The Car Nobody Could Fix Pt1

Owner of this 2012 Honda Odyssey has been trying for 3 YEARS to get car correctly diagnosed and has spend over $4000 try to get it fixed but nothing has worked.
Car has unstable idle, hesitation with acceleration and poor fuel economy with NO CHECK ENGINE LIGHT CODES!!
Can we solve the mystery?
Part 2 is HERE: • The Car Nobody Could F...
In-Cylinder Pressure Diagnostics Video is here: • How To Check Valve Tim...
Get tutorials on how to do basic diagnostics at my website:
www.schrodingersboxqm.com

[@gross43]

It's commonly known that the valve clearances on Honda V6 engines tighten up over time and cause issues. It's surprising that all the mechanics before you failed to check for this issue. Good job!

[@TassieLorenzo]

Especially as it is on the scheduled service list!

[@Eastahtata]

Nice case study! I believe these have no cam phasers and the valve timing is changed solely by engaging the 3rd rocker arm (VTEC) Surprised no one thought to adjust the valves which actually is a job that is "needed anyways" after a certain amount of miles.

[@foyjamez]

every 100k for my old Element V-tec

[@stephennichols586]

You would have thought valve adjustment was done when timing belt was duh huh I r maybe they did it but not correctly that MN are it seem like problem was not fixed

[@Gregg0112]

Do a running compression check to see volumetric efficiency of the cylinders. You could also put a vacuum gauge on the engine and analyze the movement of the needle. You have the hood prop in the service position. There is another hole that would allow you to remove the fuse cover.

[@ACommenterOnYouTube]

Low compression would yield a LEAN condition on a MAF sensor vehicle.

[@rustynail9793]

My truck had a high idle issue. I checked all my sensors. Found nothing. Replaced no parts. After 2 years it went away. My theory is it must have caught COVID since COVID mainly effects your respiratory system aka my truck was breathing hard, causing a fast idle

[@mph5896]

One of the Drs I work with, his wifes car broke. He said it had covid. Broken valve spring, so yes respiratory😅

[@tonyt1554]

Actually, if your truck had covid it would run rich because it was lacking oxygen and it would have poor performance above idle 🤣

[@rustynail9793]

@@tonyt1554 true. I did find one issue that would cause a high idle but it fixed nothing. I was doing the ole carb cleaner spray on everything and when I got to the back of the throttle body the truck straightened out. I found it had a crack/hole in the intake manifold. I replaced it and it helped nothing. After that I left it alone. Checked all sensors and nothing. Being a 91 Silverado it didn't have many sensors. All tested good but I should have replaced anyways, right? Hahaha. But it's running good these days. I love driving it

[@jeffcard3623]

Thermostat?

[@knight6757]

🤣🤣🤣🤣🤔

[@ehsnils]

Running rich - that's at least some symptom to put your hands on. I have seen the opposite - running lean condition code and that was the MAP sensor, but the ECU didn't have a fault check for the MAP sensor. But driving the car revealed a situation similar to a lean carburetor. A nice idle is also a good start, it makes things a lot easier.

[@Gardyflux]

Extremely informative. Broke down loss of power whilst trying to accelerate - Garage diagnosed MAP problem. Pipe blocked with carbon including connection into manifold. This video so helpful. Going to take a look at readings using volt meter

[@Jpilgrim30]

Manufacturers really need to get on board with in cylinder pressure transducer diagnostics. Give us specs for valve timing or just flat out give us known good waveforms. I mean we’ve been using pressure transducers for years so it’s about time they recognize it for the powerful tool it is.

[@SchrodingersBox]

Agreed!!!!

