oldskewel

Thanks for stating this. A failed ECU temp sensor will pop a code, and they are easily tested. Specs are provided to ensure that they are within range, but mostly when they fail, they fail completely and the engine goes into limp home mode. As well, the fuel trims are established by the O2 sensors, so even if the sensor went out of range before failure, the O2's would maintain the fuel-air ratio. Consequently the idea that changing the sensor as one would do for a spark plug is a good idea makes no sense to me. If it ain't broke, don't fix it. To directly answer the testing question, yes there is a way. A pdf from the shop manual is listed halfway down the following page: http://www.clublexus.com/forums/ls400-foru...-read-this.html Not sure what year that is from, but it is on a different page from my '91 manual. But the thermistor plot is the same. You basically take the thing out and measure resistance as you vary temperature across a range from freezing to boiling. Resistance should stay within a specified tolerance throughout the range. They show a picture with it in a pan of heated water as an example of how to do the test. SRK sure knows what he's talking about, but it could be that there is an out-of-spec failure that would change the resistance, but not enough to fail completely. He has a good point that complete failure (e.g., open circuit) may be more likely than a significantly increased resistance. I don't know enough about these particular sensors to be sure. However, to do the test, you basically have to take the thing out, and by that time, you almost may as well put a new one in. My plan - buy a new one, replace it, then test the old one as a science experiment with my kids. If good, I'll keep it as a spare.

I noticed a pin-hole in one of my steering boots on my '91 once. The pin-hole was on the bottom side, allowing a small amount of PS fluid to drip out, which is why I noticed it. Realizing it would require a split boot (if they exist), I decided to just rotate the boot so the pinhole was on top. I had to loosen the clamps to do this. I cleaned the boot and put some tape on there, but am not counting on it to hold. This stopped the leak, and I don't think it's worth replacing the boot on my car. May be the same for you, depending on how bad the rip is.

You are correct. It's a..... Brake Traction Accumulator Assembly http://www.toyodiy.com/parts/p_U_1991_LEXU...GKA_4708.5.html Note that this is only for cars with traction control. My '91 does not have it, even though it has ABS.

If it were my car, I'd replace the part. This was actually the last repair done on my car before I bought it. I've seen a few theories regarding the purpose of this valve. Referring to the 1991 LS400 manual, page SR-92, this valve is referred to as the "Idle-up Device": ========================= "IDLE-UP DEVICE" "The pump produces the maximum fluid pressure when the steering wheel is turned fully to the right or left and, at this time, there is a maximum load on the pump which causes a decrease in engine idle rpm. To solve this problem, vehicles are equipped with an idle-up device which acts to raise the engine idle rpm whenever there is a heavy load on the pump. "On EFI engines, when the piston of the air control valve is pushed by fluid pressure, the air valve opens and the volume of air by-passing the throttle valve is increased to regulate engine rpm. "The idle-up device functions to raise engine idle rpm when pump fluid pressure acts on the air control valve, installed to the pump body, to control the flow of air." ========================= So it looks like the principal difference you'd get by replacing the part vs. plugging it is that you'd get the rpms boosted when needed. This would give your PS more power when parking, etc., but even if you don't mind the extra arm-strength required, it also may prevent the engine from stalling. I recall seeing a thread about someone who had some other weird problem (engine-PS related) that went away when this valve was replaced. Also, by the time you've done all the work to get the bad valve out, you may as well put this relatively cheap part in.

If you notice white smoke coming out the tailpipes on startup, it could be a problem with an air valve on the PS pump. Check out my posts in this thread: http://us.lexusownersclub.com/forums/index...rt=#entry359221

I started using synthetic 5W30 in my 91 LS400 after ~160k miles of non-synthetic (what the previous owner used). No problems after about 1.5 years and 5k miles. Is there a reason you go with the 10W30 instead of the 5W30?

Hi Glenmore, thanks for your excellent post a year or so ago on the engine mount replacement. It saved me a lot of time and made a hard job go smoothly. I wish more of the posts on this forum were as useful and well informed as that one. As far as I can tell, the Mobil 3309 is not just equivalent to the Type T-4, it is IDENTICAL to it. As in Mobil makes it and Toyota labels it at Toyota Type T-4 ATF. If you can't find the 3309, it doesn't really help though. Regarding buying a case of Type T-4 at Carson, it may not work. I tried to buy a case at Park Place Lexus (with free shipping due to the order being > $100) and was denied - they don't ship cases of ATF. I wish they would make it clearer on the website, but I guess some people order the parts and pick it up. I ended up calling around to the local Lexus and Toyota dealer, and got a case for a little less than $5/qt, after walking in to the Toyota dealer and asking for a discount for buying a case. So there's my tip/advice, hope it helps. It's only saving about $40 over full price, but it's always nice to pay less than full price for the best part.

