1UZ Engine Shutting off when temperature rises to half
11-08-13, 05:14 AM
#91
Pole Position
Thread Starter
So, I went to have my catalytic converters cleaned/ removed....However, after the muffler shop checked, apparently these Catalytic Converters have already been removed from this vehicle.
But whats weird, is that even though these Cats have been removed, this vehicle is very silent.
If my cats are removed Im supposed to be getting a louder/ hollow sound ?
Therefore, from the following pictures, please confirm whether or not my exhaust system is stock for a 1996 Celsior/ LS400....
But whats weird, is that even though these Cats have been removed, this vehicle is very silent.
If my cats are removed Im supposed to be getting a louder/ hollow sound ?
Therefore, from the following pictures, please confirm whether or not my exhaust system is stock for a 1996 Celsior/ LS400....
11-08-13, 06:22 AM
#92
Pole Position
Thread Starter
IMPORTANT NOTE
I dont believe I mentioned this before. But During the Problem ( At half temp, and rough idling) when I floor it (Highway) theres One big clump of black smoke that come out....
This has to be incorrect mixture guys......I therefore need to identify what can go faulty when warm, that would cause this rough idling, and one big clump of black smoke when I gun it on the highway..
I dont believe I mentioned this before. But During the Problem ( At half temp, and rough idling) when I floor it (Highway) theres One big clump of black smoke that come out....
This has to be incorrect mixture guys......I therefore need to identify what can go faulty when warm, that would cause this rough idling, and one big clump of black smoke when I gun it on the highway..
11-08-13, 10:18 AM
#93
Lexus Champion
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 ?
if that photo with your finger is on the engine side of the air filter, which it appears to be, then someone has run this car with no air filter for quite a while, and you have a pretty massive cleaning job ahead of you, the entire intake system will be need to be taken apart and cleaned off of the car! - yikes!
this includes every intake pipe, vacuum hose, IACV, butterfly, and any other place that the post-filter air can go!
no wonder it is running like crap! - no wonder it needed new injectors, and the yahoos that replaced the injectors didn't even investigate why the injectors went out
(this is the reason they went out!)the areas beyond the air filter should always be as clean as a hospital operating table (even if the car is 30 years old, like my Nissan 300ZX) - is there even an air filter on this car right now? - whether it is there is or not, and even if it looks new, CHANGE IT
also, make sure there is not an ill-fitting joint in the air intake pipe beyond the air cleaner, and I would replace that rubber accordion tube as well, and run some strong injector cleaner in the gas tank through this thing when you are done.
Is it too late to bail on this car and just start again with an LS400 that has been cared for?
11-09-13, 06:11 AM
#96
Pole Position
Thread Starter
What would be the effects of these 2 resignators missing? Besides a Louder noise....
11-09-13, 12:01 PM
#98
Have you checked for vacume leaks? Rough idle, hunting idle, and fat mixture can be caused by this. When was the scheduled maintenance done?( timining belt, water pump and such.) Have you pulled codes since the ecu fix?
11-09-13, 05:13 PM
#101
wow, ok....
You do not need to replace the ECU Caps to diagnose a problem or rule it out.
ALL SENSORS operate within a specific voltage range and internal resistance.
You can check the condition of ANY AND EVERY sensor with a good DVOM and service manual.
I recommend that EVERYONE who wants to work on a car have either a older Snap-on Vantage or a Fluke 88 in their tool box at home. Sure you can buy a cheap $50 DVOM at Harbour Freight or pep boys or where ever but a good DVOM/Multimeter will last you a lifetime!
I prefer the Vantage because it is a graphing multimeter with a built in vehicle database on sensors, locations and acceptable values. With the KV module, you can even use it as a ignition scope, something very beneficial on older coil/distro/wired cars like the LS400s. The graphing feature is exceptionally useful for finding dead spots in variable sensors(TPS) as well as seeing transitions in voltages from O2 sensors and such. The vantage used to be cutting edge tools back around 1999-2004 but have been successively replaced by later and greater devices, but the original is still a VERY powerful tool!
