Jeep 4.0 - Flashing Engine Light BUT NO MISFIRE!?
Рет қаралды 207,652
Come along with Eric O. at SMA as we have a look at the infamous "misfiring" Jeep 4.0. Now many of you in the shops have ran across this before when you have a 4.0 Jeep and the engine light is on and flashing but there is no felt misfire. We all seem to know it needs a Crankshaft Position Sensor, BUT do you know why!? Check out the files captured on the old sensor and the new sensor and let me know your thoughts. -Enjoy!
- AES uTest Advanced Terminal Test Kit: www.aeswave.com/cart.php?m=affiliate_go&affiliateID=2525b91fc8e906e8215984074c9d9e8f&go=www.aeswave.com/uTest-Advanced-Terminal-Test-Kit-p9573.html
- 4-Channel PICO 4425 Advanced Kit in case and foam: www.aeswave.com/cart.php?m=affiliate_go&affiliateID=2525b91fc8e906e8215984074c9d9e8f&go=www.aeswave.com/4-Channel-4425-Advanced-Kit-in-case-and-foam-p9525.html
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@rtchrg440 6 жыл бұрын
Thanks again @South Main Auto Repair for fixing my Cherokee! The 4.0 ran smooth as silk driving back to PA, no money light! Wife says I should keep it now that you fixed it... LOL
@Sandbag1300 6 жыл бұрын
rtchrg440 sell it a run, run fast. I have been a Jeep owner for over 20 years...and still own two in the Family. I swear those vehicles are designed to make money for the Chrysler company in parts sales AFTER the initial vehicle sale.
@rtchrg440 6 жыл бұрын
I know what you mean. I was a faithful Toyota owner before I bought this XJ, never had a vehicle like this that always seems to need a part every other month. One thing I will say, I usually buy aftermarket parts for the Jeep to save money, and at least 50% of the time the part has failed in a year. So I really bought the part twice, and probably didn't save in the long run. Frustrating! This crank sensor was aftermarket (either from RockAuto or AutoZone, can't remember), and it was doing this from the beginning. I shot a ton of other parts at this Jeep thinking it was a legit misfire.
@Sandbag1300 6 жыл бұрын
rtchrg440 I only go OEM for my Jeeps either new or the used parts market - from junkyards - that has recently and robustly sprung up on the internet in the last few years like partsmarket. Mopar rear drive shaft new $895, from the salvage yard $65 plus $50 for shipping and I can get one from States not in the rust belt. I tried the Chinese made parts once. Part was a rear window strut that holds up the window. Lasted 18 months. Then I purchased Mopar OEM and it so far has lasted 4 years.
@louiemoscatel585 6 жыл бұрын
rtchrg440 nice Jeep! I have a 2k XJ myself and I love it. I have the OEM sensor and after this video I might swap it in, got that tiny flutter going on but no money light. Have a great weekend.
@dinobot_maximize 6 жыл бұрын
stinking "aftermarket junk". as eric and many of us say.
@bigclivedotcom 5 жыл бұрын
What an odd and annoying fault because it is so indecisive. As someone else mentioned, the transient spikes after the new sensor were fitted seemed lower, so maybe it was just a connection resistance issue or the new sensor might have a low value capacitor in it as a filter. It could possibly be one of those things that didn't occur when they were writing the software, but as age crept in it became an issue. There are some industrial control systems where you have to use a specific brand of contactor because the auxiliary contact closure timing is so critical that the software shuts off the machine and flags it as a contactor fault if the wrong brand of contactor is used.
@tiredoldmechanic1791 5 жыл бұрын
It's really annoying when the timing isn't critical to the job the machine is doing, it's just critical to the time that was programmed. Programmers set it up to see a value in a very short time like .002 seconds when it wouldn't matter if it took 5 seconds.
@AmosMosesJr 4 жыл бұрын
@@tiredoldmechanic1791 The rise/fall time on the aftermarket sensor most likely is causing the computer to get confused as it's not seeing a sharp transition to measure rotational acceleration. This allows it to run but not monitor itself. I suspect the "square" edge of the signal starts to round over. The programmer needs something consistent to trigger off to accurately measure acceleration. If we only cared about rpms I would agree that it's the programmer's fault. I'm a hardware guy and like to blame software too but this time it is not the programmer's fault. This suspected rounding (rc effect) is only visible if zoomed in. Then again I could be wrong as the data from the video is zoomed out way too far.