[@stephennichols586]

Very intelligent way to troubleshoot and diagnose them A.K problems that 99% fail because they get overwhelmed and frustrated after they start with most commonly replaced part that is the part that resolved them symptoms . Reminds me of how I have seen my dad diagnose engines back in the. 60"s and I still use a basic vacuum gauge inmy diagnostic procedure that will help you know what the engine vacuum should be at certain given conditions and how the exhaust smells as a SWAG on the fuel ratio and just by watching the gauge and seeing the vacuum and ne needle fluctuations tells you what is happening with the engine and the component that causes the gauge to react like that while engine is running at the condition of your diagnostic procedure enjoy your videos and I am always learning when I see different ways people use to troubleshoot some things you don't use and sometimes you can see the difference ways that several people used and take all them and b are a better way that works for you

[@JM8686]

Had same issue but with a pilot! Problem was clogged catalytic converter! Hello from California 👋

[@MrShekoexile]

I hate it when they dump extra platinum into a catalytic converter. 😁

[@tonyt1554]

I had a Honda CRV Come in with similar issues. Tuned out to be the Cat and REAR O2 sensor. Took a long time to figure out because in school I was taught the rear o2 is only for cat. monitoring........not the case anymore, it actively changed the fuel trim!!!!

[@SchrodingersBox]

Yeah that would have been a tough one! Yes since the early 2000’s cars started using the rear sensor for some fuel trim adjustment, not just cat activity.

[@larryreno8293]

It appears that since the introduction of wide band O2 sensors that catalyst monitors can now effect A/F ratios. Yes it was a hard learned lesson.

[@The_Noticer.]

Surging idle usually means it's not compensating for the lean/rich cycle the engine does to prolong the life of the catalytic convetor. Typically caused by a bad MAP sensor. Also explains the hestitation of the engine during accel, because that's what these Honda's predominantly use during WOT, as it goes into open loop. Not saying 100% this is the case, but it'd be what I'd look at first. But that'd just be me projecting, because I already regularly send my Acoord in for valve lash adjustment :D So it couldn't be that. And yeah, I had to really press my mechanic for the adjustment, because he didn't believe a modern car needed it xD

[@pantelis241]

Mat, it is just a pleasure to watch your videos and learn from you. Thank you very much.🙏

[@SchrodingersBox]

Happy to hear that!

[@mattbickford2640]

Hood is in the "service" position(opened a little more than just an oil change), if you move it to the other position(hood is closed a little more) you can open that fusebox easily/easier

[@calholli]

10:00 Long Term fuel trims were absolutely stuck at - 8.6 and never made any adjustments at all.. So something is fishy there to me-- I've never seen them stay stuck and not fluctuate at least a little bit. ?? I'd definitely want to look at the 02 sensors with a scope and/ or a scan tool and see how they actually graph.. I wouldn't trust any of those parts just because they are new. Generic parts fail right out of the box all the time. Especially precision sensors like 02 and MAF sensors.

[@SchrodingersBox]

previous total trim was minimum neg 16 on average with range of neg 14 to Meg 21. Now LTFTaverages neg 7 with STFT at +4. no doubt about it- there was significant change in fuel trim. And it continues to adjust towards positive as well. obviously it is relearning specific cells which is why you see STFT at zero for periods of time.

[@calholli]

@@SchrodingersBox Yeah.. I wrote when the video very first started... Nice fix btw. I watched both videos.

[@Turbo_Q]

Everybody always skips the valve adjust. 210k service (timing belt, water pump, spark plugs AND valve adjust).The shop that replaced the timing belt was looking for easy money and didn't follow the recommended service interval properly. Surprised the HONDA dealer didn't look at the valve adjustment as a possible performance and drivability concern.

[@noelvillafane7747]

no doubt he is a master great case study definitely is going to be fix on part 2 can wait thanks master

[@SchrodingersBox]

Thanks for watching!

[@jahrain1693]

Very informative..the best teacher and diagnostician

[@nathantechnician2475]

Nice study case sir. Many thanks to this channel as it helped me to pass (1st place) Motor vehicle electronics with a merit🤗. Am grateful for the free subscription as well🙏🙏

[@SchrodingersBox]

Well done! glad to hear that!

[@faith4freedom76]

With restrictions in fuel trims, that's an indication of lower combustible air volume, right? As to why the reduction in fuel?

[@SchrodingersBox]

Yes, I believe the rich condition is due to improper “breathing”- particularly , exhaust leaving early.

[@Face2theScr33n]

Your moments of humility are a great balance for all your knowledge. Awesome video!

