How to perform a compression test with a scope (Verus-Vantage)

Рет қаралды 202,315

13 жыл бұрын

Relative compression test using the Snap-On Verus. You do not need a Snap-on scope to do these tests. The same procedure can be followed using any Lab Scope.
Testing procedures shown:
- how to use starter current to determine cylinder compression
- how to synchronize the starter current pattern with an ignition firing event to determine exact cylinder location
Tools used:
- Lab Scope
- Low amp probe
- High amp probe (preferred)
- Secondary Ignition Pick-up
Related Videos:
- How to perform a compression test with a scope (Picoscope)
• How to perform a compr...
- Relative Compression Testing Variables (3 cylinders have no compression)
• Jumped timing chain (n...
- How to check for a jumped timing chain or belt
• How to check for a jum...
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.scannerdanner.com/join-sc... 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.

Пікірлер: 228

@65blablabla 6 жыл бұрын

Great info and step by step on how to do this I just bought a modis and running a shop alone I need to learn these skills,thanks for great tech info videos.

@felplayvina 12 жыл бұрын

I did this test with my old vantage and low amp probe set at 40 amp, really good test..Paul..thank you.

@Thefox2000unit 2 жыл бұрын

Just got the low amp clamp the other day. Looking forward to using it for easier/quicker diagnostics. Love all of these videos! Very helpful!!👍🏻

@Loofles 8 жыл бұрын

never even occurred to me to do a fast compression test like this..right on great video

@PaulysAuto 4 жыл бұрын

Thanks for this video Paul, very good tests to know!

@triggera3851 3 жыл бұрын

I definitely heard it. Your knowledge and information is gold.

@ScannerDanner 13 жыл бұрын

@DerekLMartin I do but it is not complete yet, as soon as it is done I will post the link for you. Thanks for your interest and comment!

@integrityautocarehomeofthe145 6 жыл бұрын

Brotha Dan, THANK-YOU for helping me make a big difference in Auto Repair and showing our customers that those shops that can keep up with diagnosing and fixing today's CRAZY COMPLEX cars are just like a good Doctor..always learning and studying, even on a Sunday! Dr Rob The Car Doctor over and out.... PS: Love your e-book as well.... :)

@ScannerDanner 6 жыл бұрын

Thank you brother

@oscarventura8337 6 жыл бұрын

Thank you Mr. Paul you really have a a flair to teach this important stuff.

@ScannerDanner 6 жыл бұрын

Thank you! I am a teacher at a technical college, so this is good to hear :-)

@Zavodney 5 ай бұрын

Wow ive never heard of this method before. Very cool. Thank you sir

@MitzvosGolem1 5 жыл бұрын

Sometimes irregularities in starter itself draw can send a erratic signal .Very often most good mechanics car "hear" variations in cranking sound indicative of a low or Dead cylinder. Good test and use of scope. Thanks

@ScannerDanner 13 жыл бұрын

@JrUnKrownedKing Thanks for your comment! It really means a lot.

@BespokeRyan 5 жыл бұрын

Very awesome video I will put more use to my verus edge and low amp probe, recently also took my DMM home so I’d get the most out of my tool and use the built in DMM

@dreamer2355 13 жыл бұрын

Another great video. Thanks again!

@ScannerDanner 12 жыл бұрын

that would be a good question. I have never done a relative compression test on an odd fire engine. I imagine that it would be as you said have natural dead spots

@sureshbabu-fl5kx 2 жыл бұрын

Great experience to my work shop . thank you very much sir

@ScannerDanner 12 жыл бұрын

@bartewer This test is used to determine the cause of the misfire, not which cylinder is misfiring. Imagine you are working on a system where the intake manifold covers the back cylinders. The middle cylinder in the back is misfiring as noted by misfire counters and a trouble code. You would need to sell a customer an upper intake R&R to inspect the misfiring cylinder for a lack of spark, fuel or compression. With this method you could identify a mechanical problem without removing the intake.

