Is it pre-ignition?

[Talus]

If there is pre-ignition under boost, would it be in the low rpm's? I have a hesetation or missfires right off idle under heavy load when it's hot out and the engine warms up, but I dont know what pre-ignition feels like so I dont know what it is.

[Danielson]

my car is doing this, my car doesnt have a turbo though. i have a A/F guage i noticed that it could be ur oxygen sensor or wire. my car hesitates and feels slugish but its just the wire that is loose on the sensor.

[crazycam31]

If there is pre-ignition under boost, would it be in the low rpm's? I have a hesetation or missfires right off idle under heavy load when it's hot out and the engine warms up, but I dont know what pre-ignition feels like so I dont know what it is.

Here is an article about Pre-ignition vs. Detonation. Its an interesting read. Hopefully this helps you locate and fix the problem.

[Skaterkid]

Check for arcing on your plug wires.

[gjcivic]

Here is an article about Pre-ignition vs. Detonation. Its an interesting read. Hopefully this helps you locate and fix the problem.

where?????????????????????? ;NutKick;

[john]

I'd suggest that neither pre-ignition or detonation will not occur under low load / low rpm / low boost.

Do you know these events are, and what causes them?

Take a look here (http://www.misterfixit.com/deton.htm) - it's an "ok" explanation.

[Talus]

I still dont understand much of this. Let me explain the full story:
I havnt been able to replicate the problem, but I have since raised the octane of my gas from about 89-90 to 92-93.
This only happened once on a hot day- it was friday when it was around 90 degrees and my engine temp was very high, and right when I would start out from a light, the car would missfire and there would be an extreme loss of power. This happened under moderate/heavy throttle application from around 1500 to 2200 rpm. If I used less throttle (kept it out of boost), or if I went full throttle at an rpm greater than around 2,500, there was no problem. I dont know what psi it was at, but max boost is supposed to be around 6-7 psi. This is on a supercharged VW 2.0

So I am still wondering if knock/pre-ignition/detenation/whatever would happen in low rpm/heavy load.

[john]

Engine(coolant) temp was higher than 'normal'? Is your ECU storing any error codes? Are your plugs burnt?

You could be experiencing detonation if there's a fuel delivery problem in that RPM range.

[HONDA GHANDI]

From what you are describing it sounds more like a loss of good spark. It may not be as serious as detonation/preignition and may be as simple as incorrect plug gap or a failing plug or wire. (or coilpack)

[Talus]

Thanks, I havnt had the problem anymore, but if it does, I will look at spark, or if there is enough fuel. I should get a dyno soon.