SBQM Free Sample: Proper Use Of Test Light To Check Ignition Coils

[@miq_9]

One of the most beautiful channels I have watched, I wish you permanent health my brother

[@ThunderbirdRocket]

I really enjoyed how you got us thinking and how you explained the system operation along with a diagram to make sure we got it ! Thanks !!

[@SchrodingersBox]

This is how I always do it on my paid content channel!! Glad you appreciate it.

[@jum5238]

Having learned about this from you awhile back, I was wondering what was wrong with you hooking to negative with the test light. I'm glad you had your forehead slap and explained it early. I hope you feel better soon.

[@darrendesmarais8124]

Thanks for the video. Get well soon.

[@SchrodingersBox]

Trying!!! This sucks lol. Been sick for over a week. In fact someone even caught in my video before this one that I sounded like I had a cold coming on lol.

[@atlantasamedaydelivery1769]

Keep going Matt. We appreciate your time and knowledge

[@TheAmsweb]

Just subscribed to the Schrodingers Box Quantum Mekanix. I hope to learn a lot more and sure I will

[@SchrodingersBox]

I 100% guarantee you will. It will prove to be the best decision you have made in a long time!

[@GripFreak]

Excellent information done the scientific way. Thanks for sharing your vast knowledge and experience Matt!

[@SchrodingersBox]

Glad it was helpful!

[@JohnDoesGarage]

I don't know if you know this or not, but Matt is a scientist, that's what he does for his day job, and nobody uses the scientific method better than he does.

[@m.b.smoshitoa8325]

@@JohnDoesGarage okay, yar the way this guy explains this is amazing 🤩. No wonder is scientist

[@alejandrovelazquez2378]

Keep it up bro I love watching your videos

[@SchrodingersBox]

Thanks! Will do!

[@bernardaflores1720]

Nicely done, hope you get well soon. Respiratory infection have been my enemy since I was born and they are not fun to deal with!

[@SchrodingersBox]

Yes I have a condition where I use immunosuppressants and therefore when I get sick it hits pretty hard and let’s twice as long as it should :-/

[@m.b.smoshitoa8325]

You videos deserves two thumb 👍 ups. I searched on internet on how to make two thumb ups , unfortunately I didn't find MBS Moshitoa south Africa

[@SchrodingersBox]

Hahaha thanks my friend. One will suffice!!

[@m.b.smoshitoa8325]

@@SchrodingersBox whenever you go to white board I pause, make a tea and come back. That is where you explain stupidproofly. Atleast this days that virus that was thumb downing video is no longer there. Hahaha 🤣 Thanks Matt

[@SchrodingersBox]

Hahaha thanks my friend. I always appreciate when people say their favorite part of the video is the white board!!

[@notsohairybiker]

Fantastic explanation Matt, not so obvious but the result is proof. Many thanks.

[@MechanicTechnicianRepair]

exselete dianostic master mi respeto master good videio

[@ablackformula]

Also be careful of what amperage your test light allows... when you had the test light hooked to ground, the coil windings have a current flow through them, then through the test light, to the test light's ground (in series). The amount of current flow is now dependent on the resistance of the test light (assuming the coil winding resistance remains constant.) If you use a low enough resistance of a test light, when the pcm opens the ground supply, the collapse of the magnetic field will not be as strong, and you may inadvertently create a weak spark just by having the test light installed. This is a test I would have performed, with a low current/led test light, and would have gotten burned. I would've expected the test light to go out during coil command. This info has been stored in my brainbox! Thanks for sharing.

[@paulpaquette1961]

He is testing an output Circuit. Output circuit driver's can handle the current of an incandessent lamp. An Ignition coil can draw up to 12 amps and sometimes more + the initial in-rush current. You could substutute a 9004 headlamp bulb here if you wanted to! These driver's are designed for this load. Where you need to be carefull is with input circuits. For example, using Matt's extremely nice OTC 3633 test lamp to test a three wire map, it would not be wise to pull the 5-volt Ref to ground with an incandesscent that draws more than 1.1-1.5 amps. But, in Matts case, his only draws 750 mA, so if he accidently shorted the 5v ref, it wouldn't let the smoke out of the PCM. There is a big difference between testing OUTPUTS and INPUTS.