@PaulLorenzini-ny2yw 4 жыл бұрын
Shit up Engineer.
@thomasvlaskampiii6850 4 жыл бұрын
Electronics are fickle things... It's almost like programmers don't give enough leeway for things as they age. But, it is what it is I suppose
@wendwllhickey6426 Ай бұрын
I have shot part at a car a few times and that's was the problem fixed😂
@rollingrockfan2482 6 жыл бұрын
It is one thing to shoot parts at it when nothing shows wrong but another to look up data talk to others and then take an educated guess very well done.
@farmermiyagi1338 6 ай бұрын
When I trained as a tech in the military we had a W.A.G. and a S.W.A.G. Wild assed guess or a scientific wild assed guess. ;) This was one of the later. I know, old video, but I enjoy watching them when they pop up in my feed.
@22video11 6 жыл бұрын
Eric, I like how informative your videos are, plus I like when I hear that you help out other channels with their diagnosis ( Will R.A.) COOL
@PatrickJago 5 жыл бұрын
Thanks Eric. You have helped me out of a pickle with the wife’s Chrysler minivan more than once. (2009 3.8L) hope you make more videos of them. I enjoy watching you work on any vehicle. Including this one.
@denniswilkinson1118 6 жыл бұрын
Well done Eric, yet another satisfied customer brought in by You Tube. Great video!!
@wyattoneable 6 жыл бұрын
That's why working on vehicles can be fun. You give something a try when your out of options and it works. That's a good feeling. Great information in the description box. That's going to help a lot of people. Another crazy KZfaqr out the door happy!
@baxrok2. 6 жыл бұрын
Reminds me of the educated guess you made on the Chivy Colorado. It's beyond cool that we can share waveforms like this. Well done Dr. O. Thanks!
@fonzo2525 6 жыл бұрын
as always,sma comes through with a perfect repair,great job mr o.
@pookatim 6 жыл бұрын
He sure keeps that old Jeep clean! Well done, Dr. O!
@mikevonkleist6767 5 жыл бұрын
That's unlikely, my friend. You are one of the best mechanics that I've ever seen. I have been doing this thing for 38 years and you're. good. And fun.
@atoukatly3809 6 жыл бұрын
I am in Buffalo NY with the exact problem. Installed an aftermarket sensor a few months ago. I think this video just saved me a lot of time and effort! Would love to have you do my rear main seal for me
@ericstoneberger4504 5 жыл бұрын
awesome diagnosis and work. I actually did one of these jobs while I was in a high school auto shop class! of course, My school didn't have any real awesome scope software or anything. After WEEKS of testing with a DVOM, I had isolated the crankshaft sensor, and replaced it and verified the fix. My shop teacher was super impressed with me. I owe all my success to the man.
@Gt403cyl 6 жыл бұрын
Key word here is EDUCATED guess, there is a difference vs just a wild guess!
@tewgomoo 5 жыл бұрын
SWAG vs pure wild guess....
@shaneharrison4775 3 жыл бұрын
Difference being no beard strokeing
@eliezerramosjr1017 3 жыл бұрын
Indeed
@bobbybentley8136 6 жыл бұрын
I've found that gut and others experiences have bettered the high priced scanners alot of the time most customers do not understand the scanner jargon great video Eric O
@vladmoskalow2230 5 жыл бұрын
Yes! Great video, had random cylinder misfires just like this on a 2001 4.0 Jeep Wrangler with AT. Had a new aftermarket crankshaft position sensor, all the other things too, new plugs, new coil, checked all injectors for resistance, etc etc. Saw this video along with another one from Scanner Danner, both said to use the factory original Mopar part, so I took the chance, replaced the aftermarket crankshaft position sensor with the factory piece and problem solved! Thanks for posting the video! Great videos as always!