I agree strongly with the importance of this maintenance procedure. There's a post on here somewhere with photos + everything. What I did to make removal easier (instead of using a big wrench [would need to be like 2"]) was to first mark the "nut" (not really a nut but a hexagonal flange) vs. the solenoid body with a line - sharpie or scratching with a screwdriver. This way, when you put it back you tighten until the marks line up. Then, instead of using a wrench, I used a flat head screwdriver on the "nut" and tapped it with a hammer to begin unscrewing it. It can then be done by hand. On my car (1991, with 160k miles, and I'm sure I was the first to do this job) it came with one medium size tap. All of this is done after removing the wires. I jack up the left front of the car for better clearance. You may also want to remove the left front wheel for an even better angle on the work. Not a bad idea if doing it the first time.

I've read a few things here and there about making a shield to prevent PS fluid from leaking onto the alternator. I'd be interested in making one of these for my 91 LS400. Can someone who's done this please post some instructions? Thanks

If it's the PS air valve, then, no I don't think anything they could have done in replacing the starter could have harmed it. EGR is a different story ...

If it IS white smoke at startup then the good news is it is a relatively easy fix. Bad news is that it needs to be done ASAP (may be too late) to avoid ruining your alternator. I am NOT suggesting that it is a PS pump failure (although of course it could be). Just this little valve (that seems to go by many confusing names using some combination of these words: power steering air idle control valve. Not to be confused with the "idle air control valve," which is completely different.). Your "Power Steering Pressure Valve", PN 17630-16040 (what my 91 needed) is probably bad. I see one is for sale by a club member at http://us.lexusownersclub.com/forums/index...showtopic=55790 (looks like a good deal to me) The valve leaks, allowing PS fluid to flow into the vacuum lines passing through the valve. It collects there, and then on startup, it all gets sucked in to the engine and burned, producing the white smoke. The part costs <$100, but workarounds exist if you want to block it off instead. If you don't replace it soon, leaking fluid will cause the alternator, right below it, to fail. Symptoms: losing PS fluid; puff of white smoke on startup; PS leaks observed under PS pump. You may have an EGR problem as well, but this PS valve problem is very common, and if the symptoms fit, you probably have it. Some other relevant posts: http://us.lexusownersclub.com/forums/index...?showtopic=6583 http://us.lexusownersclub.com/forums/index...showtopic=41440 http://us.lexusownersclub.com/forums/index...showtopic=34005 http://us.lexusownersclub.com/forums/index...showtopic=10364 http://us.lexusownersclub.com/forums/index...?showtopic=2836 And here's the KEY to reducing PS problems - find and clean the filter/screen in the PS rack solenoid: http://us.lexusownersclub.com/forums/index...showtopic=12024 As I recall when I did that, there are some posts you'll find where it sounds like people had tons of problems getting the solenoid removed. For me, it was a very easy job, so hopefully you're not unlucky. After doing it, the PS felt noticeably lighter+smoother. By removing the blockage there, upstream pressure (causing leaks and other pressure-related failures) was reduced, and downstream pressure was increased, improving steering power.

White clouds of smoke on startup (then going away) is a symptom of the infamous valve failure on the PS pump. Maybe the fluid loss is not detectable yet, but will be? Agree that blue smoke usually indicates burning oil. I agree on the pain of the 4-character minimum on searching. To get around this slightly, you can try searching for things like "EGR tube" or "EGR system" (use the double-quotes when you type in the search box), which shows this thread: http://us.lexusownersclub.com/forums/index...gr+system\

You'll want 2 distributor caps and 2 rotors. There was an interesting thread recently about whether it made sense to touch the cam seals. As I recall, there were very informed people on both sides. You may be able to skip on the gas cap seal replacement until it starts leaking. Not as if it will be any harder to change later. Since it seems you're trying to hit everything you can (like I did too when I got my '91), you probably want to flush the PS fluid. My 91 takes DEXRON III for that. On the 91 there's a key filter in the rack solenoid, near the left wheel that needs to be cleaned. Not sure if your 95 has the same issue. Like many others, you may find yourself obsessing over getting the smoothest ride possible. One easy step in that direction is to replace the transmission mount (may be called a rear motor mount?). Another big, but harder step is to replace the 2 engine mounts. I did all 3 at once, and it really made the car feel like new. I've got a few of the parts you might need, listed on http://us.lexusownersclub.com/forums/index...showtopic=53436 (I overbought when giving the car an overhaul after buying it) Good luck.

