shoob

no, i know when this was fixed back in january when the previous owner had the car.....but, its all fixed now, and it still hasnt cured the problem......

crcuevas

Are you still having the same problem? My does sort the same problem. i replaced the knock sensors and when I put everything back together the car idles fine but stalls after pressing the gas pedal around 1100 rpm. can it be the TPS?

cmedavid85

wow im glad im not the only one having the exact same issues as you. i have a 95 sc300 that has done everything to date that yours has and im still working on it and trying to figure it out. my problems started almost a year ago with just intermittent cels/trac off lights w/o any kind of stall or hesitation. this eventually progressed though to cels/trac off lights with stalls and minor hesitations. my car would have week long periods of time where it would run absolutely perfect and then start a day or two of intermittent cels and stalls. the cels would eventually work themselves out and return to normal for another period of flawless operation. the problems kept getting progressivly worse though as time went on and i would start having bizarr electrical issues like tail light out warning lights coming off and on, brake light flashing on whenever i made a left turn, occasionally my telescopic steering wheel would not work but if i restarded the car it work just fine, the stalling problems kept getting worse and i was getting horrible gas mileage, i could tell it was running rich, then last week, all of the sudden my rear speakers stopped working. the speakers cut back on briefly one more time and then went back off again. right after the speaker issue my car died pulling into my driveway and i have not been able to get it back to drivable condition since. i have replaced every single thing that you have replaced except the ECU. my sc has 110,000 miles on it and has always been very well maintained. i have installed an aftermarket stereo which was a very easy install on that car and i connected the stereo via wire harnesses. the stock amp is not being used and has been disconnected since i installed the stereo. i have searched high and low for ground problems, vacumn leaks, fuses, harnesses, etc... the only thing i have not done is remove the stereo to check for any kind of short there. also, every now and then when i try to start it, i just get a click sound and nothing turns over at all. i still have all accessory power though. i then rapidly turn key off and back to start several times and it finally cranks up but dies immediately unless i have my foot on the gas. if i kept it running that way it spits and sputters and will not go past 2k rpm. when doing this though, it is blowing crazy amounts of smoke out the tail pipes and the smell of raw gas fills the air. i nearly passed out from the fumes. i have not been able to pull any codes since im not familliar with that trick you used to pull them. its OBD 1 also. i did take it to a lexus dealership several months ago to get it diagnosed and all they came up with was the MAF or AFM which i replaced myself with a brand new one. it made no difference at the time. sorry so long but i figure these small details are important. i have read hundreds of treads with the same problems but nobody ever post when they solve the problem. its like i have been going down dead end streets all day. i will make sure once i solve this beast, i will make it known.

PedroD400

Man my car has been doing the same thing as well. My cel and trac off light comes on after the vehicle reaches a certain temp and I put a heavy acceleration load. The codes that my car throws at me is my knock sensor. Man I hope you find your problems.

SC400slide

iTrader: (11)

Yes. it can be the TPS.

SkulCracka

ok so you did all this work............... fixed some bad caps in two different ecu's??? i do see where you said you checked the traces. but i do not see where you said you cleaned the traces of the goo the caps spill all over the board.

so if you have not done this. pelase do and tell us if it made a difference. rubbing alcohol and a q-tip works great for this.

shoob

ok, update.

went to the u pull yard today, well....2 of them. first yard was the more popular yard, every LS400 was stripped of its ecus, and most frequently worn parts (seat memory module, lcd a/c panel, fuel pump control module etc.) no tps's, afm's, IACV's, or any of the likes of the sensors were chasing after.

so i go to the second yard as theyre driving in an exact 94 LS400 just like mine....SCORE!!!! i got to examine the car, running, revving, etc. no CEL, just the usual bad trans.

so i snag the ECU, TPS, AFM, ABS/TRAC module, working cluster, and a few other items......basically rapped the car while it was still warm, lol. (no necro pun intended)

get home, throw in the ecu, my original ecu was an 89661-50141. ive read that the 50142, such as i had purchased was the better of the ecu's, and had most of the previous issues resolved, and also was less prone to failure.

on warm up of first start, car was amazing!! no issues, free revving to redline, bouncing off the rev limiter, no smoke, not rich, awesome!! problem solved!!

