LS - 1st and 2nd Gen (1990-2000) Discussion topics related to the 1990 - 2000 Lexus LS400

Finally got around to replacing the Coolant Temp Sensor

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Old 08-15-11, 01:25 PM
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sethjon
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Originally Posted by BrettJacks
Well, some of you remember my thread a month or two ago about the coolant temp sensor and the difficulty reaching it. I finally went at it again today(been busy as hell and unmotivated to work on this thing in the heat), and managed to get that damn coil out of the way and change the sensor. The dang plastic connectors on that coil were old and stuck on there, but I got it. It sure seems to have better throttle response now. I'm going to have to try and keep my foot out of the pedal and see if I can get better than 12-14 mpg around town. I also pulled plug # 4 and inspected it. I had read that they go well beyond the 90,000 mile interval without problem. I'm at 116,000 currently, and they did look like they could use replacement. Maybe in the coming week I'll go buy some plugs and do it. I wanted to do it on the spot while I had it torn down, but the only 2 part stores in our town were closed.
I'm still on the fence about whether or not to shell out the extra $$$ and get a set of wires for it. I like to be sure that everything is good, but I also really hate spending $$$ that i'm not sure I have to spend. Maybe I'll do plugs first and see how it runs.


Also, to learn from my mistake, have a bucket or something under the car when you change the sensor to catch all the antifreeze that runs out. For some reason I didn't have the foresight to do that......
The CT Sensor is on the top of the engine. Why would you need a bucket? It unscrews and you replace without leaking anything.
Old 08-15-11, 02:55 PM
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FrankReynoldsCPA
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I had let the car set for probably an hour, but the engine was still fairly warm(hot in some spots). My guess is there was still a little pressure from the heat.

Update: I topped it off today. It used 4.228 gallons over 51.1 miles, giving me only 12.08 miles to the gallon. It...got...worse......

Maybe i'll change the spark plugs after all. The gap did look might big on them. I'm going to wait though to see if I have to pay a $750 fine this week for accidentally selling smokes to a minor at work(Punishable in Utah for a first offense as a Class C Misdemeanor, up to $750 fines and 90 days jail time).
Old 08-15-11, 03:31 PM
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forget to ID or did he have a good fake?
Old 08-15-11, 03:36 PM
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Immo
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I changed mine about 2,5 weeks ago and when stepping on the gas every chance I get and 90% city-traffic I seem to be getting 281 miles before the fuel light lights up which will let me get about 17 galllons of fuel.
Looks like I'm getting about 16.4 MPG which would make me quite happy.
I also replaced the spark plugs for some new NGK iridiums, see if that helps more.

Did you reset the ecu as that already helped me a bit even without changing the CTS.
Good luck, hope you get some better mileage soon
Old 08-15-11, 03:57 PM
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Originally Posted by PureDrifter
forget to ID or did he have a good fake?
I don't ID my regulars, and she could have passed for a twin sister of one of my regulars.....
Old 08-15-11, 03:58 PM
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Originally Posted by Immo
I changed mine about 2,5 weeks ago and when stepping on the gas every chance I get and 90% city-traffic I seem to be getting 281 miles before the fuel light lights up which will let me get about 17 galllons of fuel.
Looks like I'm getting about 16.4 MPG which would make me quite happy.
I also replaced the spark plugs for some new NGK iridiums, see if that helps more.

Did you reset the ecu as that already helped me a bit even without changing the CTS.
Good luck, hope you get some better mileage soon
I did disconnect the negative cable on the battery for a few minutes while I cleaned up my tools.

Edit: Also, I have asked my mother to start tracking her around town mileage with her 91 LS400. We just took that car on a 2600 mile trip into Idaho, Montana, and Wyoming, with some mountain ranges, and everytime we filled up we were getting an average of 26-28 mpg. I **** you not, we hit 32 mpg between Loa, Utah and Brigham City. In mine the highest I have seen is 24 mpg, and that was giving it hell through the mountains, and going between 90-100 on the freeway after the mountains. I usually average 23 on pure highway conditions, going 80-90 on the freeway. It doesn't seem to go up much by slowing down to 65.
Old 08-15-11, 05:21 PM
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Originally Posted by BrettJacks
I don't ID my regulars, and she could have passed for a twin sister of one of my regulars.....
Nah, it's probably just b/c it's SHE.
See that would **** me off, just doing your job and you get screwed that bad for making a little mistake like that. I couldn't work for someone that holds ya responsible for accidents like that. I worked with a guy, (construction) this one time we were just getting done with lunch and he threw his cigarette out and we went inside. 5 minutes later we heard an explosion, the cigarette landed in the truck, blew that up, which ended up burning the house down. Pretty expensive insurance settlement, but no consequences.
That MPG dosen't sound right at all, it should not have dropped that much. I've heard sometimes it drops but not that bad. There's deffinately something else wrong. Are you sure you put the connector back in? Jk.
Old 08-15-11, 06:18 PM
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It's not my employer though that's holding me responsible. The State holds both the employee AND employer responsible. The licensee(store selling tobacco) also receives a $300 fine if an employee sells tobacco to a minor. That fee becomes $1000 for a second offense within 12 months of the first IIRC. Third offense is an even higher fine and revocation of license to sell tobacco.