[@SchrodingersBox]

I appreciate that! but I don’t think most people would compliment me for humility lol!!’

[@Face2theScr33n]

@@SchrodingersBox It shines through, I see it. I know you can be brash toward trolls, too- but they have it coming! LOL

[@andrewwmacfadyen6958]

Only watched a few minutes in so far but with high miles Honda the valve clearance is always a suspect due to valve seat recession.

[@user-ys7pt8je4s]

I was about to say the same thing about valve adjustment. When I used to work for honda we saw a lot of driveability issues but with valves being too tight. I believe there is even a maintenance schedule for valve adjustments on most Hondas.

[@billygriffin3079]

Check exhaust back pressure at 2500 rpm. Oxygen sensor 1 bung is a good place to check the pressure. Bill G

[@garyhill1659]

I ran into the same problem .it ended up being a charge air temp sensor in the air filter box. Now to add a little more to this . The map sensor also can read air temp along with barometric pressure but the sensor I'm referring to is in the air box it's self .. I've seen problems with the plug and wires being broke from air filter being changed.. persons changing the filter sometime tend to be rough when trying to remove the filter.

[@SchrodingersBox]

interesting. seeing as how an IAT contributes maybe 1% to STFT it seems impossible you would have a drivability problem from it. what was the voltage you saw from the IAT

[@fstlnj29]

Came for the artwork, stayed for the education! Love the thought process!

[@aterack833]

When you reved it the first time I heard knocking/tapping and was thinking valves and then you started mentioning them and did a compression test and I had to make this comment before you do anything on the valves or even see them

[@SchrodingersBox]

It had no engine noise and in retrospect we know why.

[@rrcoster]

Surprised dealer didn't suggest valve adjustments as that is something is missed lot until eventually usually will trigger random misfire or rich code. This very common on all v6 3.5 2003-2015

[@OutlawEntertainmentlmc]

What about a 97 f150 4.6 4wd,?, Mine does the same as the Honda. Except mine will eventually start after it backfires 1 time through the throttle body, rough , violent idle, no throttle under a load, I've replaced everything they replaced, still no change

[@confuse9]

Just a data point. 2001 Jeep Grand Cherokee. Surging idle, but usually runs well. Look like the computer was seeing variable load (commanded ignition timing was all over the place. Finally, it stalled and I got the data from the computer. Seems the MAP sensor went from good vacuum to zero vacuum instantly. Turns out the MAP sensor itself was faulty - every now and then indexing to atmosphere. So... Look at the data streams. 12.9% load at idle? As for cam timing - yes compression test, but also vacuum. The scan tool said the absolute intake manifold was at 3.x psi and your barometer was at 11 (Are you in Colorado? - shouldn't it be more like 14....) so that is 8 psi vacuum (about 16 in Hg) That's a little on the light side for most passenger side cars. Hail Mary - put a smoke machine on it and look for a vacuum leak. The weird thing with computer control, just because it's not idling lean, doesn't mean its not a vacuum leak of sorts. The computer adjusts.... What would be really cool is to find another Honda, similar engine, and see where the sensors should be reading. As for your in cylinder pressure. That is a slippery slope. You can spend years on cam timing esp cam timing at idle. But if the exhaust valve timing is 250 degrees advertised, that means it has 70 degrees more than 1/2 turn. Split that and your looking at 35 degree advance. As for valve opening vs. air actually flowing. Most cam guys tell you NOT to look at advertised degrees - just because the valve is open .001 doesn't mean air is actually flowing... If you really want to see what is going on, they have laser drilled spark plugs that have piezio sensor directly in the combustion chamber.

[@louisdisbury9759]

Why didn't the main dealer check the service intervals? Tappet adjustment would have clearly been shown after reaching a certain millage,200,000 miles without adjusting tappets is crazy,A great diagnosis but when I work on my Pickup or one of my bikes I always carry out Maintainance according to service interval,

[@chrismcfadden325]

Okay so I know this seems stupid but also take a look at the power steering pressure sensor and connector/wires. Issues here would cause drivability issues.

