SENTRA from HE*L , Runs lean, won't start cold ???

[@JeffinTD]

Nice job. Appreciate the care you take to make sure you aren’t about to waste someone’s money.

[@CartersDiagnostics]

I try my best to get it right the first time. Money ain't easy to come by, so I try not to waste mine or my customers.

[@rodvan-zeller6360]

Great video. I am 62 have been working on cars since 1979, retired automotive technology teacher, always kept a part time job in a shop doing diagnostics, background in computer test engineering. Still work part time diagnosing drivability, electrical and one on one teaching. The feeling you mention has not gone away. In my case I know the reason why it is there after deep psychological analysis with a professional. I have learned psychological tools and strategies to deal with it, not a complete solution just alleviation.

[@CartersDiagnostics]

Keep up the good work. Until I finally retire the anxiety of calling expensive parts will always get me. But its fuel to go the extra mile to triple check everything, and hopefully get it correct.

[@rodvan-zeller6360]

@@CartersDiagnostics Love your videos. Thank you for the reply

[@paulw2791]

I think we all doubt ourselves when saying it's a module. That's a lot of money when the smallest detail could be missed during a diagnosis. This is why I will double, triple, and quadruple check my work now. I will run jumpers to bypass circuits to ensure integrity of the circuit to a module. I will meticulously go over inputs/interlocks the modules look at to control an output. People don't understand these modern cars are rolling embedded systems with complex networks. They are not like the old cars, where it was analog. Almost everything is digital. We get inadequate troubleshooting and training, even at the dealer level, over how these modules function. It would be impossible to become a modern auto diagnostician without knowledge of electronics. Thanks for the high quality and thorough videos you continue to put out, Mike! I hope to see you at the next Picogroup meeting next year... as you have put us in quite the conundrum. Hopefully we will get it resolved and make it a good test to utilize.

[@CartersDiagnostics]

Its these great comments that speak to the integrity level of those posting them , Thank you for taking the time. It seems we share the same desire to make the correct call, it seems the bulk of the folks that have commented share the same value to get it right. That is awsome. I should be at the next meeting...lord willing. And yes the conundrum is real even for myself.

[@jimforsyth2.]

I enjoyed this video

[@CartersDiagnostics]

Thats great 👍

[@lonniepeterson-xq3vx]

Great video and great comments. I understand the anxious apprehension Mike. I can't count the many many times i got involved with a car that had a super intermittent problem. One particular one i remember was an early 2000's Pontiac Bonneville 3.8 that just liked to stall when it felt like it. Would not restart until it sat. Came in on the hook and would always start right up for me. I once kept the car and drove it home for over a week with no problem. Tried all the usual harness checks , tap on components , pin fits, temperature extremes and nothing. After several tries without duplication I put a new pcm in it and problem never came back. I hate doing that and that car ate my lunch but sometimes you just have to say a prayer and do it and move on.

[@CartersDiagnostics]

I appreciate the war story. Thanks for tuning in.

[@DarrenOgorman-d8e]

I loved this video!! I doubt myself everytime i replace a module. I appreciate someone else Feeling the same way. I have serviced cars since the eighties. It doesnt go away.😮

[@CartersDiagnostics]

Wow. Nice long career. I was hoping it would get easier. Thanks for sharing 👍

[@carguy1312]

Couldn’t agree more - other side of that same coin is that we’re “practicing” - no different than doctors and lawyers etc.

[@CartersDiagnostics]

Nice comment 👍 We are just paid way less!

[@spirokattan3655]

You're not alone Mike. I'm sure many of us feel the sameway when it comes to replacing a control module. Thanks for sharing!

[@CartersDiagnostics]

Maybe we need a support group. hahaha. This topic has really got people talking. Thanks for commenting.

[@mrblonde2013]

I Always struggle with the decision to call a module. A module that still (mostly) functions are always the hardest to call. Several people way smarter than me have told me Several times that most of the time it's NOT the module. Keith from L1 actually quoted some numbers recently saying that in only 22% of cases where he gets called to a shop to program a replacement module it actually fixes the car...😮😮😮

[@CartersDiagnostics]

Wow , did not know that. Very low fix rate for an ECU. That makes it even tougher to call it.