@ScannerDanner 12 жыл бұрын

@MrKevg59 Depends what your market is. There is no better scan tool than a factory one, but if your an aftermarket guy like me and work on everything the Verus is the way to go. There are cheeper alternatives though, you could go with a Solus Pro and Vantage Pro which would cost you a few thousand less than a Verus. Snap-ons troubleshooter and component test meter is un-matched in the aftermarket for experienced based help.

@ScannerDanner 12 жыл бұрын

@romeoadryan Good question. It was the only probe I had with my Verus. I would have used a high amp probe if I had one.

@ScannerDanner 12 жыл бұрын

cool! I'm sure it isn't as clear on that screen but it is good to know it is at least do-able

@sollykhan2385 2 жыл бұрын

AWESOME video, Dan, Thank you for this great info filled Presentation, much appreciated, will watch more, BLESS 🙂😇👍

@joemikos900 6 жыл бұрын

Great job Paul! I'm going crazy at Car Care Ministry but in a good way. This past Saturday was our monthly Ministry's car repair day where our volunteers come in. We did about 13 cars! My job is primarily diagnostics. I had to call two bad computers, both injector drivers as well as a clogged exhaust and there's the regular MAF stuff ect. I have to be accurate because as a Ministry our funds are donated and obviously we have to be good stewards. Plus as you always say and I couldn't agree more..."don't be a parts changer". My problem is we don't have adequate diag equipment. My friend Eric "ETCG" did get OTC to donate an Encore scanner which has been our go to scanner and we are very grateful for it. As of now we don't have any subscription service e.g. All data. We are hoping to upgrade due to the fact we are taking on more cars in light of recent publicity. For "front door" (scope) type testing I'm limited to (no scope) a multimeter and Power Probe. Anyway I was wondering if the old Vantage would work for relative compression. That's something I think is in our reach. I've seen them on EBay for around $3-400. Just need to know if it does R C. Thanks again Paul

@ScannerDanner 6 жыл бұрын

It will but we need to get you a Vantage Pro. We are upgrading our equipment at Rosedale Technical College. I can check to see what our Snap-on rep will sell the trade-ins for if you want? It would be an older Vantage Pro but to be honest. The Vantage Ultra and Edge where downgrades in my opinion. I loved the VP. I absolutely hate the newest one. It is slow and lanky. Yeah, it is touch screen but so what, even that sucks.

@joemikos900 6 жыл бұрын

ScannerDanner That would be a dream! A for real game changer. I literally just got home from the "Barn" (our Ministry's shop) because I'm struggling with a 3800 GM donner car that I had to do an old school gauge compression test on and will have to take off a valve cover to check for timing chain slack chasing a weird idle misfire. The car is irrelevant but the point is I would of been home hours ago and not OCDing about the diag if I had a scope...LOL I will send you a quick email in case it works better for you. Thanks so much, I'm excited that there is even a chance. Amazed you even have time to respond. Either way, you are much appreciated. God bless, goodnight

@cucogallegos3974 Жыл бұрын

thanks you are awesome! needed to know that thanks again!

@mohammedcherifi9206 3 жыл бұрын

The best channel for ever

@ScannerDanner 11 жыл бұрын

you can and the amp probe you buy does not need to be from snap-on. thanks for giving me a chance and buying my eBook! I'll try to help you in any way I can.

@labradormcgraw 3 жыл бұрын

Still the best on KZfaq.

@ScannerDanner 3 жыл бұрын

Thanks my friend

@ScannerDanner 13 жыл бұрын

@dreamer2355 no problem! thanks for the comment

@ScannerDanner 11 жыл бұрын

@import0408 as long as the low amp probe fits the wire you shouldn't need a high amp probe especially because i generally only use it for starter current and as you saw in this video i used the low amp probe

@ScannerDanner 12 жыл бұрын

@romeoadryan I don't see it damaging the probe as it just reads magnetic field strength. I think the only concern would be accuracy of the probe at higher than normal amperage. Which is not a concern for this test as I am looking at relative numbers.

