Stutter on boost :/

[stevenc8084]

Hey, my evo has a stutter moment when on boost. Its at around 4 - 5000 rpm. It jerks violently hard, just changed the plugs as a starter, BPR8ES, didn't adjust the gap as I don't have the tools. Is the standard gap fine? Its a evo 6, probably around 300 BHP. Still doing the stutter after the plug change, plug leads next?

 

[mattyb26]

Gaps should be ok they ain't usually that far out

 

[Mikeyc]

Doesn't sound like plugs to me mate, when you say violently? Lol how violently

 

[stevenc8084]

Its a hard jerk which throws you forward, I then come off the boost at that point......

 

[Mikeyc]

Throws you forward? Yeah look at the mounts first to see if the engine is moving, do you know if the jerk is coming from the movement of the engine which then throws you causing you to come off the throttle or is it actually the engine itself

 

[stevenc8084]

Yeah throws you forward, I would say its the engine itself as the boost is building to its peak

 

[Aidy]

Hey, my evo has a stutter moment when on boost. Its at around 4 - 5000 rpm. It jerks violently hard, just changed the plugs as a starter, BPR8ES, didn't adjust the gap as I don't have the tools. Is the standard gap fine? Its a evo 6, probably around 300 BHP. Still doing the stutter after the plug change, plug leads next?

Sounds more like a fuel cut. Are you using the standard actuator? They don't last very long on VIs due to there being no protection from the elements. Do you have a boost gauge fitted?

 

[stevenc8084]

I think its standard, only had the car a few days, previous owner didn't mention anything. And yeah there a boost gauge its a cheapie though. Its got a electronic boost controller too, can this have an effect?

 

[Aidy]

What does the boost go up to when it happens? Is it about 1.2/1.3?

 

[stevenc8084]

No idea, won't be able update a figure till the morning too. I will update soon as, and il check the mounts but it definitely feels like a boost problem with the engine.

 

[stevenc8084]

Ok, boost goes to 15 psi according to the gauge, holds there once spooled up but that's when the kick back comes in. Any ideas? Seems to be running a touch better since changed plugs.

 

[deanmac]

I thought plug gaps should be about 0.55mm which is a lot smaller than they normally come set.

I put new plugs in the other day and had to close gap quite a lot.

 

[Aidy]

Ok, boost goes to 15 psi according to the gauge, holds there once spooled up but that's when the kick back comes in. Any ideas? Seems to be running a touch better since changed plugs.

It's not likely to be fuel cut at that boost. You really have to start with the basics and get the spark gaps checked, as even being fractionally out can cause stuttering under boost.

 

[stevenc8084]

Ok, the gauge showed it spool up to 15 psi peak, where it then threw in its problem. It does seem to run a little better after the plug change though. Any ideas???

 

[stevenc8084]

Sorry, written that twice :/ ok I will try and get a exact gap with the plugs. Will update soon, thank you for the input guys.

 

[Chris@epp]

Might be worth finding a mapper/geekmapper and having them log when it happens.

Is it on WOT, or are you slightly off WOT? Is it 3rd and 4th gear?

Where abouts are you - I am sure there will be someone around who can give you a hand.

 

[stevenc8084]

Iv ordered myself a spark plug gap adjuster. Il start with the 0.55mm as stated, as I have read most have set at this. Fingers crossed, if not then I may seek a mapper. Does it in 2nd and 3rd, not really took it through the other gears as not been on any long enough roads. I'm from Rotherham. As i say its much better since the plug change so im hoping closing the gap up on the plugs may fix this, its a big hope lol. Will update when i have tried this, thanks guys.

 

[Simon@NTS]

Hi mate I can have a look at this for you as I'm just down the road

 

[DDS789]

Hi mate I can have a look at this for you as I'm just down the road

Get yourself to Si mate, he'll have it sorted in no time

 

[xiii]

Apologies to the op but it sounds like my e8 although mine isnt violent and it only sometimes flutters on boost. i thought it was a crappy dv. il check my plug gaps tomorrow. cheers for the tip.