@AnhYeuEmMaiMai69 6 жыл бұрын
another awesome video by Eric O....looks like your parts cannon has some serious experience to get it right on the first try...
@kevinwoodcock7578 6 жыл бұрын
some serious aim on thats parts cannon... Laser scope i think.
@ib516 5 жыл бұрын
An experienced based guess is what people pay you for! Your knowledge is valuable!
@v12alpine 4 жыл бұрын
Found this video after going thru the same thing on my 96 XJ, occasional high rpm check engine light with random misfire codes but it always ran smooth. Swapped the CPS sensor with OEM mopar and it seems to fix it so far. This video provided the needed confirmation :).
@Mark-vc7rm 6 жыл бұрын
Just came in from rustling up the dear and laying some corn 🌽 and a new SMA. Good morning just doesn’t get any better than this on a Saturday.
@wadet73 Жыл бұрын
I absolutely love this engine. I've had 3. Yes odd issues here and there but reliable and smooth regardless how many miles were on it. I took one to 356k, one to 375k and the last one was totalled in 2019 with just under 340k with a mint leather interior. Yes, that crankshaft sensor caused an issue on my 1997 Grand Cherokee TSi. Just stopped on me one day and I had no idea which direction to go. Luckily I had an uncle who worked at the Chrysler Jeep dealer in town and he helped me over the phone. I admit hearing those 6 cylinders firing up brings a tear to my eyes. Reminds me of years of worry free driving across the southeast. I drove one from 2000-2019 (2 1997 ZJ TSi and 1 2003 WJ Laredo). Always looking for a good one to keep a few years 1996-2004 only. Hope you and Mrs. O. had a good New Years Weekend. 🎉
@toms1499 6 жыл бұрын
Will have to remember this fix! I have the exact same jeep with 193k on the clock and counting, been the best vehicle I have ever owned.
@jerrodl 6 жыл бұрын
Nice to see you do it my way sometimes! I do it because I'm certainly no pro, have no expensive analytic tools (but appreciate those who do!) and it's a constant weighing of paying for labor vs parts. I'd pay for the former if I got as much out of it as your customers do, Mr O...if there are any here in MN, commenters, let me know.
@How2Wrench 6 жыл бұрын
Nice video on using what I teach as "educated guessing". Your video example is "NEEDED" is the "toolbox" of technicians or DIY wrench turners. In the real world sometimes things just don't make sense. Theres no visual or measurable evidence to go from and to fix the problem we turn to what I call "the medical method"....This is where you consider what worked for a 100 other people get healed and go for it. There is still much thought and consideration put into this decision based on research, peers and OEM support. Just reminds me how glad I am to be a technician most often working from pure evidence and not "practicing medicine"! Once agian, great job and I bet you would like my "Every Mechanic Should know This" Playlist. I'm a fan of South Main Auto videos for sure....Coach Conley
@uzaiyaro 5 жыл бұрын
Shane Conley yet another example of ‘it works in practice, but does it work on paper?’
@63256325N 5 жыл бұрын
Nothing wrong with an educated guess now and then especially since you're so experienced, and as it turned out you were right. Thanks for the video.
@NoName-tz5ji 5 жыл бұрын
When it comes to crank/cam sensors I learned a long time (the hard way)ago to only use OEM.
@ben10nnery 4 жыл бұрын
Those 4.0's love Mopar sensors only.
@NoName-tz5ji 4 жыл бұрын
Ben R Fords also.
@pontiacsrule8761 3 жыл бұрын
Add Gm fuel pumps only & MAF sensors on GM cars. Been burned too often with non OEM parts. Cost more, but I only want to do it once. Especially dropping the tank for a fuel pump replacement
@Longtrailside 6 жыл бұрын
Once again, experience, and knowledge of the trade, wins over a stubborn vehicle.
@MultiFindus 6 жыл бұрын
This is what they call "an educated guess"!! Nothing wrong with that. Good work. I think this is a very good looking car, Been looking forone for a while here in Sweden. But hard to find in good shape. Good work, love your channel!
