so I'm being very mellow, coasting down the lower stretch of California Route 9 through the redwoods, enjoying the sunlight filtering through the tall trees, no hurry, had just dropped my 16 yr old off at her babysitting job in Felton, and the Costco in Santa Cruz was my next destination. roll on a touch of throttle at a spot where the gentle downgrade stopped, and heard a funny clattering sound, like a hammer hitting a solid iron casting at engine RPM speed, oooh, THATS not good.. off throttle, quiet and smooth gliding through the woods. roll throttle on, klank-klank-klank-klank. ugh, NOT good. so I nurse it into town (just a few more miles ahead, park in a partially shady spot, pop hood to inspect. ugh, engine at idle is bucking like its running on 3 cyls, rev throttle, and here just a little touch of the clank-clank-clank up around 3000rpm. double ugh. note the intake hose from the MAF had come off the turbo intake again, sigh, but that just results in high throttle power loss, not this. shut car off, get out cellphone, and call wife, and immediately discover my cell battery is nearly dead, so I had her call for a tow to the shop as this is probably beyond me.

Towtruck driver shows up after car had sat about an hour (busy sunday afternoon), and we try and start it, and it won't even idle without givin git a lot of gas and its running really rough. off throttle, it stumbles a bit at about 300rpm and stalls.

I did note it threw a new 121 engine code, which I gather is AMM/MAF but of course, running without the intake hose connected to the turbo would do that, but it shouldn't be missing as badly as it is.

Oil was fine (about due for a change, but didn't smell burned, wasn't any silver flakes in it, level was OK). coolant was good, too.

so its sitting at the shop awaiting diagnosis ... sigh.

anyone wanna take side bets? i'm guessing something borked in the valve train, tow truck driver suggested the turbo coudl have sucked something in (but I'd expect that to make a way different sound than KLANK-KLANK-KLANK). could have thrown a rod or cracked a piston I suppose, that would explain one cyl running but I'd expect a horrid noise at idle and not just under throttle.

hoping that I'm not going to be shopping for a complete B230FT. Head I can deal with. whole engine? ugh.

 

The clank and misfire sounds like a dropped valve to me. If a turbo sucked in anything big enough to cause that sound, the turbo would be dead and you'd know it.
A dropped valve will be easy to find, just pop rocker cover and have a look/listen.
If it was a rod, the sound would be constant and I doubt you'd throw a rod cruising.
I've had my B230 running on two cylinders and they aren't that rough (in fact, will drive O.K on flat ground), so it could be pretty bad.

 

wouldn't a dropped valve clatter even at idle?

anyways, was suggested elsewhere its something much simpler, bad knocking because the intake was open and things were running way out of spec.

I'm going to replace that intake hose before I do anything (the old one got oil soaked in the past, and the bottom 1/4 of it is all mushy and half melted).

I'm guessing there's more than one thing wrong here.