[@SchrodingersBox]

Hmmm never heard of that- how would that cause these issues exactly?

[@alnov91]

Awesome!!! Cant wait to see part 3! i mean 2

[@RaysLaughsAndLyrics]

The car nobody could fix finally fixed by somebody.

[@s.jrobertochoa9097]

I have a 2010 I changed the engine immobilizer on a Toyota Camry 6cyl 3.5 and now it starts but it sounds like a vacuum leak

[@jeffreyanderson5106]

The oil is it black does it indicate any metal in the oil pan. These things are known to have camshaft lob ware problems

[@ivanstrickland7741]

A 4 CH Scope would be of great help here. And fuel gas angelize test. After hearing what all has been replaced and listing to the vehicle, I would have to narrow it down two things. Do we have stoki in the cylinder's? 14.7 to 1. Is there valve timing issues here. I'm thinking mechanical here.

[@twistedwrench490]

Just listening to idle definitely not cam lobe wear. Just by ear and years of working with Honda engines they tend to develop a very noticeable TICK with worn lobes

[@tigerkhuon2548]

What does the valves clearance looks like? Honda vehicle likes valves clearance to be on the max side, tight valves will cause fuel rich run rich condition

[@alexfvalen]

Same problems to my Nissan Murano...and change the alternator. Problem Solved.

[@SchrodingersBox]

and what was your diagnosis with the alternator?

[@alexfvalen]

@@SchrodingersBox not charging enough... causes protect any electrical transmission parts(I punch gas and won't run).

[@jamesward5721]

Without watching yet - 3 culprits likely/possible - non OEM MAF.. non OEM Lambda sensor, V-tec not adjusted/starved for oil. With no lights lit - it's the Vtec more than likely. Maf/Lambda would probably light the light. That's after the boggo servicing/check exhaust etc etc is done. First up - go through the Vtec. Chances are it's not getting activated/enough oil/is out of sequence blah blah. Wouldn't even fire up the scanner for this one - poke the cams.

[@bigsquatchsasfoot1964]

We bought a brand new bmw m1 convertible back in 2014 it had a similar fault to this out the dealers and I’ll give bmw there dew they tried and tried to fix it but in the end they actually took it back gave us another one because they couldn’t fix it either lol Interesting vid enjoyed it 👍

[@SchrodingersBox]

That’s hilarious… but kinda sad too lol. glad they made it right though!

[@bigsquatchsasfoot1964]

Not as glad as me 🤣 I was bricking it thinking they’d flogged me lemon but they were great . I believe because they couldn’t fix it it may have gone back to bmw HQ to be looked at or so the sales guys said to be analysed in case it became a problem on other cars I guess anyway no harm done , wish I’d bought something else it was a pretty car and nippy but it was like driving a go kart with no suspension horrible thing didn’t last to long 🤣 cheers my good man 👍

[@markloubser2433]

Time to check exhaust back pressure. ----2kpa, +6kpa, intake, exhaust respectivley.

[@SchrodingersBox]

Based on what evidence though? what evidence are you seeing that backpressure is the issue? looking at the MAP voltage how can a clogged exhaust be the issue?

[@s.jrobertochoa9097]

Would a fuse on a immobilizer system cause it to run like a vacuum leak?

[@SchrodingersBox]

No. It would cause a no start.

[@samedbensaad4391]

Would a vacuum guage help you to pinpoint the issue?

[@SchrodingersBox]

how would that help?

[@becbusman7721]

The problem is the manufacturer gave the Odyssey a reputation for not being a quality vehicle sadly enough , certain years are worse than other years

[@jessemedina4482]

The ending of this video clearly shows how master technicians like myself are getting slaughtered financially. Generally we are only paid an hour to figure ALL of this out.. and generally speaking shops don't have Pico or anything with transducers. Worst of all, even when you have concrete evidence of a valve timing issue.. you have to offer to eat the cost if it doesn't fix everything. I should have gone to engineering school and do this as a hobby too. There is no payoff in the auto industry for being this smart.. which is why the parts cannon is prevalent (not in my stall).

