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smithm92

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  • Lexus Model
    LS400

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  1. I would follow the lead of the underhood "steam" and presume that what you have is a coolant system leak. If enough coolant was lost perhaps this affected the water pump or sensors feeding the ECU. I would disconnect the battery in order to reset the ECU and then check for reported diagnostic codes. If you have white smoke coming from the exhaust, you may have a coolant leaking through the head gasket.
  2. I did the warm up test this morning and the LS dropped to the correct 600 rpm when it reached normal operating temperature. Based on this, it seems as though the idle speed control valve is operating correctly. So I'm left wondering why my LS maintains a high idle speed until two conditions are met: (1) normal operating temperature; and (2) zero mph. I verified yesterday that the high idle speed remains in effect if I enter the freeway before the car has met both of these conditions (even after the car has warmed up after a couple of miles at freeway speed). The tell tale sign is coming off the freeway, with a fully warmed engine, and still having high idle until after I've braked to a stop and am still for about 4-5 seconds. It sure acts like its another input to the ECM which in turn controls the idle speed control valve. Before I go on a wild goose chase, would others please confirm that their gen I LSs idle properly after running fully warmed-up (but not having had the 4-5 second stopped condition). Thanks in advance.
  3. VMF, Good idea. I'll try that and report what I find.
  4. glenmore, Thanks for the info on your similar warm-up characteristics. My LS400 actually delivers 20 mpg in city driving and about 27-28 on the highway. In the city I'm drive with a light foot and rarely use my AC. Do you have the same "floating" high idle until you come to a stop and then experience the idle drop to 600?
  5. Agreed, a vacuum leak could cause a higher idle, but in this case the motor does settle down to the correct 600 rpm idle. So, I don't think the problem is vacuum...
  6. I'd appreciate your thoughts on this one... When cold, my '90 LS400 (132K, dealer serviced all of its life by PO) will high idle at 1200-1400 in park. Once I shift into drive, the idle will drop to 1000-1100. All fine so far... After a couple of miles the motor will warm to normal operating temperature where I would expect the idle speed to drop to 600. What I am experiencing, though, is that when I brake the car to a stop the idle remains at 1000 for 4-5 seconds before falling to 600. Is this normal? Do other LS400s operate this way? I've found somewhat of a temporary side-step to the issue: when I brake the car to a stop, I shift into neutral. This momentarily raises the idle but then drops the idle to 600 in 2-3 seconds. It's as if the ECM must sense that the car is at 0 mph before dropping the idle to the normal 600 setting (or the ECM is overriding some errant sensor input to bring the idle speed down when it senses normal operating temperature and 0 mph). I've seen other topics on the Idle Speed Control valve and considered whether this might be the cause of what I'm experiencing, but what throws me is that the idle does eventually come down. A secondary symptom I'm experience, that I think may be related to the above, occurs when I jump on the freeway before the motor has warmed to normal operating temperature and can I brake the car to 0 mph in order to "set" the idle to 600. In this situation, the car seems to maintain a higher coast rpm (like 1400) rather than dropping to a more relaxed 1000 or less setting. When I'm slowing down on the freeway, this causes the transmission to downshift but then slightly accelerate as the higher rpms catch the lower gear. I have yet to check the EGR and PCV valves. Are these inputs to the ECM that could cause what I'm experiencing? Any other sensor inputs to control idle speed? Thanks again.
  7. ls99guy, Well, I had at the ps fluid again this weekend. I did finally manage to get the return hose off, just like you said, I kept at it and managed to push it off. The hose into the milk jug got a little squirely :whistles: . Steering feels better. I still have a little groan very first thing in the morning backing out of the driveway but nothing thereafter. So, I'll try in a couple of weeks going back underneath and cleaning the solenoid filter one more time to remove any clogging remaining with the prior dark fluid. The word "chisel" sounds scary. In this case one doesn't have to break anything. It just so happens that the solenoid filter tube is collared by what looks to be a 1" or so thin hex side nut. I'm sure whan the rack assembly is on the bench a deep socket could easily take it off, but it's when the rack is installed that just makes it unlikely to get any tool on the thin hex side nut. First, make a note the original hex side positions since you can use this as a gauge when you reinstall and tighten. Next, I used a 1/8" nail punch and hit one of the hex nut sides until the unit loosened. Thereafter it was easily to unscrew the filter by hand. Be ready to catch a little less than a pint of ATF as it comes off. After rethreading by hand to finger-tight, I used the same nail punch to tap it firmly in place to about the original position.
  8. mbp, From what I gathered, the procedure is (at least for Gen I LS): 1. Disconnect the return line coming back to PS fluid resevoir. 2. Disconnect the hose plug resevoir in line. 3. Connect the return line hose via clear tubing to an external container/jug. 4. Open the ps fluid resevoir and be ready to add new fluid when someone starts the motor for you. 5. Start the motor. This will turn the pump and begin expelling old fluid through the return hose out to your container/jug. At this same time you'll need to add ps fluid to keep the level mostly constant. 6. Add fluid/run the motor until the expelled fluid runs clean. 7. Stop the motor. Reconnect the return hose to the resevoir in line. 8. Run motor and make sure PS fluid is at the right level in the resevoir. Then, with wheels lifted off the ground, run the steering wheel back and forth a couple of time to bleed air out of the lines.
  9. Thanks for the pointers. I was able to use a set of pliers to rotate the hose, just couldn't get any rear motion. I needed a break from the morning solenoid removal and didn't have the fresh patience to keep at it. I'll try it again this weekend. When I did remove the filter I found it pretty clogged. I felt lighter steering immediately after I had the clean solenoid reinstalled and (some) new fluid poured in. But I cringed since, knowing the dirty condition of the existing fluid, the filter will shortly clog again. Ah, well, the solenoid removal/cleaning will certainly go faster the second time. My PS pump had been replaced about 35K ago (car has 130K) but the rack was not replaced and I suspect the solenoid filter was not cleaned. The fluid in the system is dark/dirty. The pump has been making a slight groan once after starting. After reading the posts here and looking at the state of the fluid, I thought it was likely the filter. I hope after flushing the system and cleaning that filter one more time, I'll have both lighter steering and no noise.
  10. Just had an epipany and realized that I could cut off the first inch or so of the hose if necessary. Sometimes it just takes time to realize the obvious. <_<
  11. I removed and cleaned the rack solenoid filter only to realize that I should have flushed the system fluid first (learn from my mistake ). Another gotcha for those that try this is to remove the two-wire mating connector from the rack bracket by squeezing the back of the connector flare that mounts into the bracket. Once this is removed disconnect the mating connectors by lifting a latching tounge and a side flare between the two. Now you can unscrew the solenoid without stressing or breaking the wires. Anyway, so I went to flush the system fluid by removing the return hose and hit a ridiculous wall. I can't remove the return hose from the resevoir body. I pinched and moved the collar spring back a good inch, but the limited space combined the return hose wrap doesn't allow room for a good tug. What is the secret to removing it?
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