Misfire Quick Tests (Is it a spark, fuel or compression problem?)
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- Опубліковано 22 чер 2024
- 2007 Dodge Caravan/Chrysler Town and Country 3.8L with a misfire. In this video I will walk you through some simple tests to help you isolate the cause. Even if you do not have a lab scope, the cranking sound test I show, will help you determine if you have a compression problem or not.
Tests shown:
- how to perform a cylinder drop (RPM drop) test using a test light
- how to perform a cranking compression sound test
- how to perform a relative compression test with a scope
- how to determine which cylinder has low compression on a starter current waveform (how to sync a relative compression test waveform)
Tools used
- OTC 3633 Mini Circuit Tester
www.jbtoolsales.com/otc-3633-...
- PicoScope 4425 4 Channel Standard Diagnostic Kit
www.aeswave.com/cart.php?m=af...
Related videos
- Cranking compression sound and scope test
• Cranking compression s...
- How to perform a compression test with a scope (Picoscope)
• How to perform a compr...
- How to perform a compression test with a scope (Verus-Vantage)
• How to perform a compr...
For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available at www.scannerdanner.com as an eBook or paper book.
Want even more diagnostic training? Whether you are a DIY trying to fix your own car, someone looking to become an auto technician, or a current auto technician that wants to get more into diagnostics, subscribe to ScannerDanner Premium www.scannerdanner.com/join-sc... There is a 14 day free trial.
On ScannerDanner Premium I will bring you right into my classroom at Rosedale Technical College. You will find page for page lectures taken right from my book as well as exclusive classroom type case studies. What is so special about these classroom case studies? I pull live problem vehicles directly into my classroom and we troubleshoot them in real time, using and applying the theory and testing procedures we learn during the classroom lectures. There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere!
Disclaimer:
Due to factors beyond the control of ScannerDanner LLC, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. ScannerDanner LLC assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. ScannerDanner LLC recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of ScannerDanner LLC, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not ScannerDanner LLC. - Авто та транспорт
I've had the paid channel for almost 2 years. Even having experience I find the channel exceptional for training. Let's say, top 3 best on You Tube IMHO. It has something for everyone for sure.
Joe Mikos how much is it?
Hi I'm not a technician but I am interested to learn these electrical engineering.if I resisted in played channel,did you think I'll learn.
It's $11 a month and I offer a 14 day free trial. Thanks for your interest!
I need a guy like you to help me find my problem , got a bad first /cold start issue with a 1.6 8v SR 102 hp vw engine . Starts right up but then idles poorly in 3 cylinders and then drops rpm and dies . after driving it for 5 minutes when car gets warmer it starts right up no issues any more . it has got power and pulls ok but sometimes around 2000rpm it shakes a bit . Help?
If Scannerdanner is among the top three here on UA-cam, I'd be curious to learn about the other two channels behind him! Lol
I love advanced diagnostics , this guy is a diagnostics master in automotive.
He gets to the root issues quickly, teaches his tricks all without editing, he's the real deal!
Straight to the points. All of them. Acknowledged mistake in assumption and explained it all clearly. Thanks, Dan!
I like watching you do things hands on which puts things in perspective for those of us who lack experience with troubleshooting in certain areas. +1
Or those of us that lack these fancy tools lol
Happy to see that Pico scope out. Great Job Paul it's always a pleasure to watch you work.
The best I’ve ever seen do it so far
When you present on video I feel like you are talking directly to me very effectively. Thank you for All your videos S/D!
Thanks Paul,
The real time out in the field diagnostics like this drive the learning from the Premium Channel home.
Take care
Bill
Thank you Bill!
Can't get much more professional than that, Thank you very much.
Valve spring?
Quick, efficient and effective. Time to move on. Great vid Paul.
Good job sharpening production skills Paul.. your channel is just getting better
Excellent video. Although I don’t understand the scope diagnosis completely it certainly opened my eyes to deeper diagnostic techniques.
Thanks a lot Paul for the quick response and great explanation. Appreciate Artie
You have a unique ability. Thankyou so much for all the help
You’re a beast. Definitely completely thorough.
