1994 Lexus ls400 Nightmare!!!!
02-10-15, 10:52 PM
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1994 Lexus ls400 Nightmare!!!!
First of all let me start by saying this is the worst car issue I have ever experienced. $1000.00 later I could use some help. Here's the story back in November/2014 I was pulling out of the driveway pushed down on the gas and noticed a severe dramatic loss in power/acceleration. So severe I had to place the car in 1st gear make my way to 2nd then to drive. After this incident the car experienced a HARD start. The car would crank over and over with no start. Finally after consistently turning the key the car would finally start and stall, after 3 or 4 times starting and stalling the car would start and stay on. I took the car to a mechanic who tried to pull codes but the scanner was getting no communication from the ecu, so a whole lot of guessing took place. Here's what I had checked or replaced.
PART Result
1.Catyilac Converters Not Clogged
2.Fuel Filter Replaced Problem Still Exist
3.Vaccum Hoses Replaced Problem Still Exist
4.Compression Test Specs Within Proper Range
5.Fuses All in working condition
After all this I was done with the guessing and decided to purchase a new refurbished ecu. So I plugged in the new refurbished ecu and the car preformed totally different. The hard start was gone and the car started right up, but would stall/die mid drive, which was totally different then before. I decided to see if I could pull codes from the new refurbished ecu
. I did and pulled codes 13 rpm signal and 31 air flow meter. I replaced the MAF and the problems still exist. I'm in over my head in this money pit and could use some suggestions.
PART Result
1.Catyilac Converters Not Clogged
2.Fuel Filter Replaced Problem Still Exist
3.Vaccum Hoses Replaced Problem Still Exist
4.Compression Test Specs Within Proper Range
5.Fuses All in working condition
After all this I was done with the guessing and decided to purchase a new refurbished ecu. So I plugged in the new refurbished ecu and the car preformed totally different. The hard start was gone and the car started right up, but would stall/die mid drive, which was totally different then before. I decided to see if I could pull codes from the new refurbished ecu
. I did and pulled codes 13 rpm signal and 31 air flow meter. I replaced the MAF and the problems still exist. I'm in over my head in this money pit and could use some suggestions.
02-11-15, 06:34 AM
#2
How many miles on the car and when was the last time the timing belt was changed? Sounds like the belt might have jumped a tooth. You can also visually check the camshaft position sensors to make sure they are plugged all the way in and the wires are not pinched.
https://www.clublexus.com/forums/per...help-guys.html
https://www.clublexus.com/forums/per...help-guys.html
02-11-15, 12:40 PM
#3
you are right to go straight to the ECU, which sound like your symptoms. however a refurbishied ECU may still have the bad capacitors that plague these cars.
enjoy the read:
https://www.clublexus.com/forums/ls4...capacitor.html
then check for loose vacuum hoses, and clean your air idle control valve!
http://planetsoarer.com/IAC/iac.htm
IMPORTANT: It is critical that you use the exact premium Japanese low ESR capacitors I have linked to below in the recommended capacitors section, even if you are having someone else do the work, the correct capacitors are very rare type and they will not have them locally - if they use other capacitors, the repair will not solve the problems you are having!
https://www.clublexus.com/forums/ls4...capacitor.html
then check for loose vacuum hoses, and clean your air idle control valve!
http://planetsoarer.com/IAC/iac.htm
03-25-15, 02:18 PM
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Video of my Poor lex performance
03-25-15, 06:25 PM
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03-26-15, 02:40 AM
#8
I just looked at the first video. I don't understand why people that post these always goose the throttle. If your gona push the gas pedal hold it constant, we could already see the rpms fluctuate it does not need your help doing that.
It sounds like plugged exhaust to me. Likely plugged cats or ?
It sounds like plugged exhaust to me. Likely plugged cats or ?
03-26-15, 08:24 AM
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03-26-15, 08:27 AM
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I just looked at the first video. I don't understand why people that post these always goose the throttle. If your gona push the gas pedal hold it constant, we could already see the rpms fluctuate it does not need your help doing that.
It sounds like plugged exhaust to me. Likely plugged cats or ?
It sounds like plugged exhaust to me. Likely plugged cats or ?
03-26-15, 09:41 AM
#11
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03-26-15, 11:11 AM
#12
Did you try to run it with the exhaust open when the cats were off? How does the air filter look? With all the noise are you sure the timing belt is timed right?
Code 13 rpm signal
Timing belt off
Cps ( like Yamae says and he is right deal with the code first.)
Cam sensors
And wires to all this stuff
ECU
Since it does run you need to check for the signals from the sensors. Best way I know of is with a scope.
Code 13 rpm signal
Timing belt off
Cps ( like Yamae says and he is right deal with the code first.)
Cam sensors
And wires to all this stuff
ECU
Since it does run you need to check for the signals from the sensors. Best way I know of is with a scope.
Last edited by dicer; 03-26-15 at 11:41 AM.
03-26-15, 02:21 PM
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03-26-15, 02:26 PM
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Did you try to run it with the exhaust open when the cats were off? How does the air filter look? With all the noise are you sure the timing belt is timed right?
Code 13 rpm signal
Timing belt off
Cps ( like Yamae says and he is right deal with the code first.)
Cam sensors
And wires to all this stuff
ECU
Since it does run you need to check for the signals from the sensors. Best way I know of is with a scope.
Code 13 rpm signal
Timing belt off
Cps ( like Yamae says and he is right deal with the code first.)
Cam sensors
And wires to all this stuff
ECU
Since it does run you need to check for the signals from the sensors. Best way I know of is with a scope.