Strange Pressure Capture
I had an interesting capture today that I would like some help interpreting, more for my files and records of case studies and curiosity. Vehicle history is the customer towed it in to the shop after performing a lot of DIY work including head gaskets, timing chains twice ( bought the Amazon tensioners, they broke second set was FOMOCO), new crank sensor, new cam sensor, new plugs, wires, coils. The customer stated that the project started because the engine had dropped a valve. After performing the repair he said the vehicle drove good for about a week then started running poorly, stated he could smell fuel under the hood. After pulling codes, vehicle had a p0340 and a p0300. I did a visual and found some creative mounting of the cam sensor where a bolt had been broken off in the block during prior replacement but it was seated properly and no visual harness issues. I started the vehicle and could hear some compression issues and after firing verified the poor running condition and also experienced a backfire through the air box. I performed a relative compression test with a sync on # 1. After piecing together the terrible pattern with the firing order, it appeared as if I had no contribution from the entire second bank. I pulled a plug to do an in cylinder capture, and noticed an excessive amount of fuel in the cylinder. After pulling the other bank 2 plugs, all cylinders were fuel washed. I drained the oil replaced, added some oil to in each cylinder and slowly cranked with the injectors unhooked. Reinstalled the plugs and performed an in cylinder on each bank #1 and #7 respectively. The first psd file shows running comp on cylinder 1. This was a theoretical good and I saw no obvious issues so off to cylinder #7. The second psd file shows #7 same conditions. After seeing the initial waveform results, I saw that there appears to be no exhaust event at all. I rechecked my connections, re calibrated the WPS and re ran the test with the same results. I added a jpeg at idle for those that do not have psd files. I feel there is an obvious timing issue. I could not verify the cam/ crankdue to the p0340(no signal from the sensor or the bulk connector on the fire wall) code and the customer did not approve the time to get to the bottom of that issue. I do not believe this is going to move much further into a repair because the customer wants to do all of their own mechanical repairs. My questions are surrounding the exhaust pocket or lack there of. Or am I seeing a HUGE spike during the exhaust event? Steps to verify potential hypothesis? Thanks in advance for the help.