ATF and differential oil changes are easy and unrelated to all the other stuff. If you're not sure when they were last done, you should do them. A lesson I learned on the first car I ever bought was to not take any fluid changes for granted (when I bought it, the manual transmission was bone dry, as I found out 4 months later when I finally wore down all the teeth on the input gear). Led to a good story though ... I completed my ~200 mile trip using only 4th gear (which was still there since it did not use the lay shaft at all). No reverse or anything.

Here's an easy thing to try that may fix the window fogging problem: run with the AC turned off and the heat set on max for as long as you can stand it. My 1991 LS used to have that problem as well as a weird smell. Running on full heat seems to have burned all the extra moisture out of there. No tools required. Good luck.

I agree. Nothing special about these screws. Just get ones that match the size, from your favorite hardware store. Metric of course. As I recall, they are countersunk. Their main purpose appears to be alignment (that's what the countersink does). The lug nuts provide all the mechanical force - these screws just hold the rotor in place until the lug nuts are torqued down.

I had the same problem as #3 on my 91 LS400. Might have been from rain as well though. Had been a problem for a long time until I fixed it. I don't recall exactly how I removed the parking light (driver side), but here's what I do remember: - I took the battery out, thinking it would give better access, etc., but it did not really help. - the light kind of came out at an angle. There's like one screw, and then it is snapped in at the other end. - I pried it and it popped out. I think it's pretty tough, and you should not be afraid to pry on it. Regarding the water collection, I looked at the light. It has a vent, so it is already exposed to air going in and out. But the vent was high up, allowing water to collect. My solution, was to drill a hole at the lowest corner of the light (on the black plastic inside, of course), allowing water to drain. Solved the water collection problem perfectly, and since the light was already exposed to air, I don't think I caused any extra problems by drilling the hole. I couldn't figure out why the light was getting wet in the first place, but this solved it. No problems on the passenger side. good luck

I think the confusion here is in what "the distributor" means. The "cap & rotor" is not the "entire assembly." The actual distributor may really cost a ton of $$, and may last forever (on my first car, I replaced everything on the whole car except the starter and distributor!). The distributor cap and rotor are definitely wear items that should be replaced periodically (60k mile intervals for the LS?). They should cost ~$60 for the set (2 caps, 2 rotors). Ignition wires should last longer (between 60k and infinity), maybe 90k or 120k or whenever a problem is detected.

Might it be possible for the dealer to look up the VIN and at least see any service that was done by Lexus dealers? My '91 had a T-belt job at around 90k, but they did not replace the water pump. Done at a Lexus dealer, previous owner generally had them do everything they thought should be done. The water pump then failed at 122k, resulting in another T-belt. So, if you can verify a T-belt change, but no water pump, keep an eye on it and be prepared.

One piece of info I can add is that in 1991 the sunroof came in a package with the leather seats. The original owners of my '91 did not want a sunroof (good choice), and to get that they had to get cloth seats. They did an immediate aftermarket leather setup, which has held up very well and looks great. So if you're looking for cloth seats, look for a car without a sunroof and hope they did not do an aftermarket leather install. My car is a dark green metallic color (I forget the exact name), that basically looks black except in bright sunlight. It has a gray interior.

Cool find there about the Mobil ATF 3309. That link seems to say that Mobil made this product to the specs of the AT manufacturer, Aisin AW Co. Ltd., (which makes the AT for Lexus, Toyota, ... http://www.aisin-aw.co.jp/en/index.html ). This makes a lot of sense, as I think it's clear to most that having the "right" ATF is important. I guess Toyota then renames it Type-IV (right? are they identical?) and puts a Toyota part number on the AT as well. If Type-IV = Mobil ATF 3309, can the Mobil be found for any cheaper? I've got 11 quarts of Type-IV sitting in my garage, so I won't need to know any time soon. This Mobil product does then seem different than that Valvoline MaxLife stuff - the Mobil was developed specifically for these AT's, whereas the Valvoline aims for compatibility across a wide range, including these. Right? Or am I doing a little too much reading between the lines. Agreed about the dangers of misinformed general mechanics.

Maybe you could try to rig a tube/hose that bypasses the heater valve completely - as a test? I agree with others that say it sounds like the heater valve is not opening like it should. This test should determine in a very simple way whether that's true or not. If true, next step would be to figure out whether it is a bad valve, bad cable, bad control signal, bad sensor ... that is causing it not to open. (and until you figure that out, you could just leave the bypass hose in there if you can stand the heat) Looking at the service records on my 91 LS400, the heater control valve was replaced at 96k miles due to leaking.

As far as I know, the IACV is the Idle Air Control Valve, which is an actuator, not a sensor. I have not had any problems with the IACV on my '91 LS400, but I have successfully fixed IACV problems on other cars (Honda, Mercedes) just by removing the valve and cleaning it out with brake cleaner and Q-tips. It usually just gets clogged up and needs to be cleaned. Good luck.

