DIY Coolant Temperature Sensor change (PICS)
05-31-13, 04:18 PM
#167
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Changed mine yesterday with a MasterPro one from Oreilly's. I have noticed a better throttle response since changing it. However I did have a problem. After I finished installing it and put everything back together, I pulled the ECU fuse and disconnected the battery terminal for over 30 mins. When I turned on the car I noticed only the front ac button light was flashing and the CEL was on. There was also some weird odor that I wanna say smelled like coolant. I turned the car off immediately and pulled the fuse again. This time there was no CEL and everything was working back to normal. I walked around the car while it was idling and saw some smoke coming out the exhaust. Not much but still and I could lightly smell fuel as if the car was running rich. I took the car out for a drive around the block a couple times and didn't notice anything wrong and when I got back there wasn't any smoke either. Has anyone had this problem or know what happened?
Back to the ECU fuse, I have a 1997 LS400 and in the fuse box it calls for a 15A fuse for the ECU but mine had a 20. Is there a big difference in the two? Im planning on putting back the 15A fuse. Could this be why I the car wasn't running right? I never had any problems like that in the past even with the 20 fuse.
Back to the ECU fuse, I have a 1997 LS400 and in the fuse box it calls for a 15A fuse for the ECU but mine had a 20. Is there a big difference in the two? Im planning on putting back the 15A fuse. Could this be why I the car wasn't running right? I never had any problems like that in the past even with the 20 fuse.
08-03-13, 01:33 PM
#169
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I'd like to point out here that the temperature *SENDER* and the temperature *SENSOR* are not the same item. If you go to Autozone and they give you the "Sender", that's the dashboard temperature sensor. I made that mistake but it's a cheap part and needed replaced anyways so I just dropped the new one in. Needed a 10mm socket, didn't have to use a deep well but it probably would have helped. I'm waiting to get my "sensor" later this afternoon, and hopefully I'll get some more power out of this thing. I've been getting under 16 mpg for the last two years, and that's with 90% highway driving. If this fixes it, I'm probably going to end up dancing or some other nonsense.
1994 LS400
212K miles
MPG update to come later. The pictures helped immensely, by the way, I would have had no idea which was the correct sensor without them.
1994 LS400
212K miles
MPG update to come later. The pictures helped immensely, by the way, I would have had no idea which was the correct sensor without them.
08-03-13, 03:20 PM
#170
Lexus Champion
we can get to the bottom of your lack of power and gas mileage, at 16 mpg, something is seriously wrong!
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Louie7 (10-14-19)
08-04-13, 11:10 AM
#171
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This is actually the same symptoms described in the .. I guess "parent" thread to this one that the OP referred to in the beginning. roughly 16 mpg. That being said, this car is going on 20 years old, so I'm almost definitely going to be replacing the O2 sensors and pretty much everything else I can get my hands on over the next few months. I've already gotta get CV axles, lower control arm bushings, etc etc etc... car repairs never stop, yeah?
On that note, I think I'll actually go ahead and buy the OEM sensor. Once I've finished with a few of the other repairs, I'll actually do a one-month trial run of each and see if there's any significant difference. I know people are arguing OEM vs AutoZone a lot in here, I might as well just test them both. Can't hurt, and the sensor's not that expensive anyways.
As far as results go so far, the sensor's been installed less than 24 hours, but I've already noticed a marked increase in available power going past 3K RPM, and the same above about 70 MPH. However my 0-60 is still down in the range of 11 seconds (which is kind of crappy, even if I have very little experience with that kind of driving), so there's likely to be a few more things that need fixed that I just don't know about yet.
08-04-13, 04:33 PM
#172
Lexus Champion
As far as results go so far, the sensor's been installed less than 24 hours, but I've already noticed a marked increase in available power going past 3K RPM, and the same above about 70 MPH. However my 0-60 is still down in the range of 11 seconds (which is kind of crappy, even if I have very little experience with that kind of driving), so there's likely to be a few more things that need fixed that I just don't know about yet.