The upside to all the new versions, is that you can find one of the older units in great condition with all the bells and whistles, updated to around 2006 for $100-300 when they were $2500 all optioned out when new.
As far as the problem at hand...
BEFORE you condemn a part, the diagnostic method outlined in the service manual should be used to check the resistance of the part, the voltage INTO the part and the voltage OUT of the part. if there is a problem with the resistance, it's usually the part. However, if the voltage in is also out of spec, That could be WHY the resistance is not right on the part. You need to trace it back to find out why. Could be a bad connection, a deteriorated wire sheath causing corrosion on a wire increasing the resistance OR the ECU IS NOT SENDING THE RIGHT VOLTAGE. This does NOT mean the ECU is Faulty or the Caps are the issue, another sensor could be sending the wrong info causing the ECU to send the wrong voltage tot he sensor (assuming that it is not a static 5V ref). If the voltage in is correct and the resistance is correct then the problem lies in the output from the sensor. Again tracing the problem forward, checking for bad connections, broken/damaged/corroded wires.
If you check everything out and nothing is making sense as per what is outlined in the service manual's diagnostic procedure or the procedure keeps pointing back to the ECU, then you have probably pinpointed the problem as the ECU or the caps inside.
At any point on your little roller coaster ride here, have you watched the data-stream coming out of the the ECU on your scanner or does it just check codes? does the JDM Celsior have a ODB2 port or just the toyota port under the hood?
Do you have a quality DVOM?
Do you have a mechanical service manual and electronic service manual? If so, have you tested anything that you have replaced as per what I outlined above?
What is the voltage coming out of the alternator when hot/cold?
Have you checked for loose grounds, battery terminals and at major junctions?
Realistically, I would start over from the very beginning with a NEW plan of attack. Assume that no part is working properly, systematically work through all of the parts/systems and eliminate possible problems locations as you go, verifying good parts. (The reason why I say assume that no part is working properly is because even new out the the box parts can be defective. About 5-15% of all new parts are defective no mater the brand or the source. that and a manufacturing/production standard the world over.)
=====> Don't go off half-cocked and start replacing parts here and there, FOLLOW THE DIAGNOSTIC PROCEDURE TO THE LETTER AND STICK WITH IT!!! You will find the problem and you will learn so much along the way! Not to mention feel exceptionally proud and fulfilled when you finally get it nailed down and then fixed.
Also, every part your have replaced so far, I would check again cold and hot as if it were never replaced!
Hope that helps.
You do not need to replace the ECU Caps to diagnose a problem or rule it out.
ALL SENSORS operate within a specific voltage range and internal resistance.
You can check the condition of ANY AND EVERY sensor with a good DVOM and service manual.
I recommend that EVERYONE who wants to work on a car have either a older Snap-on Vantage or a Fluke 88 in their tool box at home. Sure you can buy a cheap $50 DVOM at Harbour Freight or pep boys or where ever but a good DVOM/Multimeter will last you a lifetime!
I prefer the Vantage because it is a graphing multimeter with a built in vehicle database on sensors, locations and acceptable values. With the KV module, you can even use it as a ignition scope, something very beneficial on older coil/distro/wired cars like the LS400s. The graphing feature is exceptionally useful for finding dead spots in variable sensors(TPS) as well as seeing transitions in voltages from O2 sensors and such. The vantage used to be cutting edge tools back around 1999-2004 but have been successively replaced by later and greater devices, but the original is still a VERY powerful tool!
The upside to all the new versions, is that you can find one of the older units in great condition with all the bells and whistles, updated to around 2006 for $100-300 when they were $2500 all optioned out when new.
As far as the problem at hand...
