Testing a starter's health 

Hi Duane, enjoy your tutorials. I noticed that at @8:45 the waveforms for the Ford Econoline starter look perfectly normal! The truck actually tries to start (fires up)...that's why the starter amps drop...not a sign of "aging". Maybe try a longer crank time after disabling the ignition to see some repetition in the compression humps? Also cool waveform on the Caravan! Looks like the starter bearings are worn out, so when the armature is stressed by the upcoming compression stroke, it shifts and causes a momentary loss of contact with the brushes. Great work!

Thank you so much for sharing this information and testing techniques. It is by far one of the best techniques out there. This really saves time and effort pulling parts and testing. Time optimization and quick diagnoses are major corner stone in this field.

Great info. I've never seen this anywhere else. Thanks!

thats the best demo of the scope and starter i ever seen

It's always nice to find another way to solve a problem. Next time I'll give that technique a try. Thanks for posting.

just wanna say thanks for making these videos there awesome! ive been able to extract the information from your videos and put them into practice on my own vehicles.

This is great tutortial with a lot of awsome in depth information. but there is one thing that is incorrect. the humps in the waveform are actually the compression humps for each cylinder. the amps/volts fluctuate high and low due to the more power needed to crank the engine during the compression stroke. This is the new and improved way of doing a compression test to see if all cylinders are contributing evenly and its also a great way to check the starter condtion I like the comparison of the voltage drop of the battery and the starter amps. this video helped me diagnose an intermittent bad starter in a Honda crv today. the bad waveform that I got had good voltage drop and amp draw but was full of hash, which I thought to be interference in my equipment but after the starter replacement I took a known good pattern and it was almost exactly like the know good in this video and much more stable than the wavefrom taken off the original starter. great vid thanks for taking the time to explain how to do an an old test on a newer scope very helpful.

you and scanner danner are the best on you tube !!! would like to see the 2 of you pair up on problems. would anticipate that like an ali- fraiser bout !!!

Great video as always.

it's a nice demo and yes, you can prove battery and starter that way with 80% accuracy.

Great info. To put a cherry on top of the vid, Duane, all you would have to do is disassemble the starter and show the bad commutator or winding that is making the dropouts.

Great video! Some very useful info here...

I guess for those of us who don't own a great scope like this would have to go by the average life of a starter. The question now is what is the average life of a common starter before it needs replacement. This is still very good to know.

I am confused, what is the difference between this and a relative compression test?You appear to use the amp clamp on 600 amp and set scope to see 60 amp. Wouldn't this give you a relative compression?

great video i just replaced my battary and later the next day my wife went out and then no start after it was hot...had the battary checked and it was fine but when he did an amp test my starter would draw 400 amps ...witch is to high for a v6 car...from what i read it should be up to 210 amps...so im replacing the starter.....

Hello Duane, Conserning the low amp probe you showed. You have used the terms digital and analog refering to the settings. I've known them as ac/dc. I understand that at times you want to see the ac sig. but I've seen you use ac on the clamp when I use dc does it matter as long as you match your scope setting.Thanks for all the great videos.

I'm curious Victor, how is a inductive high amp clamp going to damage a scope when it is taking the amperage reading and converting it to millivolts? Is this problem only on the modis? I have never heard of this problem, can you elaborate a little more?

Ive been trying to find a video to use my modis and my EEta501C amp clamp just to check starter amperage draw. How to set it up ans use it. my clamp says im only pulling 19 amps and this video looks like its only 10 amps.

They seem to either work on them frequently or at least they always have 'em around the shop. They're in a few more of the videos too.

Good Question, as starter prob draws about 150 to 200 amps...Fred

can you do that with a vantage pro

I use 2 volts and two second time base and don't AC couple works great learned it from scanner danner

this is awesome if you have your versus

correct me if i'm wrong but this seems to me to be a relative compression test, at least the one i know how to do with a scope which checks cylinder compression according to the humps in the trace. also what kind of scale is the green trace?is it in 10's?

The amp and voltage spikes could be due to simple corroded battery connections also, no?

Wish my dealer had known this stuff before I was stuck. I had them look at it because I was suspicious, nothing wrong they say, two weeks later I was stranded out in the country side with a no start.

Duane, I think you can use a LOW amps clamp if you select 20 MV on the set-up scale, is this right or not?, believe 20Mv is = to 200 AMPS, referring to message below, don't forget Eric the Car Guy he is pretty good, bit more hands on though - Fred UK.

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it's what i thought too.

not sure who makes the scope but the interface looks like it is terrible, really need physical knobs for the fine adjustments or multi-touch

I think you can use it, if you set it on 20mv and not amps scale F

I need a labscope. I hate seeing these easy definitive component tests that I can't do.

Never mind the clamp, I wish I could afford one of those scanners. How much do they run, $1,000-$2,000?

WHAT!!!! WOW!!!!

you disable spark and fuel, and block open the throttle for that

Hi-amp draw = low resistant. And Hi-resistant = Low amps draw. Corrosion creates some extra resistant.

Yes, I guess it is... when everything goes fine nothing happen, don’t you think? But, what if... it gets saturated. We never know all vector involved in an imperfect system day by day. MurphyLaws had taught us many things since ever, he was always right… nevertheless Modis got fried in the pass. Perhaps SnapOn have fixed that issue already.

I do and I'm the only one who counts! :D

I would say in the very first demo, battery is bad and… from using a hi-amp clamp on snap on scopes no really a good idea.They are not meant for hi-amp test... You COULD HAVE cooked it. Old Modis got cooked all the t.Good Starter always takes up to 125 amps but, a bad starter can go even hirer than 400 Amp and that’s can damage scope. I use MTS 5200 for thistest .about D GC, I’d say batt and str are.superOK

12,000 for that model.

This is based on assumption ur compression is good, otherwise this theory wont work. You wont get hump if compression is bad and u get all short of wave form.

I think they are $10,000+

Made By Snap on Tools USA

9699.99USD from the Snap-On website.

FIRST!!!

Hi Dwayne, enjoy your tutorials. I noticed that at @8:45 the waveforms for the Ford Econoline starter look perfectly normal! The truck actually tries to start (fires up)...that's why the starter amps drop...not a sign of "aging". Maybe try a longer crank time after disabling the ignition to see some repetition in the compression humps? Also cool waveform on the Caravan! Looks like the starter bearings are worn out, so when the armature is stressed by the upcoming compression stroke, it shifts and causes a momentary loss of contact with the brushes. Great work!