Any Open Source Solutions For DIY Auto Diagnostics? 270
slaxx writes "As an avid tinkerer, I really want to collect as much data about my car as possible. Using On-Board Diagnostics (OBDII) sounded great to me, but the pricetags of systems like AutoTap Scanner are a bit much for my college budget to handle. Are there any free, open source solutions available? What do Slashdotters do to tinker and record the inner workings of their own vehicles?"
Have an arduino board? (Score:5, Interesting)
When I have the time, i've been meaning to try something like this:
http://en.wikipedia.org/wiki/OBDuino [wikipedia.org]
Into my Car so I can get additional performance gagues + graphs. I have the Arduino board, and can solder things here and there, I've just never gotten around to it ....
Cleverness is free (Score:1, Interesting)
IF you need a scanner, that's an amazing price.
A *really good* scanner will cost you another zero. This one looks pretty good.
However, most electrical repairs cost more than $200 because the most important tool (the diagnostician's brain) isn't working properly. It's amazing how many people replace the starter and battery for a low crank, when the real problem was a $10 battery cable. I've seen people replace the entire secondary ignition system because they didn't look for a broken ground wire.
If you failed a smog test, the most likely faults will be fixed for pennies. Like a loose wire or broken vacuum line. But you can usually diagnose a failed sniff best with the sniff results.
If you have a lot more time than money, you can diagnose the pre-OBD way. With a table of normal computer inputs and outputs (try the library -- Mitchell publishes these) and both analog and digital voltmeters, plus tach and dwell/duty cycle, you can get pretty far.
Re:As an engineer... (Score:2, Interesting)
I'm not a mechanic now, but I have worked at an auto shop. I don't think it's any different now with modern technology than how it's ever been. Good mechanics use all the tools at hand to find out what's really wrong, and then fix it. Crappy mechanics replace whatever part the flowchart, manual, or computer says is wrong and hope for the best. Computers only help both types do what they were already doing.
Of course the trouble is that most shops that I am aware of pay their mechanics based on fixing specific things - there's a specific amount they get paid for, say, replacing the O2 sensor or the throttle body or whatever, but there's no pay for figuring out what the hell is really wrong with the car. So it creates an incentive to find something to replace as quickly as possible, replace it, and get paid and move on to the next car. Even doing it wrong isn't that much of a disincentive - the car comes back and they guess something else to fix and hope that works too. Being a good guy and not getting the customer pissed is really the only incentive to do it right. I'm not saying that it's all bad or that I have a better system for how to pay mechanics in an auditable way*, but that's one of the issues.
* It's nice for the higher-up managers and accountants to do it this way because they can say "this guy replaced 20 O2 sensors this month, and each one takes X hours, so we pay him for that and everyone's happy. But this other guy says that he spent 20 hours this month diagnosing problems. How do I know he really spent 20 hours doing that and wasn't just screwing around?" You can't tell, because of the nature of troubleshooting, so it kinda slips through the cracks.
Re:Buy an oldtimer or get a Matlab license (Score:3, Interesting)
Probably a solid state analog fuel/ignition 'controller', not really a computer in the modern sense. I guess it's a gasser thing. An '81 Jeep I used to own had one, but the '84 MB diesel I have now has no 'black boxes' at all. You can disconnect the battery after it's running if you want.
Tool rental service!!! (Score:1, Interesting)
Just borrow a code scanner from Autozone or other autoparts store (deposit usually required). They are simple enough to use. The store may even do the scan for you for free.
The tool rental service that autoparts stores have is a great way to use expensive tools that you may only need once.