BEFORE you condemn a part, the diagnostic method outlined in the service manual should be used to check the resistance of the part, the voltage INTO the part and the voltage OUT of the part. if there is a problem with the resistance, it's usually the part. However, if the voltage in is also out of spec, That could be WHY the resistance is not right on the part. You need to trace it back to find out why. Could be a bad connection, a deteriorated wire sheath causing corrosion on a wire increasing the resistance OR the ECU IS NOT SENDING THE RIGHT VOLTAGE. This does NOT mean the ECU is Faulty or the Caps are the issue, another sensor could be sending the wrong info causing the ECU to send the wrong voltage tot he sensor (assuming that it is not a static 5V ref). If the voltage in is correct and the resistance is correct then the problem lies in the output from the sensor. Again tracing the problem forward, checking for bad connections, broken/damaged/corroded wires.
If you check everything out and nothing is making sense as per what is outlined in the service manual's diagnostic procedure or the procedure keeps pointing back to the ECU, then you have probably pinpointed the problem as the ECU or the caps inside.
At any point on your little roller coaster ride here, have you watched the data-stream coming out of the the ECU on your scanner or does it just check codes? does the JDM Celsior have a ODB2 port or just the toyota port under the hood?
Do you have a quality DVOM?
Do you have a mechanical service manual and electronic service manual? If so, have you tested anything that you have replaced as per what I outlined above?
What is the voltage coming out of the alternator when hot/cold?
Have you checked for loose grounds, battery terminals and at major junctions?
Realistically, I would start over from the very beginning with a NEW plan of attack. Assume that no part is working properly, systematically work through all of the parts/systems and eliminate possible problems locations as you go, verifying good parts. (The reason why I say assume that no part is working properly is because even new out the the box parts can be defective. About 5-15% of all new parts are defective no mater the brand or the source. that and a manufacturing/production standard the world over.)
=====> Don't go off half-cocked and start replacing parts here and there, FOLLOW THE DIAGNOSTIC PROCEDURE TO THE LETTER AND STICK WITH IT!!! You will find the problem and you will learn so much along the way! Not to mention feel exceptionally proud and fulfilled when you finally get it nailed down and then fixed.
Also, every part your have replaced so far, I would check again cold and hot as if it were never replaced!
Hope that helps.
11-09-13, 08:58 PM
#102
Lexus Champion
the problem with all of that, according to Yamae, Nippon Denso, and other ECU experts of world renown, is that a Snap-On scope or CAN scanner or Toyota's own diagnostic tools are heavily dependent on the ECU providing accurate information and and acting as it is supposed to. When the ECU is confused or malfunctioning, all bets are off!
This ECU caps problem is epidemic on these cars, anyone who doesn't do this replacement, even proactively with no symptoms, is just asking for a headache down the road. I won't even begin to diagnose a driveability issue on an LS400 that still has the defective caps, and I'm sorry, but I am on the same side of this debate as the guys who designed your ECU in the first place, so just fix the caps, and then you can do accurate and meaningful diagnosis, and not just be chasing your tail!
I do agree about not going off half-cocked and just replacing parts - fix the ECU so you can rely on it, as it is the key to accurate diagnosis, and then follow the service manual diagnostic steps, but also keep in balance pattern failure (aka Identifix) - i.e. we have pretty much seen every possible failure that the LS400 has, many, many times in the past!
This ECU caps problem is epidemic on these cars, anyone who doesn't do this replacement, even proactively with no symptoms, is just asking for a headache down the road. I won't even begin to diagnose a driveability issue on an LS400 that still has the defective caps, and I'm sorry, but I am on the same side of this debate as the guys who designed your ECU in the first place, so just fix the caps, and then you can do accurate and meaningful diagnosis, and not just be chasing your tail!
I do agree about not going off half-cocked and just replacing parts - fix the ECU so you can rely on it, as it is the key to accurate diagnosis, and then follow the service manual diagnostic steps, but also keep in balance pattern failure (aka Identifix) - i.e. we have pretty much seen every possible failure that the LS400 has, many, many times in the past!