08-18-13, 02:01 PM
#173
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If you want a big change in gas mileage and power and 0-60, fixing the factory defect of the failing ECU capacitors is only $10 in parts, however you will have to find a world class solderer for this tedious and challenging microsurgery soldering job. - and that won't be cheap, but great bang for the buck, and should pay for itself quickly in gas - mine is getting 22 around town now!
Turns out, when I disassembled the air intake system and whatnot to replace this sensor, I managed to completely ignore one of the vacuum hoses connected to it.
If I'm not mistaken, that often causes quite a decrease in gas mileage, depending on what that particular hose goes to. Since my mileage hasn't changed at all since that happened, and the sensor replacement and hose issue happened at the same time, I'm hoping that's the reason that I haven't had an increase in mileage yet: the issues caused by the unattached hose were counteracting the benefits from the new sensor.
In any case, a week or so from now I should have some actual NUMBERS to post in here, mileage-wise, and we'll see how things go from there.
08-26-13, 12:47 PM
#174
Pole Position
glad I saw this in time...was now about to order an after market ECTS
09-28-13, 03:55 PM
#176
Lexus Champion
10-07-13, 07:03 PM
#177
The last two days the MPG dropped significantly. On the 60 mile loop with a full tank, by the time I made it home the gas gauge was at just shy of 3/4. Stopped by the gas station to verify fuel used and the MPG came back at about 16 MPG. Well off for an all freeway run. 
Not wanting to foul anything downstream, like the O2 sensors, EGR the dealer was 2 miles away. Total out the door was a wallet ripping $72. 
After the engine cooled some I went into it. Just pulling the cover the culprit was obvious. The no 5 vacuum hose that connects to the intake piping had split from the fitting down about 2". Plenty of air is being sucked in through the crack. I checked the other vacuum hoses and many are pretty firm now. Those will need to be replaced soon.
Since I had the time, might as well put in the ECT since it was $72. I dislike all the covers modern engines have to make them look "pretty".
Makes it into far more time to RR parts. If this were the Celica, the job would have been done in about 6 minutes. Anyway...
This is how the old one came out with 185K miles on it. Top fitting is pretty loose and there are signs of corrosion under the plastic.
Not wanting to foul anything downstream, like the O2 sensors, EGR the dealer was 2 miles away. Total out the door was a wallet ripping $72. After the engine cooled some I went into it. Just pulling the cover the culprit was obvious. The no 5 vacuum hose that connects to the intake piping had split from the fitting down about 2". Plenty of air is being sucked in through the crack. I checked the other vacuum hoses and many are pretty firm now. Those will need to be replaced soon.
Since I had the time, might as well put in the ECT since it was $72. I dislike all the covers modern engines have to make them look "pretty".
Makes it into far more time to RR parts. If this were the Celica, the job would have been done in about 6 minutes. Anyway... This is how the old one came out with 185K miles on it. Top fitting is pretty loose and there are signs of corrosion under the plastic.
10-15-13, 07:18 PM
#179
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I'm going to try this, my mpg is around 16 and my current 1996 car does feel a tiny bit more sluggish compared to my old 1991.
Driving around, my temp gauge doesn't even get to halfway and I live in tropical Malaysia.
Driving around, my temp gauge doesn't even get to halfway and I live in tropical Malaysia.
10-15-13, 08:54 PM
#180
Consider this also:
https://www.clublexus.com/forums/ls4...uum-hoses.html
The first 5 gallons turned in ~16MPG. Replaced four hoses with the ECT and the remaining 10 gallons of gas to the 1/4 mark, the GPS showed 336 miles traveled. Calculated that at 25MPG. That combo fix has done well. More fresh vacuum hose is coming in next week.
https://www.clublexus.com/forums/ls4...uum-hoses.html
The first 5 gallons turned in ~16MPG. Replaced four hoses with the ECT and the remaining 10 gallons of gas to the 1/4 mark, the GPS showed 336 miles traveled. Calculated that at 25MPG. That combo fix has done well. More fresh vacuum hose is coming in next week.