They got me really like looking for sounds now 😁... It's very amazing what a vehicle can say just by that sense.
Thank you for sharing your skills and video,you are the best diagnosis master.
Scanner "no sugar coating" Dan, well done again. Nicely explained.
Always gain something from your channel, thanks for sharing your knowledge. If you ever get the opportunity, I'd love to see your take on ECU tuning. Especially for a forced induction engine.
learned alot about the picoscope great vid very informative
Great video man. Thanks for sharing your knowledge. I wish if i could use my pico as good as you as im currently trying to find an intermittent missfire on an almost new engine
I have that same problem on my 3.6l pentastar!i think you just solved my problem!i will keep you updated.Subscribed!
Absolutely brilliant! Great job. Very impressive.
My daughters 2002 mazda626 has a cylinder 3 misfire, changed the spark plug, coil and wires with no change with rough idle I’m at my wits end. Your video has given me other possibilities to explore. Thank you for your video.
Take to someone who knows how to properly diagnose instead of throwing parts at it. You will save money in the end.
Gonna sub, not only for the great info, but I see you are still replying to comments today on a 5 year old video. Very rare and commendable. Much respect. Thanks.
Wow thank you! If that's not motivation to keep answering questions, I don't know what is.
Very comprehensive video, thanks for the information
Super! Never a sync done on a waste spark system. Thanks!
Thank you for watching!
Great video Paul, I'll be definitely watching more, I believe I'm hooked.
Thank you!
EXCELLENT SCANNER DANNER THANK YOU FOR SHARING PARTNER!!!!!
I had to learn something before I could learn from your content. Thank you and Schrodinger!
Stumbled on the channel today and it's awesome. Wife's 2008 caravan 3.3 has a intermittent cylinder 1 misfire. I did plugs and coil and it ran good for a day now the light is back on. I'm guessing I'm dealing with a lifter problem.
Thing has 109000 and is a decent ride. When you first start it she idles a little rough but smooths out after a bit.
Is that what it was my car is doing the same plugs and coils don’t last
I see why it's pointless to further check for anything else than physically checking the valve train, thanks I learned a lot today.
Nice troubleshoot Paul!! As always~ That's a tough call on this one. But face 😂
Good job sir and well explained
I had a 94 Chrysler Laser years ago with intermittent low compression on one cylinder similar to this case. It turned out to be a bad valve guide. Using a compression gauge it would read bad one time and OK the next. It also fouled the plug with the bad valve. It was bad from new. The dealer knurled the guides and it worked for 6 months or so, long enough to get out of warranty. I ended up replacing the cylinder head after which it ran far better than when new. Oil in the cylinder made it want to pre-ignite. The knock sensor backed off the timing and it was a stone. After the fix I could lay rubber with it.
great video paul
Awsome video as always!
Hey Paul, thank you for an another excellent learning video showing your technique of performing an on the spot diagnosis of an engine misfire through the process of elimination. While others may overlook, I also appreciate you taking the time to discuss the economics of maintaining an obviously beat up vehicle with a high mileage on its rap sheet vs looking at other viable options. This is huge. You just don't run a vehicle and expect it to work for you without giving the needed TLC. Wear and tear caught up with it and just feel sorry for the owner who probably was thinking that you could reverse it. Albeit, well done, my man.
Nice job. Trying to catch that with a compression gauge isn't easy. I've been trying to get the guys I work with to do relative compression test because it is so quick and easy to do.
Auto Ditex has a unit that can do relative compression from the battery . Unsynched takes about a 10 second crank . Or you can connect an extra cable and synch the pattern . It's about $ 300.00 . Diagnose Dan has used it . No lab scope needed . They also have a lab scope and other test equipment .
it's a dodge caravan, it was beat when it left the dealer lot :))
Thanks ScannerDanner Great Info 😎👍🏼
I just changed the heads on the 2000 Ranger 3.0 with 188,000 miles. They had known exhaust valve issues over time. Turns out I had cylinders 4 and 6 getting coolant in the chamber which was cracking spark plugs and then once I had the old heads on the bench, 5 out of 6 had brake parts cleaner leak past the exhaust valve seats. Now with new heads with hardened seats, all new head, intake and valve cover gaskets, I am battling high LTFT's. Got new O2 sensors on the way since mine have about 60,000 miles on them with raw fuel from misfires for who knows how long. Good news is that there is no sludge in the motor and the cylinder walls still have the cross hatch on them.
