT to do" type of thread!


I'm a youtube expert!

LScowboyLS

If you do it yourself, I suggest weeks of practice and the desoldering and hole making are some of the more challenging parts! - if you push the soldering pad out of it's hole, you are done for and it is time for another ECU from ebay to have another try on!

usoff89

iTrader: (2)

Thank you sir! Still not sure if I'll do yet. But like I said, I'm ok with the outcome either way. It will be that much better if I can do it myself and say that I fixed it myself.

LScowboyLS

the trickiest part is where there is electrolyte corrosive damage, then parts do not want to solder well, or desolder well, and making the holes is tough as well - this is where a ton of that Radio Shack (CAIG) rosin flux I specify the part number of, can really help!

steve2006

By swopping over the ECU from my running Celsior into the other one with misfiring/poor running issues I have confirmed the ECU is causing the problem.
C751(Now looks like C75 on 1st picture) ( located slightly to the right of C740 marking on second picture) was leaking badly and after removal I have cleaned the PCB as recommended.
However I have now come across another problem in that the positive connection to the capacitor is fairly obvious as I can follow the track but the negative connection appears to go nowhere either from the component side or the track side via the thru print.
After 38 years of electronic engineering this has got me stumped.
I have attached some pictures,hopefully detailed enough to see my point, the print side shows the cap as C75, I used a fibre pen to clean up the board.

LScowboyLS

just keep in mind two things:

● this is a multi-layer board (not just 2 sides)
● you had better not have removed any traces with your fiber pencil, none of them are optional!

where are your "before" pics you are supposed to have taken via my instructions in post #1 ?

I don't have a Celsior ECU available to compare, do you have the ECU part number?

steve2006

No not removed any tracks.
I will post the pre repair pictures with the green gunge.
ECU is a 89661-50170.

LScowboyLS

you don't have to post the before pics, just study them yourself, you have to carefully inspect every trace and insure it is not broken once you are done - sometimes the corrosion can break a trace

are you using the exact caps I linked to in post #1

PS - I would keep the finished lead length on the capacitor side of the board to 3mm or less - there are low-ESR capacitors - I only leave enough lead length to see under the cap to inspect the solder joint and no more!

KYLS400

1995 LS 400 - read thru this forum and tried a search, but found no mention.

I've had this problem occur for 6 months sporadically, but now has gotten much worse.

I'm having problems with my power windows. Seems as if Drivers window always works - up and down.
However, the remaining three will work for a short time after start up (up and down), but after the car has warmed up a bit ...10 minutes or so....the remaining three windows no longer function - DOWN or UP.

If I wait for the car to "cool" off....I can roll those windows back up again.

Is this related to the capacitor issue in the CPU???

Twista4004

I'm sure this is something that Cowboy will be glad to harp on...... It's honestly worth the effort to just do the ECU repair "and see". Your car will most likely benefit from it TREMENDOUSLY regardless of if it solves that specific issue.

WhoRok305

Just went through the whole thread. I have a '93 Ls that cuts out at half to full throttle. I definitely need to do this. Only issue I have is actually finding someone qualified enough to do the job properly since I am not experienced. Anyone in the Miami area knows of a place when I can take the ecu to?

usoff89

iTrader: (2)

Ok, my gramps and I got the caps in this morning. Took us about 3 1/2 hours from start to finish. The major part is getting the old ones out without doing any damage to the traces or board. We took our time, and got it done. Put it in the car, turned the ignition on for about a min or so. Then she fired right up. Sounded good too! Currently my radiator is busted, but I took it for a quick spin threw the neighborhood and it seems to be running so much better. Nice and smooth. I new it was fixed when I felt the tires spin with the afm/maf plugged in!

But like I said I just took it around the block. I'll have a new rad in it tomorrow and take her for a nice drive to see how she runs. Thanks cowboy! Also digikey did a great job at sending all the right caps, and in a timely manner!

Dutchy

Finally got the caps changed in my Celsior, not done by myself but by a pro. It took about 2 hours changing all 9 of them, we took our time to do it right. Looks like its factory done !

The ecu is still learning new settings, but the car is allready a lot more economic, and the transmission shifts smoother by the minute.

Thanks a lot for all this info on here. A big 10 for Yamae and Cowboy

Greets from Holland