I recently got my car tuned. running 24 psi. Sometimes when i get on it the car feels like it cuts out for a split second. maybe leak a from stock bov? boost holds though. only happens once in a while. is this knock?

 

I doubt it. I don't think you can really feel knock like that. Knock is usually identified when you log the car.

 

you can feel the car pull timing as the ECU reacts to the knock.

I would talk to your tuner. could be knock, cold be a slipping clutch. I would def get it checked out.

 

Sounds like misfire/spark blow out to me.

 

Thanks. What spark plug gap should we run. I bought somew NGK 1 step colder plugs they said it came pre gapped. Could the clutch slip fell like that? It feels like a sudden loss of power for a split second. Wierd?

 

.024 is the gap I used and I believe that is the recommendation for most Evo spark plugs used.

Hope this helps.

 

Aren't the NGK ones pre gapped to over .030? That could be your issue.

Doubt what you are experiencing is knock, you can feel timing being pulled but the car does not hesitate.

 

Even if plugs are pregapped it's a good idea to double check, you can never be too sure.

 

Do you have a boost gauge? I bet your blowing spark out.

 

At 24lbs. blowing out the spark on stock plugs?? I'd put my money on just a hiccup in the tuning or something. Where and when is this occurring during your pull? Post some specifics so it narrows it down a bit.

 

It happens when i'm about 6k in over. I have a STOCK BOOST GAUGE RIGHT NOW. IT HAPPENS SO FAST THAT I HAVE NO TIME TO LOOK AT THE GAUGE TO SEE IF IT IS A SUDDEN BOOST LEAK. DOES STOCK BOV NEED TO BE CHANGE OR CRUSHED? KEEP IM MIND THIS HAPPENS MAYBE ONCE OUT OF 15 - 20 PULLS. tHANKS FOR ALL THE INPUT!

 

do you have a way to log the car? if it happens one out of 15 or 20 pulls then you could be "feeling" timing being pulled if the car knocks enough. I mean the information your giving isn't much help - you need to get some data so I would suggest going back to who tuned the car and explain what is happening. Unless you have the capabilities of logging the occurrence with a 1.3/2.0 cable and evoscan / mitsulogger.

 

Sounds like detonation. Check plugs, check AFR. It's not a clutch or a leaky CBV, both of which are steady-state failures and will not cause jerking motions.

 

My guesses are, in order: Boost leak, knock/detonation, tune. I doubt its blowing out spark.

 

Thanks guys. just to check the plugs to be sure. what would i need to look for?