coolant temperature sensor
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From: Ray O on 21 Mar 2010 02:16 "Michael" <mrdarrett(a)gmail.com> wrote in message news:642dba86-806e-4276-9602-3bcd9119e4bb(a)k5g2000pra.googlegroups.com... On Mar 19, 9:28 am, "Ray O" <rokig...(a)NOSPAMtristarassociates.com> wrote: > "Michael" <mrdarr...(a)gmail.com> wrote in message > > news:3227af09-4037-496e-ae1b-fc27d8018d64(a)u5g2000prd.googlegroups.com... > On Mar 18, 9:47 pm, "Ray O" <rokig...(a)NOSPAMtristarassociates.com> > wrote: > > > > > "Michael" <mrdarr...(a)gmail.com> wrote in message > > >news:8d68a62e-c06e-41dd-833a-ea073cdc86d6(a)n39g2000prj.googlegroups.com... > > <snipped> > > > > > Technically, the IAC is not supposed to be serviceable, but IMO, if > > > > it > > > > is > > > > gummed up, there is no harm in trying to free it up. It usually > > > > takes > > > > several doses of carb cleaner to free it up. There should be another > > > > hole > > > > or opening on the other side of the throttle plate. While you are at > > > > it, > > > > clean both sides and the edge of the throttle plate and the pin that > > > > the > > > > plate pivots on, and the inside of the throttle body. Wipe out the > > > > residue > > > > so it doesn't re-deposit itself in the throttle body. > > > > > My un-scientific observation is that throttle bodies and IAC valves > > > > get > > > > more > > > > gummed up on cars that have not had engine oil changes done quite on > > > > schedule. > > > > > Your car will have a mass air flow (MAF) or a manifold absolute > > > > pressure > > > > (MAP) sensor, but not both. I think Camrys had MAF sensors. When you > > > > clean > > > > the MAF sensor, spray some brake cleaner or electronic tuner cleaner > > > > in > > > > the > > > > opening, let the stuff drip out, then air dry. Do not use anything > > > > that > > > > will leave a coating like carb cleaner on the MAF sensor and do not > > > > stick > > > > anything inside the opening like a q-tip because you can damage the > > > > hot > > > > wire > > > > inside the opening. > > > > > 2000 RPM cold idle seems a little high but it is Ok for the first > > > > 10-20 > > > > seconds. A prolonged high cold idle could also be caused by a gummed > > > > IAC > > > > valve. > > > > -- > > > > > Ray O > > > > (correct punctuation to reply) > > > > Ok, cleaned MAF (MAP?) sensor (it's an I-4) w/ non-chlorinated brake > > > cleaner. Seems like the pipe won't go in all the way into the intake > > > manifold... can still see some threads protruding.. but it's tight > > > going in. Didn't want to damage w/ my adjustable wrench. > > > > Two trips around town... no stall yet... (crossing fingers...) > > > > Thanks for all the help. will do the throttle body next time I get a > > > spare moment. Hoping to also change the throttle body coolant hoses > > > while I'm there... > > > > Michael > > > > ********* > > > let us know if the fix sticks. > > > -- > > > > Ray O > > > (correct punctuation to reply) > > > Fix seems to work... will let you know if it stalls again... > > > Thanks again > > > Michael > > > **************** > > I guess I have to practice what I preach - my daughter told me that our > > '97 > > Avalon is occasionally stalling on warm startup. > > > -- > > > Ray O > > (correct punctuation to reply) > > On startup only? hmm... I had the warm stalling at stop signs/red > lights, and after much frustration narrowed it down to a faulty ECT > sensor. Fails when warm, confusing the computer. Mileage suffered > too. Changed it (it was a cheapish part, so didn't care to test it > out of the car - wouldn't help anyway since it's intermittent) and no > more warm stop sign stalling ever. > > Michael > > *************** > Once the car is started, the engine coolant temperature shouldn't have any > effect on how the engine runs, whether the engine is hot or cold. While > the > engine is cranking, the engine computer will send an extra shot of fuel if > the engine coolant temperature is below a certain threshold, something > like > room temperature. IIRC, once the engine is started, engine coolant > temperature is not one of the inputs for engine operation. > -- > > Ray O > (correct punctuation to reply) I was skeptical too when I read this (message 53) http://toyotaownersclub.com/forums/index.php?showtopic=8158&st=50 but it worked for me. About two years ago I replaced the ECT sensor. Prior to that I'd get the stall maybe once a month, maybe once a week, esp. in the summertime. I thought I'd had it fixed by changing an EGR modulator in the wintertime, but the summer the stall came back until the ECT sensor was changed. I even managed to confuse the ECT sensor with the ECT sender... that set me back a few months too... :D Michael ********** What was the difference in voltage between the old ECT sensor and the replacement ECT sensor? -- Ray O (correct punctuation to reply)
