P0008 code 26k miles after timing chain replacement
Looking for advise , Replaced customers timing chain @157k miles (customer provided timing chain set think it was aftermarket) the shop provided the cam gears, cam bolts and thrust washers. I cant see any reason why it wouldn't code for 26k if i had chain out of time. Yes have cam holders to do the job. The vehicle had P0017 code from notes on last repair order in July of 2021. I only have a 2 channel Pico and have scoped the cam/crank, Crank / ignition, Crank/IN cylinder. Vehicle is AWD and looks like I will have to pull axle and cat to see crank reluctor ring position. Don't mind pulling it but Has anyone found away to see it on the scope. Using a know good wave form from Pico it looks like crank gear is one tooth I have included my wave forms. comparing wave forms it looks to be out of time to me. Update Added Reluctor video that looks to be good position and reference pic from TSB. *Customer has agreed to teardown and diagnostic time now with what i have showed him. Customer is waiting on Retailer of his parts to give answer if and what there paying for.
… It's PAYBACK for letting him bring ANY of his own PARTS… Dan H . …Hobbs
I don't see the cmp/ckp waveform capture from your 2010 CTS.
Trying to down load them again , just noticed only 2 were uploaded
There is a TSB for the reluctor wheel shifting causing those codes. static.nhtsa.gov/odi/tsbs/2014….pdf
Thanks have that already, just wonting to see it there is a way to see it on lab scope. Being a single tech shop right now I can get wave forms fast and keep the cars flowing .
It’s a GM 3.6. The chances of the reluctor wheel shifting is far higher than the timing actually being off.
Still waiting to see the cmp/ckp capture from your 2010 CTS, all the ones you've uploaded are labeled 37,000 miles known good. When comparing the distance between the changes in the wave forms using time is not a very good way, how do you know the engines were running at exactly the same speed (rpm)? You should use degrees of rotation for your comparison measurement
Sorry Edited notes, and reloaded files, will look at it with phase ruler
How does looking at the reluctor show that it is slipped or not? If you can index it to something like a certain piston at TDC will position the missing tooth at the sensor, then using the scope to watch the state of the sensor the engine could be “barred” over to count the reluctor teeth. The hall effect sensor will change states as the wheel is turned and hold the current state. So the wheel…
Gm has a TSB showing what it looks like. I'm pretty sure (not 100%) that if you remove the crank sensor you can see it with a borescope camera. Hmm, I guess technically it is using a scope.
I can see seeing the reluctor. I don’t see how that would indicate if it had slipped.
Pitifull. I read the TSB but stopped at the page end. Thanks
Cylinder 1 TDC is 13 rising edges from the CKP sync notch: diag.net/file/f1msjuvjc… Ignition strike is 14 rising edges from the CKP sync notch: diag.net/file/frohonmig… This is close enough, so it looks like the CKP is aligned correctly to match the ignition strike with the TDC. CKP-CMP waveforms: EDIT 1: I think I am misinterpreting which one is which. diag.net/file/f23koc9r3…
I agree with your data but the incylinder trace shows the valve timing to be close to correct. I wouldn’t expect it run with 90* out of time and the incylinder shows that it is not far out. Unless the “reluctor” on the phaser/ cam gear has moved, how could both of these situations exist?
I think I am misinterpreting which trace is which in the CKP-CMP waveforms – we have a choice of intake versus exhaust, vehicle-under-test versus known-good, so please disregard that 90 deg number, my bad. But I also put phase rulers on the pressure waveform (see previous post), and it shows intake camshaft timing off by ~35 deg, no?
Yes, going by typical numbers, IVC looks about 20* or more late, vacuum drop at 400 is also over 20 late. But isn’t that shown on the CKP-CMP waveform captures? I can’t open the files on this Ipad so, I’m working off of your screen shots. In answering Eric, it was revealed that there was some confusion about which file was known good and which was under test. So, I wondered if your CKP reluctor…
Ok using the phase ruler like you did comparing the know good to what I got I'm seeing everything to be 18 to 20 deg late on bank one so wouldn't that be a chain streached on that side and the tensioner extended causing this? thank you for reminding me of using degs and not millsec
I don’t see the reluctor shifting causing this code are there any other symptoms u could provide does it code right away on start up or after it’s been driven.
In scan freeze data it show recoding in about 300 miles and show that has passed last two drive cycles and next drive cycle has not run yet . Customer had no complaint of how vehicle drove , I will reconfirm that today with his update he request daily on his vehicle , Cleared codes and no light on first trip but did code in system , no running problem that was noticeable and customer confirmed…
I looked at your waveform and compared it to 2 different known goods I have. Both of my known goods match each other within less than a crankshaft degree of each other. Here is a screen capture with your waveform on the left and my known good on the right. I changed the channel colors to make it easier to compare the waveforms. diag.net/file/fyzwmphw7… As you can see, your…
Can you share your known good wave form for bank two, the one i down loaded from library seems wrong compared to anotherone
Here are the bank 2 intake and exhaust captures from a known good, I checked 3 known good vehicles I have and they all match these. Intake bank 2 diag.net/file/f5c3v504y… Exhaust bank 2 diag.net/file/f6fbbzwws…
Thank you, trying to learn as everyone puts out info, looking at your good and what I got , it seems that bank 2 is off 4 to 6 deg and bank 1 seems to be off about the same amount . looking at next step of dropping front drive shaft and using bore scope to check reluctor ring on crank.
Customer took vehicle until him and retailer come to agreement
Vehicle back for repair, Primary chain stretched and both secondary chains stretched, added pic . Customer and chain kit manufacture going back and forth . Chain pic of 2 is primary old /new and 3 chain pic is old B1 , B2 and new. Primary is almost one full link and Sec. are half link stretched. but my part is done , thanks for all the help