These captures are from a 2004 Chrysler PT Cruiser with a 2.4l turbo.
Close examination alongside a known good waveform shows that the cams are out of time.
Here is the pressure transducer with the crank sensor and the cam sensor.
Saturday, March 29, 2014
Friday, March 14, 2014
A Weatherbug Spring Auto Tip.
We got to the shop this morning and found this on weatherbug.
http://weather.weatherbug.com/weather-news/weather-reports.html?zcode=z6286&story=8134
Well they asked for a reply, so why not?
................................................................
Who wrote that article? Does he/she actually have any formal training to work on cars?
O2 sensors:
"Faulty sensors are the most common reason for a failed emissions test. Precise oxygen sensors can increase your mileage efficiency by an average of 10-15 percent. Replacing a faulty oxygen sensor is easy and costs between 60-80 dollars on average, which is inexpensive compared to the amount of gas money it can save. The most obvious way to know when your oxygen sensor needs to be replaced is if the "check engine" light appears, but they should ideally be replaced every 50,000 miles."
Nobody should just on a whim replace an O2 sensor, or as they are more correctly named on most cars today an air/fuel ratio sensor. The cost to replace some of those components isn't the fifty or sixty dollars as suggested by the article but quite often can approach three hundred dollars per sensor. Besides, the computers on today's cars constantly test the performance of these sensors so they should be left alone until either the PCM reports them as failing or if a emissions control specialist technician proves that they need to be attended to. With today's cars some of the O2 and air fuel sensors have the potential to be lifetime components. That essentially means if your author was a tech and doing that work for someone else, the advice given would be a rip-off of that vehicle owner.
Spark Plugs:
"Spark plugs are good indicators of engine condition. Spark plugs should be checked every 30,000 miles, even if your car is low-maintenance."
In many cars scheduled maintenance for the spark plugs occurs at the 100,000 mile range, not 30,000. Plus many engine designs today have the spark plugs buried under the upper intake manifold and you need an experienced hand to deal with some of these because of the complexity at even that level.
Engine Oil:
"Oil filters: Oil filters are easy to replace and can help prevent unnecessary wear and tear of the engine. Oil filters should be replaced with engine oil every 3,000 miles."
Extended oil drain intervals are the norm today and the old 3 month or 3000 mile has been inaccurate for at least a decade. We have O.E. recommendations that run from the 5000 mile range to as much as 15000 miles. In fact there are some manufacturers maintenance reminder systems that could allow a car to go even further mathematically, but in practice routinely average 11,000. The real advice that should have been given would have the writer explaining to the readers how to choose the correct oil for their car so that it meets all of the O.E. requirements. Today vehicle owners cannot just grab any oil that shows their recommended viscosity on the front label.
Filters:
"Air filters: Cars run on both gas and oxygen. If the flow of air is blocked by a clogged air filter, a car`s performance and fuel efficiency will go down. Air filters should be checked and replaced every 12,000 miles."
A dirty air filter does not impact fuel mileage. Now power, maybe but mileage no. We have cars on the road today that do not have a scheduled air filter replacement. The ones that do it is often in the 30,000 and as much as 50,000 mile intervals.
"Transmission filters: A blocked transmission filter can produce transmission slippage, engagement problems and engine hesitation. This filter should be changed every 12-15,000 miles to extend the life of your automatic transmission."
Transmission filters on many designs are not serviceable without major disassembly and are considered a lifetime component, only to be addressed if the transmission needs a repair.
#weatherbug, #O2 Sensor, #transmission, #service, #air filter, #engine oil, #gas
http://weather.weatherbug.com/weather-news/weather-reports.html?zcode=z6286&story=8134
Well they asked for a reply, so why not?
................................................................
Who wrote that article? Does he/she actually have any formal training to work on cars?
O2 sensors:
"Faulty sensors are the most common reason for a failed emissions test. Precise oxygen sensors can increase your mileage efficiency by an average of 10-15 percent. Replacing a faulty oxygen sensor is easy and costs between 60-80 dollars on average, which is inexpensive compared to the amount of gas money it can save. The most obvious way to know when your oxygen sensor needs to be replaced is if the "check engine" light appears, but they should ideally be replaced every 50,000 miles."
Nobody should just on a whim replace an O2 sensor, or as they are more correctly named on most cars today an air/fuel ratio sensor. The cost to replace some of those components isn't the fifty or sixty dollars as suggested by the article but quite often can approach three hundred dollars per sensor. Besides, the computers on today's cars constantly test the performance of these sensors so they should be left alone until either the PCM reports them as failing or if a emissions control specialist technician proves that they need to be attended to. With today's cars some of the O2 and air fuel sensors have the potential to be lifetime components. That essentially means if your author was a tech and doing that work for someone else, the advice given would be a rip-off of that vehicle owner.
Spark Plugs:
"Spark plugs are good indicators of engine condition. Spark plugs should be checked every 30,000 miles, even if your car is low-maintenance."