I've noticed some smell from the HVAC system. Also, some residue on the windshield. No wetness in the passenger footwell. Looking on the forum here, I concluded that there is a problem with drainage from the evaporator drain tube. Short term, easy fix, which worked great at eliminating the smell was to "burn out" the bad stuff by running the heater on full blast for as long as I could take it. But I'd like to fix the drain problem. I gathered notes from the forums (repeated below, with some questions) and yesterday checked the end of the drain tube with the AC running. No water came out, but there was a slight but steady flow of air coming out of it. The tube I think is the drain tube is black, about 3/8" ID, with some bends in it. I removed the kick panel by the passenger footwell, and could not see anything I could do there. I have a compressor (that I use every chance I get, and then some) so if something needs to be blown out, I'm ready. Any suggestions? I'd like to fix the drain issue, figuring the smell (which is gone for now after the "burn out") will take care of itself. ---- "It's the HVAC condensate drain pipe most likely; it gets full of nast and then the water backs up and won't drain properly; I've heard of this problem happening on other toyotas. Usually I just run the CC system with the AC off for the last 5 minutes of my drive and the problem hasn't recurred; but if you want to dig around on this forum you'll find instructions for finding the pipe (it's on the firewall on the passenger side I think) and how to clean it." I found the pipe, but not how to unclog it. ---- "Take some Orange Blast, Simply Green or Lysol and spray into the vents directly under your wiper blades. Run the AC on high and re-apply the procedure a few more times. Every now an then you might need to do it again. It's caused by mildew." I did this with Simple Green, since it seemed easy and harmless. To be clear, the vents I put it in were in the interior, right along the bottom of the windshield, making sure air was going in there, not out (like it does depending on the HVAC settings). ---- "96030 Kool-It Evaporator and Heater Foam Cleaner - The stuff foams. You put it into the ducting upstream from the evap core and run the fan, it foams and cleans the core, and exits through the condensate drain. The instructions are pretty comprehensive." Not sure what "upstream" location I should use? Same as I did with the Simple Green? ---- "it's probably condensate from the evaporator thats draining onto the floor on the passenger side. Check the drain tube thats on the firewall under the passenger side and make sure it's not crimped, etc that would prevent the condensate from dripping out onto the ground. Run the a/c and look under the car on the passenger side and see if you have water dripping out the drain tube, if not, it's probably clogged up somehow." "The drain tube connects to the evaporator housing and directs the collected water that condenses on the evaporator core through the firewall to drip on the ground . You can see the drain tube if you get under the car near the firewall on the passenger side and you should have water dripping out of the tube with the a/c running. If you're not seeing any water dripping on the ground, the drain tube is either disconnected or clogged up and in either case the condensed water will drip onto your passenger side carpeting instead of on the ground." I had no water coming out of the tube and no water on the passenger side carpeting.

[last updated 8/21/11 (dropped prices) - will continue to update as parts are sold] Recently updated to expand compatibility listings, drop prices on idler bearings. These parts were for my 1991 LS400, but most will fit many LS400s, SC400s, LS430s, SC430s, etc.. I've listed my best info on the years + models they fit, but can only guarantee the part number - please check for yourself if it is what you need. These will probably fit for other years as well. I've used http://www.toyodiy.com to check compatibility - you can check for your car there as well. All are brand new. They are boxed, wrapped, or sealed if they came that way, etc. Located in the SF bay area. Prefer local pickup if that works for you. I'm a person trying to sell off some stuff I overbought, not a business. I don't think you'll find lower prices elsewhere, but if you do, I'll beat it. You can PM or email me at <my lexusownersclub username>@yahoo.com for more info, offers, etc. Already sold: T-belt, water pump, ignition wires, cam and crank seals, tensioner, spark plugs, spark plug tube seals, 2 caps and rotors (1 of each left), front and rear brake pads. Part number, price, item, brand, model year(s) ========================================================================= 13503-0F010, $28, "idler pulley, timing belt, #2, left; was 13503-50011, 13503-50010", Koyo (OEM), "90-00 LS400, 92-00 SC400, 01-0? LS430, ??" 13505-50022, $45, "idler pulley, timing belt, #1, right; also 13505-50011, 13505-50021", GMB (SNK is OEM), "90-97 LS400, 92-00 SC400" 80480-76026-71, $2, PCV valve grommet; was 90480-18001 and 90430-20004, Beck Arnley 90210-07001, $8 for 16, Valve Cover Washer, Stone, "90-00 LS400, 92-00 SC400, 01-0? LS430"