ITW #11 - Electrical Testing Shortcuts with Vince Fischelli: Part Two (Starting Systems)

hey everybody people higher motor age magazine here with another edition of in the workshop and the return of a very special guest to introduce here in a moment what's he what's we going to talk about today electrical testing the probably things most Tech's face with some trepidation to say the very least but this gentleman has been helping Tech's overcome their discomfort with testing electrical systems for a long time very Playa proud to welcome once again mr. Mitzvah Shelly that's how you doing this morning doing great Pete how are you oh just awesome just awesome I know you've got a lot of material we're going to try to get through so I'm going to go ahead and and bring your material up here front for everyone to be able to see and share and turn it over to you thank you this is a presentation about a book I wrote called electrical troubleshooting shortcuts and I've been training since oh my about 1985 I started training full-time and in those days electrical troubleshooting was a real problem for many technicians and today almost 30 years well 30 years later it's still a problem and as as I go around the country and do training and people come to Dallas and attend my workshops I find that what they consider electrical troubleshooting most of the time is changing parts and when the parts don't fix the problem then they get frustrated and have difficulty and spend a lot of time and money wasting time a lot of vehicle downtime per fleets because of incorrect electrical troubleshooting but you know today we live in a world where automotive technology is very advanced we have can bus and all sorts of technologies obd2 and what this does is it causes a technician to focus a lot on the advanced system technologies and diagnostic systems that we have while neglecting the essential electrical troubleshooting principles relating to battery problems cranking problems and charging system problems but the fact remains if this part of the vehicle is overlooked you can have considerable difficulties trying to repair an electrical problem because the problem relates to a battery failure of some type which we're going to discuss or something about the cranking circuit that's not working correctly and of course the charging system which is the electrical power source for the vehicle while the vehicle is running so problems in these areas are often overlooked or dealt with in in a haphazard manner so as a result of that when I started doing training in 85 I started putting get a little handouts and I would do these sessions and as the years went by I would update the handouts and eventually got to the point where the handout got so thick and it left some things out that I would cover verbally in the class I decided to put together this electrical book called shortcuts and when the printer looked at my first draft and he saw 250 pages he said you can't go any higher than 250 pages without creating a larger book and binding would be a problem and all kinds of other issues so I stopped the book at about 250 pages but shortcuts is what I call it electrical troubleshooting shortcuts because I'm going to show you some shortcuts on how to troubleshoot battery cranking and charging problems and take into account some of the new technology that you deal with every day and show you that it's really not that difficult because shortcuts cuts through all the fuzz and get you down to the nitty-gritty on what's wrong with the particular circuit so the book shortcuts is what we're going to look at today and and the diagrams that I show you will be from shortcuts and this is an outline of the book shortcuts it's seven sections and we're going to look at section four five and six we're going to do the section four first in which I show you some quick troubleshooting of battery circuits and then after that we'll do section five quick troubleshooting cranking circuits and section six quick troubleshooting charging circuits and in all these examples I use some shortcuts and that's what we presented so why is shortcuts successful teaching vehicle electrical troubleshooting because it it takes into account two important factors if you're going to troubleshoot any circuit on any vehicle I don't care if it's a car a pickup an SUV even a commercial vehicle running on a twelve volt system it or a twenty-four volt system it the two things you need to know about the particular circuit that's giving you trouble is what are the voltages we call them circuit voltages and voltage drops these values of voltage about a circuit give you a clear picture of that part of the circuit that is that problem in the circuit that is revealed by the voltage readings and the second thing is the electron current in the circuit at different times of circuit operation when you have these two factors these two values determined and you compare them against a known good value from a good circuit then any electrical problem is easily understood and quickly repaired and what makes this so effective and helpful is all you need is a DMM and a earng clamp and it's surprising sometimes when technicians realize with a DMM and a current clamp i can do all of this troubleshooting and I don't need all that expensive test equipment that's often sometimes not available some of the independent shops do not have the access to very sophisticated and cumbersome diagnostic machines that are used to help a technician diagnose the problem all you need is a digital multimeter and a current clamp which you see here the meter on the left is just a basic digital multimeter nothing fancy and the current clamp on the right is absolutely essential if you don't have a current clamp you need to get one because the two together allows you to give a full picture of the voltages in a circuit and also the electron current values in order to draw a complete picture as to what's wrong with a circuit when it's not working right