[@NS-YT-PV]

It’s always hard to believe it’s the computer especially when it’s a black box to us other than inputs, outputs, and communications. I wish decision logic was also part of stuff like all data. I’d like to know why manufacturers omit that type of information. For example I recently read a TSB for cold starts with winter gas on the subaru FB20B engine. It would be interesting to see how the computer determines whether it’s winter gas or not, maybe something with temperate but who knows! Also I bought a 4425a off of autonerdz to upgrade from my 2204a. I told them I felt the need to upgrade after watching your channel so hopefully they throw you a t shirt or something. Can’t wait for my early Christmas present to myself haha

[@CartersDiagnostics]

Congratulations on your purchase! Great scope. Thanks for using Autonerdz, great people. I would like to have access to more "inside' information on the logic. I've heard you can purchase SAE papers "very expensive " to get more of an inside look at things. I've also heard the are written on an engineering level so it may be a tough read especially for me.😅

[@MrJgonzalez2]

Aside from being a great video with testing procedures you made everything very clear explaining it all, for that Thank you.

[@CartersDiagnostics]

Thank you

[@markferraro5250]

Great one Mike I can relate. One thing I want to mention and I learned this from Mail Salazar on his channel. He had a very similar situation with a Ford fusion or something with a blue oval on the grill. and he removed the PCM. shell to expose the circuit board and used a thermal imager and you can see the hot spot turn into the cold spot totally in sync with the symptom. Blessings to you Mike keep these gems coming

[@CartersDiagnostics]

Great information, gonna have to remember that. Thanks for commenting 🤘.

[@thakiid1013]

Glad you posted! Definitely go through the right call/wrong call stress, but that's a sure fire way to know that you care a lot about being the best and that reputation matters. Pesky computers!, wish they made it easy to open them up! Great catch. Love the E-scan. little rich for my blood. Id rather buy more pico goodies with that 1k bucks, but there isnt a more user friendly real time VE tool in existence!

[@CartersDiagnostics]

Great comment. Thank you.

[@thakiid1013]

NO! Thank YOU!@@CartersDiagnostics

[@MR.KNOWITALL1982]

Hi Mike, Great Video,keep em coming! I think it's fair to take a logical guess and throw a part at it. I undrestand the customer may have kids,bills,.... but what about you? Should you take the hit on labor/testing/research involved? Mechanics don't get paid like an engineer but they're expected to be knowledgable like one and at the same time no need for a license or anything! Thats one of the great thing about this trade! any Joe can open shop"we do it all" Think of the shop(s) that attempted repairs before you. Im sure they got paid!! They probably made more money on the job and far less time! They probably dont even have service info! Such a rewarding trade to get into eh?:) I hope the Dealer you work for pays you upwards of 50.00hr. you desreve it! Actually Autotechs deserve FAR more per Hr than 50.00!

[@CartersDiagnostics]

All great points you make. Thanks for commenting. All the parts put on, someone paid for hopefully, it was fairly distributed. Luckily for them and me my salary is already established, but I truly feel for the folks on flat rate its hard to make a living and put in the hours needed for a proper diagnosis.

[@High_Tech_Mountain]

Great case study. It’s always hard to make that call. But like you said you test everything else, what you can’t test is what’s left. I believe it’s Jim Morton that said if you suspect a part is bad, before replacing it. Think ahead. If you replace it and it doesn’t fix it. What other tests can you perform. That’s always been in my head since hearing it. Thanks for sharing! Maic Salazar is on KZbin. He’s a great tech and he’s been doing board work and putting on KZbin. If you ever have some free time and take a look.

[@CartersDiagnostics]

Jim Morton is one of my heroes. Great stuff he does. I will check out Maic. Thanks for the info. Appreciate that.👍

[@oldsilkhat7893]

Weird in that first capture, it seems once you got the single injector pulse, the overall capture had less noise. Good work

[@CartersDiagnostics]

The starter was disengaged and the inertia rolled the motor just a slight bit more, that why it was less noisy at the end.

