Good day!!!! Heres a wave form of a 2013 ram 1500 5.7L hemi with lifter tick/clunk in cylinder pressure at idle and im baffled to what could be going on in the first 180* rotation prior to exhaust stroke!! Theres no engine codes or misfires or anything to point me to anything really truck runs fine other then lifter noise after it warms up!!! Any insight or analysis of this would be most appreciated Thanks kindly
I guess it could be! but on every cylinder? i thought out of time at first but truck seams to run fine other then the dreaded lifter noise on both banks! cam and lifters were just done due to the notorious hemi cam lifter issue. truck fires up decent no long cranks no misfire data!!! this ones really got me confused!!!
That's an interesting one - this is at idle I assume from the intake vacuum.
I would say a leak between cylinders as the pressure starts to increase at 60 ATDC when all the valves are shut (or supposed to be) that can only come from another cylinder. If an exhaust valve was open it would decrease - or not build pressure in the first place.
The only other thing would be a change in volume caused by a sloppy bearing - but then I would expect it to level out not increase.
So i got a capture from another 2014 pick up with a 5.7 hemi and its very similar!!! So im not so concerned so much any more but pls feel free to explain if anyone knows whats happening here!!
I've seen similar shaped waveforms from this specific engine with a two plug per cylinder design on a working cylinder where the second plug was not disabled from sparking. The peak pressure obviously was significantly higher but the contour of the capture looked almost identical. It calls my attention that the example Vasek shows is also from an engine with dual plug design.
Awesome observation!!! im going to further look into it over time to just get to potentially see why its like this!!! seriously thank you everyone who has inputted some theory behind the capture and by all means if someone has definitive info pls share!!!!
edit: so your saying that because the engine is firing on the other plug we will get this type of wave form?