okay the next thing I want to do is show you some shortcuts around the cranking circuit because I don't care what kind of vehicle we're talking about if it's got a starter motor and a battery that's a cranking circuit and I've seen cranking circuits on all kinds of vehicles they all work the same way so let's take a quick look at the basic simple straightforward everyday cranking circuit you're going to have a battery you're going to have a starter motor the battery is grounded to the engine block with the battery cable on the negative side and the starter motor is going to be bolted to the engine block and that creates the ground circuit for the cranking circuit and then you have the positive cable which goes through the starter solenoid which is the heavy-duty contacts we have to energize that solenoid to close the contacts to engage the starter motor now when we're talking about this circuit we have some shortcuts on how to test it and for one you're going to test the cranking voltage and you're going to check the cranking amps these values must be measured and determine and we'll give you some readings that tell you what's good and what's bad so let's go through here the first one a shortcut cranking voltage test now all I'm going to do here is take my trusty D mm and connect it to the battery terminals and I'm going to crank the engine now when I crank the engine the battery voltage will drop from its ocv reading of well let's say twelve point six six it's going to drop down when the engine is cranking the starter motor is drawing its 300 amps to crank the engine on some of the diesel pickups a starter motor is going to pull 600 amps but the voltage drops during the cranking scenario so I watch for the drop in the voltage now how low well let's say cranking voltage is too high well actually the higher the better because a good battery when is cranking the engine will maintain probably more than 11 volts it'll drop from twelve point six six maybe down to eleven volts when it's brand-new but as the battery ages the cranking voltage will begin to drop below eleven maybe ten and a half and now you're looking at this reading here ten point two five volts so it is actually the higher the cranking voltage the better the battery so it's not a question how high the higher I'm the higher I see it the happier I am because that means I've got a strong battery but now how low can the battery voltage drop so here we run into an area that I have found no documentation for what is it acceptable cranking voltage for a battery to eliminate the battery as being a problem and all i can tell you is for the last 25 years that I've been doing this test all over the country in workshops in fleet shops all kinds of vehicles I have determined that most batteries will hold 10 volts are higher when they're cranking now I might see a battery that's cranking at ten point one volt well it's still over ten volts so I consider the battery to have some good life left in it when the battery is reaching the end of its life cycle the cranking voltage will drop below ten volts now it's still cranking the engine so but but because it dropped below that 10 volt threshold I want to see how low I've seen batteries drop down to nine point seven and still crank the engine and the reason for that is with computer-controlled engines you only have to roll the engine over one time and it starts running if if the engine if the battery voltage drops to nine point seven with one roll over and starts running you're good to go but the battery is reaching the end of its life cycle if for some reason the engine had to roll over three or four times before it started the run that nine point seven would drop down even more and you'd probably hear the engine beginning to drag as as it's not getting rolled over fast enough so the answer then is how low should the cranking voltage drop I say the threshold is above ten volts 10 volts or above if it drops below 10 volts you know the battery has been in there a long time and it's not long for this world so I would tell the customer in a situation like this your battery is a little weak and it's still cranking the engine but winter time is coming and the first cold morning you may not be able to crank your vehicle so it might be a good idea to change your battery now now that's up to the customer to decide but at least when that first cold morning comes along and he can't start his engine he's going to remember you and give you the chance to maybe replace his battery at that point now this brings up the reason that this test became a necessity was when I was doing those interstate battery clinics people would raise their hand and they'd say well you know I did the carbon pile load test just like you showed us but it tests bad it dropped below 9.6 volts as the standard Carbon pile load test but he says that the car still cranks the engine is still cranking what am I going to tell the customer you fail the load test but is still cranking I look like I don't know what I'm talking about well the fact is the carbon pile load test is a severe test of a battery it was designed to be used in a laboratory to establish the kokrak amp rating of a battery now we have taken that laboratory test and brought it into the service bay and it doesn't fit a lot of batteries we'll show you a lower than 9.6 load test voltage but they're still cranking the engine if you test this battery for a cranking test I bet it will hold over 10 volts or it may drop to nine point nine volts indicating it's beginning to reach the end of its life cycle so by doing the cranking voltage test and you get more than 10 volts you don't have to tell the customer he's got a bad battery and so the carbon pile if you don't have one really you can get by with this test it's just simply using your digital multimeter a simple test and now the other thing I want to mention about the cranking voltage test you may have to do it two or three times just bump the start a two or