Chevrolet Spark - Compression waveform - help!

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sid
Newbie
Posts: 2
Joined: Tue Sep 30, 2014 10:38 am

Chevrolet Spark - Compression waveform - help!

Post by sid »

Hello
Here I have a Chevrolet Spark 2010 1.0l 16v. Starts and runs but lacks power with a slight misfire (incomplete combustion) at idle. Suspected valve timing. Timing marks are coloured chain links and only one mark on the crank gear. Old chain had stretched by one link. New chain fitted. Waveform captured is with inlet choked. Without choke vacuum pocket on exhaust stroke was -2.5bar! What are your thought?
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Autonerdz
TwoWaves
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Posts: 387
Joined: Wed Nov 20, 2002 4:19 pm
Location: Washington State USA

Re: Chevrolet Spark - Compression waveform - help!

Post by Autonerdz »

Since that pressure does not exist, you have an instrumentation issue.

Start by selecting DC coupling not AC.

sid
Newbie
Posts: 2
Joined: Tue Sep 30, 2014 10:38 am

Re: Chevrolet Spark - Compression waveform - help!

Post by sid »

School boy error! Must have changed it accidently.

Lesson learned, always check your scope settings.

Thank you :D

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