gtolds

Gawd!! ... I love it when he talks "dirty" like that!!! I think I may have a solution. It was so simple, I can't believe I didn't think about it earlier... I'll just go buy a 2009 G8 GXP 6 speed in obnoxious blue, order the LS3 to LS9 turbo/intercooler kit and install a stonger clutch. That package should not only idle about right, it'll have about 650 hp too!

Well, if I ever have any questions about electrons..... I'll know where to start!! Heck, all this time I thought he was "plumber". Of course, I have learned my lesson about avitars..... you just can't tell! Threadcutter Rocks!! Outstanding replys everyone - especially the one that discussed pulling wings off of flys : ) In talking me back from the ledge of foolishness, you have accomplished two things: 1) you talked me out of melting a perfectly good ecu 2) you shamed me into measuring the input voltage for the sending unit - it was 5 volts Thanks again and I guess I'll just live with what seems to me to be a high cold idle Now I'm back to not having any problems with my car so I have nothing to do all weekend. Maybe I'll go hang out with my wife or something... yawn.

Both my old and the new temp sending unit I bought read the same resistance per temp so we know the temp sending unit is good. I'll slice in a 2 ohm, 2 watt resister this morning and let everyone know if it worked. If not, I'm out a dollar for the resister ...and a little pride.

What will the ECU "see" in ohms after the engine is at normal operating temperature - coming from the CTSU? Great question. The answer is as follows: On my 1996 LS400, the temp sending unit has the following resistance given the following temperatures (the brain sees these numbers) 4 ohms resistance at 43 degrees 3.8 at 47 2.75 at 61 1.83 at 81 1.37 at 98 1.05 at 110 .88 at 120 .57 at 145 .45 at 160 .30 at 195 My issue is that I need to know how much power the brain sends to this temp sending unit because if I put a 2 ohm, 1/2 watt resister inline and the signal is stronger than a 1/2 watt, the resister will just blow. I'm just looking to right size my resister. By the way, the whole idea is to trick the car into thinking it is warmer than it is so that the idle will drop from 1500 to 1600 down to a more reasonable 1100 or so during cold start. I've heard the cause for the excessive high idle is anything from a dirty/bad idle air control valve to motor mounts but no one can tell me for sure. My IAC works just fine other than cold start so how can it's failure indication be too much air? I can see no reason why a motor mount would cause a high idle either so I'm down to what I think I know and that's the temp sending unit. Anyway, maybe I'm whacked but I think the resister idea is worth the time to try and there's no downside (can't do any harm). Thanks all and if you can come up with another explanation, reason, I'm all ears.

X2 on this. Ask them to show you that in writing. If there isn't an official statement from Lexus on their vehicles' draining a battery in a week, the dealer is lying. The RX400h manual specifically addresses our vehicles draining during several weeks of non-use, but we are a different animal than the average Lexus. I have heard that some cars have a problem with the seat belt not retracting and that somehow drains the battery. Don't know much more about it but I thought it was interesting... Maybe a longshot but add it to your list of things to check. GL

This one will stump all but the most seasoned mechanics. I need to know the output wattage from the ECU to the coolant temperature sending unit so I can jump the wires with a resister (I'm installing a 2 ohm resister to limit idle speed for cold start but I need to know if my 2 watt, 2 ohm resister is good enough). Best of luck with this one!

amc; Yeah, sure......some will say that replacing the motor mounts does wonders to solve this. I haven't done it, but I 've read enough other posts to take stock in it. E/U/B/T; When you say 650 RPM, you mean while in gear, with brake on, right? Also, I've seen you make numerous comments about "cleaning" the IACV. I've only ever replaced them. Have you been successful with cleaning them and if so, how much longer did they operate before finally packing it in? Thx, The problem with the high idle is that it drives itself to about 40 mph when cold and you have to be on the brakes just to do 25 in town for a full 5 minutes which is way too long. No other car I have ever owned idles this high this long. It was a rolling hazard when it was snowing and icy. I'm going to throw a two ohm resister on the colant temp sender wires and see if it idles lower and let you all know what happens... wish me luck

The bottom of the temp guage has a fat white line and when the car is cold, the needle sits just below that fat white line. There are thin white lines above the bottom line and a fat white line at the top. When the car is warm, the needle points just a hair above the 2nd thin line above the bottom fat white line. The thing is that this guage gets its signal from the temp sending unit that sits right next to the temp sending unit for the ECU. I'm not aware of how the guage sending unit could affect idle speed but I'll cross my fingers that it can... Thanks for the help.

I have experience with two LS400 cars - a 1990 that ran perfect and a 1996 that idles too high when cold. I know that they are similar but they do have differences. I'm going to try to solve the 1996 problem and want your opinion before I touch anything. I know there are atleast three temp sending units: one for the ecu, one for the guage, and one for the radiator fan. I have measured the functionality of the sending unit for the ECU as follows: 4 ohms resistance at 43 degrees 3.8 at 47 2.75 at 61 1.83 at 81 1.37 at 98 1.05 at 110 .88 at 120 .57 at 145 .45 at 160 .30 at 195 I have only had the 1996 during this winter so the outside air temp has never been over 60 degrees. Even at 60 degrees however, the cold idle is still 1500 rpm - too high for me - I would rather have 1000 or 1100. How to get there s the question. Do I just jump the wires leading to my temp sender for the ecu with a 2 ohm or so resister? I don't even know if that would work. I'm a simple man. Do I have to go after my Idle air control valve? Do I have to do something else? I checked my TPS and it was tripping at just the right spot. The TRAC position sender was OK too - not that it has squat to do with the problem. Let me know what you think of jumping the temp sending wires with a 1.5 ohm resister to make the car think it is never colder than 88 degrees or so and thus idle lower. Thanks

02 ls 400 When a normal car's knock sensor detects engine knock, it retards timing. The question I have is if the ECU faults one of the two knock sensors (code 55 in my case), will the ECU not !Removed! the timing, default to the retarded timing or only !Removed! the timing if the knock happens on the remaining good sensor? Thanks and I know this is a hard question so thanks if anyone can figure this out.

Great, so they're not struts?

Has anyone got a trouble code 55, right side knock sensor? If so, how much did it cost to fix, did you do it yourself, was the wire harness the problem, was the sensor loose, etc. Thanks

I have a real bouncy 1992 non air bag LS 400. How difficult is it to replace the shocks (or are they struts?) and how much should it cost? Thanks