@centralcoastcamper9631 4 жыл бұрын
Thank you for the fix! I had the same problem with my 1998 Jeep Wrangler 4.0 . Only 3000 miles on a complete reman. longblock, ran like a top but the check engine light came on and I scanned it and the codes showed multiple misfires across all 6 cylinders. It still ran silky smooth. I ran across this thread yesterday and so I removed the newer aftermarket crank sensor and put in a used oem crank sensor I had laying around and it cured it. No more codes. Now I can get this Jeep smog tested tomorrow so I can get it re-registered. One thing I noticed is the magnetic tip on the OEM crank sensor is very strong and can pick up a wrench, but the aftermarket version can bearly pick up a screw. Thank you so much for sharing your technical knowledge, you saved me some money for sure!
@Gunmetalbluejeeptjs 2 ай бұрын
I have a 98 4.0 With a new motor Also , I can’t get a oem cps so I put a hvwells one in and still has a misfire , she’s been in the shop for a few days , I hope they figure it out
@Paneltrucker 6 жыл бұрын
Sooo "test then guess"? Now you'll have to change all those sma bumper stickers. Great vid, thanks Eric.
@grumpysgarage4790 6 жыл бұрын
Great video Dr. O. 👍 Sometimes an educated guess coupled with past experience gives you a fix. Got to get me a PICO.
@waltershulas623 6 жыл бұрын
Good video Eric it pays to be honest that jeep is in nice shape and it looks clean again great video
@benjaminstockton3431 6 жыл бұрын
Eric O. You didn't guess your just that good . Thanks for video's keep them coming
@htcinc9296 5 жыл бұрын
My guess before the video was the crankshaft possition sensor, but like the guy said I didn't see any discrepancies when the Pico was reading it. I loved the video a big thumbs up and subscribe to this guy
@christinehucklebridge1534 6 жыл бұрын
sometimes my parts cannon needs a good re - load !! great vid, eric. thumbs up all the way
@mschmitz57 6 жыл бұрын
Jeeze, the engine bay is clean on that old Jeepster. He must be crazy.
@johnislow 5 жыл бұрын
Good job on getting a Mopar sensor. I had a 97 grand Cherokee 4.0 and I had a similar issue and I replaced the crank sensor with an aftermarket. It ran great for about a month then the same issue. I got a Mopar one and never had the issue again. I learned Jeep's are picky with sensors.
@davenay1645 6 жыл бұрын
Had the same issue on my 2000 Grand Cherokee and replaced the same sensor with OEM and it fixed it that was 2 years ago
@34k5 6 жыл бұрын
I've been chasing this same problem for a year. I have had 4 CPS installed during that time, and only when I finally got a Mopar part, was it resolved. The previous owner who swapped the engine in my wrangler, dropped one of the flywheel/torque converter bolts inside, it rode around in one of the grooves of the flywheel eventually hitting the CPS and breaking it (twice) before I discovered it. The CPS did continue to work while missing plastic! Eventually I discovered that issue, removed the bolt, and replaced the CPS with a Napa premium part. From day one that sensor always triggered the misfire code at 3000 rpm and above. I looked everywhere else assuming it was not related to the CPS. Now after seeing this video I went ahead and ordered a Mopar part and after 4 days the misfire code never happened. I can finally engine brake through the mountains around here without dreading the flashing misfire light. I watched this video during an international flight and then ordered the sensor as soon as I got home. Glad I have been subscribed to you for some time now.
@vetman98 3 жыл бұрын
Love your honesty. You gave us an educated guess. Better than I could do
@JA-rc4uy 2 жыл бұрын
That is one clean looking engine compartment, even the undercarriage looks dry. Loved that.
@AntonioClaudioMichael 2 жыл бұрын
Wow Never seen a Missfire On all 6 cylinders before And the Engine Run Smooth as Butter that is Interesting Defenitly looks like a Crank Sensor Failure good Video as Always Eric O great find on this video @SouthMainAutoRepairLLC
@mikewarman9910 6 жыл бұрын
Noooooo that’s a cherokee..... you can’t wear a jeep hat and get that wrong!!
@dunebasher1971 6 жыл бұрын
There used to be a video somewhere on YT that used waveforms etc to go deeply into the differences between OEM and aftermarket crank sensors on Jeeps. I can't find it any more, but I recall that they *did* pinpoint differences that could account for why Jeeps are so picky about them, and they weren't in any way obvious.