I have the same problem cylinder 4 .sometimes it runs good sometimes it runs bad.but always cyl 4 .the car had a ticking noise after the head gaskets were replaced .so I replaced both rocker arms and lifters .i don’t know that it had a code p0304 before I replaced the rockers because like I said it had a blown head gasket .the machine shop said the heads and valves were ok .when they resurfaced the heads .so now I’m stuck with the cyl 4 misfire .compression test showed bad compression .bit some times it runs great .you nailed it for me .its a bad lifter ona new rocker assembly but more than likely a piece of some thing is blocking the oiling orifice for that lifter. Thanks a million your thorough diagnosis lead me to the only problem it could be .bad lifter or more likely a piece of silicone blocking the lifter orifice intermittently.now I can fix the car for zero dollars .
I had almost the same problem on a 2000 dodge G/C the only difference was the misfire was sporadic but we couldn't recreate the misfire over several months and 2 trips into the shop. 3rd time being the charm my customer brought it in when it was actually misfiring. For the misfire to surface they had to be on there way home from work with lots of stop and go traffic and the temperature was above 85 degrees and still intermittent. After checking spark and fuel that were good, it had low compression on cylinder 3 with a leak down test proving it to be a bad exhaust valve. After removing the heads we could see the issue which was a hairline crack in cylinder 3 exhaust valve. After watching this I started to think what the vacuum gauge would show while doing a cylinder balance test. Next time I get a misfire like this I'm going to have to look at this just to see if there's anything of value in it. Thank you for the great videos you always have great content.
Excellent call
Dude this save me wasting money on ignition coils and fuel injectors on my z3... thank you so much. I do engine work in the Pittsburg, Ca bay area.
I am in Pittsburgh, PA :-)
Send it to Eric, he loves those vans
HAHAHA! He sure gets alot of those!
Make my living on Chrysler's haha
not what i wanted to hear i just bought one haha
i love your channel to SMAR
too
Like my Verus Pro...graphing shows you so much
Excellent video. Subbed and liked 👍 cheers from Australia 👍 ❤
I had a few of these Vans and I had good luck got over two hundred thousand miles on both of them.
Haven't been able to watch much since Hurricane María sent us back to the stone age, but now that I could watch this I have to thank youfor all your work. Shalom brother.
Shalom my friend. Are you okay now? Do you need anything?
ScannerDanner We're ok thanks to The Almighty. We have no power and water comes and goes, I've been able to work on a local auto repair shop and we're slowly coming back on our feet.
ScannerDanner We're ok thanks to The Almighty. We have no power and water comes and goes, I've been able to work on a local auto repair shop and we're slowly coming back on our feet.
I didn't know you were doing videos now! And I didn't know you spoke Spanish. How many repair videos do you have up?
ScannerDanner I have 13, and I'm from Puerto Rico, spanish is my first language. I have a TPS code video that I did with techniques I learned from you. Thanks for everything Paul. btw, I sent you a Google Hangouts invitation, check it out!
nice vid Amigo thanks and God Bless !
Rear valve cover isn't that bad on that van. I did stem seals on one at 485,000 miles. Last I heard it was still running just fine North of 500,000. Commercial van with lots of miles and few cold start heat cycles as well as being in an arid environment and having a dedicated mechanic helped it reach a round trip to the moon and back.
Great new tools for the toolbox on my shoulders. Thanks Paul.
Love your work your are a walking brain
Nice find Paul. Gravy :D!
Mr. O! I was told I should have given this van to you since you like them so much? Haha, don't know the background there but I'm sure it's good. Hope everything is well with you and you family. Thanks for dropping by.