[@Z14kt12timandjes1]

Really nice video and great information here. Thanks for posting this. I am having a similar issue with a 2007 2.4 l Camry. Lean condition (@ idle ) isn't quite high enough to set a code, but it's getting pretty high, above 20's. No drivability problems. I have checked everything I can think of multiple times. The idle high fuel trims are screaming vacuum leak, but my smoke machine, and propane, just can't find any vacuum leaks. Strange thing is, I can drive the car for a short 15 minute drive and at some traffic light stops the fuel trims are around 10, then the next traffic light they may be around 20, then the next traffic light they may be back down around 10. I'm beginning to wonder about my PCM, but I feel like I would just be throwing a part at it to try that.

[@CartersDiagnostics]

Just reading your comment makes me nervous. It sounds like your in the same situation I was in. Good luck. Remember trust your methods, if you are 100% sure of your tests then you gotta go with the obvious. Its a tough call, Over the years I have had lots of grey hair and sleepless night on cars like this. Thank you for commenting!

[@nickayivor8432]

ASTUTE, Carter's Diagnostics 👍 From Nick Ayivor from London England UK 🇬🇧 ⏰️ 07:49am Good Morning 🙏 🌄 🌧 and more 🌧

[@CartersDiagnostics]

Thanks again! 💯👍

[@AlejandroMartinez-qb6jl]

I also work for Nissan and I’m the same way, it’s really really hard to put a control unit in a vehicle. I’ve gone to the junk yard before if I suspected a bad ECM, of course if available. Nice job on this one and keep these videos coming!

[@CartersDiagnostics]

An ECU is always a tough call. Availability of used is a big issue, for us and also the "refurbished " one's are not that great. It does calm my nerves some when we do locate used. Thanks for commenting 🤘.

[@ford03369]

Nice find.

[@CartersDiagnostics]

Thanks!

[@advancedleveldiagnostics]

Great case study. Thanks for sharing! I'm the same way; I always have that doubt nagging me. I know it's not popular but on Nissans, I usually just put used modules in.

[@CartersDiagnostics]

Its like the only part on a car that really gets my anxiety up. Maybe its a good indicator for someone who really cares 💪💪

[@vickenkaragozian2041]

Great diagnosis. It seems like the ecm was not pulsing the injectors enough at wot. It would be nice if you had checked the injector pulse before and after the repairs and that is what was causing the lean code. Thanks for posting another great video.

[@CartersDiagnostics]

I remember looking at injector pulse width with the scan tool nothing stuck out. But its possible I missed something also😄. Kinda glad this one is gone!

[@bartscave]

Thanks for sharing!

[@CartersDiagnostics]

👍

[@prashanshan7125]

Good work 💪..!

[@CartersDiagnostics]

💯

[@DiagnoseDoc]

Hi, really appreciate your honest words. I think it’s very important to be selfcritical in Diagnostic jobs. Is there a reason you use Picoscope over the eScope? And do you use 4 or 8 Channel?

[@CartersDiagnostics]

I bought my picoscope over 10 yrs ago, I had not heard of the e scope then. I use a 4 channel its an older model 4423 it still performs great. I do like some of the e scope features

[@tedgtfan]

Just curious did you check 5v sensor readings like your other vid "No start...masked Maxima"? Curious as to whether those where reporting wrong values. Trying to decipher whether computer has physical (circuitry) malfunction or programming malfunction. Great vid though, just my brain always wants to know why-what caused computer to function that way? If you or anyone here figures it out please let us know. Heat usually affects computer circuitry but cold not as much, unless possibly garbage in garbage out from one or two sensors. Anyway thanks again for the great info. .

[@CartersDiagnostics]

I looked at lots of data pids during key on before crank no start. Temp. sensors, pressure sensors, start signal ect. All appeared normal. I also tested physical value of Maf. It was good also. The ecu showed injector pulse width time in the data pid. When we actually saw none on the scope. Makes me think it was more of a physical issue for the no start issue. The lean issue has me scratching my head as to what happened.

[@fluke2352]

Great job dude!!

