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mwebb

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Re: firstlook
Reply #105 - Aug 17^th, 2007 at 9:04pm

ani gif , same as above , but different .
, but you learn a lot while trying .

2000 VW / AUDI ATQ V6 2.8 DOHC .

like this , a running compression waveform captured while an Omega pressure transducer [set on AC coupling ] is connected to the intake vacuum ... higher vacuum is up on the waveform . this cylinder's fuel and spark are disconnected .
you can clearly see the effect or affect ? that the induced misfire has on the intake vacuum waveform , and you can see that the intake vacuum aligns with the valve events in the running compression waveform .
a Fluke PV 350 transducer grounded to battery negative was used to capture the running compression.
the two transducers do not have the same response time ... the waveforms are very slightly staggered , but close enough to see ... that the misfire is reflected by dip in the intake vacuum equal to about 25% of the amplitude of the change in vacuum in the waveform itself . a tiny but very measurable amount .

so now we know , misfires are reflected in dips in intake vacuum that line up with the intake valve opening events of the misfiring cylinder . at least on this ATQ V6 engine .

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2000_passat_ATQ_RC_Omega_Intake__4_Misfire_ani.gif (89 KB | )

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jarvissamuel

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Re: firstlook
Reply #106 - Aug 18^th, 2007 at 6:55am

Hi Michael

I have a question. What benefit does hooking the pv350 to bat neg? Everytime I have used it I have hooked directly to the scope leads.

I think mine is broke I was trying to check for a timing issue on an 98 explorer 4.0 ohv and it would not show the vacuum portion. It has in the past and this was with a new 9v batt.

Anyone know where to get a pv350 checked/fixed or is just cheaper to replace it?

Here is an image of the pv350 capture

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98explorer4Lohv_comp_1.gif (47 KB | )

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fisher

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Re: firstlook
Reply #107 - Aug 18^th, 2007 at 11:52am

Hi Sam,
   I remember you told me some things about my own Fluke. I evetually took it to Branom Instruments, here in Seattle and they took care of me as they sell Fluke equipment and service. They dont restrict their business strictly to Fluke however. The price for me to have them check it was worth it, mine needed nothing.
   You ought call them, I think if it needed repair the cost to fix it would be about 75% that of a new one, max... You can find them on the web and one number to call is 1 800 767 6051.
      They repair 'process control instrumentation' as well as testing equipment including DVOMs, transducers, etc.
For sure you can look for a company that repairs and calibrates instruments.

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mwebb

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Re: firstlook
Reply #108 - Aug 19^th, 2007 at 5:57pm

jarvissamuel wrote on Aug 18^th, 2007 at 6:55am:

Hi Michael

I have a question. What benefit does hooking the pv350 to bat neg? Everytime I have used it I have hooked directly to the scope leads.

for better resolution with the PV350 i use the "metric" setting .

the adapter i made to use the PV 350 threads into the spark plug threads , a 1/2" copper pipe with a quick disconnect fitting on top for the PV 350 , it electrically connects the case of the PV 350 to the spark plug threads ... so the benefit is that if there is a voltage drop problem on the ground side , it puts RF hash in the waveform , so if you ground the PV 350 to the battery negative , it helps to diminish the RFi hash ...
i have take the liberty of overlaying one of my good running compression awo files on your capture , you have an rfi problem but your resolution is not good either ... what kind of adapter have you fabricated to use in the spark plug thread ?

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Fluke_pv350_s_jarvis_autonerdz_ani.gif (116 KB | )

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jarvissamuel

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Re: firstlook
Reply #109 - Aug 20^th, 2007 at 6:47am

Thanks Mike I will give it a try. My apadter is just hose connected and clamped to the hose from my compression tester. I may have been having a problem wiht my usb connection on my pc as well I went to use the scope and the voltage was reading 5v less than what it was wiggling it would correct it.

