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Discussion Starter #1
Hi

I often wondered if it makes any sense to have a database or listings of the typical values of the most important PIDs for each vehicle model ? The idea is that one can compare, diagnose and check for variances against data sets that represent engines in good working condition. In order for the data to make sense, there would be some common baselines such as RPM, coolant temp and perhaps also intake air temp.

I know that a lot of pros and DIY enthusiasts are equipped with OBD scanners (I personally use an ELM327 interface and a laptop installed with FORScan) but since I cannot find any reference values, I'm always at a loss to figure out what's optimal and what's not.

Would be great to have your opinions on this ?

Cheers
 

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I agree. Kinda like the old expression of "a pig with a wristwatch".

I did some datalogging using the Torque App and the result was NOW WHAT? I downloaded a log-file I found that someone here made public. Problem is; he used a different data-logging tool AND had a slightly different car. To make the comparison of your data verses someone else is difficult due to many subtle or drastic differences. You and I might be able to use our data and find something very wrong BUT it takes time and experience to learn to use the data to find something that is "slightly off".

A guy here (iminhell) helped me on this subject a while back, but I did not bookmark the thread so I am unsure where it is at the moment.

Did you know about the FF Tuning Area? -located here->
http://www.focusfanatics.com/forum/forumdisplay.php?f=79

LiveLink Gen II highly recommended and is free here->
http://www.focusfanatics.com/forum/...tp://sctflash.com/software/LiveLink_GenII.exe

Here is a link to the datalog (csv file) I found and it was created by someone else. I believe it was created with an SCT Xcal3. It has some of the PIDS and values that you asked about.
https://drive.google.com/file/d/0BwoYnd3KRtjceHdfRFNqRHV5U28/view?usp=sharing
 

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Discussion Starter #3
Thanks so much Marde. I followed the links you supplied and well - there are some clever guys out there doing some really scary stuff on their ECUs. Their goals however are a little bit different than mine - given that all modern vehicles are equipped with live data, one should be possible to diagnose (or at least narrow down) a problem through analysis and correlation. Very often it's not easy to tell what is wrong right away and vehicle owners frequently end up on a wild goose chase, pulling out parts that don't need to be replaced until they find the holy grail.

For instance, an idle or stalling problem can be due to a number of things. But instead of taking out the fuel pump or replacing the filter, shouldn't this be a question of just looking at the Fuel Pressure PID and verify that the value is in range ?

Going through your links, I stumbled on the following reference that provides some insight into the typical PID values for the Canadian / US market -

http://www.focusfanatics.com/forum/showthread.php?t=214389

Unfortunately I cannot find anything similar for the European version so for now all I can do is take a snapshot of the PID values at different RPMs while the vehicle is still OK and use them as a reference later when something crops up.

The LiveLink Gen software looks interesting especially the playback feature. Will have a go at it tomorrow.

Thanks once again.
 

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The problem is that you seem to think there is a 'general rule'. There is not.

You will have much better luck asking a direct question pertaining to what you want to know about your car.

A GM car is not going to present the same data as a Ford, or Lexus or Nissan or VW.
There are similar trends in the data, but not values ... apart from air mass, fuel mass and a few other things. The scale of the PID can differ widely.

And if any of this went over your head, do you really expect anyone else to be able to understand and use it for general diagnosis?
There is a very good reason modern automotive technicians have training and then brand specific training. It's not something the backyard joe can be taught in a matter of a few days/weeks; and simply looking at numbers doesn't mean you understand them or know why they are.


Again, ask specif question and maybe we/I can provide relevant answers.


Here is a description list of what you may have --> http://www.palmerperformance.com/support/supported_vehicles/ford_enhanced.php
And a Wiki --> http://en.wikipedia.org/wiki/OBD-II_PIDs
There is also a command line command to retrieve a supported PID list, but I can't recall it off the top of my head. Might be in the ELM327 datasheet (which assumes yours is genuine)?
 

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Data tables can give too much information, scan tool that gives averages with detail avail. graphed is handier.

Some things are more useful than others when looking for faults, fuel pressure mentioned is one that's helpful - the problem is getting someone to check it (grin) when they'd rather spend on guessing the right part for a possible problem.

IAT is one I've mentioned to be checked, as a wrong reading there is easy to see and can cause some real problems.

In general, you're often looking for wacky readings like those indicating a sensor failure for basic diagnostics.
 

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As I've said before-throwing parts to see which one sticks is so much easier (and fun!) especially when the first one thrown is usually the brain. Having to think about things hurts too much, why it gets tossed first.................
 

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Discussion Starter #7
Thanks for the input guys.

@iminhell - Of course I expect that different makes, models and even perhaps ECU firmware versions will yield different PID values. There is no particular issue that I need to address at this point but I was just wondering whether there is more that can be done with an OBD scanner than just chasing and clearing DTCs. Going by what I read on this forum, the MIL / CEL / DTCs rarely come up inspite of the pletora of issues that are raised on a daily basis, from idle problems to engines not starting at all. It seems to me that the ECU is only designed to flag hard faults but lacks the required logic to determine the cause for variances outside the normal behaviour envelope of the engine. It could be that such intelligent diagnostics are only available to the authorised dealers but I don't see why this procedure cannot be done manually if one has to have a set of min and max thresholds for the critical PIDs and how they behave under certain load conditions.