[@SchrodingersBox]

i appreciate the honest insight. Yes I have always tried to make it clear that I have a huge, huge advantage over a tech in that I can take much more time to diagnose things than they typically can. no doubt- I would probably be doing some educated guesses if I was in your situation!! thanks again- I always appreciate comments from the pros.

[@marcinkornas2402]

How to find rich or lean condition in petrol cars?? Thanks.

[@robertofkennedy]

What's the MAF designed for a different size engine?

[@SchrodingersBox]

Yes- I believe later model years used this design.

[@michaelsparmann3368]

at 15:15, it seems like you're mixing up VTEC/VCM with VVT. I'm not an expert, but my understanding is that even a VTEC system used for variable valve timing would not affect CMP signal, because it isn't phase shifting the cam, but instead affecting the rocker arms. However in this vehicle, IIUC, there isn't such a thing, but instead VTEC is only used for cylinder (de-)activation (VCM), and that seems to be what that test is for. VVT tests are probably hiding somewhere else.

[@The_Noticer.]

No. VTEC only changes valve lift. i-VTEC has a phaseshift on the VTC gear where it can adjust the timing, next to the valve-lift from VTEC.

[@ashwalker6221]

(VTEC) solenoid has a oil screen in it that likes to get clogged.... WatchWesWork does a good video on this problem

[@SchrodingersBox]

The VVT data indicates this cannot be the issue though.

[@Dr-YouTube]

What elevation are you at? That baro reading looked really low unless you’re at like 7000 feet or something. If you’re nowhere near that elevation might look into exhaust restriction especially if it’s down on power.

[@SchrodingersBox]

i am at 6580ft. Good observation though!! i am used to that by now! Healthy vacuum here is about 17 instead of 22!!

[@Dr-YouTube]

Just realized there’s a pt 2 lol. Nice job getting it figured out. I’m sure the customer loves you!! 3 years trying to get it fixed must have been frustrating.

[@nickayivor8432]

SUBSTANTIAL Schrodingers Box Thank you very much for sharing with us great tutorial God bless you and all your family around you Schrodingers Box From Nick Ayivor from London England UK 🇬🇧

[@shadowstorm1928]

Rich condition with everything else being changed. I'd have guessed wrong or damaged fuel injectors.

[@romanjaspe4172]

Thanks so much

[@SchrodingersBox]

you are very welcome!!

[@roxanneabbott8424]

Is it broken pin in cam?

[@SchrodingersBox]

No we know it isn’t because the cam and crank sensor correlation is correct. Good thought though!!!

[@pingpong9656]

Bad injectors?

[@jiyushugi1085]

The more mysterious the cause, the simpler the solution.

[@gazgf]

Please fix my 5.7 hemi then….rich running…but happy’ish after 1500 revs?.?

[@SchrodingersBox]

What’s “happi’ish” mean? Sounds like the clue is there.

[@isb170swap8]

when doing the running compression signal why not add another channel with ignition signal?

[@SchrodingersBox]

There is no need. Since all cylinders are the same there is no need to identify a particular one.

[@isb170swap8]

@@SchrodingersBox true but if you had that data you could look at the actual reported ignition timing to found timing with the cylinder pressure?

[@SchrodingersBox]

Ohhhhhh!!! ok yeah think I see what you are saying. what we would have found is ignition timing would be perfect. remember the valve lash is independent of the ignition timing. now, if the intake cam was off a tooth or the VVT was stuck in an advance or retard, we would definitely see ignition timing not in proper place compared to the compression peak. but valve timing due to lash adjustment will have no impact on that.

[@isb170swap8]

@@SchrodingersBox yes and during the phase of diagnosing it may be very valuable information before starting an hours long "repair" on somewhat of a "guess". I saw the second video and agree that this may not have shown anything, but many times of you have the tools and it may only take 30 seconds to probe an ignition coil signal it may be worth it. Thanks for your thoughts also on the subject.

[@boduke2299]

Cylinder leak down test? Fault in valve sealing.

[@SchrodingersBox]

very good thought but look at the compression- no leak at TDC.

