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

Small work, yields big results.

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Old 07-04-05, 12:53 PM
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GRAND_LS 4
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Default Small work, yields big results.

Ladies and gents, clean your MAF sensor, the small sensor after the air filter in the intake tube. I cleaned it using a simple $0.99 STP carb cleaner from wal mart, and it made a world of difference.

I had noticed over the last few months that I lost some low-end torque, and when the car gets to 3000RPM, you feel the acceleration kick in. It was never like that before, the torque curve was much more even all thought the band (I especially noticed it after getting the LS, since my previous car had weak low end).

So one day, after cleaning the gunk on the intake manifold butterfly, I decided to clean my MAF, and the acceleration is great once again. Big difference and it only took me literally 5mins.

You must pull it out though, and spray against where the air usually flows into the maf from the right side. You will know what I mean when you have that piece in your hand.

Don’t you just love free power?

Also, while your at it, you can use the same bottle to clean up your PCV valve.

WARNING: Carb cleaner is a POWERFUL desolvent, dont get ANY of it on your paint!! and avoid skin contact. Make sure you store it in a safe place when your done
Old 07-04-05, 06:08 PM
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Pagong
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Good stuff....

I always like DIY stuff.
Old 07-08-05, 05:12 PM
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phillipin
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i was having a small rattling noise at 1200-1500 rpm, took it to my good car buddy who is a master at motor work, he said it sounded like it was pinging. So we cleaned the maf with a eletronic cleaner spray, it didnt completely fix the issue, but it did help, the noise isnt as loud and the duration isnt as long. I need to get the o2 sensors checked and probably change the plugs even though thet are decently new.
Old 07-08-05, 11:02 PM
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Tote
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Can I use "throttle body and air intake" Cleaner? Not sure if it would be harmful. I don't mind picking up a bottle of carb cleaner , but I have a 3/4 full bottle of throttle cleaner, and thought I might as well clean the throttle body while i'm there at the MAF Sensor.

Any info would be appreciated and thanks For the MAF sensor cleaning info., one of my ls's is having the same problem.

Thanks
Old 07-08-05, 11:33 PM
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Thanks for the reminder.

Yes, the carb cleanr is pretty harsh, some containe toluene which isn't a good thing to breathe. Obviously use in a well ventilated area and if possible use a OSHA approved respirator for acid gas and pesticides. I believe that the paint respirators are also acceptable. This stuff is hard on the skin so wash immediately or wear chemical resistent gloves.

http://en.wikipedia.org/wiki/Toluene
(Tried the Cornell edu but the site was not connecting for MSDS info)
Old 07-09-05, 12:08 AM
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phillipin
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Originally Posted by Tote
Can I use "throttle body and air intake" Cleaner? Not sure if it would be harmful. I don't mind picking up a bottle of carb cleaner , but I have a 3/4 full bottle of throttle cleaner, and thought I might as well clean the throttle body while i'm there at the MAF Sensor.

Any info would be appreciated and thanks For the MAF sensor cleaning info., one of my ls's is having the same problem.

Thanks

was your LS missing power or was it making the low rpm pinging sound, i'm very curious
Old 07-09-05, 09:27 AM
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GRAND_LS 4
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Originally Posted by Tote
Can I use "throttle body and air intake" Cleaner? Not sure if it would be harmful. I don't mind picking up a bottle of carb cleaner , but I have a 3/4 full bottle of throttle cleaner, and thought I might as well clean the throttle body while i'm there at the MAF Sensor.

Any info would be appreciated and thanks For the MAF sensor cleaning info., one of my ls's is having the same problem.

Thanks

They are pretty much the same. I used the carb cleaner to clean my throttle body and MAF, and worked very well. They are both VERY powerful solvent like RA40 pointed out.
Old 07-09-05, 11:06 AM
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Originally Posted by phillipin
was your LS missing power or was it making the low rpm pinging sound, i'm very curious
This Is my 3rd ls and it seems to not have loss of power at first and then seems to kick in( in comparrison to the others). In the last three weeks I have heard a rattle. I can barely hear it. I have to be next to a wall or a car next to me when leaving a parking lot for the sound to bounce off of it.
I bought the car in january of this year. Items done. Within the first three weeks.

Power steering Pump
Spark plugs and cable ( I don't plan to change them for years to come)
Oil + Oil Filter
Transmission fluid - 4 drain and refills - Once a week for 4 weeks

I'm hoping the maf ceaning will fix the rattle as well.

My sister has a mercedes and the engine started to rattle and it felt like the transmission was bad because it didn't change gears properly , Check engine light also came on.
Check engine code reported maf sensor. It was swapped and everything went back to normal.

If the rattle on the car doesnt stop after the cleaning. I'm going to swap MAF sensors and report my findings. Maybe the MAF is Faulty but not enough to trigger the check engine light. I'll be doing this on monday or tuesday

This is on an ls400 1993
Comparison is to a 90 and 91

Last edited by Tote; 07-09-05 at 11:10 AM. Reason: Model Info
Old 07-09-05, 12:20 PM
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GRAND_LS 4
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Originally Posted by Tote
This Is my 3rd ls and it seems to not have loss of power at first and then seems to kick in( in comparrison to the others). In the last three weeks I have heard a rattle. I can barely hear it. I have to be next to a wall or a car next to me when leaving a parking lot for the sound to bounce off of it.
I bought the car in january of this year. Items done. Within the first three weeks.

