Misfire caused by a vacuum leak
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- Опубліковано 10 лют 2025
- Typical to an intake manifold gasket that is leaking, is an engine misfire, especially with the engine cold. In fact many cars will exhibit absolutely no misfires or idle speed roughness with the engine hot. Some may not even have lean condition trouble codes, in particular with speed density engines (no MAF sensor).
Engine Performance Diagnostics chapter 1 pages 9-14
Symptoms
check engine light (P0300, P0301)
misfire especially at low RPMs with the engine cold
customer replaced plugs, wires, ignition coil and fuel injectors in an attempt at fixing this problem
Fix
replace intake manifold gasket
Tests shown
how to perform a cylinder drop test (rpm drop test)
how to test for spark with a test light
how to use water to locate a vacuum leak
Tools used
scan tool
squirt bottle
Playlist
(Chapter 1) Misfire ID, Compression Tests, Vacuum Leaks, Fuel Trim, Head Gasket, Restricted Exhaust, Low Power, DMM
• (Chapter 1) Misfire ID...
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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.scannerdan... 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.
I really want to say thank You, I have been looking for this vacuum leak for a really long time. Changed my throttle body, injectors,spark plugs,coils, upper intake gasket,and a few other things. Really wanted to find it myself and not deal with a shop, and watched many many vids and thought to myself, I guess it’s compression BUT when I saw your video, I immediately did what you said and it was my lower intake gasket and changed it .It is running so smooth and I felt a relief come over me. Thank GOD for you!!!!!!!!!!!
Bravo Homeboy...you think in the way i think too👍
I feel you on that one, I literally did everything you did. I found an OBD2 reader that does live data. My Short Term trim was eratic and way too high which while idling which means a vacuum leak somewhere. I hope I can find my issue. Videos like this really help the DIYers out here.
This may be my problem with the po302 on my 2006 Subaru sti
I know man, for sure I miss our "daily bread" in the morning. Still haven't found someone as dedicated to share in the word with me. God Bless, talk soon
I knew I liked your videos for a reason! Ain't God great!!! Lol take care bro!
Thanks for the great info! This is exactly an issue I have been having. DTCs occasionally tripped due to cylinder 1 misfires on 98 Saturn SL1. I wish I would have watched your video prior to buying new plugs, wires, coil, and injector over the course of a year. I also checked the compression just before buying the injector and it was fine. After the injector didn't fix it I opened my ears to hear a hiss. I then found an intake leak right by cylinder 1 using carb cleaner. It looks like water would be a safer way to go, that's what I will use next time. I am going to consider your purchasing your book. Well done.
In 35yrs as a tech I have never used water to find an intake leak..I have used oil,brake cleaner, carb cleaner smoke test etc..I can see water is a safer viable option..Thanks for sharing,
I really love the content man I've been binge watching you since I found your channel it's really refreshing to see somebody truly confirm a problem and not just replace on a hunch you've taught me a lot of things. I was also very pleased to find out you were a man of God. God bless I wish you and your family the best.
Thank you and nice to meet you my brother 😊
I think my original comment got erased or something idk,thank u for this video i will DEFINITELY be back on here after trying this.ive got a spray bottle,now i just need a prayer
New coils plugs, injectors,swapped them all around too,and still cylinder 2 missfires code but also p300 which i didn't get before replacing it all.however it runs better after injectors replaced.the2nd cylinder injector had a crack around knozzle so i saw that and got excited like i found it.well it runs better now and the warmer,the smoother and less spudding or jerking..if I'm smooth and easy with the throttle its good and idles great after warm up.this leads me to believe now there is also a vacuum leak somewhere and i will be trying this in the morning.thank you for this video i wish i found you years ago
Unfortunately for the car owner this is true. There simply is not enough good technicians in my field and WAY to many parts changers.
Danner was my instructor.
Hell of a guy, passionate smart and great to learn from. I'm no longer in the field and still watch his videos. Keeps me interested in diagnostics and sharp on what he taught me. Tell me my man don't look JUST like Karl Hagelin
Thanks Needs!
Scanner danner, you're a professional. I learned a lot from you. Keep up the up the good work. BRAVO ZULU.