@ScannerDanner 12 жыл бұрын

@import0408 Yes, you can use the RPM pick-up and trigger from it, however once you freeze the capture you will lose your reference point. Go to AESwave dot com and buy a sync probe which will plug in to one of your channels. Watch my pico relative compression test to see what I am talking about. Email me and I'll send you a link to the sync probe.

@johnbonifas6040 4 жыл бұрын

This is a good test I AC couple mine works great

@felplayvina 12 жыл бұрын

Hi Paul, can I do this test with the low amp probe at 40, with the old vantage mt2400 and the RPM pick up? or at least one at it time?

@Jason607 9 жыл бұрын

This is awesome, why didn't I think of that? Huge time saver when diagnosing a misfire just hooking up an amp probe and disabling fuel and ignition vs. pulling all the plugs and wires and attaching a compression tester. However, if I saw what looked like a misfire in your test I would do it the "old fashion way" to confirm and of course add appropriate labor.

@mikeemirian3867 7 жыл бұрын

Thank you Sir you are Legend

@ScannerDanner 12 жыл бұрын

No, it should have worked on the 40 amp setting. Did you make sure you were on the correct battery cable? Sometimes systems will run multiple main cables, just make sure your on the one going to the starter itself.

@billrimmer5596 5 жыл бұрын

Great vid! Could u also use a second amp probe on channel two. And trigger off a coil or injector?

@forrestkim4828 4 жыл бұрын

You can do vacuum test instead current clamp also ! ...good job. !!!

@brianmason1414 5 жыл бұрын

AWESOME AWESOME AWESOME content.... unfortunately, right now I only have access to a Pico (shop equipment), but as soon as my SO account can take it, I plan on getting a Modis or something similar to have my own.

@mustangdemon87 4 жыл бұрын

Modis ultra with euro pack is half off right now fyi

@Mike-yq7ce 4 жыл бұрын

I love my modis it would be a good buy. James Lucy is correct I bought a modis last month for 3100 off the snap on truck

@CoroPlanesLLC Жыл бұрын

A friend took his Honda van to the dealership, and they tried to sell him an engine replacement using this test. They told him he had poor compression in multiple cylinders and the engine would have to be replaced. They wanted $6000. A few days before, it began making a clattering sound that he thought was coming from the top of the engine around the valve covers. Suddenly the engine began running very bad. It would not idle without giving it some throttle and could not be driven. He asked me to look at it as a second opinion. When I heard the engine, it sounded to me like an engine with a valve timing problem. I pulled the inspection plugs off the timing belt cover and I could see a huge amount of rubber debris and some belt chunks, but the belt was still in place. Turns out, one of the tensioners failed. The belt slacking and then getting tensioned again was the sound he was hearing. The belt could only take so much of that abuse before it jump a tooth or two on a pulley. The dealer was going to replace an engine for $6000 when all he needed was a $100 timing belt and tensioner set. He helped me change the belt and he was able to learn a lot about his engine in the process. If I learned anything from your videos, it's that you should never simply replace parts based on what the scanner tells you. It takes a little troubleshooting, in addition to the scanner to get a proper diagnosis!

@thebronze907 11 жыл бұрын

romeo, sure, but just watch the battery voltage. As the amperage rises on due to the pressure on each cylinder, the battery voltage drops. It typically what I do, after all, it is just a relative compression, we are figuring out the pressure (unless you have a pressure transducer installed, which is super-cool).

@humblestrengthgaragetraining 2 жыл бұрын

Nice video Paul! would a wyzeprobe do the same job as to identifying the firing order? Many thanks again for the videos and your knowledge, your channel is awesome! keep it going!