@keithfrisell4271 6 жыл бұрын
Eric sometimes it's better to be lucky than good! We all have done it and if u say you haven't your either lying or u don't work on enough cars. Have a great day and GOD BLESS AMERICA. GO CUBS! Keith
@robertrichardson6800 6 жыл бұрын
You sir are freaking awesome. I just replaced a CPS on my daughters 4.0 jeep and I am trying to find a misfire in the engine.
@djquack13 6 жыл бұрын
I remember a story where a huge diesel motor on a giant cruse ship wouldn't run. None of the technicians could figure out why. They gave up and called in an old retired dude. He looked at a while. Pulled a large hammer out a bag and gave it a hard WACK! It Stared up and ran perfectly. When he gave them the Bill it was for $10,000.00. They all freaked. "you didn't do anything" they said. Give us an itemized billing statement! The bill he produced said. One hammer blow: $8.99 Knowing where to hit: $9,991.01
@kamdaddypurp3341 6 жыл бұрын
Dj Quack lmao that made my day
@frankmuhammad9660 6 жыл бұрын
I love it!!!
@breeze787 6 жыл бұрын
"knowing where to hit" is ABSOLUTELY RIGHT! In so many cases we have to draw from our experiences, Eric knew which part to change and the old man knew where to hit. 1 + 1 is 2 because my 1st grade teacher taught me so. NEXT!
@63256325N 5 жыл бұрын
I saw the video that story came from, definitely priceless!
@iepljoshua 5 жыл бұрын
Eric I was wondering on that crank sensor do you think that the aftermarket sensor is a different kind of sensor then the OEM I know there are two different kind of sensors. One can be hall effect sensor and honestly I am not remembering the other type of sensor. Just a thought
@wayneg1184 6 жыл бұрын
Just changed my crank sensor today (Mopar OEM). I strongly recommend taking five minutes to drop the driveshaft at the differential. I swung it over toward the passenger side and ziptied it to the catalytic convertor. I was then able to gain much better access to the sensor bolts. I only had to use one extension and a wobble joint and was actually able to reach around the exhaust and get both hands up into the area to start the bolts when reinstalling. I still had to work by feel but it was much easier than fighting the driveshaft. I hope this helps those of you facing this repair.
@lifeaccordingtobri 10 ай бұрын
Classic video. I had a grand Cherokee similar issue. It would run like crap while crossing railroad tracks. Bunch a shops couldn't figure it out. Customer brought it in, through a monitor on it and cranked it up. Went behind the truck and climbed on the ball mount and started jumping up and down. Jeep began running like crap. I said crank sensor. Took a long screwdriver and then tapped the sensor and again ran like crap. I feel better about your guesses than other peoples facts. ;)
@stigonutube 6 жыл бұрын
yeah good fix for the owner+SMA as it's tricky with new aftermarket parts, scannerdanner has covered this type issue a few times with the jeep 4.0 and is a common issue. glad you mentioned air gap as this seems to be where diy stuffs up often but not always..
@tapia79r4p 6 жыл бұрын
THANK YOU, THANK YOU, THANK YOU, Mr Polish Guy! Just fixed my Plymouth Neon with the same shit (money light, flashing, P0300) after replacing CKP, CMP, plugs, wires, Coils, fuel pump, fuel filter, PCM, O2s, PCV, Intake gasket, Injectors and many cuz words nothing. After watching this video I ordered a MOPAR CKP and problem SOLVED! Thanks again Eric O.
@darnellkaehler6899 3 жыл бұрын
Loved this one, keep up the great Video
@angelaracino6236 6 жыл бұрын
Thank you Eric O I’m learning a lot of using diagnostics tools and how wave forms should look, love the videos, from an ATP pilot and aircraft mechanic Thank you
@Asomesauc 6 жыл бұрын
One of my all time favorite vehicles of all time !!!
@mmiller1188 6 жыл бұрын
daniel w Cherokees are awesome!