Thanks so much for the video. I have an '03 Dodge Dakota 3.9 ltr with over 300,000 kms on it. Long story short the fuel pump had to be changed. Just after the pump was changed I had a misfire on #5 cylinder code. Have changed out plugs, cap, rotor. Checked operation of injector using a stethoscope...all injectors were humming away. Did a compression test today and have some wonky numbers from that but that's another story. Bottom line will do the water check on the #5 and see what comes of it. Again...thanks for the video. Cheers.
+oldesarge2000 thank you for watching!
+ScannerDanner sometimes in life it's the simple things that work. Changed out the plug wires did a vacuum check.....seemed to hang a second on the bump but looked good otherwise. It had been a while since I had changed the plug wires. Changed them out and all is good. Hanging my head in shame but hey...if it works I'm good with it. But after watching this video I'm now aware of how an intake manifold leak could cause a misfire situation. Learn something new everyday.
Best car troubleshooting video for any car or problem that I've ever seen. Thanks. You saved me lots of money with my Neon.
i love the smoke. smoke is great for confirming your repair. i hate come backs and charging twice for what could have been spotted on the first visit
I still come back and watch your teaching videos because you are so fucking thorough, detailed and fastidious. You ALWAYS prove your theory. Thank you! Truth told though, when I fix things, sometimes I just accept a good result and move on without being certain.
Wish I saw this video before installing new plug, coil plug, maf sensor on my 08 Lexus ls460. I ended up doing a smoke test this morning and found smoke leaking from my intake manifold. Well at least I'll know I have done a somewhat tune up on my car and I guess I'll change all my gasket to be on the safe side. I'm no mechanic but UA-cam, Google, and forums help me out a lot
Thank you so much. I've been looking for all of the information in this video on how to troubleshoot this without throwing parts at my truck.
I don't know what to say, but you are the best boss sir👍
Helpful. Others suggest spraying brake cleaner at the leak to listen if the engine will run better, due to the extra fuel. I do believe that making the engine run worse would be easier and more conclusive. Thumbs up for sure!
I more like water test it not make fire. But seem like water test only can do at intake manifold gasket test but not other small leak from other rubber hose. But still good way without any harm.
Piece of cake on that engine. Whole different story on my 3.0L V-6. Great video. Thanks.
It is a great "pinpoint" test. Propane will give you an area, but the water shows exactly where.
Thanks for the comment
PRODIGY Sir ScannerDanner
From the start to finish loved it tutorial great video amazing footage thank you very much. Take care and have a great day
PRODIGY Sir ScannerDanner
From Nick Ayivor from London England UK 🇬🇧
Never had an issue with that. I understand your concern though, just be careful if you decide to use a garden hose. No danger with a squirt bottle.
Scanner danner, you're the man. Intake manifold gasket leak will trigger a misfire.
yes it will. Thanks!
this is a great video, very helpful for us non mechanics. I've got a 99 civic with a miss fire under load and this may or may not help me but it is nice to have another diagnostic tool to track down the problem. thank you I'll be subscribing to you channel for more information. keep doing what you're doing.
Under load misfire will not be from a vacuum leak. For additional help....
It is becoming more and more difficult to answer questions here. I have 80,000 people asking me for help now. So I have created a forum to help you guys better. It is free to join and we can exchange pictures, wiring diagrams and waveforms if needed to help guide you through the process of troubleshooting your vehicle. Thank you so much! Hope to see you there.
Paul Danner (ScannerDanner)
www.scannerdanner.com/forum/post-your-repair-questions-here.html
7 years late, Did you ever figure out your problem?
I've also used the techniques you've demoed for finding vacuum leaks, and in addition have a stethoscope I modified with several different interchangeable open end probes; made of various tubing scraps.
It's far from perfect, but allows me to listen closely around most anything I can see, and some I can't. Running along gasket lines, there is no doubt when a leak is found. Some are dramatic.
It's also great for quickly finding dead/shut off injectors, exhaust leaks, and more.
Good Video,
Found you through Eric The Car Guy. Happy i did, good info and easy to understand. Thank you for posting
As others said, I never tried water for leak testing but it looks like a great idea.
I think this would work better than propane.
Gonna try it now on a problem child car that won't idle too well.
Thanks for sharing.
SD we love you bro. You are one of the best technician I ever know
Appreciate you bro, this may be my issue on my 03 forester. Grateful for your input time in this video.
Ty... awesome info... I like the great tip using spray bottle with water... vs flammable liquid sprays.. I've seen so many cars catch on fire with techs using brake clean.... so dangerous..