@Dansyoung 5 жыл бұрын

Will this test be sensitive enough to identify a cylinder that has compression, but there is a valve that has a duration problem. I work on dodges and it’s common to have a hemi with a wiped camshaft lobe, so the engine will have good compression it just won’t pull as hard as the other cylinders. Or a pressure transducer monitoring the cylinder pressure will be the best option? Thanks

@KALUPO78 11 жыл бұрын

Yes, Not all scanners have a lab scope built in. A lab scope shows the wave form. A code reader tells you the code. A scanner will show what the engine/sensors are doing. IF it is a bidirectional scanner you can control sensors and motors ect. You can roll up windows, flash lights move the gages things like that.

@russellmcallister6830 4 жыл бұрын

Hey paul. Can i use this method on heavy trucks with my verus using the principle volts dc and and doing a conversion. Select 10volts and convert to 1000 amps which i reckon it will draw?

@phillipkang1782 9 жыл бұрын

Hello Mr. Danner. Im loving your videos and knowledge your are sharing. I was wondering why this test doesn't work on the scope part of the verus and only on the volts dc part. I just figured since the scope's faster it would pick up the compression signal but it goes straight up to 12-14 volts and doesn't move until i stop cranking. Thanks again and I love your lessons! Take care.

@ScannerDannerPremium 9 жыл бұрын

Phillip Kang This was the scope. Volts DC is just a default for a single channel.

@nickayivor8432 2 жыл бұрын

Good Evening ScannerDanner 🙏 ✨ Have a great day and take care ScannerDanner 🌟🌟🌟🌟🌟🌟 Tutorial Great 👍 👌 👏 From Nick Ayivor from London England UK 🇬🇧

@KALUPO78 11 жыл бұрын

If its a EFI And most are nowadays if they have coil packs Or COP Just use the injector disable to check RPM drop. If it has a distributor, you can reach the plug and/or distributor.

@xxrevansblackopsxx 10 жыл бұрын

hey paul I have a quick question, I wanna perform a compression test on my chevy trailblazer i6. I know im supposed to take out the fuel pump relay but am I supposed to disable the ignition system too?

@cam72100 11 жыл бұрын

Hi Paul, my name is Melchor I just bought your Ebook is a very good information book, I have been learning a lot. I just got the modis from snap on and I was wonder if I can do the relative compression test with this tool? and if do I need the low amp probe from snap on or can be done with any other brand of low amp probe? thanks

@radmilakrejci8581 2 жыл бұрын

i know you said you disabled the ignition (fuel pump fuse out i assume or similar), my question is when you have your helper crank the engine is he on the gas pedal when cranking? thanks

@DraGSLight Жыл бұрын

hi ! would you be able to hear it in any kind of scenario if you had low compression in one or more cylinders ?

@oscartrujillo5223 10 жыл бұрын

ScannerDanner Another awesome video. I am a bit skeptical on the effectiveness of this test in that, from the video a relative compression test would clearly show a completely dead cylinder without problem, which in most cases, with some exceptions, are easier to identify without much testing. I would agree that this tests most powerful use would be in checking compression at inaccessible cylinders. In your experience how have you found the effectiveness of relative compression testing with more common engine mechanical faults such as burnt valves, head gasket issues, etc.? Thanks dude!

@matthewrockle5106 5 жыл бұрын

Thanks for the great content you put out. You have taught me a ton and have given me the confidence to tackle the more complex diag jobs. Do you have to use the adapter for this test? Why not just plug your trigger right into the scope?

@rdh1001 2 жыл бұрын

No, you don't need the adapter. You could low amp probe the coil or backprobe it or a injector for that matter, ignition is easier because its more in line with compression. You don't plug ignition straight to a scope because they generally aren't rated in KV for automotive use.

@ScannerDanner 12 жыл бұрын

no sure, I never tried it. I think you probably could do it but synchronizing it with another channel may be difficult at best

@LewsSpeedShop 11 жыл бұрын

Is there a difference between a labscope and a snapon scanner for tests like these?