[@robertollervides3911]

Do you know that Honda use mechanical lifters

[@SchrodingersBox]

I know now! I didn’t until this video

[@larryreno8293]

I must respectfully disagree that the data looked fine, other than the fuel trims. I believe that when viewing the data stream as true mechanics, we tend to be a little complacent when the data values are “close enough”. I will explain why I say this. When there is a mechanical issue with a ice that effects power or efficiency we know that the volumetric efficiency of the motor is effected. What does this mean? Well, with a PID value list you can see what sensor values should be at a specific operating range so map and maf input would have to be off just a little bit. This is where our complacency kicks us in the ass. These are just nominal numbers from my past diag of the “unfixables” like this Honda. What I have seen on some data streams is the map is reading .92v and 15” vacuum at idle and maf is 4.2 g/ps when our pid values list shows that they should be.75v @19” vacuum and 5.5 g/ps. Just one other thought, I would like to have seen a before/after on a compression test, I’m sure there was a significant increase…. But since there is no actual spec, only a allowable percent of difference, there is nothing to check those findings against.

[@SchrodingersBox]

So what data was it exactly that did not look fine from this car that indicates the issue? I didn’t see you reference the actual data you saw.

[@larryreno8293]

@@SchrodingersBox you are correct, I didn’t refer to the data from the Honda. As far as the Honda goes there was no before and after data shown in part 2 for a comparison furthermore I don’t have a vehicle specific sensor value list. I was speaking in generalities as to the effect of a engine’s data running outside of its intended specifications and how the signs are typically overlooked because the sensor readings are “close enough”. If you feel this was something directed at your repair of this vehicle, it wasn’t.

[@SchrodingersBox]

Well your first post said you disagreed that the data looked fine so I thought it must be referring to this video of course.

[@brownwrench]

My 2006 Caravan had a bad TPS with no codes. Batty idle speed at times

[@dosgos]

We had same issues on 2 cars TPS and IAC were the problems.

[@daytonpyro]

lol i got that too. NEEDED IT ANYWAY

[@ecologic786]

I bet Exhaust valves are too tight, adjust the tappets, they are manual not hydraulic.

[@frazerguest2864]

Watched. Liked. Subscribed.

[@SchrodingersBox]

Appeciated!!

[@peterphillips1493]

Why didn’t they use the data on their scan tool?I have a few cars like that around the shop now.I’m a one man band at the shop I work at.I can’t find the time to give them the attention they need.but if you could only charge the customer for the time u spend thinking about this stuff……

[@SchrodingersBox]

Maybe they did and didn’t see anything wrong or didn’t know how to interpret it. I am curious what scan data would you have pulled? I also found nothing abnormal.

[@Niknteen1]

This might be silly but.. "Is the Cat in ok condition?" Sometimes they can let go and "hang up" in there,( 205k miles ) car idles ok.. but suffers Ehaust breathing probs.. Everything "upstream" of them should be reading ok? Anyway thought I'd throw it out there.. My Apologies if someone has brougth it up already.

[@SchrodingersBox]

good thought but we can see from the MAP there is no exhaust restriction.

[@tomdns4273]

I can't help only to say CPU firmware could be issue

[@SchrodingersBox]

how so? what evidence is indicating that?

[@Gregg0112]

Guy took the car to a bunch of garages that where all incompetent. These j series engines need to be adjusted at 100k but are not out at that mileage. When they have close to 200k you will find most of the exhaust valves are tight. Simple engines with fixed cam gears and vtec and vcm

[@SchrodingersBox]

exactly. this car had 210K and never had valve adjustment.

[@scottlangille9900]

It will run without the MAF Sensor but riched

[@fieldsofomagh]

A spider supposed to have 6 eyes. Maybe he was looking into the problem ?

[@SchrodingersBox]

Oh my god lol. smh!!

[@niklak1542]

"fueltrimonology" :)

[@ShakeelAhmed-zd3pq]

certainly maf over reporting than actual. why dont you give artificial signal from maf. check it

[@mynyasabut]

i'm 5 min in and i guess the exhaust is clogged, that is: a bad cat, let's see if i guessed right....