[@SchrodingersBox]

Paul is correct. It is impossible for only 250mA to melt a circuit like that. The only time you would find that to be a concern is with milliamp circuits like in modern dashboard circuitry for A/C, radio and other microprocessor controlled signal that use very very low amperage. You could indeed put a 5V reference directly to ground at the battery and still not damage the PCM. I’m face- some sensors do exactly that when in full range- a CKPS for example does it over a thousand times a second.

[@ablackformula]

I wasn't concerned about the pcm driver in my comment. Purely looking at current through the ignition coil winding. You gave the coil a second/parallel path to ground. When the pcm grounds the coil, the coil gets full current flow. When the pcm opens the ground, the coil still has a current flow through the test light. If the current flow doesn't drop enough, the magnetic field may stay, and you'll get reduced spark.

[@paulpaquette1961]

@@ablackformula In this scenario we follow Ohm's law, and the test light is now a current limiting resistor. Is it enough to keep the coils energized while the PCM Driver is off? Most coils are 1 to 2 ohms on a good day, the OTC 3633 is 11.8 ohms. So applying Ohm's law there isn't enough current flow to make the sedondary "happy"

[@ablackformula]

@@paulpaquette1961 That's why I wrote to be careful of the amperage test light you use. You wrote in your first response you could use a headlight bulb and the pcm would be safe. A headlight bulb would indeed keep the coil energized. This same test could also have a different result if testing a fuel injector, which could possibly flood a cylinder with fuel. Perhaps another way of wording it is that you have a solenoid already receiving 12v, which will be activated if a ground is found: you are giving the device a ground through a test light. Be careful just how much of a ground you give it is all.

[@MagnumOpusSRT]

Always enlightened by your videos. Thank you. Remember to empathize “GROUNDS!!”

[@SchrodingersBox]

Thank you, I keep forgetting to do that hahahaha!!!

[@chads8720]

I make my apprentices watch your videos after hours in the customer lounge with pizza. Great vids

[@SchrodingersBox]

Did you mention this before a few years ago?? If not there is another shop owner who told me the same thing!!

[@chads8720]

I don't believe so..but it's very good and well put together information. And I'm fortunate enough to have these ambitious young apprentices who actually want to learn.

[@SchrodingersBox]

Oh yes you are fortunate indeed!!!! Thats not the norm, I do know that much.

[@TheDisgruntledMechanic]

get feeling better Matt!

[@SchrodingersBox]

Thanks Mike!!

[@faith4freedom76]

@13:33 - Ugh, there are rabbit holes in automotive too!? Lol. Great clip bro...very informative 💪

[@kennydoolarchan9515]

Excellent video Matt. Can you use the hertz frequency feature on a Multimeter to test if the ECM is controlling the ignition coil?

[@SchrodingersBox]

yes you could!

[@RobertoGomez-bi5it]

thank you for all your help

[@SchrodingersBox]

Anytime!

[@mtrltoolman]

Good explanation 👏 👍

[@raulgonzalez-uj6wo]

Great explanation Matt. I just want to be sure if the test light should be connected on positive when testing 4 wires coils?.

[@SchrodingersBox]

It depends on whether you are testing reference signal or ground. Test light should be on positive when testing ground OR if if you are attempting to input a signal to the base of the transistor.

[@nickayivor8432]

Get well soon, Schrodingers Box Brilliant video tutorial, amazing stuff 👍 QUICK-WITTED Schrodingers box From Nick Ayivor from London England UK 🇬🇧 ⏰️ 05:48am Good Morning 🙏 🌄 the 🌞 is out

[@SchrodingersBox]

Awesome, thank you Nick. always appreciate your support.

[@sheerwillsurvival2064]

Brilliant professor 👊🏻😎

[@SchrodingersBox]

Thank you!

