Using EEDM5030 tranducer and M2module

[19mopar]

Question about this pressure tranducer and the M2 module. What I am trying to do is tell if cam timing is off. I purchased the TDC software from AES and performed some cylinder testing on a known good vehicle. Here is the cranking compression 1991accord pressure.vss. the question i have is i should have a hump after max compression to see when the valves open but the transducer isn't picking it up. I tried a running compression 1991accord running compression.vssand the hump is seen but isn't a smooth curve like the waveforms shown on AES. Wondering if the EEDM5030 won't work properly for what i am trying to do or do i need to set up something different in my scope settings. I thought this would be a cool addition and cut some diagnostic time. Thanks in advance.
Darren Nelson

[crackerclicker]

darren,

i can see the "dips" in the cranking capture, but not very well. is the EEDM5030 basically a fluke pv350? if it is, those are usually quite reliable.

[Kris H]

In the running comp test you should change your time base to zoom in to get a better look at whats going on. What are you using to connect the transducer to the cylinder? You need a stiff hose or a pipe as short as possible for the application, the longer the hose the lower compression reading (changing volume), and the more flexible hoses will distort things a bit. Yes you should be able to see the exhaust valve opening after the compression tower in the cranking compression as well although not as pronounced as the stroke is happening slower so more of the air is easily escaping out the valve versus the rate of escape at a higher rpm. Also noted your not showing very much vacuum at the bottom of the towers before the exhaust valve opens which made me wonder if your hose is to flexible. Here is a good engine with a flexible hose it really made this vehicle look like it had a valve timing problem but when a good stiff hose was used the waveform looke perfect (sorry didn't save the good one damn it). I don't own the transducer your using so it may just be inferior to the others snap on sells but it's worth checking into.

[kebo1970]

transducer

the EEDM5030 is more accurate than any of the other transducers that snap on sells. you should not see the vacuum in the waveform. that's the problem with the other transducers that snap on sells; it shows a vacuum reading when doing a running compression test. go to oreilly's auto parts and buy the compression tester with the braided hose. take the gauge off and screw in the transducer with teflon tape. with your transducer you can't use the 100,500,or 5,000psi transducer scale. you have to use the millivolt scale. one millivolt is equal to one psi; ten millivolts is equal to ten psi. i use the same tdc software your talking about; it works good for me.

[19mopar]

Thanks for the replies. I was using the hose attatchment to install air into the cylinder to keep the valves closed when removing valve springs. That hose was not steel braided and very flexable. Took my compression gauge and removed the gauge. Installed tranducer with a quick disconnect for an air hose. Got a little better waveform. Removed quick coupler and installed transducer directly to hose and waveform seemed to be the same. My waveform still isn't a smooth curve like waveforms i have viewed on iatn. My scope is set to either 200mv static compression or 100mv for running compression. Do you guys think i have tool long of a hose or is this the way this tranducer will react and not create a smooth line wave form or doesn't it matter. Just starting to learn about this process and am learning alot. Here is the waveform for cyl1 running compression at idlegeri knut4.vss and here is the one for cyl2 running compression at idlegeri knut5.vss they look ok to me but i am a rookie at reading compression waveforms. how would the waveform look different if the chain was off one tooth. Thanks again for the help

[crackerclicker]

. My waveform still isn't a smooth curve like waveforms i have viewed on iatn. Do you guys think i have tool long of a hose or is this the way this tranducer will react and not create a smooth line wave form or doesn't it matter.

i really don't know why it comes out that way . assuming that is basically the fluke pv350, my best guess would be that the snappy scope is picking up some "noise" that those transducers were famous for. there have been many methods used over the years to "quiet down" a pv350. i recommend you try to place a ground wire between the body of the transducer and battery negative to see if there is any change in your waveform.

. how would the waveform look different if the chain was off one tooth. Thanks again for the help

advanced or retarded one tooth? you wouldn't likely see a big difference with only one tooth off, but if you happen to capture one please post it up .