@romeoadryan 11 жыл бұрын

how about performig a compresion test measuring the voltage drop across the starter cable ? would work ?

@AmericanLocomotive1 12 жыл бұрын

I meant that since the Dodge V10 has irregular firing intervals, there would be "dead spots" naturally, and it would seem to me that it would be difficult to tell those natural dead spots from a cylinder with low compression.

@elora2525 4 жыл бұрын

What about if my amp clamp is 20-40, will it work? And the conversation will be the same? 1 amp=10mv?

@wyattoneable 8 жыл бұрын

This is great knowledge based stuff but no way to justify a Verus scope...lets see how the Pico does. :)

@import0408 11 жыл бұрын

How would you hook a high amp probe up to the verus. Would you use the same 2volt conversion cause there is no option in it for a high amp. If so is there really any use for it with this scan tool other than it has a larger clamp

@mrgalea100 4 жыл бұрын

Can I do this test by putting my snap on scope in series with the battery and the starter? Will this hurt my scanner?

@IamReadyToRock 6 ай бұрын

nice

@import0408 12 жыл бұрын

Is there another way to do this with out the sa2000 tool. Our shop has a 4 Chanel scope--modis but we do no have the adapter for the primary ignition.

@OneManOnFire Жыл бұрын

While I know this video is old I'm definitely considering a older verus as they're more affordable as the newest car I'm working on is a 2008

@romeoadryan 12 жыл бұрын

@ScannerDanner i have the same tip of probe and and I'm afraid to connect my probe in this way because I know cureent draw up to 400 amps . What do you think ?

@rodx5571 4 жыл бұрын

Funny story, A buddy of mine had just done heads and timing chains on a dodge 4.7, no codes, but cranked unevenly and ran bad. i did a relative compression test, it was an interesting pattern, high peak, lower peak, high peak, lower peak, every other cylinder was weak. I immediately suspected one of the chains was off. Because there was no code i suspected bank 1, as bank 2 has the cam sensor in it. I put a transducer in cylinder 1 just to complete the diagnosis, I used it as the sync channel, it was indeed weak all along bank 1, by about 25 PSI., just for fun i put the transducer in cylinder 2 (give him his moneys worth), Ran the test again. I verified my suspicions. Because it ran, and it was only 25psi low, i told him its probably only 1 tooth off, but its definitely off. He pulled the covers and checked his timing, yep, as i diagnosed it, tooth off on bank 1. So i went through the whole procedure for timing these engines, He got it 1 tooth off, he never rolled the engine around by hand (with a tool) after timing it to feel for low compression and to double check timing. This you should do every time. Sadly, 6 months later he did something similar with a Honda, Gets in a hurry and forgets the final checks.

@ScannerDanner 4 жыл бұрын

nice find!

@mark53123able 4 жыл бұрын

Awesome video and a great tool to have I was wondering how you would set this up if you had a coil on plug setup instead of plug wires so that you can see what cylinder is the problem? Btw. Just bought your book can’t wait for it to come in!!

@ScannerDanner 4 жыл бұрын

It depends on the coil design. If it is a two wire COP you connect to coil negative, compared to a 3 or 4 wire COP you connect to the coil trigger signal from the ECM Thank you so much!

@romeoadryan 12 жыл бұрын

@ScannerDanner can not blow the current probe when the current draw is over 80 amps ?

@michaelr6205 4 жыл бұрын

I have a Modis Ultra, do you know if there is a large difference in scope performance compared to the Verus. Besides the fact that the Modis doesn't have an Ignition Scope and the Verus does. Thank you Paul. I thought if anybody would know it would be you.

@Mike-yq7ce 4 жыл бұрын

The only difference I see is the number of channels. scope performance its self is on par. you can buy the ignition scope I seen it in the accessories list with my modis..