Thanks for taking the time to make this video... very good technicians are hard to find & your vid helps me get started on pinpointing the similar problem for my 2002 nissan quest
I have a story, which is a puzzle for me and probably for many who reads it. I went to Firestone on
Northway Hwy to do alignment and State Inspection. The car is old, and basically it is my toy-car
to practice on auto DIY projects. 2001 Saturn SL2. The car was running maybe not the best, but
normally, my main concern was alignment, bcs I did a lot of suspension work on the front, and my
husband observing how I move parts around came to the conclusion that the car will never run
again. At Firestone they couldn't do alignment, bcs they needed a special tool (for the rear), which
they didn't have and advised me to go to a dealership to do a proper alignment. To my amazement
they said that the current alignment on the car was pretty good, gave me a print, which proved it. I
assume, the alignment was good, bcs I counted turns on outer tie rod very accurately. They said
that the battery didn't pass the test (car was sitting for a long time), but passed the safety standards,
so I need to make 50 mi on it and come back. I went back home, and on the way I noticed that the car
started to shake slightly at one red light. When I came home the engine was shaking like crazy. I
switched it off, took Actron, but before diagnostic decided to start it again and listen once more what
the engine does. The car started vibrating vigorously, the arrow of the rpm jumping from 400 to
1200 and back all the time, then after a loud sound ("bum!") died. There was a small puddle on the
ground from the transmission fluid. Actron gave P0404 code, which is emission code, so I decided to
clean a Throttle Body, what I did, but there were not much changes. Next morning car died again
on idling, when I warmed it up. Now in addition to P0404 it gave a code for the Powertrain Module
(Engine computer). I started the car again and without any waiting in Idle went to the Toyota
dealership, they did some work on alignment, but also didn't have that tool for the rear of the car,
and advised one GM dealer. I suspected bad fuel, so I added like 1/2 tank to make it full, poured
good engine cleaner, car started to run a bit better, but still vibrating at stops (though at 800 rpm
already). No more leak fm transmission. In that condition (car was still vibrating on lights) I went
to Jupiter Chevrolet Dealership, where they did the front alignment perfectly, some rear, but not
toe (again no tool for that job on the rear). When I started to drive I immediately noticed that the
car runs perfectly well, no rattling, vibration, you could sit like hour in Idle, it runs very smoothly
and good. I went back to thank and ask, what it was, what did he do, but the mechanic gone for the
day. So my question for the puzzle is: what can be done to the car that it develops a vibration on
lights, and see how, not immediately after I left the Firestone, but after about 5 miles of driving?
And what the mechanic at Chevrolet Dealership did, that the car runs with no problems now, very
smoothly and quietly. Later he said that nothing was done besides an alignment, and he never
opened a hood. Thank you for the great film.
When I was a tech for Saturn we use to get the s-series cars that were at other shops for cylinder 1 misfire where the shops would replace any number of these things injectors, plugs & wires, coil, ign module and pcm. But the problem was just a bad intake gasket.
on a map (speed density ) engine you can have normal trim numbers with a vacuum leak.
Thought you said it passed the smoke test? Don't worry about the open loop fault, the PCM will do this if it cannot compensate for the condition. Do the water test as you said.
Great video Paul. It's amazing what a simple thing like water can do, oh and a little common sense and knowledge.
We always use gum cutter. Water seems wrong. Love your videos!
Thank you! That was the plan, I am trying to combine book material with case studies. I think it helps.
Excellent video
I have 1nrfe dvvti
Low rpm lack of power need to press gas more and sound from exhaust gogogo
No rough idle
No codes
No engine light
No white smoke
39mpg atm
Change spark plugs air filter cleaned throttle body inside out
Any recommendations
Its an electronic throttle body can drive 70mph at 3500rpm but lots of noise
I believe the intake leak would lean it out . Would the fuel trim numbers start to go rich ?
Not on a speed density (map) engine
That is correct and you will get shocked if you don't give it somewhere to go. It will choose you as the path.
not necessarily intake gasket, I had a time when the injector o-ring was torn in half and was missing the other half, was causing misfires like crazy.
i would have never guessed to check that on my srt. im going to do that test tomorrow and if that's the problem im going to be shocked. I have spent well over 1000$ fixing stuff that could be wrong.
