Volvo v70 misfire

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Volvo v70 misfire

Postby bullstar » Sat Oct 15, 2016 5:58 pm

Hi, Just bought a wps so thought I would try it on a misfiring Volvo 1999 model 10 valve, following the software instructions I did a compression test, the figures on all 5 cyls were identical around 167 psi but I'm not sure what the small peaks are , is this a valve reading?
with a vacuum gauge I'm reading 13 inHG steady, valve timing ?
done vacuum test also with wps , used zoom, see pics
Attachments
volvo v70 cyl relative compression.psdata
(469.5 KiB) Downloaded 34 times
volvo v70 intake vacuum test.psdata
(924.97 KiB) Downloaded 23 times
volvo v70 zoom range 3.psdata
(348.7 KiB) Downloaded 20 times
volvo v70 cyl 1 compression test.psdata
(199.15 KiB) Downloaded 29 times
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Re: Volvo v70 misfire

Postby volrem » Sun Oct 16, 2016 11:24 am

I would say that this small peak (0,8 bar) is because exhaust valve closes too early.
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Re: Volvo v70 misfire

Postby bullstar » Sun Oct 16, 2016 2:44 pm

Thanks for your input, I was thinking it was the exhaust stoke as if I put the rulers up in degrees from compression peak to peak 720 degrees the 0.8 bar is in exhaust stroke, Surely There should be no peak on a compression test
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Re: Volvo v70 misfire

Postby andrewbishop66 » Sun Oct 16, 2016 5:03 pm

Hi
how about cylinder leak back test the peak could be due to leaking valves on its companion cylinder causing the pressure increase

Thanks andrew
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Re: Volvo v70 misfire

Postby andrewbishop66 » Sun Oct 16, 2016 5:38 pm

dont know if this helps
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Re: Volvo v70 misfire

Postby bullstar » Wed Oct 19, 2016 7:37 am

Hi, thanks for your input , yes a cylinder leakage is the next test we going to do on this car , I believe the car is similar to the test results as the valve train also sounds a little noisy and could be the symptoms of valve lash.
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Re: Volvo v70 misfire

Postby volrem » Wed Oct 19, 2016 7:40 am

Measure cam and crank to see if timing is off.
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Re: Volvo v70 misfire

Postby victor2k » Wed Oct 19, 2016 9:14 am

Hello,
Or check the cylinder pressure waveforms for all cylinders to see the wear of exhaust camshaft.
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