Doubt can complicate the simple. If you let it
If you thought that my mistakes were through with my last post, You'd be wrong. I'll be the first to admit my mistakes, and the first to share them. But there is an upside to this one, at least from my perspective.
Coming back from the Super Saturday event, my confidence and motivation was renewed like never before. Good thing, because I was going to need it. At my shops parking lot, there she was, waiting for me to meet her. There to put my confidence and motivation to the test. A blue 2003 PT Cruiser, I was extremely surprised to see her as she was just here last week!
I had just done a Timing Belt kit on it. You can imagine my expressions when I see a car at the lot a week after I did this job.
Customer states his concerns as lack of power. I bring in the car and it's running terribly! Pull the codes to find a P0351.
Fair enough I have a Primary Ignition Circuit Code, Just out of curiosity, I clamp my secondary probe around the number 1 Ignition wire.
Hmm, I've got counter voltage, and a Lean waveform. Let me probe the injector.
So no Injector Pulse. So I've been burned in the past by assuming that a car did not have cylinder deactivation strategy, so I clear the code and retest my injector pulse.
Here it is zoomed in.
Just for confirmation, I zoomed in a bit more.
Now I've confirmed cylinder deactivation. Lets get back into the right direction, the primary ignition circuit. The code is specific to coil number 1 out of the coil pack. so I want to baseline by grabbing the coil number 2 primary signal. which I'm pretty satisfied with.
I then save that into my scope as a reference waveform(purple) and proceed to grab a primary waveform for circuit number one(in yellow). Notice the same time-base.
Interesting! No counter voltage, an extremely short dwell and burn time. So I overlay them to overkill the what I already noticed.
So I isolate the circuits, and I've got 0-.02 ohms on both circuit wires from the coil to the PCM, and still I load test them using a 4 amp head light bulb. Plus, I compare the resistance of the primary winding of coil 1 and coil 2.
While I'm there I grab a correlation waveform because I researched a bit and found that another individual had the same issue resolved due to timing. Also, that another individual had issues resolved from replacing a CKP due to a bad signal. I kill two birds with one stone, especially since I was about to aim my sights at the PCM driver. So this is my correlation waveform.
I jumped online and found a "known good" to compare to.
I then overlay them and line them up as best I can.
I see a wee bit of a difference but not a tooth's worth to worry about. I take my findings up to the front and call for PCM driver repair. They go and research the issue, make some calls, and tell me that they want me to take it apart to confirm timing. I tell them brazenly that it's a waste of time! I've compared the known good to mine and it's fine! They said they would feel better if I took it apart to confirm. So I keep an open mind and go with it. As I'm taking the car apart, doubt starts to enter my mind. What if that discrepancy was actually enough to be considered "out of time?" What if I just made a total fool out of myself if they see that its in fact out of timing? I was starting to give in to the doubt, and started taking it apart even faster. Nothing would have changed no matter how much I'd try to convince them, I'd still have to take it apart. but the fact that I began to doubt myself gave me a sick, insecure feeling that I'd hate to feel again. Nonetheless, its all apart and I call the Manager so that he can see for himself. It's dead on! Which should be no surprise. But that's what doubt does to you.
Anyway, He gives me a sincere Thank you, and arranges for the PCM to be repaired. An hour or two later I've got the repaired PCM.
I waste no time to install it, and on to the next one!
So the upside is that I have a dead on known good waveform, and am able to share this experience with all of you!
If you have the proof, don't give in, and don't give up. After all of this I'm happy, and although at times management may not see eye to eye with you, we're all trying! I hope this can be useful to all who read it. Thank you for taking the time!
Good job? I have been down that road, where it's a waste of time. Now perhaps they'll listen!
It does build trust! Hopefully they won't give me the run around next time.
Awesome Mario!!!! Experiences like this only help build your trust in yourself. It will (or should) also have your manager build trust in yourself!! Really, outstanding case study.
Thanks Chris! I can't say I blame management for wanting to be absolutely certain. You and me know cam crank waveform is more than sufficient. But not everyone does, so I think they can benefit this as I attempt to get the shop on board with training. The more they see me prove to them that this is the updated diagnostic technique , the more I believe they'll see the need for more training. I hope they get the picture soon though!
It’s like Brandon said in class on Saturday. The scope is like black magic voodo to our writers and the ones that dont understand. Nice Diag
There's a conversation I don't want to have. "Hello Mr./Mrs. customer. I know we just did a bunch of expensive work last week, but guess what?........"
Actually this customer was very outstanding, plus it helps to document everything 😉 thanks for swinging by Corey!
Great job Mario. That was a nice step by step logical diagnoses. I suspect that whole process built up some good trust and confidence with your boss. Don't feel bad about the self doubt, I've been doing this close to 40 years and that still happens to me.
I appreciate the wise words bob. I did get a good response from management, so all in all I'm glad it worked the way it did. Thanks for reading!
Nice job. I love hearing real world stuggles like these. It's a jungle out there, Awesome work!!
Thanks Dean! Yes sometimes it's the wild west. But I'm sure there are many that have to go through the same issues.
Excellent process. I’m a shop owner and probably would have suggested a recheck of the timing as well, although the waveform is proof you didn’t have it out of alignment. What you did was build trust in the sales staff and next time they will likely trust your initial impression.
Yeah, it's just the way it goes at times. I am pretty satisfied that this not only built trust, but also built the need for training. They looked at the waveforms like if it was Chinese. I told them dismantling is unnecessary. Now they know!
Confidence in one's abilities is often challenged in our own minds maybe more so than in the minds of others.
Very methodical! The way diagnostics should be, Good job Mario!
Awesome find, one thing I say to a lot of techs is 'the scope does not lie', your study here just proves it.
How you like that scope? I just have my verus that goes dead after 20 min of not being plugged in.
I like it, I'm pretty satisfied with it. Battery lasts maybe six hours. The only thing is you have to buy all the accessories separately. But overall in pretty happy with it
another nice write up Mario. Hey i was watching your Mercedes parasitic draw vid and wanted to know what scope is that you have? looks like a nice handheld unit.
Thanks Thomas! That's the micsig to1104. I love it, i don't have a single complaint lol thanks for taking the time buddy 👍
Beautiful job Mario! Good diagnosis process! You'll only get better, faster, and gain more confidence. I'm glad everything turned out well in the end, and proved yourself right! ;)
Hey Cuba good to see you join the network! Thanks for taking the time to check it out, looking forward to you posting 😉