Excellent demonstration, thank you. 🙂
I have the same car 97 2.0 liter sohc neon. I get intermittent cylinder 3 misfires when accelerating to highway speeds. I'm thinking I should swap wires and plugs because, the compression tested good plus i've rotated the injector positions and seen no difference. Plus I noticed minor corrosion in the inside of the wire to coil boot. Don't think they've ever been changed Has 160k miles on it. Also have to do a complete set of motor mounts and replace the egr system and tube in the future.
I don't remember who showed me that test, but it is a great test. Especially when you don't have a smoke machine. Thanks for the comment
Po302 on my 2006 Subaru sti with 150,000 miles. Runs fine. Swapped plugs, ignition coil next is injector swap then leakdown test
Might I ask you about your car / situation ? What was the specific problem actually ? And what was the fix ?
Po302. Been driving locally 30 miles tops. Ruf idle, cel flashes then steady. Did compression and leakdown test all good. Did vacuum leak test found no leaks. Taking to wrenchrite Subaru repair shop tomorrow. In branford, ct
thank you for commenting and your kind words
I think you just diagnosed my issue on my 1995 mustang 3.8l it has a lean o2 sensor reading on only one bank, bogs when cold, and has a low idle. I am going to try this soon. Will let you know the outcome. BUT when first driving, it will begin to bog and WITHOUT changing the throttle position (still under load) the car begins to accelerate back up and run normally. All in the course of maybe 2-3 seconds.
Thank You for this upload. This video was awesome. You're a really good teacher.
+Kaktus Jack thanks for watching and I'm glad it helped you
I absolutely agree. I have some educated people, as well as a couple of clown fools that reply to my channel, and don't contribute anything of value at all. You, sir, kick ass.
My Blazer just developed a misfire and sucked the electrode out of at least one spark plug, so, I'm still trying to sort that out!
How do you feel about using a can of carb or intake cleaner and spraying around the gasket to listen to idle raising?
Great test, safe and simple.
I know, you can hear her in a lot of my videos. Brings back memories, doesn't it bro.
It is helpful for me,I have my idea for DIY about misfire,thanks.
Great video ScannerDanner. Subscribed to your channel. Need to pick your brain a bit. I have a 05 Neon SRT-4. Started to get a P0301 3 months ago. Vehicle only has 17k miles on it now. Its not my daily driver. Bigger aftermarket turbo, custom fuel system (pump injectors return line) custom tune etc etc. So far I swapped plug wires.. 1 & 3. After I cleared the code. It came back on. Still P0301. I swapped 1&2 spark plugs still got P0301. I boost leak tested the vehicle and usually if the intake manifold gasket is leaking it will HISS or scream at you. Car has an aftermarket Hondata plastic intake manifold gasket. So I doubt that is it. So recently I went a step further. I took the fuel rail off and my RC 750cc injectors off and had a somewhat local shop flow test and clean them. He said they were fine and had no issues holding pressure and were perfect. So I bought a compression tester and crossed my fingers. all 4 cylinders were 120. (cold motor) So I put everything back together and put a new set of plugs in there just because. Haven't started the car up yet to drive it around. Should I test the coil pack even though it is only 17k miles? Car has an aftermarket small battery from Odyssey with just 330CCA. I noticed I started to get the P0301 when it was cold out. Could the such a small battery cause the code since it is not given enough volts to the car? Car runs and drives fine. and goes WOT fine with no miss at all. Seems to just miss a tiny tiny bit on cold starts. What say you?
It is definitely not the battery. And it still could be a compression issue even though they all show good cranking compression. Hard to say. There are a lot of variables. Also, I would test it for an intake leak like in this video.
Thank you for the response!! Appreciate the feedback! I will carb cleaner around cylinder 1 on the intake manifold gasket. Unless water is a better way. I think with carb cleaner it will idle better while water will make it more rough. So I will go water instead.
Sprayed it with a fine stream like you did. No idle change. guess I will drive it around for a bit and see if the CEL comes back on
Just an update. I have driven the car multiple times. With around 12~ startups or so. No CEL!. :) The cleaned and flow tested injectors were installed along with new spark plugs. Nothing else.
👍 super helpful as always! Thank you!
I saw the thumbnail and was like "is that a Chrysler" I knew because I have a neon and that's the only car I know with an engine that looks like that
Yes it only misfires when it’s cold! Replaced the dang coil pack and fuel injector when all I needed was a gasket
Very good development of the theme and accurate explanation !!!
