freegard

So I replaced all 8 caps with low ESR caps from digitec this morning. Replaced TPS a few days ago. What the hell do I do now? With the ECU throwing no codes, but it actually shutting everything down when the RPMs get above 2500 it seems like a wire is loose somewhere, but would that prevent the ECU from giving codes? Is the ECU still the problem, unrelated to bad caps? Or is it the wire harness at the trunk....which looks perfect by the way. what the heck do I do now?

Pull straight out starting at either end.

I use Mobil 1 synthetic oil.I have read from some people who think it creates oil leaks in the engine. I think that's absolutely rubbish. Synthetic oil does not break down as fast as conventional oils and is why it lasts thousands of miles longer--because it retains its viscocity.

Went to AAA auto wrecking in Auburn WA. armed with nothing more than a wide very large straight slot screwdriver. Removed a mirror from its assembly in 10 seconds, pulled the two wire heating connection off in 10 seconds. Paid twenty bucks for it and put it on my car there in the lot in two minutes and drove off. WOW!!! Next replace the heater core, this summer.... Now who's got those instructions? ha ha ha........... Guys in the wrecking yard laughed, shook their heads and said, "We don't do that, and we can destroy everything on the way to it." GREAT!

Hey, very impressive work. Off to the wrecking yard to get me a heated mirror; not one of those for 20.00 that do not have the heating element, are not convex and inferior; definitely not to Lexus to pay 136.00 plus tax. Nope, off to the wrecking yard to get me a new heated convex passenger side mirror. Very nice, yep, very nice. I love this site!!!

It is NOT the igntion coil because it would run VERY rough missing on a number of cylinders; You have an idle problem not a rough running engine problem, huge difference. The engine would barely run and stall if one coil were bad. It could be the Throttle Position Sensor or throttle body true. My bet is the ECU, especially if the car has lived its life in a hot climate. Heat causes the dialectric fluid to seep out ot the capacitors faster AND THEY LOSE THERE CAPACITY to moderate engine idle among other things. AND if it is true the ECU may throw a TPS code, however if after replacing your TPS the problem remains!! THEN ECU certainly!

I put my money on bad capacitors in the ECU. You are descibing exactly what was going on with my 94. I replaced the 8 capacitors myself in the ECU and that issue and other issues disappeared. One way to know if it is the ECU is to have someone read the codes. If the codes cannot be read or seem odd or incorrecvt it is certainly the ECU. The brain is malfunctioning and is not capable of diagnosis yet things are haywire.

