1UZ Engine Shutting off when temperature rises to half
10-24-13, 06:29 PM
#76
Lexus Champion
I have seen some Celsiors which were installed unusual ECU or sensors by mechanics who were desperate to fix the car. Other than those, I also have seen damaged connectors or wires caused by the rough handling. Some mechanics even replace the ECU without disconnecting the battery cable and it often partially damages the ECU. Some of them are not familiar to electronics and they amaze me often. 
For some of them, what they can't see by their eyes are beyond their understandings. Electrons can be only seen using measuring equipments, you know.
Modern cars use variety of technologies and are designed by engineers from different fields. But it is hard for those who do the repair job understanding everything. They sometimes mess the car up. I had some bad experience with them
For some of them, what they can't see by their eyes are beyond their understandings. Electrons can be only seen using measuring equipments, you know.
Modern cars use variety of technologies and are designed by engineers from different fields. But it is hard for those who do the repair job understanding everything. They sometimes mess the car up. I had some bad experience with them
It is good to hear that Japan has mentally challenged mechanics as well
in USA, half are incompetent, half are crooked and about 1% are competent and honest, it must be awful to be a woman and have the car break down!
10-25-13, 08:28 AM
#77
Pole Position
Thread Starter
10-25-13, 09:39 AM
#78
Pole Position
Thread Starter
I believe the following should be noted;
Only and and Only when the engine is warm (half temperature) and the "hunting" of the idle begins (once I accelerate between normal RPM of 800 RPM to 1800 RPM) then only do I smell a rich scent of exhaust, however colourless.
Correct me if Im wrong, but a faulty MAF would indicate incorrect mixture, not so ?
This is in keeping with the codes that I have diagnosed prior to changing my pre-cat O2's ;
Code 21 and 28
where 28 identifies the MAF
Only and and Only when the engine is warm (half temperature) and the "hunting" of the idle begins (once I accelerate between normal RPM of 800 RPM to 1800 RPM) then only do I smell a rich scent of exhaust, however colourless.
Correct me if Im wrong, but a faulty MAF would indicate incorrect mixture, not so ?
This is in keeping with the codes that I have diagnosed prior to changing my pre-cat O2's ;
Code 21 and 28
where 28 identifies the MAF
10-26-13, 02:34 AM
#79
Moderator
You still have O2 sensor issues. That is strange. Your O2 sensors are not generating proper voltage or the air to gas mix ratio is not within the correct range.
10-26-13, 04:42 AM
#80
Pole Position
Thread Starter
nope, no codes now...was just drawing reference to the codes I identified before changing my o2 sensors......How does one set the the air to gas ratio within the certain range ?
10-26-13, 07:36 AM
#82
Moderator
The ECU controls the injection time to obtain the voltage closer to 0.45V whatever the conditions are. Conditions are low rpm, high rpm, low load, heavy load, low temperature, high temperature, throttle positions and others. The actual voltage swings between around 0.1V to 0.85V crossing 0.45V evenly when the system is working properly at after warmed up. The feedback system has some delay and there always exists swings.
Is it possible for you to measure the output voltage of those pre-cat O2 sensors?
You can measure it using a conventional voltage meter at the diag connector. All you need to do is to measure the voltage of OXL1-E1 and OXR1-E1.
Does the voltage swings between 0.1V to 0.85V crossing 0.45V evenly?
Or is it biased to higher side or lower side?
You should measure at two different timings. I mean when at not warmed up and your engine is not "hunting". and after warmed up and "hunting".
Inform me those results. Then I can provide you a next step.
10-29-13, 08:09 AM
#83
Pole Position
Thread Starter
The air to gas ratio is checked by the pre-cat O2 sensor. When it is bigger (>14.7=lean condition), the O2 sensor generates the voltage lower than 0.45V. On the other hand, when it is smaller (<14.7=rich condition), the O2 sensor generates the voltage higher than 0.45V.
The ECU controls the injection time to obtain the voltage closer to 0.45V whatever the conditions are. Conditions are low rpm, high rpm, low load, heavy load, low temperature, high temperature, throttle positions and others. The actual voltage swings between around 0.1V to 0.85V crossing 0.45V evenly when the system is working properly at after warmed up. The feedback system has some delay and there always exists swings.
Is it possible for you to measure the output voltage of those pre-cat O2 sensors?
You can measure it using a conventional voltage meter at the diag connector. All you need to do is to measure the voltage of OXL1-E1 and OXR1-E1.
Does the voltage swings between 0.1V to 0.85V crossing 0.45V evenly?