Thank you!
Wow great video. I'm running on a problem as well with an 03 neon myself. Had a p0301 come on it wouldn't act up in cold start though more when it was fully warmed up. Even at idle it wasn't as much as a concern only happened when I would accelerate. The engine would bog down badly loss of power and then the p0171 came on as well. I noticed my fuel trims go way high when I would accelerate my engine and would bog down. But as soon as I came back and to park the idle was normal and the fuel trims came down again. But only starts to rough idle when I have in drive. I'm assuming that the 301 is cylinder one meaning that problem is in that area and the 171 meaning it's a air and fuel mixture that is incorrect. Which leads me to think one or the other. Fuel injector which u had swapped but no light has come one yet. And two the intake manifold on cylinder one and this video is leading me to believe I may have just that. Also I was wondering is the fuel pressure at idle normal for a neon to be 6-9 psi. I know the fuel pressure at max is around 50psi. But I never do see what the pressure is at idle anywhere. And I get that in my scanner. And also this fuel pump is Brand New from AutoZone it's a Delphi fuel pump
Propane/butane, either one is fine. I only suggest a vapor over a liquid (carb or brake clean), simply due to the fire hazard. A vapor if it ignites will quickly go out where as a liquid will keep burning. Either way you must be super careful as you can still catch the car on fire, or worse yet your garage.
Scanner Danner is the man !!!!!
thank you but I'm really not :-)
Thank you. I teach at Rosedale Technical Institute in Pittsburgh, PA.
I’m having the same issue but with cylinder number 4 I was spraying some carb cleaner around the gasket to see any change and the car died before I could finish listening to the RPMs, gonna try this trick out when I got time, just replaced all my wires and plugs and ignition coil brand new. Same issue so I believe I have a gasket problem but won’t jump gun just yet
Hello, might I ask you about the specific problem your car had ? And what was the fix ? I’m having the same problem .
@@ThunderbirdRocket the car got totaled in a accident, just needed a tune up and tps sensor replaced along with idle air control valve
@@lucianoromero777 thanks for sharing this information ! Very helpful . I appreciate your help & time .
Excellent tip/trick!
Much safer than the carb/brake cleaner method,especially around my suspected leaky EGR tube!
Hey scanner danner i have a 07 avalanche with 5.3 with misfire. I did a dod delete and took afm out of pcm. P0300 comes up frequently. Had p0101 pop up for a little but but is a new map sensor. I replaced pvc valve and it ran like new but slowly misfire came back then last week took right side valve cover off and ran it and misfire went away and ran nice. Put valve cover on and ran like a champ for a couple miles then slowly developed a p0101 then p0300. Im lost.
Great information and examples.
Doing a 2012 Explorer right now. Another shop did the timing chain set now has a steady rpm cruise random, comes and goes misfire and vibration. Doing this on weekend for a friend.
3.5L
They removed coils, valve covers, intake etc..
P0300, p0430, & evap gas cap code but doesn't use a traditional gas cap
I like the voice and accent of this guy
Pittsburgh accent no doubt.
Yins goin dahn to pants n'at?
Bravo very good ill try this my car msf c1
Nice nice. Lovin' the vids dan,got my mind goin' :) Especially the 30 min one on the crankshaft fluctuation sensor.
@scannerdanner update: on 2003 sable v6 duratec, i cleaned Maf, upon start up it went closed loop, stft wher still high average 32 on both banks.. after about 30 sec of running it back to missing at idle and open loop.. I do hear some hissing at back of intake to congested to tell tho, so I'm going to try the oL warter in the bottle trick now..
Steam cleaning while checking for air leak. 2 for the price of 1. Great test Paul.
Sweet man, it probably worked like a charm didn't it? It is a great pinpoint test for sure.
ScannerDanner, notice how those spark plug wires were improperly routed through those spark plug boots. Aw man.. the guy that did the tune up in the past :D And is that a dodge neon? Nevermind. Interesting video again.
Great video man. Are these kind of leaks more common in engines that have overheated at some point?
nope, just a bad o-ring type gasket. Thanks!
Thnx❤❤
Does a vacuum leak cause a misfire only when the car is idling or when driving as well?