Power steering Pump
Spark plugs and cable ( I don't plan to change them for years to come)
Oil + Oil Filter
Transmission fluid - 4 drain and refills - Once a week for 4 weeks

I'm hoping the maf ceaning will fix the rattle as well.

My sister has a mercedes and the engine started to rattle and it felt like the transmission was bad because it didn't change gears properly , Check engine light also came on.
Check engine code reported maf sensor. It was swapped and everything went back to normal.

If the rattle on the car doesnt stop after the cleaning. I'm going to swap MAF sensors and report my findings. Maybe the MAF is Faulty but not enough to trigger the check engine light. I'll be doing this on monday or tuesday

This is on an ls400 1993
Comparison is to a 90 and 91

Also, give the car sometime to program the ECU.
Old 07-09-05, 12:28 PM
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Tote
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Originally Posted by GRAND_LS 4
Also, give the car sometime to program the ECU.

Does that mean I won't feel the changes right away? Do I have to reset the ecu?
Old 07-09-05, 12:59 PM
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GRAND_LS 4
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Originally Posted by Tote
Does that mean I won't feel the changes right away? Do I have to reset the ecu?
Well, I cleaned up my MAF, and called it a night. The next day I noticed some difference, and it showed more and more while driving up inclines and stuff. Then I remembered that i had cleaned the maf.

So im not exactly sure if its RIGHT away, or within a few hours of driving. See what I mean?
Old 07-09-05, 01:35 PM
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how exactly do you clean the maf and sensor i would like to do mine and see if i notice any improvements
Old 07-10-05, 02:15 AM
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phillipin
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hey this was a messege to my buddy jeff on vvti.net but it applies to this issue and the problems i'm having, i was ****ing around with my maf tonight with my brother.... wierd stuff man

Hey jeff after the lexo threw those codes tonight i went home, me and my brother cleaned the maf again.....now the car was bogging worse than we first cleaned it, something it would only idle for 2 seconds before dying. He brought down his laptop to the garage and we were checking out ls engine codes blah blah blah..... we found apost by some guy who really researched the problem. Low engine speed and throttle pinging, after 40 mph complete power loss for a short moment under hard accelleration and abrupt power loss at cruising. Also his car idled at 500 rpm unlike 600-650 like it should. He check the idle valves, vaccum lines, maf sensor, 02 sensor, all good. One day he was idled really low and reved the engine in P to 5000, it idled back at 650 and ran totally smooth. When he cleaned the maf his car was bogging like mine rev it up a little and it just dumps fuel like mine was tonight. So he forced the motor to 5k and bam everything was totally fine again. He looked up other owner that had similar issues and found the only resolution was to buy a new ecu that had the original TSB update on the firmware. This is accross ll 90s to 95's.

So it looks like I just need to replace my ecu, the pings will go away and the power loss too. So I think i'll put in an ebay bid this week for an ecu. Im still gonna go get the coded puled though. But it is just so wierd that its like completel bogging like 2 cylendars arent firing its dumping fuel and force it to 5k and runs like new.

God damn toyota of japan. You make the best car with an iq of 12.

I like how we are hijacking my own thread with like 8 subjects haha

So on tuesday how about tranny flush and fill, rear brakes. easy stuff
Old 07-11-05, 06:01 PM
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GRAND_LS 4
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If you haven’t done this, then hold on a bit, there is this guy with one post ( I have no idea who he is) that says it messed up his MAF.

Anyone have any problems?
Old 07-11-05, 10:17 PM
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Originally Posted by GRAND_LS 4
If you haven’t done this, then hold on a bit, there is this guy with one post ( I have no idea who he is) that says it messed up his MAF.

Anyone have any problems?
LOL!!! I tried it today and did I scare myself good. I got a check engine light and when I tried to accelerate I found out the true meaning of a stutter. What I did was clean the honeycomb part of the air intake that holds the MAF and some of the fluid got on the maf sensor so I just sprayed it a little more, let it dry, reinstalled and saw the check engine light. Figured I would just replace. Then I saw the prices. Then it all sank in and I felt an empty spot in my stomach.

After about 2hours of recleaning and head pounding I Got on this site and the net and someone stated that if you do clean it, use alcohol ( he did mention a specific type- just Forgot) so I poured some on the sensor which I had removed from the air intake housing. Blow dried it and reinstalled.
To my suprise, the check light didn't turn on and the car started working again. I'm sure it was pour luck ( or maybe the alcohol desolved some of the gunk from the throttle cleaner).

I'm Glad I can Laugh about it now, But earlier it was a completely diferent story. So unless you know what your doing "Don't Try This At Home" LOL.

BTW The car does feel better. Maybe just happy its working.
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