@fightingfalconfan 6 жыл бұрын
I hate guessing myself. We want data to back up our claims. My theory is that the sensor it's self was on it's last legs internally (doorman maybe? or BWD) when it was put in and the coil inside is shorting it's self. Anyway awesome video as usual Eric. Keep it up!
@VWWRENCHIE 6 жыл бұрын
Sometimes the old EPG and your gut work well together. Another Victory!
@JohnRodriguesPhotographer 4 жыл бұрын
This may surprise you Eric but your guesses are more often than not better the most mechanics or technicians knowledge today. Keep knocking out those cars and enjoy your days
@dennisphillips5782 6 жыл бұрын
Great Job, I have been turning wrenches for many years, based on experience I guess on a regular bases to save time. Correct most of the time....
@GeminiSeven43 4 жыл бұрын
Missing Misfire Mystery Solved? Once again a great video and the fact that you were "guessing" doesn't worry anyone who know that your guesses are based on a solid foundation of both knowledge and experience and you can guess on my car any day. By the way I noticed that when you start the video and show the cam/crank relationship at idle the cam signals are lining up with the fourth crank signal but when you rev up the engine the cam signal now is lining up on the third crank signal. This might explain why the misfire code are being generated. I notice that after the crank sensor was replaced the cam signal stays with the fourth crank signal even at higher RPMs. Please check it out and let me know what you think. Keep up the awesome videos they are teaching me alot and you crack me up with your terminology and the ease and enjoyment that you get when working on cars. Thanks so much.
@greghamilton1638 3 жыл бұрын
Smart man! Eric you amaze me sir!!
@weshawkins7165 4 жыл бұрын
Eric, you ever wrap a wire several times around a screwdriver or socket and the touch the striped ends to the positive and negative to magnetize that socket or screwdriver. Work great when you have to hold on to nuts and bolts from a distanced with an extension.
@nhra7110 6 жыл бұрын
another awesome video as usual!
@3347861 6 жыл бұрын
Love the video. Excellent work once again. I just replaced the cam and crank sensors on my 08 Ram 1500 4.7 even though it was still running well. Why? The truck has 170,000 miles, they go out on high mileage 4.7s, and the sensors are cheap and easy to replace. I HATE a no start condition and cold weather is here. I look at them as a normal maintenance item on these engines.....
@nealfox1976 4 жыл бұрын
Great job Mr O!!!
@ecwurban 6 жыл бұрын
TL;DR: The old sensor put out a good square wave pattern but was inaccurate/inconsistent in ON time. Thanks for the captures! I've never actually used a PicoScope before. I downloaded the software to look at your captures and gotta admit it's bloody cool. I was able to do measurements and analysis in about 5 minutes whereas it would have taken 20+ painstaking minutes with my Verus... So you can't compare times between old and new. You're not running at the same RPM so times are irrelevant. You have to compare degrees of crankshaft rotation as that's the only thing that is constant. I measured the width of 4 pulses on the crank pattern on both the old and new waveforms. I used the same tooth every time to be consistent. On the old sensor I got 1.427*, 1.575*, 1.562* and 1.579*. On the new waveform I got 1.16*, 1.16*, 1.109* and 1.111*. On the old sensor, each pulse lasted more degrees of crankshaft rotation than the new sensor. I imagine that's not what set the misfire. No two sensors are exactly the same so that would probably get processed by a crank relearn. HOWEVER... the pulses are pretty inconsistent on the old sensor whereas they are VERY consistent on the new sensor. The difference between the shortest pulse length and longest pulse length on the old sensor is 0.152 degrees. Even after going back through the new trace and looking at way more samples the largest difference I could find between pulse lengths was 0.011 degrees. That's going to be what's causing the reported misfire. The time delay between when the tone wheel notch passes by the old sensor and when the sensor is able to fully turn on and off its transistor just is not consistent.
@ralphvaccaro2638 9 ай бұрын
Good job as usual
@steniofernandez824 6 жыл бұрын
Wao!cant believe you got 97,000 subs..i remember subscribing i was 1300..lol...keep up.almos you gonna get that KZfaq play bottom..
