I have a 2002 Ford Escape 3.0L engine. have a dead misfire on number 2 cylinder. found broken exhaust valve springs
on number 2 cylinder. replaced #2 exhaust valve springs. number 2 still misses constantly. checked for spark and fuel with no issues there. If i was out of time, at least the whole rear bank would miss. performed a relative compression test and found one cylinder with no compression.
next i performed an in cylinder cranking compression test on #2 and it showed 180psi??
lastly i performed an in cylinder running compression test on #2 cylinder and it looks like i found the issue. appears to be a burnt exhaust valve?
does anyone disagree with this diagnosis?
why would a cranking compression show good but relative compression clearly show an issue?
Hello,
Please look at the moment of opening of exhaust valve:look how fast the cylinder pressure decrease/compared to the cylinder pressure increase.Try to record also the pressure in intake or exhaust.Sometimes only the compression will not show the issues...
Regards
victor2k wrote:Hello,
Please look at the moment of opening of exhaust valve:look how fast the cylinder pressure decrease/compared to the cylinder pressure increase.Try to record also the pressure in intake or exhaust.Sometimes only the compression will not show the issues...
Regards
just to clarify, are you saying to use wpx500 and measure exhaust pulses, and use it to measure intake manifold pulses as well?
if the exhaust valve is burnt, it would affect both waveforms. correct?
thank you
rburgy wrote:
if the exhaust valve is burnt, it would affect both waveforms. correct?
thank you
Hello,
Sometimes you can't see a burned valve/wrong free play of valves only measuring the compression...
Adding a new measurement of intake/exhaust pressure to the cylinder pressure you will see where is the problem,or you can perform a leak down test .
Regards