P1345 App help Needeed

[Vikingdude]

I need some help that I cant find any threads on. Maybe someone here has been through this already.

1997 Yukon 4x4, 5.7 L31, 4L60e

I have the common CMP Retard fault that requires re-clocking the distributor to get the cam sensor within spec. I live in a remote community and neither of the three mechanics in town wants to look at it. I purchased Torque Pro and a bluetooth OBDII connection unit (Panlong, on an android phone).
I used a couple of threads here and on other forums and created the additional PID per instructions. I tried for about 3 hours to get that to work and was unable to generate a signal.
I then purchased Dashcommand, and purchased the 1997 GM PID package. I saw several posters with screenshots that included the CMP Retard PID, but mine is nowhere to be found. Another 4-5 hours spent messing around.
This morning I purchased CarDiagnosticPro based on a youtube video I found. While it has the PID listed, I cannot get it to generate ANY live data while connected. All I can get is MIL codes. I canot get any live data out of this app, unlike the other 2. Another 5 hours into mucking about.

All of the interfaces on these apps are absolutely awful, and Im pulling my hair out trying to generate a usable degree number. Has anyone used any of these three apps, and can you walk mew through what I'm missing or what I'm doing wrong? I though I was fairly computer/app literate until now.

 

[Vikingdude]

Figured it out eventually. After purchasing the year specific package, the first step is to perform PID validation while the vehicle is running. Next step is go to DATA GRID -> ADD PID -> ALL PIDS. Under "General" one of the first PIDs is the one for cam retard in degrees. Tick off this one, and the one for RPM.
These two will appear on the data grid page and once you rev over 1000 rpm, you'll get a value under CKP/CMP.
Mine started at 21.4*, and I was able to get it within the +2/-2 range and turn off my CEL. Hopefully this helps someone.

You must be registered for see images attach

 

[SableSlayer]

Good job getting this figured out. Sorry I didn't see this earlier. I really like Dash command

 

[62barsoom]

Wow thanks. I searched and didn't see this. Was this the answer on Cardiagnosis?

 

[Vikingdude]

This was just the result of my fumbling around for hours. Given this only applies to the 96-99 vortecs, it's harder to find a good video or thread than I wished at the time.

 

[dilerin]

More CMP Retard stuff

1998 K2500 4WD w/towing pkg, 5.7L Vortec, VIN R, bought new. Installed new distributor at 192K miles using the included fork-style clamp. After install, CMP Retard was found at -23.1 degrees. Since the forked clamp captures the distributor shaft such that it allows for very little movement, CMP-R could only be adjusted to -21.3 degrees. So I replaced the forked clamp with the original because the original clamp doesn't impede distributor rotational movement. That worked, with CMP-R able to be set, with distributor in normally accepted position.
And now to the point. I don't know when the forked clamp was introduced, but since it allows for no distributor movement, that can only mean that somebody, somewhere decided that CMP-R need not be set exactly, just clamp the distributor down with no worries unless +/- 26 degrees is exceeded, causing a code to be thrown. With that in mind, have any of you ever used the forked clamp successfully in terms of achieving a dead nuts CMP-R value?
I have a Service Manual for my truck; a 7-inch-tall stack of 4 volumes weighing 16.6 lbs. Vol. 3, a 6.2 lb tome, covers my engine. Nowhere in that volume could I find a CMP Retard value of 0 degrees +/- 2. The closest thing I could find to that was the entry:

Engine Data 1, CMP Retard, Degrees, 0-2
​

No plus or minus value is in evidence. Does anyone know the origin of the seen-everywhere 0 degrees +/- 2 value? Is it a bonafide GM spec?

Anyway, even tho there must be limits (+/- 26 deg?), I'm not convinced that an exact setting of CMP Retard is critical but may rather be nothing more than a nicety, especially since the vehicle runs well within a relatively wide CMP-R range. At least mine does.
Much truth, half truth, and fallacy surrounds all things automotive, and I've seen plenty of each in my 83 years. Where does CMP Retard fit? Could it be that it ain't no big thang? Are some of us, including me, getting unnecessarily worked up over it?
I invite comment. I, and especially my truck, would appreciate it. Thanks.

 

[Road Trip]

More CMP Retard stuff

​

No plus or minus value is in evidence. Does anyone know the origin of the seen-everywhere 0 degrees +/- 2 value? Is it a bonafide GM spec?