Here is an image of when the pv350 was apparatly working

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97caravan3L_camphasing.gif (50 KB | )

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mwebb

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Re: firstlook
Reply #110 - Sep 2^nd, 2007 at 6:08pm

using AES ANNOwave for the graphics and Pico 6 scope software.

this BMW with M54 6 cylinder engine has a COP ignition system , AceMisfire can find misfires pretty easily , but if you dont have Ace Misfire yet.... .

you can stretch aluminum furnace tape across the tops of the COP coils , then connect the secondary lead to the furnace tape taking care to not touch ground with the tape or test lead .
use primary from the #1 coil or primary current from #1 coil to sync and - unfortunately the 2ndary spark waveform did not show the misfire this time ? but the FLSe pressure transducer in the exhaust does .
,

i have overlayed a running compression waveform and matched it to equal 720 degrees of the image , so that 720 degrees in the image matches 720 degrees of running compression waveform length ,
then i drag the running compression waveform so that the Exhaust valve opening matches the Long line misfire , drop in some cursors to clarify everything and shazam one misfire is on cylinder 4.
at 2k rpm no load . this spark system is similar to ford multi strike at idle , this is about 2200 rpm.

on this car , you can also connect to the primarys with a PRB and get spark primary in parade

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DBL3501_02_325i_87899_miles_IMM6.gif (106 KB | )

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mwebb Senior Member Offline Posts: 162 Gender:	Re: firstlook Reply #111 - Sep 2^nd, 2007 at 6:10pm wrong image above ,
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mwebb

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Re: firstlook
Reply #112 - Sep 29^th, 2007 at 7:27pm

1991 BMW 535i M30 engine ,
2k rpm , spark does not show misfire , but FLSe does .... weird ? i also have waveforms that show misfire that spark and o2 do show , but FLSe does not ?

first set the verticle cursors so 720 degrees in cursors equals 720 degrees in waveforms, then i have set the cursors by swag to kinda sorta match the valve opening / closing events then added on 30 degrees in front to allow for spark advance at 2k rpm , another swag , then over lay the the cursors on the waveform and drag it around until the valve open close event lines up with the LL misfire , look where spark should be , and shazam , there it is . cylinder 4 .
i'll be dipped in fried bat poop .

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1991_BMW_535i_M30_wnew_2ndary_LL_misfire_ani__gif.gif (102 KB | )

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mwebb Senior Member Offline Posts: 162 Gender:	Re: firstlook Reply #113 - Oct 6^th, 2007 at 7:43pm here is a vacuum leak , picked up by Mr o2 sensor but although the mixture is leaned out by the vacuum leak , it was not leaned out enough to cause a misfire as shown in the FLSe waveform . disconnected purge vacuum line before purge valve , 00 saturn SL1 .
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Alex Richards

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Re: firstlook
Reply #114 - Mar 25^th, 2013 at 9:01am

Hello all,

Relatively new to the forum and hope you don't mind me bringing this one back from the dead, but I have a weird vehicle waveform that I'm attempting to figure out...

This is a 2001 cavalier 2.2L LN2 OHV engine, Firing order is standard 4 cyl stuff, 1,3,4,2

I hooked up the Firstlook to intake vac, have the sync hooked up to #1 coil (waste spark system so you'll see #4 fire 360 after) and green is system voltage while cranking.

This is a WOT cranking test, fuel disabled

Power balance says cyl 3 is the issue, wave form if I'm looking at it right says Cyl 2 is...

Not sure what to do here, This is a slight misfire at an idle, seems to smooth out while driving or if it's revved off idle. Really want to use this for a presentation I'm doing Friday.

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crank_voltage-firstlookintake-cyl_1_secondary.psdata (11329 KB | )

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crackerclicker

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Re: firstlook
Reply #115 - Mar 25^th, 2013 at 12:54pm

Hi Alex,

You'll probably get more responses if you open a new thread for your case. From your description of #3 failing the power balance, I'd guess that the intake wave is showing you that you are getting pressure in the intake during #2's intake stroke. That pressure may be coming from a leaky #3 intake valve during #3's power stroke.

I'm busy right now, but when I get home I can put up an image that can show this better. Perhaps by then others will have seen this, and can chime in.

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crackerclicker Super Nerd Picogroup Offline Elevation 834 ft Posts: 2,358 Watertown Wisconsin USA Gender:	Re: firstlook Reply #116 - Mar 26^th, 2013 at 8:54pm Sorry Alex, I meant to do this yesterday.
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