So no matter what the local PD does to me, the State will fine my employer. He does of course have the option to fire me. I think he would have, but I had already given my 2 week notice almost 2 weeks ago. My last day is on Thursday. I'm moving over to St. George for school which starts next monday. Of course, plans may change if i'm in jail, or if I pay a $750 fine and don't have any money left in my bank account to buy food or pay utilities....

Back to the car,
I'm going to run a few more tanks through to see if I get better mileage. I also only filled up after using 4 gallons, so I don't think 50 miles/4 gallons is a long enough test. Especially since you have to account for vapor and what not on fill up. The space occupied by vapor instead of fuel the previous fill up would be more visible if you only put a couple gallons in. IE, starting off 1 gallon low and filling up after only using 3 is going to make that 1 gallon low seem a lot bigger than if you fill up after 15 gallons, as far as averaging goes.

Last edited by FrankReynoldsCPA; 08-15-11 at 06:25 PM.
Old 08-16-11, 08:55 AM
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Yeah, I see what you're saying about the amount of fuel. I was about to mention that, it should be long term use. (couple tanks)
Good luck with the other thing, it's a screwed up situation. I highly doubt that you'll see the inside of a jail cell for that, believe me, they have much worse cases then yours. But, a cell is not the place ya want to be. I lost everything in the past b/c of my time. You might get a small fine if you can BS people and talk your way out of it. Hope it works out for ya, and have fun at school.
Old 08-16-11, 10:02 AM
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Thanks for the well wishes. I am hoping it will turn out well. I know a lot of people around here, we're in a very rural community. I know a few of the police officers(i even BS with some of them inside the gas station). I also know one of the judges here and I'm sure he knows that i'm not a trouble causer. THis is the first time i've ever blipped on law enforcement radar. Most people knew me growing up as the nice little mormon kid who is respectful and polite to older people. They also know i'm not like most of the trash in my peer group who had absolutely no aspirations in their life and have just stuck around this town getting high and bouncing from minimum wage job to minimum wage job, and who have regular encounters with the police. They know i'm leaving for college and haven't touched any alcohol, drugs, or ever committed any crimes.

Hopefully I'll be able to get some mercy from the judge when he hears that I'm not even going to be a cashier anymore(and consequently not in a position to repeat this mistake) and that I have productive plans that begin next week. Even if I could just get a small fine(no more than a couple hundred $$$ hopefully). Probation is a possibility, would rather not(I own firearms, and have a concealed weapons permit coming in the mail as we speak).

WHat's killing me now is the suspense. It's been a day so far and no contact yet from the police. It's not like they're the LAPD with a lot of stuff on their plate. We even have a high officer:citizen ratio. I don't know when or if they'll contact me. Hopefully whoever got the call from the state agent knew me and brushed it off......
Old 08-29-11, 08:52 AM
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Well, after a couple of weeks, I think the gains have been marginal. I filled up about a week ago on my way over, and IIRC it was about 18 mpg, mostly in town, with about 20 highway miles. I filled up later that night after doing about 85 miles(maybe 20 in heavy city traffic, the rest on the open highway). Got about 21 mpg with that fillup. I haven't filled up since, but i'm at 55 miles and the needle is setting slightly below the 3/4 tank mark. I don't really trust the gauge's accuracy though. I may fill it up later to see how it's doing.
Old 08-29-11, 09:21 AM
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The gauges aren't completely accurate from the full down to the half mark, they all jump around. Try going a full tank and then fill up (if you can afford that) and see what ya get for MPG. But it sounds like it was well worth the price of the ECT.
Old 08-29-11, 12:24 PM
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I guess if I can afford to keep filling the tank every week at a 1/4 tank, I can afford to let it go empty and fill it. I mean, the consumption doesn't change..........
Old 09-07-11, 07:22 AM
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Check in: Filled up this morning after 159.4 miles. The needle was below 1/2, it was nearing 1/4. It took 13.36 gallons of fuel, giving me 11.9 mpg. This is all city driving(some of it very aggressive though, i'm going to tone it back this tank). It rained the other day so I spent an hour or so playing with my traction control system, basically doing my own little Top Gear, lol. Definitely not good for fuel consumption.
Old 09-07-11, 07:57 AM
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There's definitely something else that's holding your mileage down, maybe it's your right foot. It was all city driving so it's really not too bad, for a 92. So, did your traction control work correctly? I always have mine off, even in the snow. Personally, I think it's useless. I drive by using the gas and brake peddles to steer the car anyway. That's the way a car should be driven.


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