Greetings dilerin,

I also had similar questions about all this, and at first the more I dug the
more conflicting claims were to be found. In terms of the documentation,
I also gave myself the giant stack of 4 Manuals, and I use them for pleasure
reading, since like yourself I was raised on telephone books. :0)

Without further ado, I can & will show you *exactly* where the bonafide
+/- 2° GM spec came from. And this will also explain why you couldn't find
it in your '98 Manuals. From the '99 FSM:

Page 1 of 2:

You must be registered for see images attach

Page 2 of 2:

You must be registered for see images attach

For completeness only, for I think you have a matching page in your '98 manuals.

You must be registered for see images attach

Anyway, even tho there must be limits (+/- 26 deg?), I'm not convinced that an exact setting of CMP Retard is critical but may rather be nothing more than a nicety, especially since the vehicle runs well within a relatively wide CMP-R range. At least mine does.
Much truth, half truth, and fallacy surrounds all things automotive, and I've seen plenty of each in my 83 years. Where does CMP Retard fit? Could it be that it ain't no big thang? Are some of us, including me, getting unnecessarily worked up over it?
I invite comment. I, and especially my truck, would appreciate it. Thanks.

EDIT: By the way, as soon as I get a chance I will share with you why this is more than just a nicety.

To get yourself into the proper frame of mind, if you divide 8 spark plug terminals into
the 360° distributor cap, we only have a total of 45° worth of rotational space (+/- 22.5°)
to send sparks to a particular cylinder.

And that at any particular instant the computer may calculate the firing of the ignition trigger
anywhere from base timing all the way to 32-34° (WOT, + even more under light loads) in
order to cover all possible spark advance timing requirements.

So if the distributor is misaligned from the 0° spec in the wrong direction, then we are setting ourselves up for
the possibility of the spark intermittently jumping to the wrong terminal during maximum spark advance...because
the wrong terminal was actually closer. And electricity don't care, just takes the path of least resistance without fail. (!)

Last but not least, the punchline for you in all this? The '99 Factory Service Manual had
added this info to the contents of the '98 manual when it came time for the '99 edition.

Good news though. Instead of having to buy another stack of paper manuals, consider
downloading these from the GM Factory Service Manual cache found over here.
('99 Specific FSM download reply)

Hope the above explains the mysterious origin of this oft-quoted Vortec ignition system specification.

Cheers --

 

[Road Trip]

More CMP Retard stuff

Where does CMP Retard fit? Could it be that it ain't no big thang? Are some of us, including me, getting unnecessarily worked up over it?
I invite comment. I, and especially my truck, would appreciate it. Thanks.

Sir,

If my previous reply whetted your appetite for more info, I'm including link to a thread
where all this was discussed a bit more in depth than my overview above.

Essentially, you were able to swap out the (nonsensical) fork-style clamp included with
your replacement distributor, reinstall the original GM part, and successfully adjust your
CMP retard to the factory specification.

After reading this string, you should consider yourself fortunate, for this member's
replacement dizzy was incorrectly assembled during manufacture, and thanks to
the SBC's 13-tooth distributor driven gear, this set him up for failure. And sorting
all this out took some effort, but once he did his truck did indeed run smoother/better.
(Aftermarket Dizzy can not be adjusted in order to clear a P1345 code.)

A little more later on, after one more dive down the rabbit hole. :0)

Cheers --

 

[Schurkey]

Did GM ever use the fork-type, non-adjustable distributor hold-down clamp?

Far as I know, that's a crazy aftermarket invention.

My '97 K2500 7.4L has an adjustable distributor; it was 29 degrees off when I bought the truck and was adjusted within spec not so long thereafter. But I have to admit I wasn't paying enough attention to know whether the distributor is plastic or metal. I don't think I've ever had the cap off of it.

 

[dilerin]

Sir,

If my previous reply whetted your appetite for more info, I'm including link to a thread
where all this was discussed a bit more in depth than my overview above.

Essentially, you were able to swap out the (nonsensical) fork-style clamp included with
your replacement distributor, install the original GM part, and successfully adjust your
CMP retard to the factory specification.

After reading this string, you should consider yourself fortunate, for this member's
replacement dizzy was incorrectly assembled during manufacture, and thanks to
the SBC's 13-tooth distributor driven gear, this set him up for failure. And sorting
all this out took some effort, but once he did he truck did indeed run smoother/better.
(Aftermarket Dizzy can not be adjusted in order to clear a P1345 code.)

A little more later on, after one more dive down the rabbit hole. :0)

Cheers --

Thanks so much for your reply(s). It's always extremely satisfying to be furnished with valid info whether for a truck or anything else. Again, thanks.