[@sheerwillsurvival2064]

Matt have you seen pro lines new rubber intake and exhaust plug kit . It’s awesome

[@SchrodingersBox]

yes I have it!!!

[@sheerwillsurvival2064]

@@SchrodingersBox I like it

[@pigeonsil240sx]

this was great man, i was seriously picking my own brain to try and figure it out before you explained it but couldn't figure it out in time. were you also stumped for a bit at first?

[@SchrodingersBox]

yeah at first I was until I looked over and saw I was on the negative. Then I knew exactly what the issue was and thought “this is a learning opportunity”. years ago- yeah, I would have been stumped though. But I have made this mistake enough times that now I usually don’t make this error.

[@sliderdriver1]

Ford use what I was taught, a "wasted spark" system. A system first used in the late 80's, early 90's. Ford called it EEC 4 from memory?

[@SchrodingersBox]

Yes GM uses it too in some models.

[@aatonhernandez3561]

I have no knowledge in automotive repair, is your paying suscription recommended for begginers? Can you recommend me a scanner. Thank you

[@SchrodingersBox]

It would be excellent for beginners in electrical and computer testing. On that channel we go much more detailed as you see on how the electrical works. My recommendation is to start with the series "Basic Electrical for beginners" and then once you master the electrical, you find everything else is so much easier to understand. As for a beginner scantool- ANY scantool that has "Live Data" available will be a good starting point. I have seen them under $150 now. Once you get good with it you will probably want something more advanced but even a $140 scan tool will work as a starting point to do advanced diagnostics.

[@calholli]

The best starters are Thinkdiag 2 or xtool A30M.. They both have most of the bi-directional controls and are way above other things in that range and work off of your phone. If you're gonna spend eight, nine or thousand dollens- Just get the Thinktool Pro, best bang for the ducket. Xtool D8 is another great one (which is what I have), topdon Phonenix. Autel 906. I wouldn't really get anything in between; either get the cheap ones I said, or spend a grand and get one of those.

[@aatonhernandez3561]

@@calholli than you so much

[@calholli]

@@aatonhernandez3561 Good channels to watch are "Pine hollow auto diagnostics", "South main auto", "Scanner Danner", "Automotive Diagnostics and programming", and "Watch Wes Work".. All those guys are wizards just like this channel. You go through all their history and watch every video and you'll be an absolute master. There are a couple dozen others, but these are my favorites.. and they post often.. and have thousands of videos each.

[@JohnDoesGarage]

@@calholli Excellent advice. For the inexpensive choice I have the A30M because right now they have lifetime updates. That's why I went with it instead of the Thinkdiag 2.

[@CarNRadio1]

So did you fix it?

[@SchrodingersBox]

yes I did. the repair is in a video series at www.schrodingersboxQM.com.

[@bernardocisneros4402]

It's like having the test light duty cycled 83% of the time when connected to battery negative.

[@peacepoet1947]

Could you use a cellphone camera and slow down the recording of the video to see the light dim?

[@SchrodingersBox]

that’s a good question. never tried that!!

[@peacepoet1947]

@@SchrodingersBox I'd only go to do it if I really couldn't tell. Also being darker would give more contrast on the dimming of the bulb.

[@Dyllanman]

Hello Mr. Schrödinger excellent videos. I’m having I similar problem and I believe you can help me. I have a 2005 ford expedition 5.4 with 150,000 miles. I have a crank no start. I can confirm that I have fuel, spark, and compression. Fuel rail 75psi and when I took out a spark plug and cranked it there was fuel in the cylinders. I tested the coils and they are fully functional with good on and off intervals, I also changed the sparks to new ones. I am getting good spark too. Checked if the engine is grounded and it is as well as manually grounding myself. When I crank getting roughly 200 rpm’s and the engine temp is ambient temp which is 80F here in miami Florida. All fuses are secured in their slots, inertia switch not triggered and throttle position within parameters. I’ve tried using starting fluid but it does nothing. I am complexed as to what it could be, I am no mechanic by any means but I believe I’ve tried almost everything. Clearly I am missing something, you are clearly an expert so what do you think could be the cause of this anomaly. Thank you for the videos!

