BMW F10 M5 compression testing gone wrong... (Part 1)

[@MK-if8pp]

Good thing is that results are consistent on each cylinder 👍🏼 Do test again with warmer engine or drop little bit of oil into cylider before testing. Nice videos! 👍🏼

[@AlfisGarage]

@@MK-if8pp Thank you! Yeah that’s what is making me think there may be something wrong with the gauge or something - it’s not far off, but a bit on the low side. I’m trying to source a different tester and will try again. Thanks for your input!

[@vz6235]

Hope you get it figured out dude, F10 M5's are amazing cars

[@AlfisGarage]

@@vz6235 Thanks mate!

[@W.Khairi]

Many possibilities Could be no oil on cylinder walls due to extensive setting. Have someone fully depress the accelerator pedal while testing. Also could be the valvetronic in closed position if u can have it checked.

[@AlfisGarage]

@@W.Khairi thanks for the tip. I think Valvetronic should not affect it regardless in what position it is - it just adjust how much the intake valves can open, but once the piston goes to compression stage, the valves must be fully closed. I’m waiting now for boroscope camera and will check as much as I can 👍

[@J562-l6r]

Is 165 good compression for this car? I did mine today for a continuous misfire in cylinder one even after replacing spark plugs, coils, injectors… a guy I know that builds these engines says 165 is good and my issue might be my DME mosfet that’s causing the misfire

[@AlfisGarage]

@@J562-l6r that could be just lower reading from the tool, so it sounds OK to me. If you look into my follow up video, you’ll see I got about 175-185 at the end on mine. Mosfet issue is a possibility

[@J562-l6r]

@ not sure if me performing the compression at a cold start gave me 165 and not higher but I did see your video where you got higher compression.. I’m hoping it’s a mosfet issue. Will be replacing DME tomorrow and coding it into the car… did you get yours fixed btw?

[@AlfisGarage]

@@J562-l6r yes mine got fixed if you watch the other video. 165 PSI is OK, that shouldn’t cause a misfire. I heard about the mosfet issue on an Audi, but it is certainly a possibility here as well. I would first start by checking the signals for coil and injector at the coils and injectors with oscilloscope - if no signal is present, then move the test probe to the DME connector. Let us know what you find out!

[@J562-l6r]

@ sweet glad to hear from someone else 165 being good compression. I was afraid that was low even after engine builder said it was okay lol .. will be doing DME swap today will update

[@asocialo]

It goes wrong when u change oil each 30k its not a Renault

[@AlfisGarage]

Agree, but M5 oil replacement interval is 10k km's... even that is a bit long... Thankfully, nothing wrong with the engine! :)