Or is it biased to higher side or lower side?
You should measure at two different timings. I mean when at not warmed up and your engine is not "hunting". and after warmed up and "hunting".
Inform me those results. Then I can provide you a next step.
The ECU controls the injection time to obtain the voltage closer to 0.45V whatever the conditions are. Conditions are low rpm, high rpm, low load, heavy load, low temperature, high temperature, throttle positions and others. The actual voltage swings between around 0.1V to 0.85V crossing 0.45V evenly when the system is working properly at after warmed up. The feedback system has some delay and there always exists swings.
Is it possible for you to measure the output voltage of those pre-cat O2 sensors?
You can measure it using a conventional voltage meter at the diag connector. All you need to do is to measure the voltage of OXL1-E1 and OXR1-E1.
Does the voltage swings between 0.1V to 0.85V crossing 0.45V evenly?
Or is it biased to higher side or lower side?
You should measure at two different timings. I mean when at not warmed up and your engine is not "hunting". and after warmed up and "hunting".
Inform me those results. Then I can provide you a next step.
Im guessing I'll have this done when I have time over the weekend, since I would need to put the vehicle on a ramp
10-31-13, 04:21 AM
#84
Pole Position
Thread Starter
I purchased the CRC MAF cleaner the Cowboy advised a couple weeks ago, however it was labelled as a "HAZMAT" item, and is taking too long to reach into my country...
So, From pic #1 I bought a M.A.F. meter reasonably from the local junkyard, came off another 1996 LS400 with not much mileage to talk about..
Picture #2 Is a comparison of both MAFs, with the new one to the right.
The problem still persists...
So, From pic #1 I bought a M.A.F. meter reasonably from the local junkyard, came off another 1996 LS400 with not much mileage to talk about..
Picture #2 Is a comparison of both MAFs, with the new one to the right.
The problem still persists...
11-01-13, 09:50 AM
#86
Pole Position
Thread Starter
So, the HAZMAT has finally arrived...
I took picture #2, after I removed the MAF...It's dirty isnt it ?
Im thinking I should still use this cleaner to clean the recently purchased used MAF....Also, since I changed my air filter a week or 2 ago..
So just to clarify,
1)im removing the MAF in its entirety to clean
2)but how do I clean that dirty section in the picture without letting the MAF cleaner residue go into the throttle body ?
CAUTION Question ! : After reading the directions, #10 states NOT to use on vehicles with a KARMAN-VORTEX air flow sensor, e.g Toyota Supras, Mitsubishi's, and MOST LEXUS VEHICLES
I pray to God my 96 LS400 doesn't have a Karman-vortex
I took picture #2, after I removed the MAF...It's dirty isnt it ?
Im thinking I should still use this cleaner to clean the recently purchased used MAF....Also, since I changed my air filter a week or 2 ago..
So just to clarify,
1)im removing the MAF in its entirety to clean
2)but how do I clean that dirty section in the picture without letting the MAF cleaner residue go into the throttle body ?
CAUTION Question ! : After reading the directions, #10 states NOT to use on vehicles with a KARMAN-VORTEX air flow sensor, e.g Toyota Supras, Mitsubishi's, and MOST LEXUS VEHICLES
I pray to God my 96 LS400 doesn't have a Karman-vortex
11-01-13, 12:15 PM
#88
'89-94 ls are karmann vortex AFM, signature trademark is the square grating which smooths the airflow before it hits the optical sensor.
yours is a hot-wire maf iirc. Just spray into the black cone, all around in there. The cleaner is usually volatile so give it a couple minutes and anything that remains should dry up. Double check against directions on the can.
yours is a hot-wire maf iirc. Just spray into the black cone, all around in there. The cleaner is usually volatile so give it a couple minutes and anything that remains should dry up. Double check against directions on the can.
11-01-13, 05:56 PM
#89
Moderator
The photo below tells me that the throttle body and the IACV are also clogged with full of carbon dusts. You'd better clean them first.
11-02-13, 09:22 AM
#90
Pole Position
Thread Starter
Thanks Gene01 and Puredrifter ! Guess ill proceed to use this CRC....
and as Yamae advised Im guesing I should have the throttle body and IACV cleaned first, even though the last receipt I got for a service to these parts was when all 8 injectors were changed on this vehicle. Which was in JULY 2013....How could this possibly get dirty so fast ?
and as Yamae advised Im guesing I should have the throttle body and IACV cleaned first, even though the last receipt I got for a service to these parts was when all 8 injectors were changed on this vehicle. Which was in JULY 2013....How could this possibly get dirty so fast ?