[@SchrodingersBox]

Good thought. typically clogged exhaust will run for a bit and then die after the backpressure builds up.

[@mikesbb77]

Kinked fuel return line to the tank

[@SchrodingersBox]

But if so why does fuel pressure INCREASE with load? Also fuel pressure was normal anyway.

[@scottlangille9900]

MAF sensor unplug it

[@SchrodingersBox]

there is no need to do that because you can see the MAF is obviously not the issue. Also it’s a myth that if a car runs better with MAF unplugged it means the MAF is bad. that’s the number one cause of misdiagnosis of a MAF by far. NEVER change a MAF if a car runs better with it unplugged.

[@JoesAutoElectric]

No one can diagnose it because it is going to the wrong people.

[@gregjavi5934]

Maybe is a clogged cat as there Is loss of of power.

[@SchrodingersBox]

yes good idea, but look at the MAP voltage. can’t be clogged cat.

[@tomasnokechtesledger1786]

Killed another nuked fat cat, Matt?

[@rtaylor3670]

They designers of cars could make them easier to fix. Invent better long lasting parts. This has to be on purpose. Its 2022

[@ednewell1847]

You mentioned the fuel injectors were replaced.🧐 Is it possible they built in a problem by using aftermarket low quality parts with inferior flow rates causing the rich fuel trims?🤔

[@SchrodingersBox]

I don’t think so because the fuel pressure was normal. low flow rate would have increased pressure.

[@Graham_Wideman]

@@SchrodingersBox Surely fuel pressure has a feedback loop. like pressure regulator returning fuel to the tank or somesuch, and would be unaffected by low or high fuel injector pulse times. After all, the fuel rail presumably has to work correctly even when the injectors are shut off, such as when coasting downhill, right?

[@ednewell1847]

@@SchrodingersBox I was inferring they have a higher than stock flow rate to create the rich condition that the ecu is compensating for , and also I believe this van has a returnless system which dose not vary pressure much in correlation to flow rates

[@Mitsubeasty1]

Probably the VCM

[@SchrodingersBox]

Based on what data?

[@Mitsubeasty1]

@@SchrodingersBox TSBs

[@SchrodingersBox]

TSB aren’t data. Data is actual reading that indicate the issue. TSB just shows a possible guess is all.

[@Mitsubeasty1]

@@SchrodingersBox data is facts and statistics collected together for reference or analysis. i.e., a TSB. What you were originally asking for is data points.

[@SchrodingersBox]

Then you should use the TSB. I am going to use the actual data parameters from the engine which would indicate how the engine is compensating for the issue and thus tells me what the issue must be. I guess we agree to disagree. Good luck, I hope the TSB “data” is the same was what that actual engine is outputting.

[@caryhill570]

In not a mechanic but it sounds like cam lobe problems

[@stacydornan9765]

Shoulda replaced the vehicle,maybe that would fix it

[@pwinden01]

I don't have any audio.

[@SchrodingersBox]

Audio works fine for me. Check the mute button in lower corner of video perhaps.

[@pwinden01]

@@SchrodingersBox I'll take a look. Thanks I like this mechanic.

[@billgator2005]

hummm,,, plugged catalytic convert.....

[@SchrodingersBox]

See this is the difference with diagnosing. No it’s not a plugged cat. it can’t possibly be. LOOK AT THE DATA. i don’t do enough “mekanixing” as you said earlier and yet here you are looking like a fool guessing plugged cat when it is impossible.

[@billgator2005]

@@SchrodingersBox might as well guess. diagnosis canon versus parts canon

[@SchrodingersBox]

How incompetent. there is no diagnosis cannon. i didn’t even have to replace parts to fix this car. i diagnosed the exact issue and fixed it THE FIRST TIME with no guessing or parts changing. you on the other hand wanted to put a catalytic converter in it at $1300 and waste yet even more money on unneeded parts. You clearly don’t get it. now go grab that wrench and keep mekaniking. what a moron.

[@stuartbear922]

Do you work on BMWs? If so, you could retire early.

[@m.b.smoshitoa8325]

It needs it anyway. Hahaha 😂 Mbs moshitoa south Africa

[@adaniel69]

10:50 maf 0.01??