@Pablo_Automotive 6 жыл бұрын
Thanks for share the files Eric =)
@roscoe454 4 жыл бұрын
yes the millsec would make a differance, since no ditributor to turn then im guessing the random delay in the crank sensor is making the light come on :) great work as allways!
@OneAuto 6 жыл бұрын
IVAN!! Eric has a crank sensor he needs dissecting. Good job sir 👍
@lowellstokes5328 3 жыл бұрын
I have a 1998 with 205k miles, runs great but I’m having this same issue after complete tune, hopefully this will solve the “misfire” issue! Thanks for the info!
@chrislemaster2695 5 жыл бұрын
My Grand Cherokee 4.0L did the same thing and it was the Crank Positing Sensor. These 4.0L Straight 6 are noted for these.
@izzynutz2000 5 жыл бұрын
I've heard from different sources that the aftermarket sensors have some kind of weirdo diode in them or something like that but in the process of heating and cooling this diode for the 5 volt reference ends up popping and it allows it to bleed through the reference wire essentially giving it 2 signals it's throws the computer out of wack but when you go to look at through the Pico you're seeing the direct line in and that's why you can't see a fault you're not seeing what's bleeding back to the computer if that makes any sense.. at least that's what was explained to me.... just an FYI for your information keep up the good work Mr.O
@cluelessdiagnostics7982 6 жыл бұрын
Hi guys Great video. Take a look at the Pico files Eric captured. The 'bad' sensor is grounded at about 79mV where as the 'new' one is grounded at about 54mV. Now, I know this doesn't seem much but is does affect the misfire counters and can trigger P0335 DTC if it gets much higher. Had my ass kicked with a PT Cruiser that had the same issue. The car had been fitted with aftermarket crankshaft sensor. Took a long time to find and work out. Thanks Eric
@stephenirwin2761 4 жыл бұрын
Another case of a stupid system telling you something is wrong when it is not. How much did the owner spend at the multiple shops where the fix was just to make the false message go away? Even the diagnostic system doesn’t know. Good on you Eric! Wish you were nearby to diagnose my cars!
@TheCowgirlNiamh 6 жыл бұрын
I guess, sometimes an educated guess takes the guesswork out of it ;). Nice work Mr O!
@robinsonsmotorcycleandauto3929 6 жыл бұрын
Awesome I will look closer at the waveforms when I get back from Pennsylvania.
@mrred123 6 жыл бұрын
That feeling us mechanics get when shit goes right
@rodx5571 4 жыл бұрын
Sorry, "when shit goes right" is an alien terminology. Words that dont live together peacefully in my world. LIke oil and water in the crank case. :-)
@frankv9068 6 жыл бұрын
Nice work! One again I learned something Thank You.
@Carlitosway211 6 жыл бұрын
Love it when the part cannon works!
@rickjljr11 6 жыл бұрын
WAG #1 Rise/fall time of the sensor. Based on misfire is detected by slight rpm variations after a spark.
@CARRJ142 3 жыл бұрын
Another great video.
@brizzle757 6 жыл бұрын
The Jeep obviously noticed your hat and you meant business...no frickin around
@klwthe3rd 6 жыл бұрын
Will s And that's a REAL JEEP! Not one of those Fiat based monstrosities.
@scottraymond558 6 жыл бұрын
Lol... You won the comments..lol
@Rottidog 6 жыл бұрын
2001 GC with lots of pissy-little-'minor'-tooling-around-getting-it-right-things-that-annoy-me-so-it-doesn't-let-me-down-&-I-know-things-are-right-issues. They're not bad vehicles, just vehicles that need maintenance! Liked & subscribed! TYVM for an informative channel. O2 sensors are another red headed stepchild for these as well as clean battery terminals. I've seen on a few occasions these Jeeps are fussy about very clean voltage & copper core spark plugs. No better plugs for them.
@theponzona1 4 жыл бұрын
So sorry for your loss,He must have been quite a father and teacher, rest in piece.
@mrb1864 6 жыл бұрын
Gives you the right to wear that cap with a jeep in the shop lol . cool to have a vid on a saturday too, have a day off tomorrow lol .