three times get it run and turn it off bump it again get it run and turn it off and take three readings to get an average reading because what happens when you're doing this test the starter motor will initially draw seven hundred to a thousand amps the moment the heavy-duty contacts close up there at the top where it says click when those heavy duty contacts close the starter motor appears as a dead short so the amount of current that flows from the battery is every bit of current the battery can dump into the circuit and that bursts of in rush current that the starter motor is what jolted into life to turn over that cold engine that's sitting there at rest so the system is designed to do what it does but if my meter samples the current during the inrush period I'm going to see an extra lower reading so you have to take an average reading and sometimes you can disable the ignition and crank it over two or three revolutions and get your stable cranking voltage that's to be determined later normally rather than disturb anything I'll just try it two or three times until I get an average reading sometimes you can do it only two times and have a sufficient reading of over ten volts and you know the battery is okay that's not your problem okay well now let's talk about cranking amps tests in this situation here's our current clamp again if you don't have a current plant you need to get one because you can't do this test without a current clamp and this test is extremely important because you need to know how much current the starter motor is drawing from the battery when it's rolling over the engine now you can put your current clamp here on the negative cable and it's usually easy to get to and simply crank the engine and you can put a voltmeter on the battery terminals and the current clamp with another DMM on the negative cable and take both readings at the same time now here we're looking at the cranking amps on this starter motor is drawing about two hundred and twenty-eight amps so I have an idea of how much current is flowing through the circuit now what if the cranking answer - hi now sometimes the starter motor will have a difficulty turning over sometimes the the bearings and the rotor inside the starter mode of the armature the bearings are wearing down and it allows the armature to distort when the currents flowing and it might rub against the field coils inside the starter motor and as a result the starter motor can't roll over the engine fast enough now when a starter motor is turning slow this is a DC motor and basic DC motor theory says that when a starter motor is turning at the proper rpm that is designed for it will draw a fixed amount of current but if for some reason the motor the DC motor is unable to reach the target rpm it's turning slowly the current through the motor will be higher than normal because the motor isn't developing the counter electromotive force that is supposed to have when it's reached its target RPM so when i check to start a motor draw and i see 4 400 500 amps when i know it's supposed to be around 220 then I and I can hear the starter motor it's just the heat to eat the hearing is also part of your diagnosis and you're going to hear the starter motor dragging and you're going to see the high starter motor draw then you pretty well have identified that it's not the battery because you're cranking voltage is still up there that the starter motor draws too much current so something's wrong inside the starter motor that won't let it turn fast enough and most of the time that's related to a defective starter motor so high current draw is usually an indication of a defective starter motor and in addition to the high reading on the meter you're going to hear with your ears that's the engine dragging while is trying to roll over what if the starter draw is too low actually the lower the better provided the engines cranking and you'll find that sometimes on if you've seen the same make and model car on a regular basis in the summer months when the engine turns over very quickly and fires off right away you'll see a lower current draw say like this example here 228 amps and then that same vehicle on a cold winter morning you check to start a draw and you might see it's 300 amps well that's just the indication that the engine is turning slower because it's very cold but it still starts it's not a problem the problem is when the start of draw is too high and the engine is dragging and it won't start or it takes four or five rpm to before the engine will actually begin to run so the starter motor draw test is very instructing about the condition of the starter motor circuit so with the voltage test and the cranking amps test I can pretty much diagnose any cranking circuit and all I need is a voltmeter and a current clamp now next thing suppose you have bad connections in the circuit well that's going to impact the fact that the starter motor is not turning fast enough but the current draw was too low and got to be something to do with excessive resistance in the cranking circuit now in the first program that we did Peter remember we did the voltage drop of the voltage side the voltage drop the ground side with the troubleshooting trainer I had pictures of oh yes yes and if those who are watching web bends is referring to as a last in the workshop episode that we did and you can find it in the art pro workshop here at motor acecomm or on the motorized magazine youtube channel right well here's applying that same principle to the cranking circuit and you notice that the first test we're trouble with testing the voltage drop of the voltage side I'm measuring between the battery positive post and the B+ terminal on the starter motor now that puts the entire voltage side of the starter circuit between the test leads and now I crank the engine and if I have a good cranking circuit on the voltage side the voltage drop will be somewhere around 1/2 a vote some vehicles we've seen a size point seven