Idle and low speed only
I'm so glad I found the channel. Your knowledge is incredible. Thanks for posting these videos!! Keep them coming :)
Hey Dan, I gotta tell ya, your the man dude. Awesome videos. I'm guessing your from the burg somewhere. I'm from Steubenville. Keep up the good work and....keep on scanning
haha yep, about 10 miles south of Pittsburgh and my name is Paul Danner but it's okay, I get "Dan" all the time :-) Thanks Sean!
Just a random story for anyone reading....one time I had a Ford Taurus come in that barely ran, it ran really rough, and no power at all, barely pulled up on the drive on lift at the shop I was working at ay the time. Got lucky in the first thing I checked was spark. ...it had the waste spark set up with one big coil pack that housed three different coils. ...and on two of the towers (one coil)there was no spark at all. So I had the boss order a coil pack, installed it real quick and the car ran a thousand times better now that it was running on 6 cylinders instead of 4. Well I talked the customer into getting a bit of a "tune up"to go along with that repair. Plugs, wires, Air filter and oil change just for good measure. And it was a good thing I did, and that they agreed to it. ...the air filter was really dirty,plugs were black AND wet, BUT THE REAL KICKER is that when I pulled the oil Drain plug, SO MUCH GASOLINE POURED out of the oil pan, it was crazy, it poured out for almost ten seconds strong flow before the oil started to drain out behind it. ...it was crazy. ...just where those two cylinders had a dead miss and all that fuel wasn't being burned, alot of it washed the cylinder walls down and seeped through the rings and into the crank case. ...if they would have NOT bought oil change etc that engine probably wouldn't have survived much longer. ..they said they had been driving it like that for a while out of necessity for waiting until they had enough money to bring it in. Not sure how they made it that long. That was the first time I had ever seen something THAT extreme from an ignition missfire. Pretty crazy. Because you know that the oil pickup/pump had to have been pumping straight gasoline all through the engine.(probably the cleanest oil galleries and bearings in a high mileage taurus in the world at that point after that lol the gas had to have cleaned any carbon build up or sludge or varnish it came it contact with i would think) Not sure how much damage it acquired in that time as far as cylinder wall damage for lack of lubrication and also oil pump damage from pumping super lowviscosity gasoline or bearing damage, , all I know is after the coil pack, plugs, wires, oil change and air filter i test drove it for about 10 to 15 minutes and it ran great, no knocking or any weird noises at all. And it rangood for a longtime after that, theycame in for regular oil changes after that for a while, for all I know they are still driving that old taurus. Lol. THEY WERE EXTREMELY LUCKY I'd say. They were so happy and extatic that the bill was pretty cheap considering how bad it was running they thought it was gonna be a major problem, but it left out of there a totally different running car than when they pulled it, made me feel good too Because I could tell they didn't have much money to spare and REALLY needed that car to get back and forth for Their family. Kinda makes me think that God was looking out for them.
Has anyone else ever pulled a drain plug and got straight gasoline or anything else, like coolant or anything, and then the engine still ran good an gold afterwards???? Every time I ever seen contaminated oil ,not even anywhere close to that bad, the engine started to knock.....I would've like to disassemble that thing just to see what kind of impact that had pumping gas through the oil system, my guess would be super clean, but extremely accelerated wear. ....
My '91 Mazda 626 has a misfire and won't hold idle. If you rev it above 2000rpm it will run ok, and if you drive it a few miles, half the time it will start to idle, but half the time it still won't. I feel like its a vacuum leak, but not entirely sure. I was also told it was a maf sensor, and a few other things, but not sure. There is no obd port for this car, so I may have to do what you did with the plug wires on each cylinder. Do you have your test light grounded to anything?
It would have, but I didn't check it. I was focusing on showing the water test.
Fantastic !! Well done as usual.
Beautiful. Simple and effective.
Love this videos. Keep up the good work. Looking for more information on intake temperature sensors and the effect they have on fuel delivery
We'll scanner Danner that is a great trick of the trade and my neon 2.0 is having the exact problem even with num one cyl but unfortunately my intake gasket is not problem and the coil plugs wires and sprayers ain't it either , I hope it's not a burnt up valve I don't know what to do its my daily driver and I have an hour commute every flipping day
Compression test is next my friend
+Ugc1911 We just repaired one with a poor idle/misfire condition with NO trouble codes. Turned out to be a bad primary ignition coil... Even though it looked like it was replaced recently, replaced the coil and it fixed it. runs smooth now.
that a nice unique teat ,I'll try to use it in the school
learn something new everyday! thanks, keep the vids coming!
thanks for the info good tip quick question you sometimes refer to using propane is that different to butane in anyway is it safer or more flammable etc
I have a P0300, P0301, P0303, P0305 all bank 1 misfire. Could a vacuum leak be the issue?
