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A Mechanic's Life - Tales From Under the Hood

2782 messages,  Last post on May 18, 2013 at 10:36 AM

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Messages Page 101 of 279

#995 of 2782 Re: I'll need more time to read this article [Mr_Shiftright] by andre1969

Jan 27, 2013 (1:31 pm)

Replying to: Mr_Shiftright (Jan 27, 2013 10:36 am)
And old car hobbyists say it's the government that's trying to destroy old cars?
 
IIRC, the government destroyed that one, once they seized it. I think they scuttled it.

#996 of 2782 Re: I'll need more time to read this article [andre1969] by Mr_Shiftright HOST

Jan 27, 2013 (2:42 pm)

Replying to: andre1969 (Jan 27, 2013 1:31 pm)
one must presume it was already "modified" beyond redemption anyway.

#997 of 2782 Re: I'll need more time to read this article [andre1969] by imidazol97

Jan 27, 2013 (2:46 pm)

Replying to: andre1969 (Jan 27, 2013 1:31 pm)
>IIRC, the government destroyed that one, once they seized it. I think they scuttled it.
 
Do you know the story on that picture?

#998 of 2782 Re: I'll need more time to read this article [imidazol97] by thecardoc3

Jan 27, 2013 (3:23 pm)

Replying to: imidazol97 (Jan 27, 2013 2:46 pm)
Do you know the story on that picture?
 
http://www.floatingcubans.com/

#999 of 2782 Re: This is some of what we study today [thecardoc3] by thecardoc3

Jan 28, 2013 (1:53 pm)

Replying to: thecardoc3 (Jan 27, 2013 1:01 pm)
Hmmm, I thought this would bring out some needed dialog. Or maybe everyone's been waiting because they want post #1000....
 
When you really see what goes into diagnostics, which Dan has done a great job representing, it takes the perceptions like CarMD, and others who think pulling a code and slamming a part is all there is to it and proves they couldn't be more wrong with what they preach. It's never been the way that they want to try and say that it is and trying to convince the public that their toy of a tool will do everything that a consumer might need wasn't being honest with them. The trick is Dan's site doesn't even cover everything that we do today, he's only got on there material for his students to work from, not some of the really complicated stuff that we have to use to challenge the real master techs that are out there today.

#1000 of 2782 Re: This is some of what we study today [thecardoc3] by srs_49

Jan 28, 2013 (3:09 pm)

Replying to: thecardoc3 (Jan 28, 2013 1:53 pm)
I thought this would bring out some needed dialog.
 
First time through, I wasn't sure what we were supposed to look at on the site you linked to - scannerdanner.com. Went back and found out you could scroll through the graphics.
 
It was hard to tell what they were trying to show, in some cases.
 
Fig 17&18, I didn't realize some manufacturer's biased their O2 sensors above ground.
 
Fig 23, not sure what we're looking at - injector current?
 
Fig 4 (Saturated Switch Waveform) was really informative. So was 13, 14, & 12 (dirty throttle body).

#1001 of 2782 Re: This is some of what we study today [srs_49] by thecardoc3

Jan 28, 2013 (4:30 pm)

Replying to: srs_49 (Jan 28, 2013 3:09 pm)
Fig 17&18, I didn't realize some manufacturer's biased their O2 sensors above ground.
 
Yea that's a Chrysler trick. Toyota's A/F sensors are even stranger where you read the current flow to know what the actual A/F ratio is. The sensor voltage would be read between 3.0v (rich) and 3.5v (lean), with 3.3v being "normal".
 
Fig 23, not sure what we're looking at - injector current
 
Using the low amps probe and an oscilloscope is the right way to monitor many of the outputs from on board computers.
 
Again, what you see there is the easy stuff, and actually the catalytic convertor test that he has there is actually flawed and isn't a good representation for what a tech needs to know. While to a certain level of understanding it is easy to expect that is accurate, with deeper education we learn why it's not a reliable test.

#1002 of 2782 Re: This is some of what we study today [thecardoc3] by Mr_Shiftright HOST

Jan 28, 2013 (6:21 pm)

Replying to: thecardoc3 (Jan 28, 2013 4:30 pm)
What *IS* a reliable catalytic converter test?

#1003 of 2782 Re: This is some of what we study today [Mr_Shiftright] by andre1969

Jan 28, 2013 (6:23 pm)

Replying to: Mr_Shiftright (Jan 28, 2013 6:21 pm)
What *IS* a reliable catalytic converter test?
 
A hacksaw, a straight piece of pipe, and a roll of "Tiger Paw (tm)" tape!

#1004 of 2782 Re: This is some of what we study today [Mr_Shiftright] by thecardoc3

Jan 28, 2013 (11:57 pm)

Replying to: Mr_Shiftright (Jan 28, 2013 6:21 pm)
What *IS* a reliable catalytic converter test?
 
Check for any exhaust leaks upstream of the catalyst, and before the downstream O2 sensor. Check for any TSB's and confirm that the PCM has the most up to date software. Monitor vehicle operation while checking fuel trim corrections and engine load pids, and if nothing is found then you trust the PCM in the case of a P0420, P0430.

Messages Page 101 of 279

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