In the meantime, I managed to locate some interesting Ford OBD diagnostics literature which illustrates more or less where I wanted to go with this post -

http://www.motorcraftservice.com/vdirs/diagnostics/pdf/obdsm1202.pdf
https://www.dropbox.com/s/reiqnzmir66t97u/OBDSM1403.pdf
https://www.motorcraftservice.com/vdirs/diagnostics/pdf/OBDSM508.pdf

@Marde - Tried the LiveLink Gen II but it seems that it only works with SCT Adapters. I have an ELM327 interface but it just wouldn't talk to it. I noticed that LiveLink installs its own drivers so it could be a proprietary hardware issue.

Thanks to all for your time.
 

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@Marde - Tried the LiveLink Gen II but it seems that it only works with SCT Adapters. I have an ELM327 interface but it just wouldn't talk to it. I noticed that LiveLink installs its own drivers so it could be a proprietary hardware issue.

Thanks to all for your time.
Whoops, Uhmmm? -yes. I did not mean to suggest that Gen-II works with your ELM327 device. However, if you datalog with your ELM327, and create a csv file, you can use Gen-II to open and analyze your datalog BUT ONLY IF you first edit your csv file and make it similar to the FIRST COLUMN of a csv file that was created by a SCT device. I linked (far above) to a location where you can download a csv file that was created by an SCT device.

I know this works because I did it. Yes, I datalogged with an ELM327 bluetooth & Torque App and later opened my csv in Gen-II. -only AFTER I modified it. What a drag that was doing a couple or several times.

End result tho is crap because the ELM and Torque have a couple issues (1) a few PIDS unavailable and (2) data sample rate is SLOW -fastest is 10 samples per second verses an SCT Xcal that does (maybe) 100 samples per second (3) and while at 10 samples per second, many were stale or not moving-> It is almost the same as only having 2 or 3 samples per second.

Torque App makes a fun toy and a decent tool. Datalogging with it is a test of your patience and the results are not very useful... even after you get the csv opened in LiveLink Gen-II. If you (and me) really want to get into this stuff, you gotta step up and buy a tool similar to the Xcal3.
 

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...

I managed to locate some interesting Ford OBD diagnostics literature which illustrates more or less where I wanted to go with this post -

http://www.motorcraftservice.com/vdirs/diagnostics/pdf/obdsm1202.pdf
https://www.dropbox.com/s/reiqnzmir66t97u/OBDSM1403.pdf
https://www.motorcraftservice.com/vdirs/diagnostics/pdf/OBDSM508.pdf
Did not hit those links until minutes ago. Awesome resource! Glad bottom link is a 2005 version, others are 2012 and 2014. Never seen it. Highly recommended others check it out. Thank you.
 

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Discussion Starter #10
@Marde - Glad to be of help. Usually this type of literature does not come up on Google but I just happen to come across it on other forums. If you're interested in a very good OBD workshop reference, this one is online -

http://www.lbcc.edu/attc/documents/OBD2.pdf

And thanks for the tip on how to import data on LiveLink Gen II. FORScan have similar functionality, i.e. you can save logs and replay them offline later. It is 100% compatible with ELM327 and is totally free. For now I think I would give SCT hardware a miss as I already own two systems - the ELM and one for Land Rovers, which until recently employed proprietary encoding protocols and scan bus configuration. Maybe they changed when Ford took over but up to 2002, their ECU, BCU and SLABS wouldn't talk to an ELM device.

Cheers
 

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If you're interested in a very good OBD workshop reference, this one is online -

http://www.lbcc.edu/attc/documents/OBD2.pdf
150 pages of OBD Porn. Wow! Don't plan on reading lots of it, but after a quick scan, I will return and read a few sections. DL'ed it.

Yeah, I have heard of people using FORSkin. I mean FORScan, after your nudge, maybe I will try it in the near future. btw, my 8 year old laptop runs 32bit XP, and it has bluetooth, but never have paired a bt device to it; while desktops run 64bit win7.

Thanks again!
 

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Discussion Starter #13
@Marde - Always found XP a pain for bluetooth pairing. I think it was the first MS OS with native bluetooth support. Check the bluetooth version supported by your OBD reader and compare with this chart - http://msdn.microsoft.com/en-us/library/windows/hardware/dn133849(v=vs.85).aspx

If you have them, you'd be better off installing the XP bluetooth drivers that came with your OBD kit. As for the desktop, Windows 7 is way better but you'd probably gonna need a bluetooth dongle. I had very good experience with BlueSoleil mini dongle and the software that comes with it makes things much more intuitive. Here's the link -

http://www.bluesoleil.com/products/productcatalog-hard-1-sales-desc-0-1.html#selectDesc

@iminhell - Great stuff. Thank you.With such resources, there's no excuse today if one wants to educate himself ! Wish I can find something more recent i.e. 1950s, 1960s. My dad has a long retired Ford Anglia and Ford Cortina which I plan to restore someday. No OBDs there though :)
 

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I haven't got far in this set of links, but finally found "19th c. Ottoman binding" very quickly and Free too. Joking aside, Thank you.

Book-marking this thread now and will get these bookmarked into the web browsers on my kids PC's in a School Edu Folder. (kids 11 and 14).

Cheers!
 

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Stickie has a Ford link in the OP that will lead to Ford's listing of OBD system descriptions for all model years.

Just had to update it the second time as their links changed. Worked within the last week, didn't recheck it tonight.
 
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