Engine stumbles... can this be tuned out?
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Engine stumbles... can this be tuned out?
When I am accelerating hard and abruptly lift the throttle - like when someone cuts you off... my evo bucks/stumbles a fair bit.
Some of can be alleviated by lifting less abruptly, but can some of this be dialed out with ecuflash?
Some of can be alleviated by lifting less abruptly, but can some of this be dialed out with ecuflash?
what type of bov are you running? What type of air intake are you running?
These are usually the culprits. Aftermarket tube style intakes with a cone filter and VTA bov's are the major cause of the typical stumbles. There are a couple people working diligently to help cure these issues using ecuflash, but their not quite there yet.
These are usually the culprits. Aftermarket tube style intakes with a cone filter and VTA bov's are the major cause of the typical stumbles. There are a couple people working diligently to help cure these issues using ecuflash, but their not quite there yet.
I think I know what you mean It happened to me after I got my flash because I got more power. When I drive it fairly hard then suddenly let go of the gas, it kicks for like a second because its no longer pulling so hard. It has nothing to do with the tune if thats what you mean.
So Mitsu MR BOV and K&N Filter? 
Have you got your 720cc injectors all dialed in via fuel trims etc? How bad is the stumble?
This is usually caused be a overly abrupt change in fueling between WOT --> mid --> low load. Like what you would do while feathering the throttle in a turn or letting off quickly. Check your fuel cells in those transitional areas in the fuel maps.
A load bearing steady state dyno would work well here.
Have you got your 720cc injectors all dialed in via fuel trims etc? How bad is the stumble?
This is usually caused be a overly abrupt change in fueling between WOT --> mid --> low load. Like what you would do while feathering the throttle in a turn or letting off quickly. Check your fuel cells in those transitional areas in the fuel maps.
A load bearing steady state dyno would work well here.
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From: Sacramento, CA
So Mitsu MR BOV and K&N Filter?
Have you got your 720cc injectors all dialed in via fuel trims etc? How bad is the stumble?
This is usually caused be a overly abrupt change in fueling between WOT --> mid --> low load. Like what you would do while feathering the throttle in a turn or letting off quickly. Check your fuel cells in those transitional areas in the fuel maps.
A load bearing steady state dyno would work well here.
Have you got your 720cc injectors all dialed in via fuel trims etc? How bad is the stumble?
This is usually caused be a overly abrupt change in fueling between WOT --> mid --> low load. Like what you would do while feathering the throttle in a turn or letting off quickly. Check your fuel cells in those transitional areas in the fuel maps.
A load bearing steady state dyno would work well here.
I disagree about the BOV thing. I have two ECUs wired up to my car on a switch, one is a stock ROM and the other is a ralliart ROM, and boy does it jutter badly between WOT and low load when using the ralliart ECU, and is perfectly smooth with the stock ECU.
I think Evo442 and razorlab are right, it is ALL in the tune... and I also think it is heavily to do with the fuel trims and fuel maps.
Anybody with ideas on what to tune with or without a dyno?
.
I think Evo442 and razorlab are right, it is ALL in the tune... and I also think it is heavily to do with the fuel trims and fuel maps.
Anybody with ideas on what to tune with or without a dyno?
.
Last edited by evo4mad; Jan 3, 2007 at 11:05 PM.
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