Oh it is just because I work on so many soccer mom vans I get called the "Dodge Caravan Channel." Looked to be a classic broken exhaust valve spring. Been cool to see it through but if they are a toilet why go any further.
HAHAHA! A wheeled toilet. I've owned my share of those over the years ...
Loaf ... turd ... POS .... so many names for them! :D
Exactly
Im with eric on the broken ex valve spring. Seen it many times. Same on windstars.
Thank you Paul.
Great info bro thank you
Dont skip anything please i wanted to see how you connected that vaccuum gauge. Edit: I'm a fairly new mechanic with 3 years experience and these videos have helped me advance in my career. I look like the smart guy at work thanks to your videos.
Join my classes I offer on my website. They will elevate you even more my friend. Thanks! Hope to see you there!
www.scannerdanner.com/join-scannerdanner-premium.html
@@ScannerDanner I checked it out and I'm actually going to give it a go I have your book already.
@505fastlife6 awesome! It really makes the book come to life. Looking forward to your questions and comments on the classes and case studies.
Really great info! Could a valve hanging or sticking cause that low spike on # 3? Thanks for sharing. Learned good info today. Cheers from Motown.
Hi Mr danner yes everything is good now. Since I logged in with me and my wife's Facebook account lol. But everything is good now and happy I will see you're very good videos you're the best teacher I ever had. Big THANK YOU MR. DANNER and to you're son that he's helping you do the videos say hi to him for me thanks .
Thanks bro! Really appreciate you being a SD Premium subscriber.
Here from holland thank you again for this video!
thank you for watching from holland!
Paul I recently purchased a Pico 4425 kit. It is awesome by the way. I enjoy your videos and I am learning quite a bit from them. Quick question, I noticed the spark event was after TDC, do you recall if there was a timing issue? I was just wondering because I am not sure if I was looking at it properly. Thanks for all of your hard work.
timing slightly ATDC is common during cranking
Lifter problem wouldn’t be intermittent like that though. Intermittent sticking valve is my guess. Caused by binding valve guide, or weak valve spring.
Nice Troubleshooting skills!
Thank you for your help
Another good vlog, a case of why put good money into to bad. Honest call at 160,000 miles...
Wife's van with the 3.3 is at 235K and still running great. A little rusty around the edges.
In the past have found as the valve is turning a warped valve face will intermittently not seal properly. its usually thinner on one side on the exhaust valve side. I made this repair back in 2009 with a year model 1999 town and country /200,00 and its still running good today. My point to new technicians, be confident in your diagnosis and don't be afraid to repair instead of replace.
GREAT VANS!
Great diagnostics!!
I'm so glad I don't work on those crappy Caravans anymore. Oh wait, gotta fix one next week....ugh. Well, it rare that I have have to fix them. Better than the Ford Aerostar, those uber-suck.
im bending in dust, god damn your a good mechanic... best regards from a vw/porsche mechanic in denmark
Thanks man, I really appreciate your kinds words.
Hey I've never seen you get the vacuum gauge out Scanner!😀
There was an old school race mechanic telling me a while back that you can tell a lot about an engine with a vacuum test.
Good thing you qualified that POC comment.
I drive a an 02 T&C
Butt let's face it, it's another good won professor. Soooo .... Thumbs up. Tell the guy to do oil changes more often than 20 30 thousand mile intervals.
Oh and nice partial view of God's country in the background at the end of the vid.
Thx for all the people you help. I have a 1990 e150 that has a hard miss with occasional shuddering. I have replaced all ignition components, same problem. Do you think it could be a bad ecm with leaking capacitors.?
Nice one Paul. I'm trying to catch up on your videos. :)
You are amazing, your knowledge is exceptional.
Paul, please consider a video outlining requisite diagnostic instruments for HOME mechanic, including affordable scan tools. Thx
Everybody has their own favorite engine cleaning/flushing concoction, and this van would be a prime candidate for it! That intermittent compression issue is just screaming "sticky lifter" to me, and I'm all too familiar with the need to "keep it running" that commonly comes with vehicles in this condition.