[@CartersDiagnostics]

Thank you! Cheers!

[@stevejakobsen2765]

I too feel like that. There is always a level of incertaincy about what is going on inside the ecu, and i always like to bee 100% sure. And if i cant get there i get that nervous stomack feeling. Luckily for me i have been in the aftermarket ecu world for a couple decades so i have a certain sense of whats going on in those. But they are way less complicated than oem's though. About this one... I have a feeling its about the maf portion of it all. I ran across some cars that will not start if you unplugg the maf. MIGHT have been Nissans. Cant remember. Did you by any chance look at maf scan data while cranking when it did not start?

[@CartersDiagnostics]

I remember looking at the key on maf data it seemed normal. As far as cranking I did not watch it (maybe I should next time). I think the no start cold issue may have been a solder joint issue, have not confirmed that. The lean issue had to be a logic thing maybe low power or ground resistance due to a solder joint. I'm totally guessing though, just all theory. Thanks for commenting 🤘.

[@stevejakobsen2765]

@@CartersDiagnostics yes, bad joint was my guess too. In the maf circuit specificaly. That would explain both problems. If the car wont start without a maf that is...

[@ablackformula]

Do you prefer ATS e-scan over the factory scan tool? Interesting to see the dealer tech using aftermarket tools :)

[@CartersDiagnostics]

The factory tool and me have a love hate relationship. I use the factory tool when I have to. On newer cars the ATS is great for fuel trim issues. I also have a zeus, I love the graphing on it and the fact its always recording.

[@ablackformula]

@@CartersDiagnostics one more quick question .. the sharp shooter ve testing you were doing, would that work if the car was a speed density system? I get it there's no maf signal, but can e-scan still calculate the engine load to perform the ve test?

[@CartersDiagnostics]

@ablackformula I've never tried it on that style system, but I don't think it will work.

[@zygi22]

Excellent logical approach to problem-solving, as usual. A quick question: What would cause a lean condition (No CEL)at hot idle and low load conditions only? Fuel trims look great until the car fully warms up and heat soaks real good. Then the STFT will jump upwards of 3, 5 to even 15%, adding to the already high 10% LTFT. No vacuum leaks were found. Maf seems ok, but reading at idle for a VQ35 is low-ish at 2.2 g/s. No driveability issues at all. Car runs great otherwise.

[@zygi22]

I’m getting grey hair too, because of this problem. Driving me crazy no pun. 😂

[@CartersDiagnostics]

MAF does seem low. Both banks I presume are lean. What is the customer's concern ?

[@zygi22]

@@CartersDiagnostics Wow! Thank you for taking the time to answer. I am the car owner trying to figure this out on my own. The concern is the high total fuel trims (20% both banks) which I think are not normal. Not high enough to cause the check engine light though.

[@zygi22]

I think I need to find as a good a diagnostician as you are here in NYC area to get to the bottom of this. I would just like to know some kind of a direction of what could be the problem. This is a 2011 Maxima by the way.

[@CartersDiagnostics]

@@zygi22 Check the air boot at the throttle body very close. Also inspect the pcv system. Especially the bank to bank hose and the hose going to the intake.

[@jimforsyth2.]

The most important question is what if this don't fix it . Then what

[@CartersDiagnostics]

Well I guess I would have taken a step back, re-evaluated try and figure out what I missed and come up with another plan. It just worked out that I didn't have to go down that path on this one.

[@kevinobrien3063]

Why the failed VE I can only see that thr computer is miss reading the airflow meter. I call it hero or zero when you call a computer, I have the same feeling after 40 years.

[@jimforsyth2.]

I feel the same way But if I make a bad call I don't charge . Unlike most shops that say to there customers it may or may not fix it are you OK with that . And charge for a non fix .

[@CartersDiagnostics]

I'm not a believer in charging for mis diagnosis. I hate the term "it may have other problems " On the other hand on this car I was 100% confident that the ECU would fix the cold start issues, but I was hoping it would fix the lean issue. So a total mis diagnosis was not going to happen. Also complete a total transparency with the customer is key with cars like this, and they were 100% on board with the diag.