Last edited by LScowboyLS; 11-09-13 at 09:03 PM.
11-09-13, 11:20 PM
#103
the problem with all of that, according to Yamae, Nippon Denso, and other ECU experts of world renown, is that a Snap-On scope or CAN scanner or Toyota's own diagnostic tools are heavily dependent on the ECU providing accurate information and and acting as it is supposed to. When the ECU is confused or malfunctioning, all bets are off!
A Snap-On Vantage or a fluke88 are both DVOMs (digital volt ohm meter).
They do not link the the ECU, you use them to read the volts, ohms and amps of a given circuit. They function regardless of if the ECU is buggered or perfectly fine. Intact they do not even communicate with the ECU or need an ECU to function. You test circuits with them and you are wrong, every electrical engineer/ECU-guru/electrician/whathaveyou will tell you that. You posted a picture of you using a generic DVOM (if that was infact you using it), so I assumed you knew how to use a DVOM, let alone what one was... Maybe not.... I figured with you being a "Master AC/drivability/diagnostic technician at one of the largest Lexus dealers in ther world and owning/running many other shops" I figured you'd be aware of an industry standard pair of devices. The kind of devices that every tech in NA either has one, has used one or works at a shop/dealer with one. For a tech not to know what a Vantage or Fluke88 is or does, is the equivalent to a doctor not knowing what an X-ray machine is or does.
This ECU caps problem is epidemic on these cars, anyone who doesn't do this replacement, even proactively with no symptoms, is just asking for a headache down the road. I won't even begin to diagnose a driveability issue on an LS400 that still has the defective caps, and I'm sorry, but I am on the same side of this debate as the guys who designed your ECU in the first place, so just fix the caps, and then you can do accurate and meaningful diagnosis, and not just be chasing your tail!
I do agree about not going off half-cocked and just replacing parts - fix the ECU so you can rely on it, as it is the key to accurate diagnosis, and then follow the service manual diagnostic steps, but also keep in balance pattern failure (aka Identifix) - i.e. we have pretty much seen every possible failure that the LS400 has, many, many times in the past!
Now assuming they were replaced correctly, or replaced at all for that matter, you have to move on to something else.
Because no method has been followed at any point in this thread, and everyone has just been throwing darts at a board, the OP needs to start from scratch and methodically rule everything out. Even the stuff he has already replaced cannot be above suspicion! If that leads him back to the ECU and the caps, their faulty replacement or complete lack there of, so be it. I really don't care what the problem is, just that the OP starts to follow a proper path to resolve his problems!
But baring the OP flat out lying about replacing the caps, his electrician lying about replacing them or failing at the replacement, it IS time to move on to something else. And for the record, I also want to see the OP post pics of his ECU with the new caps installed. That will shed a lot of light onto what is actually going on with the OP's car.
Last edited by DaveGS4; 11-10-13 at 11:28 AM.
11-10-13, 02:19 AM
#104
Lexus Champion
the ECU cap replacement procedure is fairly tricky to do correctly, especially if the capacitors have leaked badly, the resulting damage can be beyond the capabilities of most electronics technicians. When I work on these that have leaked, I actually have to use surgical instruments from Hu-Friedy and other very high end equipment, in order to save the ECU in many cases, so the chances of some fellow in Trinidad having the experience and tools to pull this off is very iffy at best! (OP lives in Miami but his car and tech are in Trinidad)
I never said anything about not knowing what a Fluke 88 is, you must have misread, in fact, I have owned a Fluke 88 since they came out in 1990, 23 years! - and my latest one is the model 88 series V, but we rarely used these at the dealership, there are other diagnostic tools that compete with Fluke that are even more advanced that you may be unfamiliar with. As an ASE master tech for over 30 years, and a master Lexus technician for over 10, I am quite familiar with the entire line of Snap-On, Matco, Mac, Cornwell, Fluke, OTC, Toyota, Hioki, Vetronix and other diagnostic tools. My first Fluke meter was the 8020A, that I purchased 36 years ago in 1977! -
So let's get that ECU to a point where we know its functioning correctly, and then we won't be chasing our tail and on a wild goose chase trying to track down erroneous OBD codes and other misleading information, while ignoring the fact that the ECU has a very common known defect that is likely hampering our diagnostics!