@bartewer 12 жыл бұрын

Why would you use this to isolate a misfire? I could see as a general quick check of engine health, but wouldn't it easier to pull the wires off one at a time or check the misfire counter on a scanner? I have a scope but this seem the long way around the barn to diagnose a misfire.

@DerekLMartin 13 жыл бұрын

Do you have a website?? Love the videos so far.

@markferraro5250 7 жыл бұрын

Hey SD my relative compressions are always so hashey. I use pico scopes vantage uscope with quality high amp clamps ? It's all from the same car.car battery is weak.RFI ?

@armandonika 4 жыл бұрын

I think with pico filtered should be pretty clean wave...

@muhindojehoiadapatience4455 2 жыл бұрын

Thanks Paul. Am from Uganda, bought your ebook and its amazing. Am learning alot. Can any other cheap scope do the work,i may not be able to afford the vantage pro or verus ??

@ScannerDanner 2 жыл бұрын

Check out the uScope from my affiliate tool pages on my website www.scannerdanner.com

@Sctronic209 5 жыл бұрын

That’s cool 😎

@sampierson402 6 жыл бұрын

so when you are shorting out the coils with your test light, or unplugging a injector connector, your trying to find which cylinder is not contributing. 10-4. on an OBDII vehicle is it invalid to unplug the coil over plug connector?

@sampierson402 6 жыл бұрын

my thoughts have been jumbling since I bought your book. piecing all this good info together. so I'm also thinking this........... for a really fast direction test on an OBDII car, with a misfire, not sure which cylinder... could I unplug each coil over plug connecter (one at a time) and listen to rpm? then by doing the same thing with the injector connectors determine if there is a fault in the ignition or fuel delivery..?

@MrKevg59 12 жыл бұрын

would you say that the verus is the best for vehicle diagnostics.

@SS-U23 5 жыл бұрын

Thank you so much for this video. However, I missed something about the amp clamp and the tool that you connected to your Verus- vantage scope. The most important thing that I missed is that the amp clamp you used is a low amp clamp that goes up to 60 dc A. However, you had everything set up in spite of the fact that the starter may have drawn up to 200 dc Amps. Man, I really do not get how the low amp clamp handled like 150-200 DC amps that the started drew. Thank you again for sharing such a great video with us.

@ScannerDanner 5 жыл бұрын

This amp clamp can measure up to 250 amps. It's voltage output is limited to 2.5 volts. Amp probes produce voltage in the presence of a magnetic field. The current flow in the wire dictates magnetic field strength. Add a little math conversion and there is your inductive low amp probe. Hope that makes sense.

@mertylmaz2179 4 жыл бұрын

@@ScannerDanner The amp probe is able to measure max 60 amp, how could this be possible, it may give false readings over 60amp, though waveform seems allright.

@ScannerDanner 4 жыл бұрын

@@mertylmaz2179 read my comment in this same thread, it explains it.

@nuthn2do 7 жыл бұрын

Technology amazes me, in the 90's a cold start and running your fingertips along the exhaust manifold could pick a bad cylinder

@clearsailing7993 4 жыл бұрын

In the 1960s we would pull off one wire at a time and listen for a change in the engine sound. When the engine sound stayed the same, that was our bad cylinder.

@contagiousFX 9 жыл бұрын

Paul, your setting is at 2V/2s, my question is how much voltage should you see drop if a cylinder had like 50-100 psi lower than others?

@ScannerDanner 9 жыл бұрын

Not sure. I don't use this test that way. I just want to make sure they are all even. If they are not, there is a problem.

@j.helvie6563 9 жыл бұрын

***** This test is more of a relative comparison tests than a measurement. You'd see a lower hump in relation to the others, but a specific voltage amount wouldn't be useful. Under these condition, a somewhat lower hump would lead you to a conventional compression test to measure specifically & then a leak-down test to isolate leakage location.