Welcome, and it is one stunning automobile. Rated in the top five in the world when it hit the showrooms, and unlike many others it has retained that reputation despite some issues.... Power steering has a problem with a sensor that leaks and is connected to intake manifold. On start up white smoke (burning transmission fluid) billows out the exhaust. Transmission fluid because that is what the power steering pump requires (Dexron III); now Dexron VI has superseded Dexron III. Instrument cluster backlighting sometimes will fail as will other things all a result of failed electrolytic aluminum capacitors. In the late 80s and up to mid nineties the circuit board manufacturing industry worldwide used CFCs to clean circuit boards of the excess flux after the wave soldering process. Unfortunately the aluminum capacitors were harmed by this cleaning process; and so it is not only Lexus autos that have problems, any vehicle whose circuit boards underwent that cleaning have issues. A savvy engineer determined the cause of these failing caps and in the mid 90s they discontinued using chlorinated fluorocarbons (CFCs) to clean the circuit boards. I visited a good friend whose got a Masters in electonics from MIT in Vancouver yesterday who explained all this to me and brought up the bulliten for me to read on the internet while I was there. Anyway, those are my personal experiences with my 94 LS400 with 251K on it. ECU will make the car run in strange ways: It might hunt for idle; It may not allow hard acceleration without feeling like it runs out of fuel; If you turn the AC on the engine may die; 15MPG no matter how many things you replace on the engine; Does not give any codes but the check engine light is on; Again, it is due to failed capacitors in the ECU. The car is absolutely phenomenal. I have listed above EXTREMELY COMMON issues with this car. I use Mobil 1 synthetic in the motor. Engine takes about 4.5 quarts. YOU MUST USE ONLY T4 Toyota fluid in the transmission-no other type ONLY T4!! You can find it on Ebay for $6.50 a quart or at a Lexus dealer for $16.50 a quart; or at a Toyota dealer for $11.a quart. To completely flush trans you need 10 quarts. You will not find T4 trans fluid in any auto parts store anywhere. Since you do not know when your fluids were last changed; or whetehr they are correct change everything. The car deserves to be treated this way. Yes, 400K miles is no problem whatsoever. I paid $1,100 for that one there in the picture. The guy was an air force pilot and his father a software engineer gifted the car to him; it was billowing white smoke; the left macpherson strut was shot; the instrumewnt cluster backlighting only came on after the cabin warmed up to 70 Fahrenheit. (Capacitors). It was shimmying doe to warped rotors, all four speakers were rotted or blown (it has seven speakers; I am referring to the speakers in the door panels; the power steering pump was failing; the power steering rack was failing and the car would drift all over the road. HOWEVER!!! He had given it his all and spent 10K dollars just in the engine compartment: New starter, new alternator, wires, plugs, coils (two of them) catalytic converters, exhaust manifolds--in the previous 90 days before I bought it for 1100 bucks. Whereas he had mechanics do all that work; I fixed everything and spent about 800.00 to do that. And this site made it possible. Welcome to the club; it is very helpful. These guys have saved me about ten thousand bucks in the last few years. You have to learn to navigate the threads because nearly any question you may have has been answered probably over a decade ago with regard to your vehicle; it's likely the answer is here "somewhere." Some of the guys get a little surly if they do not see you trying to get the answer from previous threads; it gets tiresome repeating yourself you know.

NO! You are wrong! This circuit board IS copper etched on both sides and is soldered on both sides. Sure the wave soldering probably effectively wicks as you stated above, however, for our intentions and purposes (since we are not wave soldering) you must resolder both sides of SOME, NOT ALL, of the capacitors. Using a strong magnifying glass one can see where there is no copper and where there IS definitely copper connections on the cap side of the board and for that respective cap to connect to!!!! Yes, you are right, I did cut them off with cutters until only the leads were left, and still long enough to grab with needle nosed pliers. But it was still very difficult to pull the cut-off leads out; a result of the low powered soldering iron I used. But is is very misleading to indicate that the caps do not have to be soldered on both sides of the board when in fact they most definitely do. I went back and tested them with an ohm meter and sure enough even where I thought I had done a good job connecting to the copper etching ON THE CAP SIDE of the board, it in fact was still an open circuit on one particular cap. Scraping the laminate off to expose the copper hurts nothing; it is not game over. Even if you pull up some of the copper and rip it off the board it is still not game over. It is simply time to do some repair. To make that connection I had to scrape some laminate off to expose that copper and resolder and BINGO, continuity. But one better have a magnifying glass because there are also copper etchings a millimeter or two from the cap leads in a couple places where if you do not look close you may think that those connect to the cap lead when in fact they most definitely do not! Thank all of you for all the help and support; I greatly appreciate it.

FIXED...ABSOLUTELY EVERYTHING WORKS NOW. For the first time in two years I do not have a CHECK ENGINE light. Acceleration is akin to a detuned formula one car; and this car has 251K on it! No hunting for idle anymore. No engine failure at 2K on hard acceleration anymore. Absolutely everyhting is fine; I look for ward to twenty MPG now--yes I will be ecstatic with twenty nevermind 22 23 or 24. I am so grateful. All right my ECU is hanging by the connectors (while I test drove it) I gotta go do the tedius remainder of reinstallation. asta la vista Baby

