G37 - pinging - pre-ignition

[Morris Minor]

Coming up to 100,000 miles and the engine is knocking under mid-intensity acceleration. I hear it around 2,500-3,500 RPM - sort of random & rattly. I'm guessing it's carbon deposits. But who knows. Bollocks. I'll call the excellent mechanic who looks after it for me. 

[Eye of the Tiger]

Can be difficult to diag these things.
Load the parts cannon with new spark plugs, premium gas, and fuel system/intake cleaners.

[Eye of the Tiger]

Question: does it burn oil?

[Morris Minor]

Question: does it burn oil?

Barely any. Maybe a few ounces once between changes. 

[Laconian]

Is the check engine light turning on at all? I'm kind of surprised there is any knocking. I thought that all recent-ish cars used knock sensors.

[Morris Minor]

Is the check engine light turning on at all? I'm kind of surprised there is any knocking. I thought that all recent-ish cars used knock sensors.

No check engine light. Maybe there is something actually rattling. I'm not going to spend serious money on a 13 year-old car.

[FoMoJo]

Might be worth a diagnosis by your guy.  He can likely check the interior of the combustion chambers with a flexible tiny camera.

[GoCougs]

Is the check engine light turning on at all? I'm kind of surprised there is any knocking. I thought that all recent-ish cars used knock sensors.

Knock has to happen before it can be mitigated. If the knocking starts and then tapers off, it probably is predetonation. If the knocking starts but does not taper off, it could be external (heat shield, cats, etc.).

Could it be the gas? Lots of power, 11:1 compression ratio, 7,600 RPM and port FI (no DI) = VQ37VHR is very sensitive to octane I found. Even the manual says anything less than 91 octane is for emergencies only.

[Submariner2]

Coming up to 100,000 miles and the engine is knocking under mid-intensity acceleration. I hear it around 2,500-3,500 RPM - sort of random & rattly. I'm guessing it's carbon deposits. But who knows. Bollocks. I'll call the excellent mechanic who looks after it for me.

A friend of mine swears by SeaFoam, in particular the kind you inject directly into the intake while the motor is running (just be sure to do so down stream of the Mass AirFlow Sensor!) to clear carbon deposits.  Might be worth looking into.

[Laconian]

A friend of mine swears by SeaFoam, in particular the kind you inject directly into the intake while the motor is running (just be sure to do so down stream of the Mass AirFlow Sensor!) to clear carbon deposits.  Might be worth looking into.

The warning label on that shit is amazing.

[Submariner2]

The warning label on that shit is amazing.

DON'T LET THE STRAW BECOME INGESTED INTO THE INTAKE!!!!

[r0tor]

I'd start with new spark plugs if they haven't been done

[Laconian]

DON'T LET THE STRAW BECOME INGESTED INTO THE INTAKE!!!!

This Will Give You Cancer. Contains: Cancer

[Rich]

Why didn't they just name it cancer? 

The name Sounds like some sunblock lotion. Just rub it all over

[CaminoRacer]

I should probably SeaFoam the El Camino. I put some water mist down the carb a few years ago but I don't think that was enough to clean the valves. Still getting hot spots.

[Eye of the Tiger]

This Will Give You Cancer. Contains: Cancer

kek

[Eye of the Tiger]

I should probably SeaFoam the El Camino. I put some water mist down the carb a few years ago but I don't think that was enough to clean the valves. Still getting hot spots.

Naw. Berryman B12 >>>>> Seacucumberfoam

[CaminoRacer]

Naw. Berryman B12 >>>>> Seacucumberfoam

I didn't realize engines need B vitamins. Should I also find some vitamin C so it doesn't get scurvy?

[FoMoJo]

I should probably SeaFoam the El Camino. I put some water mist down the carb a few years ago but I don't think that was enough to clean the valves. Still getting hot spots.

"Italian Tune-up" works all the time.

[Eye of the Tiger]

I didn't realize engines need B vitamins. Should I also find some vitamin C so it doesn't get scurvy?

yea, or just eat better gasoline

[CaminoRacer]

yea, or just eat better gasoline

I put 100 octane in it once. $10/gallon. The pump meter rose so fast...

[Eye of the Tiger]

I put 100 octane in it once. $10/gallon. The pump meter rose so fast...

The meter always rises fast, tho

[CaminoRacer]

The meter always rises fast, tho

I stopped at 5 gallons because I couldn't stomach a full 12-15 gallons ($120-150)

[FoMoJo]

I put 100 octane in it once. $10/gallon. The pump meter rose so fast...

Did it run any better?

[CaminoRacer]

Did it run any better?

Yep. 91 is the max at regular pumps here but it really likes 93 better and if 95 was available it would be even better/safer. I mixed the 100 with 91 so it was around 95.

10.5-11 compression with a carb needs a bit more octane than a modern engine

[giant_mtb]

Rod knock.

[Morris Minor]

I didn't realize engines need B vitamins. Should I also find some vitamin C so it doesn't get scurvy?

Best practice is to remove spark plugs and squeeze the juice of ½ lime into each cylinder. Do this every 10,000 miles.

[Eye of the Tiger]

[Submariner2]

This Will Give You Cancer. Contains: Cancer

PROPOSITION 65 WARNING:  This cancer is known to the state of California to cause cancer.

[Eye of the Tiger]

PROPOSITION 65 WARNING:  This cancer is known to the state of California to cause cancer.

PROPOSITION 66 WARNING: This California is known to the state of California to cause California.