[@adaniel69]

I replaced 3 maf sensors on my Opel Meriva B 1.4 120hp gasoline until i found one good!

[@SchrodingersBox]

remember it’s in Lbs/s so you can’t say anything about the .01. also it would result in O2’s being lean not rich anyway if MAF was reading too low so we know MAF is ruled out.

[@chrisstanley1843]

Clogged muffler and or cat

[@SchrodingersBox]

Nope- check the MAP voltage. rules out.

[@chrisstanley1843]

....have a buddy fire it up, stick your hand over the tail pipe and rev it up. No significant exhaust pressure ? There you go.

[@topcat5988]

Your thumb nails should be more technical. Anyone looking to solve this issue will not find it with the thumb nail you have.

[@SchrodingersBox]

Anyone who has an issue so easy that it can be solved looking at a thumbnail wouldn’t need the video then. I’d go broke!!!

[@ekimbrough1413]

Jeeesuzzz are you kidding???

[@SchrodingersBox]

about what?

[@ekimbrough1413]

@@SchrodingersBox The dealer and all those garages that couldn't fix the problem. They had no clue!

[@GodWasAnAlien]

4 minutes in...My money is on exhaust valve timing. Too much overlap.

[@SchrodingersBox]

close…

[@zachmiller4930]

According to my theory if there's no check engine light then there's nothing wrong

[@SchrodingersBox]

I believe i have a video where the check engine light was intentionally removed from a used car - how would your theory apply to that lol!

[@DuNguyen-my4rq]

get another engine in first place

[@SchrodingersBox]

why? why would you get another engine as opposed to a $100 fix?

[@jeffryblackmon4846]

Very interesting! As a former air-cooled VW mechanic, I know valve adjustments are very important. And now to visit part 2.

[@JasonSpiffy]

Ive done this adjustment a few times on my classic beetle and bmw moto. Not for this reason but for routine maintenance….. because the book said so. lol

[@legioner9]

My blood pressure went high when I heard how many parts those "mechanics" replaced on this engine. Even more so since it is a Honda. You do well, Matt. 👍🤗

[@SchrodingersBox]

It is if they aren’t any better than the existing parts because then it’s just wasted money. New parts that aren’t needed make the owner feel better, but not the car.

[@MrAvant123]

Sounds like 'credit card engineering' by the various garages ! On Honda VVTi engines there may be a tiny mesh filter near the cylinder head which can become clogged and is a replaceable item..

[@bonarasmey5563]

Tell the customer to buy a new car:)

[@frugalprepper]

I think I would have started with a cam crank waveform and compared it with known good. Never know when you may have a bet off a tooth or two or have a sheared keyway, but in-cylinder pressure will tell you too if you have something opening at the wrong time. I made my own pressure transducer, and it has come in handy a few times.

[@SchrodingersBox]

Yep that’s what I initially did and upon finding timing was correct I ruled out timing. but then when I also ruled everything else out I had to revisit it.

[@GronezCastle]

Cam lobe has likely shifted on the shaft.

[@SchrodingersBox]

Cam lobe shifted???! What data indicates that??? I only see data showing that cannot possibly be the issue.

[@briancorrigan5350]

I would datalog it and see if you are getting ignition advance when you are supposed to. My guess, a bad knock sensor mistakenly pulling timing causing it to run like dog poop. Also, I don't think that fault would trigger an engine code. Can you see ignition advance against rpm and engine load. If it was pulling timing as you rev up, it would also go rich, maybe? Het, also, when doing the compression test, make sure the throttle is WOT. Also, you can do a leak down test to tell you if the valve adjustment is so bad, that it is leaking pressure. Final random thought : Is the rubber on the harmonic dampener torn causing sensor signals to be retarded compared to what is actually happening? I would use a degree wheel and a screw in stop to confirm indicated is the same actual TDC.

[@bernardaflores1720]

OneLeggedHondamechanic said, on a warm engine at temperature. the MAP voltage should be 0.85volts and that higher values can indicate tight Exhaust Valves.