Hello , might I ask you about your case … what in fact was the specific problem ? And what was the fix for your car ? I’m having the same codes / symptoms . Any help you can provide is much appreciated .
thats for this video. What happens if the missfire happens when the engine warms up?
typically that would not be from an intake manifold gasket leak, that is all, everything else that can cause a misfire is still on the table
would a misfire affect cars ability to shift properly and stop all together to a quiet idle at certain speeds? I have an 86 f150 and usually at about 45 mph after it warms up its act like its sucking too much air and jerk its more pronounced now where it use to be taking foot off gas an reapplying it would cause it, it now does it repeatedly every couple of seconds straight. I'd say like 2 secound intervals for as long as gas is applied and then I have to wait till it drops below 45 to continue driving.
Great vid. Ive been troubleshooting a massively annoying problem with a GM/TBI based system (4cyl ALDL) where the RPM is held high when shifting gears or when coming to a stop. There is also a misfire. Ill use these tests later today and see if I can find an intake leak. (I have already replaced the gasket but maybe something is warped..)
Any change you have speedometer or vehicle speed sensor error codes?
No codes logged at all unfortunately. The VSS is brand new and reports correct speed in EFI Live. (I build an ALDL cable and bought the software)
What's you tps closed throttle voltage?
ScannerDanner 0.55v
TPS is also new.
Great video! I always learn something useful with your vids. Keep them coming!
Sorry I can't help with that. Every car is different. You'll need to look it up. Go to Mitchell1 DIY auto repair and pay for a day pass for parts/labor and diagrams. Basically everything that you will need to do the job. It is cheep too, it is like $10 for 5 days or something like that. Just bill it to your customer when your done.
I have a 2010 toyota corolla. I have an exact problem with the above vehicle. I have tried different auto mechanics, they were biting around the Bush, and wants me to do a variety of test. My car runs like new at warm up. No coolant leak, no oil leak, no smoke at the tailpipe, whatsoever. I have a clean motor oil, no carbon build up in the intake manifold. The problem occurs ones or twice a week. Lately I have been experiencing poor fuel economy. I have only 97k miles. When a code comes on due to the problem, it comes as p0301. I have changed my coils, spark plugs, fuel injector., but still setting off p0301 but no solution. Only on code start. I am wondering if this might be the case on the car in the video?
Hope u can reply to this comment soon..I've had a flashing CEL for P0301 on my 2005 Neon. Spark plugs, wires, intake manifold gaskets, exhaust manifold gasket all new. Coil pack seems fine (got shocked decently when I removed the wire from the coil pack) lol. Fuel injectors swapped still remains p0301. Haven't done a compression test. Only 115k on the car. Any thoughts?
People talking about the water spray. What you think it happens when it rains and you run over a big paddle of water and steam come out of your motor? You keep going or you stop and park freaking out?
Driving though a puddle or rain will not suck water into the engine if you're using a stock airbox. they're designed to keep the water out of the engine.
Now A Lot of people with cold air intakes have hydro-locked an engine driving though "puddles"
Steam does not come out of your motor from driving though a puddle, its steam coming off the outside of your engine because its hot. There is a big difference between water hitting your engine, and water getting sucked into your engine.
maybe this is what is going on with a Trailblazer we are working on...it keeps says air/fuel metering, and we replaced the o2 sensor, and it didn't change anything
My car is doing the opposite. Misfire when hot but fine when cold. New plugs and coils checked and they are fine. Moved coils and did the drop test but cylinder one didn’t change engine tone.
check compression next
I did compression and it’s fine. 200psi across the five cylinders. Car doesn’t smoke on start up and nothing is being steam cleaned by coolant.
Thank you my friend!
I wouldn't recommend spraying water onto the engine or around electrical connectors. you can use carb cleaner and it's safe on gaskets and connectors. it will also either idle the engine higher or cause it to shudder.
It's safe on plug wires too! Oh and intake vacuum leaks around a manifold gasket like to backfire. Carb clean loves to be part of that process too.
Steve Kitch yeah i think id rather take my chances with water may be just a little bit safer lol