@ladillando1 12 жыл бұрын

Hoy trate de hacer un prueba de compresion relativa en un Mitsubishi Montero Sport y me fue imposible. El Verus en funcion de scope se congelaba y tenia que hacerle restart. Despues de 4 intentos y mas de una hora de frustracion, decidi abortar las pruebas. Alguien podria decirme que es lo que esta mal? Este problema no solo esta relacionado al scope, tambien lo hace con el scanner.

@ladillando1 11 жыл бұрын

Today I was trying to do the relative compression in a vehicle with the Verus following your instructions but was impossible. This is not the first time I was trying. Probably this scanner is bad.

@WillsHellaHeat 5 жыл бұрын

Just bought a verus 325 the wireless version what cabl do i need to buy to hook up my obd1 adapters?

@ScannerDanner 5 жыл бұрын

there is an adapter the connects to your wireless VCI 16 pin connector, I forget the number of it offhand

@josueivanruiz 8 жыл бұрын

@scannerdanner I was just wondering if an exhaust restriction would be a variable in relative compression testing especially on a V engine. if the catalyst was plugged on one bank, would that give u low humps on those cylinders?

@ScannerDanner 8 жыл бұрын

+josue ruiz I think that is possible

@simonilett998 5 жыл бұрын

I believe you would certainly see a difference on the bank with a plugged converter, so long as each bank has a separate exhaust header. Current should go high, and voltage should go low each time one of the cylinders on the 'plugged' bank came up to compression. (ScannerDanner) Would you agree Paul?

@markjohnson8162 2 жыл бұрын

I’ve tired this test with my modis ultra set it up using the same voltage and timescale and I don’t have the same readings . Could you please help me

@ScannerDanner 2 жыл бұрын

Mark, post this to my forum and share your screen with us. We can help you for sure! It is free to join www.scannerdanner.com/forum/post-your-repair-questions-here.html Hope tp see you there!

@AmericanLocomotive1 12 жыл бұрын

I'd imagine this would be hard to determine on odd-firing engines like the Dodge truck V10

@Viper81766 10 жыл бұрын

Great video. Will a 400 amp clamp be enough for this or do I need 600 to 800 or such ? Thanks brother

@ScannerDannerPremium 10 жыл бұрын

If you are buying a high amp probe get the 600. Most of the time I just use my low amp probe but it will not read higher than 400a

@Evesautomotive 7 жыл бұрын

Have seen low compression caused by washed out cylinders too, which was caused by a bad spark plug (older cars). Seen this sting a few techs.

@sollykhan2385 2 жыл бұрын

or a vehicle that had be laid up for a while, and got internal rust on valves/ seats, bore etc, 🙂👍

@texas77563 4 жыл бұрын

is the snap on verus still worth buying a used one in 2020. or do they have cheaper ones that do the same thing nowadays?

@ScannerDanner 4 жыл бұрын

stay away from the Verus and Verus Pro as they use an obsolete operating system (windows xp). My Verus Edge is window 10 I believe

@felixautotech4754 2 жыл бұрын

My teacher

@KALUPO78 11 жыл бұрын

What about a dual plug setup or a multi spark?

@import0408 5 жыл бұрын

You said you would never put a plug or a injector in it. What if you had a leaking injector that washed the cylinder? I feel like this could be a variable.

@kiracat99 8 жыл бұрын

Mr. Danner-You don't need a high amp clamp for this test? It would not harm the 60 amp max clamp? Thanks

@ScannerDannerPremium 8 жыл бұрын

+mark schaefers no you do not and you will not hurt the amp clamp but you are limited in that it will not read more than 250 amps or it will not produce more than 2.5 volts on the 10mv/a scale

@organicvids 8 жыл бұрын

to figure which cylinder is bad remove plug number one and count spikes from there

@12mak 4 жыл бұрын

Wouldn't that effect the other cylinder's reading.. as in the same when doing a mechanical compression test..