From: Michael on 21 Mar 2010 03:11 On Mar 20, 10:16 pm, "Ray O" <rokig...(a)NOSPAMtristarassociates.com> wrote: > "Michael" <mrdarr...(a)gmail.com> wrote in message > > news:642dba86-806e-4276-9602-3bcd9119e4bb(a)k5g2000pra.googlegroups.com... > On Mar 19, 9:28 am, "Ray O" <rokig...(a)NOSPAMtristarassociates.com> > wrote: > > > > > "Michael" <mrdarr...(a)gmail.com> wrote in message > > >news:3227af09-4037-496e-ae1b-fc27d8018d64(a)u5g2000prd.googlegroups.com... > > On Mar 18, 9:47 pm, "Ray O" <rokig...(a)NOSPAMtristarassociates.com> > > wrote: > > > > "Michael" <mrdarr...(a)gmail.com> wrote in message > > > >news:8d68a62e-c06e-41dd-833a-ea073cdc86d6(a)n39g2000prj.googlegroups.com.... > > > <snipped> > > > > > > Technically, the IAC is not supposed to be serviceable, but IMO, if > > > > > it > > > > > is > > > > > gummed up, there is no harm in trying to free it up. It usually > > > > > takes > > > > > several doses of carb cleaner to free it up. There should be another > > > > > hole > > > > > or opening on the other side of the throttle plate. While you are at > > > > > it, > > > > > clean both sides and the edge of the throttle plate and the pin that > > > > > the > > > > > plate pivots on, and the inside of the throttle body. Wipe out the > > > > > residue > > > > > so it doesn't re-deposit itself in the throttle body. > > > > > > My un-scientific observation is that throttle bodies and IAC valves > > > > > get > > > > > more > > > > > gummed up on cars that have not had engine oil changes done quite on > > > > > schedule. > > > > > > Your car will have a mass air flow (MAF) or a manifold absolute > > > > > pressure > > > > > (MAP) sensor, but not both. I think Camrys had MAF sensors. When you > > > > > clean > > > > > the MAF sensor, spray some brake cleaner or electronic tuner cleaner > > > > > in > > > > > the > > > > > opening, let the stuff drip out, then air dry. Do not use anything > > > > > that > > > > > will leave a coating like carb cleaner on the MAF sensor and do not > > > > > stick > > > > > anything inside the opening like a q-tip because you can damage the > > > > > hot > > > > > wire > > > > > inside the opening. > > > > > > 2000 RPM cold idle seems a little high but it is Ok for the first > > > > > 10-20 > > > > > seconds. A prolonged high cold idle could also be caused by a gummed > > > > > IAC > > > > > valve. > > > > > -- > > > > > > Ray O > > > > > (correct punctuation to reply) > > > > > Ok, cleaned MAF (MAP?) sensor (it's an I-4) w/ non-chlorinated brake > > > > cleaner. Seems like the pipe won't go in all the way into the intake > > > > manifold... can still see some threads protruding.. but it's tight > > > > going in. Didn't want to damage w/ my adjustable wrench. > > > > > Two trips around town... no stall yet... (crossing fingers...) > > > > > Thanks for all the help. will do the throttle body next time I get a > > > > spare moment. Hoping to also change the throttle body coolant hoses > > > > while I'm there... > > > > > Michael > > > > > ********* > > > > let us know if the fix sticks. > > > > -- > > > > > Ray O > > > > (correct punctuation to reply) > > > > Fix seems to work... will let you know if it stalls again... > > > > Thanks again > > > > Michael > > > > **************** > > > I guess I have to practice what I preach - my daughter told me that our > > > '97 > > > Avalon is occasionally stalling on warm startup. > > > > -- > > > > Ray O > > > (correct punctuation to reply) > > > On startup only? hmm... I had the warm stalling at stop signs/red > > lights, and after much frustration narrowed it down to a faulty ECT > > sensor. Fails when warm, confusing the computer. Mileage suffered > > too. Changed it (it was a cheapish part, so didn't care to test it > > out of the car - wouldn't help anyway since it's intermittent) and no > > more warm stop sign stalling ever. > > > Michael > > > *************** > > Once the car is started, the engine coolant temperature shouldn't have any > > effect on how the engine runs, whether the engine is hot or cold. While > > the > > engine is cranking, the engine computer will send an extra shot of fuel if > > the engine coolant temperature is below a certain threshold, something > > like > > room temperature. IIRC, once the engine is started, engine coolant > > temperature is not one of the inputs for engine operation. > > -- > > > Ray O > > (correct punctuation to reply) > > I was skeptical too when I read this (message 53)http://toyotaownersclub.com/forums/index.php?showtopic=8158&st=50 > > but it worked for me. About two years ago I replaced the ECT sensor. > Prior to that I'd get the stall maybe once a month, maybe once a week, > esp. in the summertime. I thought I'd had it fixed by changing an EGR > modulator in the wintertime, but the summer the stall came back until > the ECT sensor was changed. > > I even managed to confuse the ECT sensor with the ECT sender... that > set me back a few months too... :D > > Michael > > ********** > What was the difference in voltage between the old ECT sensor and the > replacement ECT sensor? > -- > > Ray O > (correct punctuation to reply) Didn't bother to check the resistances. From the previous article I quoted, it happens only intermittently, so I thought measuring the resistances would be a waste of time. Coincidentally though I just found the bad ECT sensor while looking for something else. It reads 2.04 kOhms at room temperature ~70F. Maybe I can use it for a non-critical science project someday...
