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I ordered all but 10 µF 50 V capacitor all 3 listed are either Discontinued or back ordered does anyone where I can purchase a couple . Or does anyone have a few they can spare ?
I ordered all but 10 µF 50 V capacitor all 3 listed are either Discontinued or back ordered does anyone where I can purchase a couple . Or does anyone have a few they can spare ?
89661-50251 was recapped, triple-checked, all seemed okay but still no comm via OBD though it's powered. Tried 89661-50341 too, still no comm. Fuses were checked and good.
Using 50251, engine starts easily, idling normally, and revved up fast. However, upon driving and kicked down, CEL lights up and suddenly back to stumbling.
89661-50251 was recapped, triple-checked, all seemed okay but still no comm via OBD though it's powered. Tried 89661-50341 too, still no comm. Fuses were checked and good.
Using 50251, engine starts easily, idling normally, and revved up fast. However, upon driving and kicked down, CEL lights up and suddenly back to stumbling.
I'm puzzled.
It is natural that you can't read codes using an American standard OBD-II scanner. You need to know that LS400 only for North American models after 95 are OBD-II compatible as is explained here. Other market models are implemented a different system and it uses the communication protocol Toyota K line bus system. American standard OBD-II scanner is not OK for other market models of LS400. You need to use a scanner which is OK with Toyota K line such as this below.
It is natural that you can't read codes using an American standard OBD-II scanner. You need to know that LS400 only for North American models after 95 are OBD-II compatible as is explained here. Other market models are implemented a different system and it uses the communication protocol Toyota K line bus system. American standard OBD-II scanner is not OK for other market models of LS400. You need to use a scanner which is OK with Toyota K line such as this below.
My 93 SC300’s tach just started reading low, kept getting lower & lower, reads around 1100 rpm @ 75 mph. Would the diodes cause this type of failure?
Yes, capacitors…….thanks
Last edited by Dave2spd; 11-27-23 at 06:09 AM.
Reason: Correct info
My 93 SC300’s tach just started reading low, kept getting lower & lower, reads around 1100 rpm @ 75 mph. Would the diodes cause this type of failure?
diodes?
Are you meaning electrolytic capacitors?
Regarding QAS capacitors, following models are affected but tachometers are mainly affected by the failing cluster board.
● Lexus LS400 - 1990-2000 (in 1997 and earlier models, the problem is extremely common)
● Lexus SC300 - 1993-2000
● Lexus SC400 - 1992-2000
● Lexus GS300 - 1993-1996
● Toyota Celica GT - 1985 -1998
● Toyota Supra Mark III (JDM) - 1986-1993
● Toyota Supra GT - 1995-1997
● Toyota Supra Mark IV - 1993-2002
● Toyota Supra Twin Turbo - 1993-2002
● Toyota MR2 - 1990-1999
● Toyota Camry - 1987-2001
● Toyota Soarer - 1992-2000
● Toyota Aristo - 1993-1996
● Toyota Celsior - 1990-2000
It appears the 10uf caps recommended back in 2012 are obsolete/discontinued. I did find one of them at digi key but there was a minimum order of 3000. I used the rubycon 50ZL10MEFC5X7. it appeared to be comparable to the capacitors on the 10uf list to me but this is not my area of expertise. Anyway, I used them and recommended caps on the ECU in my 93 ls400 that I bought barely running. The cap replacement has it running and driving great except it idles high and there is momentary hesitation upon revving it if it hasn't been revved in the last 15 seconds or so. Cold or warm it's between 1250 and 1700, doesn't surge, tends to start lower and slowly make to it 1500 and after you rev it it tends to settle in the higher end of that range. I have checked ect sensor(at 195°f signal wire has .39vdc sensor resistance is 280ish ohms) tps signal looks good .38vdc closed. Idle signal is 0vdc (should be under 3) battery voltage is 13.6. cranking signal is 0vdc once running like it should be. Ac signal is battery+ when off, and 0 with ac running(seems like it would be the other way but that's apparently supposed to be that way) I did check IAT I can't remember exactly what it was but it looked good. The power steering valve was leaking it's blocked off now. It had it idling closer to 2k. I can't find any vacuum leaks. Throttle plate shuts tighter than a lot of modern engines The ISCV does move. With the ISCV tube off, engine running(idles close to 1k like this) I can see the valve is maybe 2 mm from being closed. When the engine is shut off it opens up wide, jiggles and stops. Another note if I have it in gear, rear defroster on, and putting pressure on the power steering all to get the rpms down to 900 or so and then turn on the AC, the rpms will dip to 850ish for just a moment then go 950ish. Turn ac off and it goes up to 1k then back to 900 so ac idle up function apparently works. I'm convinced it's in the ECU, either damage from the leaky caps, me or my choice of 10uf caps. Or a ISCV that has only 90%range of motion. There's not supposed to be a plastic seat in the ISCV that could that could have broke off leaving a bigger gap is there? One last note when I very first started it after the cap job it idled rough and low for a couple seconds then saved itself by idling super high. I was able to recreate that once by unhooking battery overnight. The previous owner probably had 87 octane in it. I poured a little berryman's chemtool in the tank, ran it out and put 5 gallons of premium in it. I read just today that Yamea put his stamp of approval on the 50ZLH10MEFC5X11 I think around March of this year. They are currently out of stock at digikey and they don't show up on mouser. The 50ZL10MEFC5X7 that I used is currently available but is already set to be discontinued. I see a lot of guys on here in the last few years are looking for guidance on the 10uf cap. Sorry for the long read I was preemptively trying to answer questions that I expected to be asked. I have put at least 10 hours of testing and pondering into the idle isse to try and avoid bugging you guys. I appreciate anyone who's read this far.
10-18-23, 04:05 PM
Where to source capacitors
