I have a 2010 Honda Pilot 4x2 with 3.5l v6, auto trans, and 230,000 miles. I floored it on the interstate and something gave out. Did a compression test and found that Cylinder 1 had around 30 psi but the other 5 were around 130-150. It doesn't smoke at all but there is a gas smell coming from the exhaust. I cleared the codes and the only code that came up was cylinder 1 misfire but after a while of driving a random multiple misfire code appeared. I still drive the vehicle but it idles like a damn diesel.
For anybody wondering, here’s the backstory to this event -
https://carkiller.com/scottykilmer/qa/no-one-has-been-able-to-help-with-my-2010-honda-pilot/
Many things, none of them good:
1. A hole in the cylinder;
2. A stuck, burnt or fatally leaking valve;
3. A busted connecting rod;
4. A bent push rod;
5. A broken valve spring.
Here's a question for you: As Scotty has mentioned on numerous occasions, Honda's require periodic manual valve adjustments. (Toyota has an automatic-like hydraulic system that is self-adjusting). Every 70K or so, you're supposed to take the vehicle in to a qualified mechanic to have the valves adjusted. If you did not, it's not surprising that the vehicle has a quasi-dead cylinder. If the valves get too tight (carboned up, gunked up) or too loose (springs, etc.) damage to the cylinder will result.
So, if you never had that done, the dead cylinder is the likely result of not having that service done, every 70K or so.
"Many things, none of them good" was literally what crossed my mind when I read the thread title. Lol.
In the OP’s case he has a (single) overhead cam (SOHC) engine which don’t have pushrods (that’s for OHV engines).
Low compression in just one cylinder can be due to worn piston rings, valves, cylinder walls, even a worn lobe on a camshaft.
You now have a V5 Pilot
A catastrophic failure from the sounds of your story. Time for a new motor or a new car.
It’s curtains for your engine.
If you want to keep the vehicle, put in another known good/healthy engine, from a junkyard.