In many cars scheduled maintenance for the spark plugs occurs at the 100,000 mile range, not 30,000. Plus many engine designs today have the spark plugs buried under the upper intake manifold and you need an experienced hand to deal with some of these because of the complexity at even that level.
Engine Oil:
"Oil filters: Oil filters are easy to replace and can help prevent unnecessary wear and tear of the engine. Oil filters should be replaced with engine oil every 3,000 miles."
Extended oil drain intervals are the norm today and the old 3 month or 3000 mile has been inaccurate for at least a decade. We have O.E. recommendations that run from the 5000 mile range to as much as 15000 miles. In fact there are some manufacturers maintenance reminder systems that could allow a car to go even further mathematically, but in practice routinely average 11,000. The real advice that should have been given would have the writer explaining to the readers how to choose the correct oil for their car so that it meets all of the O.E. requirements. Today vehicle owners cannot just grab any oil that shows their recommended viscosity on the front label.
Filters:
"Air filters: Cars run on both gas and oxygen. If the flow of air is blocked by a clogged air filter, a car`s performance and fuel efficiency will go down. Air filters should be checked and replaced every 12,000 miles."
A dirty air filter does not impact fuel mileage. Now power, maybe but mileage no. We have cars on the road today that do not have a scheduled air filter replacement. The ones that do it is often in the 30,000 and as much as 50,000 mile intervals.
"Transmission filters: A blocked transmission filter can produce transmission slippage, engagement problems and engine hesitation. This filter should be changed every 12-15,000 miles to extend the life of your automatic transmission."
Transmission filters on many designs are not serviceable without major disassembly and are considered a lifetime component, only to be addressed if the transmission needs a repair.
#weatherbug, #O2 Sensor, #transmission, #service, #air filter, #engine oil, #gas
Monday, March 10, 2014
The Impala, part #2
The main question asked at this point is how to proceed. It quite often happens that the information that is passed onto the technician about the symptoms that a car is displaying turns out to not match what was initially described to him/her. The Airbag (SRS) and ABS lights flashing on, instead of the turn indicators suggests a completely different issue, and the scan tool is now the next thing to bring into play.
So connecting the TechII scan tool, and going straight for the Airbag system there was no communication found with that module. Other systems were communicating on the data bus, and they of course had active codes for the airbag module communication failure and historical codes for multiple modules losing communication. When a module has fallen off of the data bus the thing to do is confirm power and grounds. In this case with the turn signals are also being affected, looking for something common to both systems makes for a logical plan and what they share is the same power connection from the ignition switch. The fuse for the turn signals is in the fuse block on the drivers end of the dash, and measuring power on that fuse showed 7v. Meanwhile any fuse that wasn't getting power from the pink wire pin "B" of connector #2 was a showing battery voltage of 12.2v. That's a big voltage drop to that circuit.
The customer was then brought to the car and shown what we had found, she didn't have a turn signal issue, she had an ignition switch problem that was even shutting down her alternator at times and it was a good thing we squeezed this in. It was kind of fun to show her the turn signals not working, which is the symptom that she noted, then show her the airbag module not having communication with the scan tool, and then by jumping power to the turn fuse, all of the systems that were affected came back to life. When the jumper was removed, they all shut right back down, which by the way is exactly what the car was going to do to her real soon, stall out and leave her stranded somewhere. That pin of the ignition switch also powers up the fuel injection system, and all she had to do was drop just a little more power and that would have shut the engine down too. At this point it was time to get a charger on the battery, and get a new switch ordered and installed and we had her back on the road in a couple hours.
#Tech II , # Airbag, #ignition, #ignition switch, #SRS, #battery, #module, #fuse, #jumper wire, #data bus, #turn signal
So connecting the TechII scan tool, and going straight for the Airbag system there was no communication found with that module. Other systems were communicating on the data bus, and they of course had active codes for the airbag module communication failure and historical codes for multiple modules losing communication. When a module has fallen off of the data bus the thing to do is confirm power and grounds. In this case with the turn signals are also being affected, looking for something common to both systems makes for a logical plan and what they share is the same power connection from the ignition switch. The fuse for the turn signals is in the fuse block on the drivers end of the dash, and measuring power on that fuse showed 7v. Meanwhile any fuse that wasn't getting power from the pink wire pin "B" of connector #2 was a showing battery voltage of 12.2v. That's a big voltage drop to that circuit.
The customer was then brought to the car and shown what we had found, she didn't have a turn signal issue, she had an ignition switch problem that was even shutting down her alternator at times and it was a good thing we squeezed this in. It was kind of fun to show her the turn signals not working, which is the symptom that she noted, then show her the airbag module not having communication with the scan tool, and then by jumping power to the turn fuse, all of the systems that were affected came back to life. When the jumper was removed, they all shut right back down, which by the way is exactly what the car was going to do to her real soon, stall out and leave her stranded somewhere. That pin of the ignition switch also powers up the fuel injection system, and all she had to do was drop just a little more power and that would have shut the engine down too. At this point it was time to get a charger on the battery, and get a new switch ordered and installed and we had her back on the road in a couple hours.