@pumarobo 4 жыл бұрын

Just add channel 2 to the cyl 1 coil pack and use that as cyl 1 reference

@5am8011 11 жыл бұрын

how do i get your e book my friend at home bought it he z nothing but good things about it iv read bits and pieces of it but would like me own. can yu do some can bus videos? your doing a grea job cant stop watching well earned pat on the back

@radmilakrejci8581 2 жыл бұрын

Paul! subscriber to your channel here! and proud owner of the book! Everyone should get the book! quick question here! if i would be testing starter draw , is 600amp clamp safe to use with verus scope, i heard stories about modis getting fried up when using high amp probe on failing starter (they draw 400amp ). is there some kind of protection/amp conversion as the clamp itself is rated for 600A, and settings on verus scope are 40A. You should make a video btw on how to use scope and probe to do a starter draw,

@ivaneu1 7 жыл бұрын

Great video Danner, where can I buy that tools in New York or New Jersey? I'm going go there in next month.

@ScannerDanner 7 жыл бұрын

What tools? Snap-on tools are sold by Snap-on from their tool trucks.

@ivaneu1 7 жыл бұрын

+ScannerDanner I'd like a versus scope. Thanks for your reply.

@evansjean 6 жыл бұрын

What if your compression is low but missing completely? Let's say you got 120 and all cylinder and one of them is at 70 psi would that show you missing compression also?

@ScannerDanner 6 жыл бұрын

Yes, it will show as well. Watch this video kzfaq.info?o=U&video_id=tZWsOupUzhY Start at the 5 minute mark. It is a Hummer with a leaking valve causing low compression in one cylinder. Thank you!

@yanierolivera4678 10 жыл бұрын

Hi Paul, I dont find myself doing many relative compression test. I tried doing it the other day on a 98 honda crv. I was using a high amp probe set on a 60 amp scale. (10mv/1amp) Set the scope to volts dc, 2 volts on a 1 second time base. A got a wave form but it was always dropping below the 0 volt scale. I tried using my low amps probe, same settings and the same thing happened. Trying to think where i went wrong. All the best

@ScannerDanner 10 жыл бұрын

Flip your amp clamp over, they are polarity sensitive. Or select invert on your scope.

@yanierolivera4678 10 жыл бұрын

Paul I tried flipping the clamp over. When I used my snap on low amps probe the arrow on the clamp was pointing toward starter motor and same thing happened. I had peaks going over the positive side and they were even but at the same time I was getting almost like a mirror of the positive wave form below the 0 volt line. Later on i was going over my scope settings and found that I had checked "on" the AC coupling function from a precious alternator diode test I had done and I never unchecked after when setting up the vantage for the relative compression test. I have not tried to do the test again but i will for sure. Maybe this is what caused an erroneous wave form to display. we'll see. Thanks for your reply! All the best

@jaimesustaita285 6 жыл бұрын

Hello paul y'all ever sell those scanners at a discount rate after y'all get new ones, sure would like to have one, unfortunately can't afford a new one, and most of the work i do is pro bono because i love help people out.

@ScannerDanner 6 жыл бұрын

We do not. I'm sorry. I know Snap-on does though as we trade ours in when we upgrade.

@ScannerDanner 12 жыл бұрын

For sure, but the firing order was 123456

@alejandroamaro8303 8 жыл бұрын

Hi Paul. if im using an oscilliscope for testing high amperage with an amp clamp do i need to run it through an attenuator ? or is the attenuator just for high voltage readings? such as an injector voltage waveform. would i ever need an attenuator for measuring current on cars ?

@ScannerDanner 8 жыл бұрын

+Alejandro Amaro amp clamps produce millivolt signals that are equivalent to the current being measured. You will never need an attenuator for these

@alejandroamaro8303 8 жыл бұрын

Ohh. I see. Okay thank you my friend. I have my scope on its way through mail and i dont want to burn it in the process of learning how to use it. Lol