So, following the directions in my Haynes for my '96 Camry, I checked the resistance and voltage of my ECT temperature sensor (the one just upstream of the upper radiator hose). On a warm car, the resistance was about 100 ohms. Seemed a bit low.
Voltage was 10 volts. (Haynes said it should be 5V.)
I looked into this because the car stalled again, one week after changing the tranny fluid. (I was pretty sure that it was a stuck torque converter lock, too...)
So, what do I do now...? 10V seems kind of high, ya?
By the way, the Toyota dealer had no idea what an ECT temperature sensor was. Anyone have a part number for this one for my car ('96, 4- banger)?
Strange. According to the maintenance manual I have (a chapter of 72 pages just about the cooling system). The ECT is a switch, mounted in the bottom of the radiator and is just switching on and off the cooling fan.
I saw that one (bottom of the radiator) too. The Toyota dealership said that's the only ECT they could find - and it's $110 at the dealership for that part.
The ECT you mentioned is a variable resistor, not the ECT switch (Toyota could better differentiate them like the latter a "fan switch" everybody else calls.)
The variable resistor (near 0 hot, near infinity when cold). But it's on the water outlet like you described. It doesn't need voltage to operate.
100ohms is about the low end of the permitted range at around 210deg. Why do you think it's low or bad?
rockauto.com has one for as low as $23.99 (verify your application). The "fan switch" 36549 is about $50.
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STANDARD MOTOR PRODUCTS Part # TX40 More Info $27.79 $0.00 $27.79
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BECK/ARNLEY Part # 1580421 More Info $31.79 $0.00 $31.79
ACDELCO Part # D583 More Info {#19022018} SENSOR,ENG COOL T/GA $37.79 $0.00 $37.79
FOUR SEASONS Part # 36424 More Info For AC $54.79 $0.00 $54.79
Yep, I'm playing with the one on the water outlet. Is its operation critical? Does it provide information to the onboard computer, which controls other stuff?
It sure doesn't help that Toyota calls two different parts ECT. (This ECT? Oh. THAT ECT!)
I'm trying to track down my stalling problem on my '96 4-banger (stalls only when warm, when slowing to a stoplight). So far tried cleaning the IAC, changed spark plugs (which were clean, by the way - no carbon buildup, as I was suspecting), replaced the leaking distributor O-ring (but the electrical contacts inside the distributor were squeaky clean), even changing tranny fluid in case of a stuck torque converter lock. Still stalling.
Next suspects: sensors, EGR, possibly onboard computer...?
I don't think it's the coils, since they work just fine on startup, and on the freeway. Changed fuel filter ~ 5 years ago.
10V instead of 5V really does seem kind of weird.
Thanks for the prices...
By the way - I changed the single-spark Pt. Bosch plugs my dad put in the '96 to dual Pt. Bosch plugs. What a difference in power! Even when the car stalled on the usual hill in Vallejo, the engine didn't quite completely die - just hovered between, oh, 200 and 600 rpm. Must be the new plugs...? ;-)
I got the idea from this site, when I was researching my stalling problem:
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Problem found and resolved on my fianc=E9s 92 Camry: coolant temp sensor.
After exhibiting all the same symptoms as you all, I went down to the Toyota dealer who misdiagnosed the distributor and igniter as being at fault. After they charged and arm and a leg, it stalled at the next stop light on the way home. Furious at Toyota, but tired and wanting to get home, I waited for the car to cool enough for it to start again and carefully drove home, doing the gas/brake deely with both feet.
I then took the car to a friend of a friend, a trusted non-Toyota mechanic that came highly recommended. He had the problem figured out and solved in 2 days. As I came to pick up the car, he explained to me what he did and how he figured it out. He had a snap-on computer, just smaller than the size of a laptop hooked up to several sensors in the engine compartment; he actually drove the car with wires hanging out of the hood going through the window to his computer, which acted like a real-time analyzer and data logger. As soon as the symptom arose, it was the temperature sensor that caused the fault.
As most of you may know, temperature sensors are just over-sized thermistors, which are devices that output a change in resistance in proportion to the heat that is detected. The ECU measures this resistance to determine the temperature of the engine, and based on such, gives the appropriate amount of fuel to cylinders to combust. The problem is that over time (at least so I've been told with Toyota temp sensors), they can fail after getting to a certain temperature. They would function cold and as they get hotter and hotter, they short/ open and produce a false reading to the ECU. The ECU then sees this as a malfunction, and thinking that the motor is cold in an effort to avoid detonation, dumps WAY more fuel than needed and basically floods the engine. This is why after the car stalls and you try and start the car unsuccessfully, you can smell a heavy gas odor in/near the engine compartment. It's putting too much fuel for the temperature of the motor/air and stalling the motor. This is also why it stalls only when coming to a stop: because you don't have your foot on the gas to let more air in to balance out the extra fuel that is being sent into the engine.
Apparently, this is something of an issue with Toyota coolant temp sensors after a long period of time (at least told to me). I'm so
****** off with the Toyota dealer you cannot imagine. They cringe whenever I go down there because they couldn't fix my problem and charged me for something that wasn't even causing the issue. As far as I'm concerned, dealers can only fix problems to which they know the cause of, and do not know for the life of them how to troubleshoot issues! For this they can all go ........
mmm ok I spose,cant say ive herd of this as being a common problem in fact its a new one on me ,ill replicate it and see what results i get.never stop learning do we?as far as the Ecu reading this as the sole signal to provide mixture adjustment,........I dont think so it is in fact a second tear signal according to my wiring diagram and ecu scematic.possibly was a fault, but im wondering if it was the only fault. dave
Replicated this fault on the dyno today.In open and closed circuit conditions and for approx 45 mins .NO WARM STALL.,Slight hc elevation and increase in nox. dave
How did you run the experiment? After the car entered closed loop mode (after running warm for awhile), did you pull off the plug to simulate a failure? How about pull off the plug and then short, to simulate a failure by short?
If only running without the ECT sensor plugged in, from the time it was cold, the computer might never enter closed loop mode, right?
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