#Tech II , # Airbag, #ignition, #ignition switch, #SRS, #battery, #module, #fuse, #jumper wire, #data bus, #turn signal
Sunday, March 9, 2014
From the Saturday Morning Mechanic Show
I do a live radio show and one of the callers had an interesting question. Her 2002 Chevrolet Impala would randomly make a buzzing sound and the turn signals would not work correctly when she tried to use them. She also mentioned that the lights on the dash would flash to which I asked her if she was referring to the turn indicators and she said yes. I then asked her if the four way (hazzard) flashers worked normally when she pushed that button and she said yes they did.
This is a common description of the flasher unit failing inside the four way flasher button, but like any failure it needs to be confirmed before one simply replaces a part. The caller had already had several people look at the car for this issue but it wasn't acting up when they did so they did the right thing which was to ask her to return when it did act up. Just because failures of that switch are common, that does not mean that it is bad this time. In the past if a shop would replace that part based on nothing except experience, and doing that failed to fix the car, they would end up with an unhappy customer and be refunding the money and it didn't matter how it was explained, they were danged if they did try, and danged if they didn't.
She called us at our shop a few hours later that day and to their credit even armed with more information her local shop didn't want to see the car, nor change the flasher without confirming the cause and she wanted to know if we would look at it. I told her pretty much the same thing, except we would start testing and see if we can determine anything. She showed up about 3:30pm and we brought the car in the door. Now when we were talking she changed the story a little bit. The lights that were acting strangely wasn't the turn indicators, it was several of the other lights on the dash which included the airbag light, and the antilock brake lights. She also said quite happily that it started doing it on her way down to the shop. Now things were starting to make more sense, when the ABS and SIR lights started coming on, that's when the turn signals wouldn't work and a buzzing could be heard in the dash if you tried to use them. That's a completely different scenario compared to what she seemed to describe while we were on the air.
Based on this updated information, what path would you choose to start your testing? Do you have any expectations as to what you are likely to find? Use the comments to field your ideas and I'll respond with what you would have found.
#4way, #four way, #Chevrolet, #Impala, #turn signals, #Radio, #saturday morning mechanic, #antilock, #brakes, #buzz, #hazzard
This is a common description of the flasher unit failing inside the four way flasher button, but like any failure it needs to be confirmed before one simply replaces a part. The caller had already had several people look at the car for this issue but it wasn't acting up when they did so they did the right thing which was to ask her to return when it did act up. Just because failures of that switch are common, that does not mean that it is bad this time. In the past if a shop would replace that part based on nothing except experience, and doing that failed to fix the car, they would end up with an unhappy customer and be refunding the money and it didn't matter how it was explained, they were danged if they did try, and danged if they didn't.
She called us at our shop a few hours later that day and to their credit even armed with more information her local shop didn't want to see the car, nor change the flasher without confirming the cause and she wanted to know if we would look at it. I told her pretty much the same thing, except we would start testing and see if we can determine anything. She showed up about 3:30pm and we brought the car in the door. Now when we were talking she changed the story a little bit. The lights that were acting strangely wasn't the turn indicators, it was several of the other lights on the dash which included the airbag light, and the antilock brake lights. She also said quite happily that it started doing it on her way down to the shop. Now things were starting to make more sense, when the ABS and SIR lights started coming on, that's when the turn signals wouldn't work and a buzzing could be heard in the dash if you tried to use them. That's a completely different scenario compared to what she seemed to describe while we were on the air.
Based on this updated information, what path would you choose to start your testing? Do you have any expectations as to what you are likely to find? Use the comments to field your ideas and I'll respond with what you would have found.
#4way, #four way, #Chevrolet, #Impala, #turn signals, #Radio, #saturday morning mechanic, #antilock, #brakes, #buzz, #hazzard
Saturday, March 8, 2014
Here is a Honda CRV Cranks but won't start.
This car was reported to have been running very poorly earlier in the day and then it stalled and would not restart. The driver reported adding three quarts of oil earlier (it only holds 4).
The initial testing confirmed that there was spark, and while there was an odor of fuel when cranking, that actually still needed confirmed, so alternate fuel was attempted and the engine didn't even attempt to fire.
The next step was to inspect the spark plugs and they were fouled black with soot. Conventional compression testing showed the compression in #1 to be 110PSI. We have to allow for the possibility of the cylinders to be washed down from too much fuel and no combustion so the pressure transducer now becomes the best next step.
Here is the waveform that was achieved. What do you think is wrong?
The initial testing confirmed that there was spark, and while there was an odor of fuel when cranking, that actually still needed confirmed, so alternate fuel was attempted and the engine didn't even attempt to fire.
The next step was to inspect the spark plugs and they were fouled black with soot. Conventional compression testing showed the compression in #1 to be 110PSI. We have to allow for the possibility of the cylinders to be washed down from too much fuel and no combustion so the pressure transducer now becomes the best next step.
Here is the waveform that was achieved. What do you think is wrong?
Here is a known good cranking waveform to compare
#Honda, #compression test, #Autotechtitude
#PICO, #scope, #thecardoc, #cardoc
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