Idle it for half an hour with a quart of Dex III ATF (or other personal favorite), throw some fresh oil into it with a bit of [personal favorite], and ship that baby!
Always start at square one even if it had new parts and never assume the new parts are good. Found a bad brand new spark plug more than once.
omg i died @ butt face thank you for making my day
I run from people who drive a car for 150K miles with no maintenance and then want you to tell them what's wrong for free and fix it for $100 bucks.😕
Then when you find out more stuff is about to go out that will affect the first problem and you tell them...they always say " well you said this not that so now you want more"
"I thought you said it was part A. Now its B and C too? Well then" or " parts B and C were fine when i got here. You will fix B and C for free!"
sounds correct
I agree such fun work to do and potential to make money ruined by cheap ass hood customers who cry when you mention diag fees and always say “can you just take a look at it?”. Fuck them
@@ufarkingicehole if it’s not part A then your diag wasn’t correct, how’s that the customers fault? If you said you fixed the problem, yet it continues, then you replaced a part that didn’t need it. This is why we have expensive lab scopes and shit, you don’t throw parts at a car and expect a fix, you find the problem and figure out the solution.
Paul, any chance that your classroom tests could be available on SD Premium in the future? I feel as if some good tests could really help retain all of this great information. Either way, I will always be eternally grateful for you and your teachings.
Now that I'm hosting it myself, I should be able to do that for you guys. Stay tuned
awesome video thank you you sound really really smart with engines, i have this same problem i brought a 2005 town country 3.8 with 120 k on the engine i changed everything you have mentioned i mean everything so almost 80 k later and no one can figure out the problem except me yes really i have come to the conclusion its a broken spring on the rocker arm this will only affect your car while idling yes sir it will so my advice run this shit to the ground no worries she will keep going dont worry it idels like shit but she run like no other 80 plus mph no problems really
If it was a mechanical leak (valve, rings): it would NOT BE showing INTERMITTENTLY ...
I fixed a random misfire on wife 3.2V6 Acura by swapping the low mileage Irridium OEM plugs with Platinum plugs.
The hair-thin center irridium pin does not fire too well in lean mixtures... The double platinum has a slightly larger pin and provide more consistent spark path.
(I know a needle tip is supposed to spark easier but the cylinder fuel mixture is not 100% consistent, so stubby electrode better than skinny!)
Thanks,that is VERY nice; then it becomes guessing; need a compression test, with the old compression gauge, oil in the cylinder (don't think it's needed here, lol), and valve cover off.
thanks good vid
Frommy experience it possibly has a cracked spring, common in my area. They break and allow a random recurring misfire on single cylinder. IF repaired repalce all vs seals and springs. BUT car is beat, the estimated price of top end pull apart ie vc/intake/etc tell them to take repair costs and old car and trade on different car AFTER having car given an extended vehicle inspection with test drive.
Great video. One question though. What would you look for if you actually took off the valve cover?
IT would have been a shot in the dark but maybe a broken valve spring but I do not believe that was the case here.
I couldn't help notice the spark looked like it was happening after tdc. Was i looking at it wrong? Looks also like you have a lot of new followers, that's great, glad to see business is good.
That is not unusual during a cranking condition. Also, it wasn't but a few degrees. Thanks! Good to hear from you my friend.
You are fun to listen
I say broken exhaust spring, it sounded like it was alternating/cycling while running. the broken spring is riding up itself and dropping back off the other piece, probably broken near the spring base =p
What about the perfect vacuum.?
@@ufarkingicehole its intermittent wouldnt the valve spring be consistent. lifter seems more like it. maybe slow to pump up
@@dcomputers the vacuum being constant makes me believe the valve springs are ok. It sounds like the lifters are tapping or not priming properly. Based on that alone I would assume the bottom end is ok. The valves are sealing. I would want to run a test to see if all of the cylinders seem to be doing what it's supposed to. I would want to know if its running lean/rich/ or ok. Possible sticking injector?