@Ebooger 4 жыл бұрын
I know three retired Chrysler engineers who were very familiar with the JTEC PCM. While all generally praised it, the word around Auburn Hills was that JTEC was an abbreviation for "jus' tryin' to be an engine controller". I wouldn't be surprised to find a line of code someplace that checked for Brand X parts!
@JoesAutoElectric 6 жыл бұрын
I have seen this on multiple Cherokees. The first one had me banging my head against the wall trying to figure out the problem. Came to realize after that the truck originally did not start and the customer had brought it to a shop where an aftermarket sensor was installed. Long story short, my cam/crank waveform was obviously fine as was the crank pattern itself to my eyes. "Guessing" that the aftermarket sensor was the culprit, I changed it with a dealer part and problem was solved. Only thing I can think of is the air gap may be different between it and the aftermarket part. Other than that, I have no idea what else would cause this.
@terrancegrant1664 6 жыл бұрын
That Jeep is mint!
@williamgrayson4181 5 жыл бұрын
Won't last long with Pennsylvania winters
@randygentry2724 6 жыл бұрын
Had a similar situation. Friend took his 4.0 Cherokee into the shop because of check engine light at highway speeds. Shop said it was indicating all 6 cylinders were showing a "spark" miss and they began replacing parts. ECM and Coil Pack and other parts to the tune of over $2650.00 in parts My friend asked if I could check with the shop and so I called just casually asked what waveform they were getting generated when they tested They said it was great and had never showed a bad waveform and that was what throwing their troubleshooting off. I quietly suggested that they might try changing the crankshaft sensor ( which they had not done to this point. It is not my vehicle or my right to get into the middle of the problem). Long story short, they changed the crank sensor and the wave forms returned to normal. Sadly, of course they just added the cost of the crank sensor to the $2650.00 parts plus labor bill telling my friend that somehow the "ECM had defaulted in it's code and caused other parts such as the coil pack and crankshaft sensor to fail". I explained to my friend that such thing just could not happen and if he wanted to dispute the charges I would be willing to help him but he would need to start the process not me. He never did anything about it so he received an education, I received an education and I am sure the shop received an education. Aloha from Maui
@HighestRank 5 жыл бұрын
Randy Gentry I guess malpractice insurance won the lottery that day🍾
@kevineccleston8341 5 жыл бұрын
So, what is the ethical way to run through this parts changing fusillade, short of bringing it to Eric "the Swami" @ SMA ? I got $9,899.00 hammers too, but feel bad using them.
@bash5995 6 жыл бұрын
Nice Quiet Riot reference.
@arnemalmkvist8553 3 жыл бұрын
You have experienc thats half off the work , 👍 I like when you say I think I know what it is In this fall it can not be missfire on all cylinders and go okey . You are great !
@overkill0074 6 жыл бұрын
That is very interesting Eric.
@blacksheep25251 5 жыл бұрын
I've replaced a few of these. Without a lift, I found its easy to do it on the ground. Place a jack on the Trans cross member, remove the 4 bolts/nuts. Lower the trans down so it angles down, then use some nice extensions and maybe a U-Joint... I have yet to find a way to replace it easily from the top....
@andrewk778 6 жыл бұрын
Very interesting. Thank you for sharing.
@philh9238 6 жыл бұрын
itd be easy to misdiagnose as a bad pcm. if the cam/crank timing are dead on. cam and the crankshaft sensor looks good the inputs are good. good work!
@M1CHAZZ 6 жыл бұрын
owned a Cherokee for almost 20 yrs.; crank position sensors were iffy if replaced, solved problem by going to dealer & using factory one.
@ik4939 6 жыл бұрын
You are awesome! Greets from the Netherlands
@Cbarnes281Strkd 6 жыл бұрын
Great video man
@Vercus100 6 жыл бұрын
I work at an auto parts store, and no lie, this era Jeep 4.0L is literally 40% of our business. If you look at our shelves, we are jammed full with Jeep stuff. Every single day we get dozens of calls from people needing parts for these heaps. I'm not making this up. Jeep keeps parts stores in business! I'll never own one, but from a job security standpoint, I'm glad they exist.
@mmiller1188 6 жыл бұрын
Vercus100 remember how many of these things are out there ...
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