well.....

after 3 or 4 shut offs and start ups, the car still behaved well. so i go to run "the loop" we call it, (i reside on a semi-circle, off of a state highway.) car accelerated perfectly! hit second gear, 3000 rpms, and pop, pop, pop, it starts choking.....CEL, and TRAC OFF light, but only when the problem occured.

lights went off, i dropped to 25% throttle, and the car drove fine.

pull codes!!! yay!! an ecu that will give me codes. 41 and 47, which i did play with a bit when previously trouble shooting. adjusted per specs, cleared code, restart.....same issue. im finding that its cutting at exactly 3000 rpms.

continuity tested all wires between the trac TPS, and main TPS, both back to the ECU. all good. 5 volts on all 3 wires for the AFM coming from the ecu to the AFM. same with the TPS's. 5 volts where it should be and everything ohming out in spec.

replaced the trac/abs module, no difference, again, jumper fp and b+ in the diag connector to double check for proper fuel pressure, not it........

so i broke out an injector node and timing light to see whats getting pulled at 3k rpm. the injectors are going offline at over 50% throttle.

25% throttle, i can take it to redline, go to over 50% throttle and it falls on its face. reset everything, unplug battery, its fine. so this tells me the ecu is seeing something on the engine its not liking, and its pulling the fuel when it sees it and reporting it as a TPS issue, yet ive already been over that a few times.

shoob

so, basically 41 is the only code im getting now.

SC400slide

iTrader: (11)

Sounds like you fixed it. Awesome! Long haul but all was worth it...right?

SkulCracka

well much closer then you were. so this is good. you fidled so much though hmmmmmmmmmmmm your not gona like what i recomend. LOL check those caps in the ecu.

SkulCracka

there is also idle air controller which can cause weirdness too. dont remember you mentionine it. but here is a good link to all possble things it seems. https://www.clublexus.com/forums/per...on-issues.html

cmedavid85

it is so frustrating when you think you have found the problem and it starts up again! keep at it and as for me i ordered a used ecu off of ebay for my sc300 and it should be here friday or saturday. im nervous about it being used but there is a 60 day return policy on it so only risking the cost of shipping. i will update as soon as i get the other ecu in. i checked my old ecu today and i didnt see any bad caps but there were some other things on it that looked bad and i can tell that the person who had it before me must have had the ecu rebuilt. good luck on your LS and update us when you figure out the new issue.

shoob

...................?

no.

lol, great minds think alike. i just got done going through the 142. replaced 5 caps, 3 of which the same locations as the 141 previous ecu, 2 in other locations. i picked up a stock pile of 16v 220mf, 10v 100mf, 35v 15uf, and 50v 10uf capacitors, taicon of course, no more nichicon.

also im noticing a pattern....:

C103, C104 C105, and C106 are all on the same circuit and were busted in both ecu's.

C103- 50v 10uf
C104- 50v 10mf
C105- 10v 100mf
C106- 16v 220mf
C831- 35v 15mf

but with my previous luck with replacing caps, to no better effect, and finding that the data parameters on the microchip itself is corrupted:


in all honesty, whats keeping me from running a 50202? i know its obd2, i also know that it also has the same pin configuration as my current ecu......'s.

i mean, i might have to change a few wires right? put the FP on a relay off of my IGN signal....... essentially, whats so different in the 95 obd2 cars? im researching for myself right now, but i was just taking a shot in the dark.

shoob

simply because of this.....

the ecu i have available came out of a car built in december of 1994 (meaning, being built after september 94, its released as a 95')

obd2 compliance wasnt afirmly mandated till 96" most early 95's were "partially" obd2. meaning, that you didnt quite get all the SAE info parameters as the 96+ cars. so in all reality, it should work, especially with it having the same plug configuration. now will it require a "flash"?

SkulCracka

this time make sure you clean the board after the install of those new caps. look for the cola looking stains. q-tip and rubbing alch. it mine remove some of the green layer but the traces will be fine. hopefully you got 105c caps so they last. sure you know same mf,higher volts is ok.

also double check that tps plug. someone else resently had a similar problem and the hole time it was intermitant conection at the plug itself to the tps.