Hahaha so I actually watched the video and yea..... I'm sticking with a jacked up lifter
@@dcomputers Not necessarily, I had cracked valve spring on 2 GR Toyota engine and the problem was intermittent.
I do agree that in this case a lifter is probably the suspect.
Great work by Paul as usual.
I dont think i woul fix it but i would do a tear down just curious to find out the problem for sure .. Thanks for the video take care...
hi scannerdanner did you check the higher rpms (2000+) on that car? I have the same symptoms on my 1995 mustang 5.0. misfire but only at idle. ignition system is good. no vac leaks (constant 20 in hg). fuel system is fine. injectors also. engine rebuild done. but the lifter werent replaced. I'd like to check them before replacing parts with no end. your help is appreciated!
Nice one. Not including what happened to this gem of a vehicle, is borderline cruel...
Yes I would do work I personally own 2 of these it sounds like basic maintainable maintainance has not been done. The breaking issue is caused by heat warp unfortunately meaning with these and many other minivans you have to turn or replace the rotors every 6 months to a year. At this point it is a bit of an uphill battle its still cheaper than a new vehicle and if you are in need of something such as a caravan then its one of the better options.... Side note may recommend an odyssey just for the lower maintenance requirements.
My 2000 Grand Caravan gave me 343000 km (215,000 miles) before packing it in. 3.8 L engine. There is no substitute for timely maintenance.
Isn't it a 3.5L???
Yes very true 1 have 2003 with 365.000 miles original engine and transmission i bought new. Still runs but body rot is bad.
@@angelozararis7404 I have 270 k on my 1999 Chrysler Town and Country. Also have done various repairs on it. The have amazing pickup on them.
Mine has a misfire .. going to the shop.. just replaced all seals from intake manifold to the air filter all new injectors .. hands are up but not going to let her go down
@@PIANOSTYLE100 mines 270k miles 05 .. I love .. (yes alot of work and ppl yelling my just go buy new .. nah I can't give her up .. even with her Mis#5
2:11 - I thought coolant, engine, and transmission leaks were just a standard feature on Mopar vehicles. Lol. *Just a joke, Mopar fans!* Nice video, thanks for the helpful information.
Take it back or I’ll beat you about the head, face, neck and hands!
Opinion on ford focus 02 lx
Voltage drop after new alternator and battery put in and starter. But if shut car off charge back up to 12.5. But driving guage jump from 14.1 to 12.3 to 11.9 and all over I love these videos
The crusher is the appropriate fix for that vehicle....
the day it left the new car lot, or the factory assembly line :))
It will be shipped to some 3rd world country, and be driven around there, for a few more decades ;)
3rd world taxi or delivery van.
I went through all the checks on a Jaguar x type. Had a misfire on 3. #, is on the firewall side and underneath the intake manifold. No way to access the coil or injectors without removal of the intake. Fuel checked out, Fuel trims out of whack, no vacuum leaks. I broke down took the intake off and removed #3 coil....as I removed it, I noticed a drop of water...I looked in to the tube and saw that the SP tube was 1/2 filled with water! took the rest of the coils off in that bank and the same thing!
Not sure where the water came from, but I'd changed the intake Man gaskets a couple of weeks before and cleaned the area with degreaser, and rinsed. I thought I had thoroughly covered EVERYTHING with plastic. Car ran well for about two weeks, then the misfire. I bet it was running on 3 cylinders! Anyway, I dried everything and engine is running like a top.
However, I'm still leery and wondering if there is a water passage on the head that is seeping. The "water" was not antifreeze as far as I could tell. I'm hoping that maybe it's water leaking down from the windshield washer nozzles or that maybe I didn't cover the engine as well as I thought I had and it took a while for the water to interfere with the plugs.
Hey Paul, when you scoped the issue and it showed the dip in the graph for cylinder 3, were you probing the starter wire at the battery? I didn’t see you explain where you put you 600 amp clamp?
Thanks in advance!
yep, just the main battery cable that goes to the starter. I linked two other videos within this one that show this procedure in more detail. Thanks!