point eight volts but the engine is starting just fine and the reason that drops a little bit higher is because on some vehicles today they're using slightly smaller battery diameter cable so they they might have a slightly higher voltage draw but that's perfectly normal so once you establish that a vehicle is running at zero point seven on the voltage side then you know that that side of the circuit is good well you could have a bad connection on the ground side so the second voltage drop test we measure from the case of the starter motor to the battery negative post and on the ground side of the cranking circuit we should see about 0.1 volt that would tell me that the battery negative cable and it's connection to the engine block is good as well as the ground where the starter motor is bolted to the engine block problem one time last year where a shop was complaining that they replace a starter motor and it wouldn't crank very well and all it was was where they bolted the starter motor there was too much paint from the engine rebuild and they didn't have an adequate ground on starter motor at the engine block and taking the voltage drop reading they saw over a volt and a half and simply recognize the problem right away and then up on the voltage side you know we've had how many times have we all been bitten by a corroded battery cable at the positive post and and not ever really had a way to find the problem well this voltage drop on the voltage side will quickly show you if anything is wrong with the cables or the heavy-duty contacts in the solenoid and these two readings that you see here are what we consider normal yep either one of these is high that's telling you which side of the cranking circuit has the problem and all you need for this is your trusty digital multimeter any questions on that Pete no I think it's that's where the test that that a lot of guys understand how to do but often the meter measurements tend to throw them off again lots of resources at the mode range site in addition with Vince's shared and we have a lot of stuff coming up on that testing method I think it's just neo to those Universal battery terminal repair kits you know the kinds with the clamp many times have you seen those cause that click and loss of power and cycle the key and we come right back on again and the voltage drop is just right in there because of such a for for battery cable repair sure because those connections get corroded because they're exposed to the atmosphere and there's a lot of moisture in an engine compartment when a car sitting outside so that corrosion begins to build up in those makeshift emergency battery cable terminals that are for emergencies only right right but you see them used all the time as a repair let me I also want to mention something you kind of triggered a thought in my mind I hadn't said anything yet about this but one of the things that I found is confusing for some technicians is their digital multimeter is an on arranging multimeter so in order to measure a voltage they simply dial a symbol that indicates DC volts yeah and the voltmeter will then establish itself on a millivolt setting and then when you go to check voltages the meter has to sample the voltage and automatically change to the correct range to display the reading that's appearing at the probe tips right and and this when you go from one reading as a voltage reading of volts and you go to the next reading which is a millivolt reading that decimal point bouncing around is confusing technicians yeah absolutely and so that's why in my workshops and when I do a fleet class I'll bring my own meter so that if a technician has a auto-ranging meter he first starts off using mine which is manually selectable and he learns about that decimal point and he realizes it's so so much easier to do troubleshooting with a manually selectable meter to learn how that meter reads the voltages between bolts and millivolts and after a while they go back to using their auto-ranging multimeter and there's no confusion I'm sure okay all right now this is just diagnosing a cranking circuit because they're all the same they got a battery they got a couple of wires from the battery to the starter motor the engine block is usually the ground circuit and the starter motor is too low it's a very simple circuit but the question becomes and this is where it becomes a little bit more complicated that once we've established our troubleshooting procedures for the battery the grounds and the starter motor and the cables and connections the next thing that has to be considered is how do we control that starter solenoid now what you're looking at here is a schematic diagram that I put in shortcuts and have explained that the in this particular circuit this happens to be a 89 Datsun and had this problem come up and I wrote about this in shortcuts because and I told the whole story how this owner of this vehicle was having trouble sometimes the vehicle would crank and sometimes it wouldn't crank it was his wife's car so she'd go shopping get out to her car just in the parking lot of the of the shopping center and it wouldn't start it got her there but now won't get her back home so she call her husband and says I got a problem so what's he going to do he's working he he calls rip the wrecker they have the vehicle towed to the shop it gets to the shop it may or may not crank it depending on on the moment so they replace the battery gave him back the car next day had the same problem so they took it back to the shop and the shop said okay maybe the starter motors not working right maybe it's intermittent so we're going to replace a starter motor and that came with a new starter solenoid piggyback on it so guess what he spent a lot of money and he said the car in the shop twice once for a battery replacement and then the second time for a starter and started solenoid well guess what happened the next day the wife's out running around saying that crank so he calls