Knocking sound from engine

[rednofive]

I was driving in to work today and I got on it.
after I slowed down at a light almost at my work locatin, I started hearing a faint knocking sound, like a diesel tractor.

it got louder.
It modulated with my pedal.

FUCK, that sound is me.

I drove into work about a 1/4 mile while staying out of boost
Now I'm at work and I don't know what to do. I'm 18 miles from home.

It's about 40F, I'm running exactly what my signature says (but my last fill-up was with BP 93 octane) and my monthly pull logs from just a week or so ago show 1600-1700 PSI on the stock pump.

I've never had a car that did this, but it sounds like a dead cylinder.
I've attached a wav-file recorded from my phone while my coworker stood over the open engine while it idled.

I moved the R's to about 2K RPM so the knocking is more noticeable (you can hear that around 15 seconds in the recording).

the car starts OK (I stopped and restarted), though very slightly slower than usual.

I don't know that to think yet and I don't know what to do?

current thoughts are:
best-case, maybe a plug wire came lose or a plug went bad somehow and I'm not firing on one cylinder?
worst-case, I blew a gasket or something interfered or got destroyed by detonation. maybe the cause was a stock HPFP that failed in the past 2 weeks since my last log or maybe the 40F temp just wasn't well characterized in the Cobb 93octane maps or maybe just some fucker at BP decided to pump me some shitty gas.

well, I'm probably only going to be able to blaime myself for not dialing the car back to 91octane, but I've been logging a lot all summer and fall and haven't seen any KR above 0.35 to 0.7, so oh well.

I'm afraid to run it more.

should I tow it home?
should I tow it to the dealership? I've got 53K miles and the mods shown in my sig, so if I show up at the dealership, should I first unmod the intake and return the maps to stock with the AP?
I think they saw the intake the last time I was in for oil/rotation, but they've always been pretty cool and even told me the mod was fine (before I did it) and safe.

should I start it up and try to get some kind of useful log data from my AP?


advice would be appreciated.

[kish89]

Clutch pedal vibrating?
Sorry man but it sounds like a bent rod...

[G26]

You really just take a gamble with these motors


Sent from my balls via my penis

[helmetface]

Originally Posted by G26 You really just take a gamble with these motors Sent from my balls via my penis

Uggggh


Modding ANY engine is a gamble.

[vtekken]

Damn, that's rough... I would not run it, that just sounds like trouble. Demod, flash the stock tune, and tow it.

@phate @kabobulate @dbrier do you guys have any better suggestions?

[G26]

Originally Posted by helmetface Uggggh Modding ANY engine is a gamble.

Lol, I'd say it being turbo increases the odds of something happening.


Sent from my balls via my penis

[phate]

That doesn't sound healthy, sounds like something in the bottom end :/

Does it run roughly, and can you feel any vibration in the clutch pedal?

[rednofive]

Originally Posted by phate That doesn't sound healthy, sounds like something in the bottom end :/ Does it run roughly, and can you feel any vibration in the clutch pedal?

Nothing weird in clutch pedal (feels the same as always).

No codes of any kind from the ECU (I just checked).

Runs smoothly. I mean that it starts great and idles fine, but I think I recall from my short limp to work that it doesn't accelerate very well (I was keeping the car between 10-20" vacuum, so no boost at all).

sounds exactly like this video, but not quite as loud:
https://www.youtube.com/watch?v=_0CBQcccLDM

[rfinkle2]

I see in your sig that you are running an ots map with 25% e85. Have you noticed your afr's when running that mix?

[rednofive]

Originally Posted by rfinkle2 I see in your sig that you are running an ots map with 25% e85. Have you noticed your afr's when running that mix?

This tank is pure 93octane from BP.
Last night I was watching AFR's and boost for fun.

I was hitting 11.3-11.4 under WOT or at least very high WOT.
boost was 15 to 17PSI, exactly like Cobb says it should be for my car/mods/map.

I think I got too close to red-line in third gear and cold-air + and stock fuel-pump bit me.

un-believable.

[TiGraySpeed6]

+1 about feeling vibes in the clutch pedal

bent rod will (usually) translate to the crank & through the clutch. It's a pretty distinct feeling.

[MS3-a(sore)ASS-rex]

That's a bent rod amigo.

Ive driven over an hour on two different engines with bent rods. I won't say you can make the trip because it's running on borrowed time

[phate]

Pete, if you decide to tow it home and do some diag, I'll drive over to help out.

My first thought was spun bearing

[rednofive]

Originally Posted by phate Pete, if you decide to tow it home and do some diag, I'll drive over to help out. My first thought was spun bearing

wow, you are truly a generous soul.
I don't want you to have to do that, but I appreciate any coaching you can give.

I will likely tow it home and swap out the intake, just in case, then restore the ECU to full-stock.

I believe this car has a 60K mile warranty on the drivetrain and I've done almost nothing to it and Mike at Tom roush is pretty cool.

I'm at 53K miles.

Think my odds are decent it'll be covered?

I can imagine no reason it wouldn't be.

[phate]

There's no harm in trying to get it covered.

[dead-zone]

https://www.youtube.com/watch?v=NsCb...eature=related

Most likely that is your issue. If that car feels to be running ok but have the knock, sounds like a rod knock.

Edit: It looks like @phate is right, as usual

[kabobulate]

My weekend is somewhat open. I'll PM you my number and come out to help with whatever you need. I would tow it and demod since you are under 60k. Don't give them an excuse to screw you. Not even a motor mount.

[silvapain]

If the only engine mods you have are intake/TIP and AP, stock out and take it to a dealer. I wouldn't run that engine any more personally; have it towed.

I agree with Clint, a noise that loud and muffled sounds like something deep down in the engine, and something big.

[bwagers]

If you need another set of hands this weekend I'm free to come up.

[BBartley]

I am not good at diagnosing issues but I have the garage open if you need some shelter.

[Z-Indy]

That sucks man. I don't have any additional input, these other guys are all way more knowledgable than me, but stocking out and towing it in sounds like the best plan.