Never Do This to Your Car (Learn from My Mistake)

okay i'm gonna show you a common problem customer here drove through some deep water on the passenger side check engine lights on and it's not running right now as you might imagine water and electricity especially computer systems do not mix that well realize your computer all those sensors in a car work on a 5 volt reference signal not much power very low amperage maybe a few thousands of an amp power any electrical system part gets water on it you can get problems from corrosion or just plain the water is there and it inhibits the flow of electricity so as you can see under the hood it's all kinds of electronics he went over on this side which water can splash anywhere but we got to figure out what's wrong now thankfully the check engine light is on so we'll turn the key on and we'll see what it is and this guy's a kind of sneaky there's a little access panel here we take it off there's the obd port so we can plug it in of course i have it upside down you'd know that now we'll see what's going on now since the customer tells me the light wasn't on until after he went through the water we know that's gonna have something to do with the problem and as we see it's got two codes and we have cylinder number two misfire and it's twice so the problem is cylinder number two is a modern technology in my grandfather's day that you had to pinpoint everything by yourself take a lot of guesswork this tells a cylinder number two misfire checking the freeze frame data now it's gonna tell us exactly what happened and here's when it happened gives us all the information and here's all the information now we can see it happened when he was going 47 miles an hour and the short-term fuel trim it was adding 9 fuel but the long-term fuel trim is zero now that might not seem much to you but it gave me a real good idea when a trip to code was going 47 miles an hour and it had to add about nine percent fuel meaning it wasn't getting enough fuel that was adding fuel well guess what these kias are notorious for having problems with the fuel injection wiring anyway so we'll pull this stupid cover off there it goes and realize that this is cylinder number two you go from the front one two three four this injector i'm assuming got wet like i said earlier computer systems work on very low voltage very low amperage few thousands of an amp you get any kind of water fuel injection wiring to make them not work right so what i'm gonna do is spray them with some electrical spray cleaner now you can buy electrical spray cleaner that says electrical spray cleaner well i happen to have a case of this mass air flow sensor but the mass airflow sensor is electronic it's pretty much the same stuff it doesn't leave any residue so i'm using this map spray sensor because i'm too lazy to go to the store and buy a can that says spray electrical cleaner this is the same stuff and what we're gonna do is we're gonna squeeze the number two and pull it off and we're gonna clean everything the injector where it plugs in the connectors do a really good job you might as well do the number two ignition coil too maybe it got wet and on the old day we used to use wd-40 when stuff got wet because things were simpler then they didn't have ignition coils on each spark plug they had a distributor and spark plug wires if the wires got wet you could pull the wires off then you could spray them with wd-40 because that displaces water but understand you got thousands of volts of electricity on an old-fashioned spark plug wire on the ignition coil you only have that little bit of power coming at the top the thousands of volts are deep down inside and in this case you could be an absolute fanatic if you wanted to take this off but this has a big rubber seal on it an odds are no water got inside there but let's say go through some water and you're in the middle of nowhere heck get some wd-40 it doesn't hurt electronics and it does displace water so if you got water and it's shorting stuff off you can spray the wd-40 all around then just get a rag and wipe the excess off and often that will stop your problem that's what they used to do back in the day if somebody went through water the first thing we do we just get some wd-40 we spread the distributor cap and all the wires then it absorbed the water then we'd wipe it down with the rag then we'd start the car and drive it but modern cars are a little more complex than that so you're better off with spray electrical cleaner or this maf spray sensor cleaner which is the same stuff you don't want to use stuff like carburetor cleaner because that can conduct electricity and short stuff up you want to use stuff that's made for electronics well now we'll start up and see what it sounds like as we go inside we'll stir up starts right up i did push the button on my computer to reset the check engine light it's been reset so it's not on now so we'll take it for a good half hour ride and see how it does you want to do a good road test will you drive in town five ten minutes on the highway 10-15 minutes that'll give it a good road test to see if anything's going to come up then we'll just look at the data after the road test and you especially want to accelerate harshly like this because you want to stress the motor to make sure the ignition and the fuel system is working at top efficiency if you road test things like a little baby you might not stress the engine enough the more you stress the engine the more any minor problem is going to show up on both the scan tool and the check engine light now we're back home let's plug the scan tool in again well the check engine light stayed off look at the live data and if we check it out here we'll see the short term fuel trim is now minus 1.6 or minus 0.8 there minus 0.8 zero and when it tripped that code for misfire on cylinder number two it was adding fuel it was like eight nine percent it was adding now it's either subtracting a little or it's perfect seems that that fixed the problem so the next time you drive through water and your car starts running poorly now you know how to figure out what it is and fix it yourself just pray you don't suck water into the engine past the air filter because that can hydro lock your engine then the piston rods and goodbye engine so be careful around water and here's some bonus questions and answers mr mech martinez says scotty would you take on a buick lesabre with a v6 3800 motor those are great motors those motors can run forever the rest of the vehicle is okay it's not fantastic it's a gm vehicle and their quality has been going downhill gradually over the last 30 years so they're not the greatest vehicles in the world those are great engines but if you can get a used one cheap enough it could be a good knock around car god it sells me auto parts he bought one for one of my customers for a thousand bucks he's still driving a stupid thing around so what the heck you want a car knock around car for driving places if it's cheap and it runs good now it can still last a while just don't pay much for one they have no resale value paul valene says scotty gotta know what tahoe 4x4 feels like the brakes are on is it the transfer case okay the first thing you want to do when you think they're on drive it when you think it's on pull it in jack it up in the air see if the brakes are on maybe they're sticking on who knows now if they aren't then check the rear versus the front and if the front are real tight it could easily be the transfer case going up because normally it's just running on the rear now if you only have it on the rear and not the front four by fours when you're driving it doesn't stick odds are it is the transfer case there's a lot of things that go on with those things you want to jack it up and see first you don't always want to go with the most expensive thing it's like the guys that say oh man i think i need a computer in my car well maybe you do maybe you don't don't start with the most expensive thing figure the other things out first my cox says scotty should i trade my 2013 bmw 328i four-cylinder sedan for a 20-20 toyota corolla hatchback manual transmission definitely trade in yeah i would definitely trade you're not gonna get much for a bmw nobody wants to use bmws well whatever you can get for what the heck the toyota might last you forever the bmw is seven years old and it's soon to be if not already an endless money pit and unless you like falling into endless money pits i would get rid of it as soon as possible jason says scotty can i change the alternator pulley for more alternator power you can make it smaller or bigger if you can find one but of course then your fan belts might not fit right in most cases the alternators on vehicles work perfectly fine the way that they were designed and unless you're sitting there idling all day long your engines spinning fast enough to charge you with any normal design these days so if you never want to miss another one of my new car repair videos remember to ring that bell

Channel: Scotty Kilmer

Views: 484,543

Rating: 4.907373 out of 5

Keywords: common mistakes, auto repair mistakes, auto repair, car mistakes, top car mistakes, automotive mistakes, car owner fails, car owner mistakes, mechanic mistakes, car repair fails, car mistakes to avoid, car, car repair, cars, diy, repair, scotty kilmer, diy fail, mistakes, car owner, top mistakes, top mistakes car owners make, mistakes car owners make, 5 things you need to know about your car, don't make this mistake, top 5, top 5 mistakes, 5 things you should never do

Id: mn-MVh1HZtE

Length: 9min 33sec (573 seconds)

Published: Wed Aug 05 2020