me up he happened to be a gentleman I I met through Interstate Batteries a super nice guy and he's just pleaded with me to help him with this problem because he can't he didn't know what to do next so he took it back to that shop and they wanted to start this scenario all over again change the battery again try starting over again and he knew that wasn't going to work either so I said well have you got the shop manual and he said yes I do which I thought would get me out of the situation but because I don't have a shop anymore and I don't have a place to work on cars well he came over and I'm looking at the shop manual and I find the cranking circuit and I see there a starter relay so I asked him I said is anybody ever tried to replace the starter relay or check it and he said I didn't know it had to start a relay in it nobody ever mentioned it to me here it was by looking at the schematic diagram I discovered a starter relay well we go out to the car and as luck would have it it wouldn't crank and so the relay the starter relay was identical to another relay in the relay panel so I just swapped the real eggs and it didn't do anything he still wouldn't crank so I knew it's not a relay problem now what do I got to do I better troubleshoot that relay circuit and see what's going on now we have a whole troubleshooting program and a relay circuit training board which we teach trouble shooting all I can do today in this presentation is tell you how this relay circuit fail because it's really going to help you realize you've got to have schematic diagrams of the systems you're working on so you know what components are in the circuit so you know what the test and how to test it so here we are with a relay and fortunately at this moment the the vehicle wasn't cranking so I put a screwdriver on the starter relay and every time the owner clicked the key to the crank position I heard the relay click so that told me that the relay coil been 86 and pin 85 that circuit is good it told me the park neutral switch is good it told me the star switch is good and I have voltage applied and I have a good ground on the relay coil so basically that part of the relay circuit is fine well then I put my probe on pin 30 and I had B+ I had 12 volts there and then I put my probe on pin 87 and I said okay hit the key again and every time you hit the key I could tell the relay clicked but there was no voltage on 87 now I just swapped the relay so I thought well the relay contacts are pretty good I put my broke back on pin 30 and he hit the key and it went from 12 volts down to zero when he hit the key and if you look back from pin 30 down to the right and then go up you see a connector I've called it C 14 and that goes up to the B+ supply and that connector was probably corroded and making intermittent connection and I told him that to get to that connector I would have to splice open the heat shield on his wire loom inside the engine compartment and it was just so clean in there he he always kept his engine compartment pretty clean so I didn't want to do that I didn't want to destroy the heat shield on the wire harness so I said is it okay with you if I repair the circuit with a jumper wire and he said I don't care anything that's going to fix it so I spliced a wire into pin 30 and then I selected a B+ source which was right close in fact the wire was 11 inches long i soldered the wire at both ends and the circuit immediately cranked because of the supply at pin 30 was now constant it didn't depend on the bad connection so the point that I can share with you about relays that's really going to be helpful first of all make sure the relay clicks if it does click that tells you that the relay coil circuit is working properly and the next thing when you check pin 30 and you see voltage there leave your probe on pin 30 energize the relay and see if the voltage is still there when the contacts are close because when the contacts closed we have current flow through the solenoid and through the contacts back up to the B+ and that bad connection in C 14 was dropping all the voltage and that's just a simple little insight into how a relay can be incorporated into a cranking circuit now this also brings up a whole new issue that I want to cover on the next page here we have a new scenario that's that's begun to unfold in our industry where we have a computer controlling the starter relay in the previous example if you'll notice I'll go back there for a second we have mechanical switches part neutral and start those are the two that energize the relay but here we have a whole new scenario where we have a control unit that is going to operate the relay to provide the voltage to the starter solenoid now this isn't anything uniquely special well you know if you if you've been around computer control and and understand relay troubleshooting this kind of circuit shouldn't pose any kind of a major obstacle to solving a problem you know you still got your basic cranking surface you've got a battery grounded with the engine ground and start a motor bolted to the engine block and you have positive circuit wiring and connections and a starter solenoid the issue here that's different is how I energize the starter solenoid so starting with the starter solenoid you see the pin on the right which goes back to pin 87 on the relay okay now we've got a relay that instead of controlling it with a couple of switches mechanical switches I'm going to control it with the PCM now what I've eliminated from this diagram are fuses there's going to be fuses all through this circuit there's going to be fusible links in a couple of places I've left all that out I'm just focusing on how this circuit works and some principles about troubleshooting that's going to help you solve a problem because here's here or with a car that won't crank and you look at the cranking circuit and you see the computer is controlling the starter relay will look down at the computer the PCM in this case you