From: jim beam on 21 Mar 2010 11:04
On 03/19/2010 10:28 AM, Ray O wrote: > "Michael"<mrdarrett(a)gmail.com> wrote in message > news:3227af09-4037-496e-ae1b-fc27d8018d64(a)u5g2000prd.googlegroups.com... > On Mar 18, 9:47 pm, "Ray O"<rokig...(a)NOSPAMtristarassociates.com> > wrote: >> "Michael"<mrdarr...(a)gmail.com> wrote in message >> >> news:8d68a62e-c06e-41dd-833a-ea073cdc86d6(a)n39g2000prj.googlegroups.com... >> <snipped> >> >> >> >>>> Technically, the IAC is not supposed to be serviceable, but IMO, if it >>>> is >>>> gummed up, there is no harm in trying to free it up. It usually takes >>>> several doses of carb cleaner to free it up. There should be another >>>> hole >>>> or opening on the other side of the throttle plate. While you are at >>>> it, >>>> clean both sides and the edge of the throttle plate and the pin that >>>> the >>>> plate pivots on, and the inside of the throttle body. Wipe out the >>>> residue >>>> so it doesn't re-deposit itself in the throttle body. >> >>>> My un-scientific observation is that throttle bodies and IAC valves >>>> get >>>> more >>>> gummed up on cars that have not had engine oil changes done quite on >>>> schedule. >> >>>> Your car will have a mass air flow (MAF) or a manifold absolute >>>> pressure >>>> (MAP) sensor, but not both. I think Camrys had MAF sensors. When you >>>> clean >>>> the MAF sensor, spray some brake cleaner or electronic tuner cleaner >>>> in >>>> the >>>> opening, let the stuff drip out, then air dry. Do not use anything >>>> that >>>> will leave a coating like carb cleaner on the MAF sensor and do not >>>> stick >>>> anything inside the opening like a q-tip because you can damage the >>>> hot >>>> wire >>>> inside the opening. >> >>>> 2000 RPM cold idle seems a little high but it is Ok for the first >>>> 10-20 >>>> seconds. A prolonged high cold idle could also be caused by a gummed >>>> IAC >>>> valve. >>>> -- >> >>>> Ray O >>>> (correct punctuation to reply) >> >>> Ok, cleaned MAF (MAP?) sensor (it's an I-4) w/ non-chlorinated brake >>> cleaner. Seems like the pipe won't go in all the way into the intake >>> manifold... can still see some threads protruding.. but it's tight >>> going in. Didn't want to damage w/ my adjustable wrench. >> >>> Two trips around town... no stall yet... (crossing fingers...) >> >>> Thanks for all the help. will do the throttle body next time I get a >>> spare moment. Hoping to also change the throttle body coolant hoses >>> while I'm there... >> >>> Michael >> >>> ********* >>> let us know if the fix sticks. >>> -- >> >>> Ray O >>> (correct punctuation to reply) >> >> Fix seems to work... will let you know if it stalls again... >> >> Thanks again >> >> Michael >> >> **************** >> I guess I have to practice what I preach - my daughter told me that our >> '97 >> Avalon is occasionally stalling on warm startup. >> >> -- >> >> Ray O >> (correct punctuation to reply) > > > On startup only? hmm... I had the warm stalling at stop signs/red > lights, and after much frustration narrowed it down to a faulty ECT > sensor. Fails when warm, confusing the computer. Mileage suffered > too. Changed it (it was a cheapish part, so didn't care to test it > out of the car - wouldn't help anyway since it's intermittent) and no > more warm stop sign stalling ever. > > Michael > > *************** > Once the car is started, the engine coolant temperature shouldn't have any > effect on how the engine runs, whether the engine is hot or cold. While the > engine is cranking, the engine computer will send an extra shot of fuel if > the engine coolant temperature is below a certain threshold, something like > room temperature. IIRC, once the engine is started, engine coolant > temperature is not one of the inputs for engine operation. completely incorrect. coolant temp is actively monitored and part of injection math at all times. below about 75C, coolant temperature vs. fuel injected is on a steep curve. above ~75C, the usual is to keep the adjustment flat. different manufacturers have different strategies for "beyond" the normal op temp. for overheating, it's possible to "go rich" to cool combustion temps a bit for instance. some [unintentionally] go lean and fry your motor - jag v12. -- nomina rutrum rutrum |