I never said anything about not knowing what a Fluke 88 is, you must have misread, in fact, I have owned a Fluke 88 since they came out in 1990, 23 years! - and my latest one is the model 88 series V, but we rarely used these at the dealership, there are other diagnostic tools that compete with Fluke that are even more advanced that you may be unfamiliar with. As an ASE master tech for over 30 years, and a master Lexus technician for over 10, I am quite familiar with the entire line of Snap-On, Matco, Mac, Cornwell, Fluke, OTC, Toyota, Hioki, Vetronix and other diagnostic tools. My first Fluke meter was the 8020A, that I purchased 36 years ago in 1977! -
So let's get that ECU to a point where we know its functioning correctly, and then we won't be chasing our tail and on a wild goose chase trying to track down erroneous OBD codes and other misleading information, while ignoring the fact that the ECU has a very common known defect that is likely hampering our diagnostics!
Last edited by DaveGS4; 11-10-13 at 11:15 AM. Reason: remove personal commentary
11-10-13, 10:48 AM
#105
This is not a matter of oldschool techs vs new school ways
Sure the caps are a problem, however you can diagnose problems correctly regardless of if your caps are bad or good. I'm not saying do not replace the caps, or do not replace them as preventative maintenance... However using the method I posted above can point you in the direction of the ECU and the caps even by following the "oldschool method" as you like to call it. Most sensors on a car are pretty simple things. They have a power, a ground and often a reference signal. If you get a code saying the ECT sensor is malfunctioning, then testing at the sensor with your DVOM will tell you what's up. If the sensors resistance is right, and it's getting the correct voltages, it's grounded right and it's output is right as per the specs in the manual, then sensor is fine and the problem is else where.... Probably after the sensor as it was getting the right info the begin with. Same thing with O2 sensors. There is a reference circuit and a heater circuit. If everything into the sensor works, the sensor is functioning normally, then the problem lies down the line somewhere. It could be a common ground or the ECU caps. A good 30mins to an hour of simple testing can tell you a lot of info. Pair that with looking at the data stream from the computer and you can really start to figure things out quickly. If the sensor is getting the correct info, is sending the correct info but the ECU is outputting crazy info through the data stream... You pretty much figured it out to be a computer problem!
Sure the caps are a problem, however you can diagnose problems correctly regardless of if your caps are bad or good. I'm not saying do not replace the caps, or do not replace them as preventative maintenance... However using the method I posted above can point you in the direction of the ECU and the caps even by following the "oldschool method" as you like to call it. Most sensors on a car are pretty simple things. They have a power, a ground and often a reference signal. If you get a code saying the ECT sensor is malfunctioning, then testing at the sensor with your DVOM will tell you what's up. If the sensors resistance is right, and it's getting the correct voltages, it's grounded right and it's output is right as per the specs in the manual, then sensor is fine and the problem is else where.... Probably after the sensor as it was getting the right info the begin with. Same thing with O2 sensors. There is a reference circuit and a heater circuit. If everything into the sensor works, the sensor is functioning normally, then the problem lies down the line somewhere. It could be a common ground or the ECU caps. A good 30mins to an hour of simple testing can tell you a lot of info. Pair that with looking at the data stream from the computer and you can really start to figure things out quickly. If the sensor is getting the correct info, is sending the correct info but the ECU is outputting crazy info through the data stream... You pretty much figured it out to be a computer problem!
Last edited by DaveGS4; 11-10-13 at 11:13 AM. Reason: remove personal commentary