[@SchrodingersBox]

If you have fuel spark and compression it must be timing.

[@Dyllanman]

@@SchrodingersBox Thank you for the reply! That is something I didn’t want to accept. I hope it’s not the timing chain. Would you assume with the information you have, that the timing chain is operational? I believe since I got rpms that the chain is good, but so if timing is off what other component could be affecting my coils and injectors?

[@SchrodingersBox]

Your only possible variables are fuel, spark, timing and compression. If you have fuel and spark then you have a timing problem because it’s not possible for all cylinders to have low compression (well, if the timing of the cam and crank are way off then of course you won’t have compression but that’s a timing problem. I would correlate your spark event to the compression stroke for any cylinder and correlate cam and crank signals. It has to be timing.

[@Dyllanman]

@@SchrodingersBox Mr. Schrödinger I was able to start the vehicle today by disconnected all the injectors. I had a suspicion that the cylinders were being flooded with too much gasoline because like you said the timing could be off so the fuel wasn’t being burned. It ran rough but pretty strong. I was able to pull 3 codes. 2 for the camshaft sensor and 1 for the o2 sensor. The car died a little after I guess lack of fuel. But was going for about 5 minutes. After changing 3 more spark plugs for good measure I couldn’t get it to start again. I changed the camshaft sensor and nothing. My father is saying that the timing belt could be stretched or hoping gears but I highly doubt that would be causing the issue. Would changing out all the crank and cam shaft sensor fix my problem sir?

[@SchrodingersBox]

yep that camshaft sensor code is a major major major clue most likely pointing to a timing mismatch with the crank. indeed a stretched belt can cause that code but more like you jumped teeth because to have a no start you need a pretty substantial timing mismatch. changing the sensor won’t help. remember you confirmed you have fuel and spark. this means the sensor is working.

[@lawrencejacob8]

Matt help I have a customer with a 2011 Toyota sienna it has a battery light on but it’s charging at 13.9v it’s been on for about 5 months so I repl the alt as a “ customer request “ still has the light on and still charging the same . Any ideas??

[@lawrencejacob8]

Battery is new also

[@SchrodingersBox]

sounds like the voltage indicator to the dashboard has an open.

[@lawrencejacob8]

I appreciate your help I ll start on looking for an electrical problem

[@rrmech11]

👍👍

[@chadgardee1496]

I have seen the front wire harness for the coil on backwards that blew my mind that the harness fits both way smh

[@SchrodingersBox]

yeah for sure. I also hate when different components sometimes have matching connectors and even worse they are close to each other (a TPS connector that also fits an EGR sensor for example). why do they do that. use to drive me crazy when I did engine swaps.

[@petermaina2281]

I am from Kenya,help me join Sbqm,senior

[@SchrodingersBox]

Happy to. Send me a PM with your email address and we can get started.

[@chadgardee1496]

Probably needs a pcm I have changed a bunch bcz on these escapes

[@SchrodingersBox]

The full case study will find out!

[@DylanL69]

If a ford engine has prolonged misfires that will burn up a ford pcm

[@SchrodingersBox]

how so if it’s not an ignition misfire?

[@DylanL69]

@@SchrodingersBox it is still a ignition misfire because a majority of the coils aren't firing most likely because of a weak signal from the pcm like a burned driver

[@SchrodingersBox]

Say that again? A weak signal from PCM from a burned driver????? What if the misfire is from compression loss? How does that cause a burned driver in the PCm?

[@DylanL69]

@@SchrodingersBox I never said it was compression that would be a mechanical misfire

[@pantelis241]

Nice explained. What about the the COP ignition coil that has the transistor integrated ? Does not this transistor need a positive trigger on the base to switch on so that the coil energized with 12 volts ? 🤔

[@SchrodingersBox]

Yes it does. In that case you have constant ground instead of ground side control and a base signal to turn it on, as you said.

[@pantelis241]

@@SchrodingersBox thanks a lot for the answer 😉

[@aymenmohamed1134]

👍👍

[@aymenmohamed1134]

👍👍