1991LS400

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About 1991LS400

  • Rank
    Advanced Club Member
  • Birthday 04/10/1982

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    JunctionP713

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  • Gender
    Male
  • Lexus Model
    91 LS 400
  1. Have you gone through this? -> http://www.lexls.com/tutorials/EFI/tps.html It is especially interesting to note what the author says within this tutorial..."My first test drive the sensor was set too low and it caused very jumpy highway performance." I've read through that and attempted to follow it but I'm not sure whether I'm supposed to be doing the TPS adjustment when the car is on and in PARK or on and in DRIVE or NEUTRAL. Because in PARK, my car is idling at 1,300 RPM and in DRIVE or NEUTRAL it's idling at around 800 RPM.
  2. Yes, TB was cleaned when it had to be removed to replace the starter. I'm thinking it has something to do with the TPS, like steve2006 said. Just not sure how to go about checking it.
  3. Yes, it does the same when in park/neutral. How do you diagnose a "flat spot" on the TPS? Don't crucify me for this but my TPS was purchased new from AutoZone a few months ago. I wouldn't think such a small part like that would make much difference from OEM, right? Maybe I didn't adjust it correctly as I'm not sure how to go about doing it.
  4. Car: 91 LS 400 Problem: When stepping on the gas pedal (accelerating), the engine speed/RPM's drop whenever I hit 3k RPM's and then "kicks" itself back into gear before attempting to reach over 3k RPM's during acceleration. If I let go of the gas pedal and then try to accelerate again, as soon as RPM's hit 3k, it drops again and then "kicks" itself back into gear (or regular speed) while accelerating. Basically, the car "pulls back" on me for a second at 3k RPM's every time when accelerating and then lunges forward as if it's regaining it's normal speed/RPM's. Before I keep on rambling, does anyone have any ideas on what could be causing this? I hope I made my symptoms clear. Thanks in advance.
  5. That's all fine and dandy. But please, does anyone have any manuals showing how to get to and remove the alternator? I just want assumptions on what the case may be. If the battery is dead, I'll buy a new one. If the alternator is dead, I'll buy a new one. But I'd rather only have to change one thing at a time. And obviously, between a battery and an alternator, we all know it will take more time to switch out an alternator.
  6. Hey guys, here's yet another technical question... The other day, what I THOUGHT to be a starter problem ends up being either a battery and/or an alternator problem. A friend of mine charged up my battery with some cables and after about a minute or two my car turned on with NO problem. I drove it around for a few minutes and then parked it again. The next day, I came out to turn on my car and it was dead again. Same repeated clicking when I turn the key all the way. I can tell the interior lights were dimmer than the day before when my friend charged my battery up. My battery is only 2-3 years old, at the most. I am NOT running anything in my car that would be taking excessive amounts of juice from my battery. I'm not sure how old my alternator is, it's the same alternator that was in the car back when I bought it in 2003-2004. For all I know, the alternator COULD be as old as the car itself (about 17 years). For you experts, do the signs seem to be saying it's an alternator problem or a battery problem? If it's the alternator, would anyone here happen to have any type of manuals or instructions on the easiest way to go about getting to and removing the alternator? I don't think it's as hard as a starter, but I heard you have to go from under the car to get the alternator out, is this 100% the only way? Thanks in advance for any help! =)
  7. man, you guys are all awesome. Yeah, I got time to do this. A friend of mine is helping me so I say if we go at it we should be able to get it done within 2 days, 3 TOPS (working at a reasonable pace that is). I've stripped NEARLY the entire front end of my engine off just to change the damn fan bracket that busted on me a year ago. That was tedious, especially having to work on my back to get the fan bracket out and put the new one in. I expect this starter job to be just as tedious, if not less tedious than the fan bracket change. Maybe it'll be a bit harder but hopefully not by much. So basically, the starter is UNDERNEATH the intake manifold (the silver middle part of the engine with the 'L'exus logo on it, right?) and sitting in between the two valve covers?
  8. what about the WHOLE project makes it most difficult?
  9. Thanks for the help guys. This is gonna be hell...or maybe it won't be.
  10. Does anyone have a diagram or know of a website that shows how to change the starter in a 1991 LS 400? Maybe someone can just write a good walkthrough for me on here. Thanks guys!
  11. SKperformance and CUMan, thank you both for all of your help! unfortunately, I figured it out myself this morning before reading both of your guys' posts but yes, you guys were right, that skinny wire with the white plastic clip was the source of the problem and was the reason why the fan wouldn't turn faster when the A/C was on and the car was idling. too bad I wasted $130 on the coolant temp sensor and the coolant temp switch. Oh well, I already replaced those two things, anyways, the old ones looked like they were going to crack in half anyway. so I guess those two things are out of the way now.
  12. but the mechanic here at the shop said he would change the hydraulic motor on the fan because that's "most likely" the problem. he said nothing about that solenoid on the power steering pump. how would I know if the hydraulic pump on the fan is bad or if it's the solenoid by the power steering pump? I also noticed a skinny wiring harness that has a small white plastic clip unconnected near the back of the engine, passenger side, right by the firewall that was disconnected. I couldn't see where it would have originally been connected to. I have no idea if that unconnected wiring has anything to do with the overheating (if, as you say, it's not the actual hydraulic motor on the radiator fan).
  13. UPDATE: - changed both the coolant temperature sensor and the coolant temperature switch - no coolant leakage from the water pump/thermostat area - ONLY starts overheating when car is idle with A/C on for 5 minutes or more, does NOT overheat while car is driving (even with A/C on or off) diagnosis? hydraulic fan problem?
  14. Overheating problem. This morning while driving for 30 min, with the A/C on, I noticed that at one point in my trip I was idling in traffic for a while when I noticed my temp gauge going up to red drastically. Then the engine started smoking from the coolant reservoir side. I opened the hood to find the coolant ABOVE the full line and bubbling hot. It was so hot, the rubber cap had popped off and coolant was bubbling out of the coolant reservoir (overflow tank). Immediately afterwards, a check engine light came on. I read it with the OBDII and it stated the following: P0115 Engine Coolant Temp Circuit Malfunction Is this a CTS (coolant temperature sensor) problem? The radiator has been changed and has no leaks so that's not the culprit. I was thinking it was either a bad water pump and/or thermostat but I didn't notice any coolant coming out of that area this morning, however, I do want to change the water pump and thermostat soon. But for right now, I need to find out a quick fix to this overheating problem. The engine only overheats when the A/C is on too. I also noticed the fan wasn't spinning as fast as I think it should be. So should I change the sensor first to see if it fixes the problem? Also, does the 1996 ES 300 have a coolant temperature sensor and a coolant temperature circuit or is it both the same thing? Because each auto store I've gone to to try and find a CTS it isn't the right one and is significantly smaller than the one I pulled off that was located by one of the radiator hoses on the right side of the engine (standing in front of it). Somebody knowledgeable in this area, please help. Much thanks in advance.