see that the transistor which is the electronic switch inside the control unit and you notice you have can input can plus and can negative so this computer is now connected to the can bus so now we've got a whole new scenario taking place if the can system is telling the PCM something's not right the PCM will not ground the relay coil and energize the contacts to close the starter solenoid to start the engine but all we've done we still haven't changed the scenario of the basic cranking circuit that hasn't changed if I put my voltmeter on the battery terminals and I crank try to crank the engine I'm going to see the battery voltage doesn't drop if I put a current clamp on the battery negative cable and try to start the engine I'm not going to see any current going to the starter motor the starter solenoid well it's not operating some people will say well I'm going to take a jumper wire which kind of gives me cold chills when I hear that and I'm going to take D plus and I'm going to touch it to that pin the B plus pin on the starter solenoid to see if it'll engage and some and you know that particular situation here wouldn't be that detrimental but you got to be careful with jumper wires because you can create a whole kind all kinds of trouble the issue here is the computer is not turning on the relay and if you deal with this kind of an issue you've got to go to the can bus and that's a whole nother story for another time but I just want you to see these cranking circuits are getting more complicated but the complication is in how we control the starter solenoid not anything different about the starter motor and the battery that is still done the same way we talked about earlier using a digital multimeter and a current clamp as far as testing the PCM and and the relay you know for that relay circuit if you go around the pins of that relay with a digital multimeter checking your voltages you're going to see how the relay is performing or not performing in this example here if the relay is not clicking you go to 86 and you'll see B+ and 86 you go to pin 85 and you've got B+ on pin 85 but pin 85 is supposed to go to ground through the driver transistor in the PCM but the transistor is not turning on because the computer won't turn it on until it gets good messages on the can bus system that everything is ready so you could have something as simple as a control unit is not plugged in properly so the canned bus network is broken or not complete and if you measure the resistance of the can high and low with an old meter you should see 60 ohms and if you see 120 then you know that you got a bad connection in the can wiring and that's your problem got nothing to do with the PCM nothing to do with the relay with the starter motor or or the battery I guess as a side note to their events you know a lot of times and in any relay controlled by by a control module whether it's the PCM a body control module or here in HVAC the control module if it's not grounding the relay it may be an input that the computer needs that it's not seeing you know the can bus may be just fine but if you check your stand tool data and see if the the pins that are supposed to be there are there you know that could be to be one of the issues as well all goes to reading up on how the system works you know that the basics are the same the relay still got to be energized to close you know the seller always loves to be energized to close the starter minute motor still turning over just like it always has done it's just maybe how we make those things happen that's changed so that's why we always stress you know take the time to do your homework upfront understand how the particular system that you're working on operates that's right now I want to point out though that this illustration here is not in short cuts because I had I had to draw the line in short cuts the page count and all that but either work together just for this presentation to help take people into the area of why cranking circuits are becoming so complex now and it's not as simple as it used to be but again this is an area that we have addressed the PCM control and relays in some of our other training programs and I didn't want to leave this picture out of our discussion on cranking circuits because it does impact so many cars today where the PCM or the BCM of the TCM whatever has to energize the relay to get that solenoid to start okay sure and it sounds like it might be time for a short circuit or short cuts volume - well my I you know years ago I told my wife I'm not gonna write another book well when it came time to write short cuts I had to go to her and apologize I know I got a ride no the book is I'll write another book I go into a different mode you know and I'm always working and at the computer when people want to eat I can't stop I'm in the middle of a paragraph so I I don't know if I'll write a volume too but there's we've got ser blow the products on the market it's all available on our website now I'll show you the website address here a little bit sure but anyway that's the end of the cranking circuit control and to help technicians realize that even though these cars today have many complex systems the basics never change and if you understand the basics of how circuits work and how to test them I don't care what they build we can fix it you know absolutely

Channel: Motor Age

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Keywords: motor age, the trainer, automotive repair video, car repair, auto how to, how to fix my car, auto tech, auto technician, auto service professional, engine performance, auto electrical how to, automotive drivability, obd 2, obd II, onboard diagnostics, auto computer, voltage drop, ohm testing, voltage testing, starting system repair how to, diagnose automotive starting systems, vince fischelli, automotive electrical testing, how to diagnose a car that won't start

Id: EDciaypL8Vw

Length: 45min 51sec (2751 seconds)

Published: Thu Aug 15 2013