Yep, no bout a doubt it. Sent of for 8 polarized electrolytics for my 94 LS400; just installed them last night; NO EASY JOB, you'd better be VERY good at unsoldering components. Putting the new caps in is easy, getting those old capacitors out is no fun. They are soldered on both sides of the circuit board. The circuit board has two wiring harnesses that are hard wired; so you MUST find a way to do all the work without stressing those wiring harnesses. Anyway, about the circuit board; the board is printed on both sides.... You must melt the solder on both sides before removing the caps. That is a total of 32 points that need to be resoldered. Of the 8 caps I replaced 5 of them were visibly damaged, i.e., had leaked. 1990 through 94 are KNOWN AND NOTORIOUS for this; the caps in the instrument cluster and the caps in the ECU, they SUCKED for some manufacturing reason. My symptoms were: Hunt for idle, car jerks when in gear, or has a mind of its own when in park or neutral; RPMs wander from 200 to 1100. Engine dies at exactly 2000RPM on hard acceleration, every time without exception. This is when I said, "Okay that's it; I am contacting Mouser or Digitec and getting those low ESR, PS series, polarized electrolytics and doing this. Total cost for all 8 was $1.23 cents, three day shipping was $12.00; it cost me 15 bucks to fix ECU issues. (Oh and about 5 hours to do it; because I am veeerrry sloooow and I dont care that I am slooow.) My wiring harness is fine and I think the ECU is as well. The capacitors: 1@! 16v 220uf 1@ 63v 47uf 2@ 50v 10uf 2 35v 15uf 2 10v 100uf All MUST BE 105 temp. rated. Fuel mileage is NEVER better than 15.5 MPG irregardless of how gently I drive. Check engine light is on but cannott get any codes. But a bad ECU can have many other symtoms too; they vary greatly depending on which capacitor is failing, how severely the capacitor is compromised and so on. ME! Hey, I did the instrument cluster a year ago, and those issues disappeared and have been putting up with these other issues since I bought the car two years ago. I KNOW the ECU is part of the problem; it may not solve ALL the problems but I have a hunch it is going to solve the mileage, and hunt for idle issues. And 5 to 6 more miles to the gallon; yeah that is worth 15 bucks and eight hours of my time. I hope I did not hurt any other component fighting with those capacirots to get them out. My ECU is 89661-50151 a California number. Though I am in Seattle the car spent 90% of its life in Sacramento. The ECU is sitting right here next to me. Tomorrow I am reinstalling the ECU. That is a little bit of a task too. I will let you know the result. By the look of those leaking capacitors I know only good things are in store, provided I did not damage any components while doing the work.

You asked for instructions on how to remove ECU; I am sorry no one told you how. I am also trying to find some instruction as opposed to a lecture off in another direction. And yes you can rebuild a circuit board. It might be merely replacing bad capacitors for example. That is reconditioned or rebuilt; semantics.

Looks like we have the same paint and car. (199 Alpine Silver) I am looking for an exterior driver door handle and where on earth can I get a new set of these rims we both have. None of the aftermarket rims compliment the car like these and having them rechromed is untenable for several reasons. I changed out all the ten suspect electrolytic polarized capicitors with mil spec 115 F. caps and instrument cluster works. Okay that was chit chat.... Reason I am posting this here: The car will not tolerate hard acceleration; it dies as if it is governed at 2000RPM; if I gradually accelerate it is smooth and runs great. It is a new thing that began after I filled up the tank. I do not know if bad gas can cause that. I do know my temp sensor has needed replacing but I also think I may remove the ECU and replace the few caps in there too. Might do it when I wake up in the morning. A great alphatronics electronics store nearby. I am apprehensive: I have been looking for a tutorial for removing the ECU from the 1994 LS400 but all I can find are vague instructions: Remove the panel under glove box (okay exactly how?) then pull back the carpet and remove the ECU. Those instructions don't inspire me. The car is not accelerating, this thread is marginally relative. I realise this however, I have spent an hour browsing for something germane but nothing I found precisely reflects the acceleration issue I am having and so here I am. I think it that it is definitely compounded by the ECU and the temp sensor. Since I can do the work on both and spend less than $35. doing it this is where I will start. Any helpful comments will sure be appreciated and explored.

Where is the Search feature for forums? I get on these forums and sometimes I just don't want to bother with it. Then you know I will find the search feature and wont be able to find what I am looking for, so I will just ask, and someone will come on to criticise and tell me to go to the thread because the answer is there. I am not a stupid guy but these forums sometimes make me wonder.