exhaust crackle on deceleration

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9c1vs
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exhaust crackle on deceleration

Post by 9c1vs »

I am wondering how to get rid of the exhaust crackle on deceleration. I am running a12p tune for the nv ram. I have decel cut enabled and wish to keep this on. I have put more timing in and this has helped. Should I just keep putting more timing in whilst on decel cut or is there something else I should do.

I don't mind the sound but I think it is excessive and I am worried it might damage the cats?


Cheers.
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Re: exhaust crackle on deceleration

Post by jenko »

you more than likely have an air leak in the exhaust close to the heads or merge. other possible cause is poorly insulated ht leads,
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Re: exhaust crackle on deceleration

Post by antus »

If its not an air leak then there is an decelleration enleanment multiplier table you can make it pull out more fuel there.
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Re: exhaust crackle on deceleration

Post by 9c1vs »

I think there might be a cracked weld somewhere on the extractor, as its making a destinct ticking sound when I accelerate. However, it doesn't do it with my other ecu. As for fyel multiplier, does that mean it could be putting a bit too much fuel before the decel cut turns on?

Also is it bad for the cats? Keeping in mind in the vs they are way back underneath the driver and passenger seats!
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Re: exhaust crackle on deceleration

Post by delcowizzid »

is the PPK setup for vr/vs pulses in the tune so it reads the correct speed if it doesnt get the right speed reading it may never hit the decell enleanment or decel fuel cut
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Re: exhaust crackle on deceleration

Post by 9c1vs »

delcowizzid wrote:is the PPK setup for vr/vs pulses in the tune so it reads the correct speed if it doesnt get the right speed reading it may never hit the decell enleanment or decel fuel cut
Havn't checked ppk, I would assume it is correct as I have only modded than standard vs tune on the mv ram. Either way i think decel cut is working as I watch the wideband go full lean.
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Re: exhaust crackle on deceleration

Post by vlad01 »

9c1vs wrote:I think there might be a cracked weld somewhere on the extractor, as its making a destinct ticking sound when I accelerate. However, it doesn't do it with my other ecu. As for fyel multiplier, does that mean it could be putting a bit too much fuel before the decel cut turns on?

Also is it bad for the cats? Keeping in mind in the vs they are way back underneath the driver and passenger seats!
don't think so, My Vp crackles all the time, even between gears sometimes.

Cat still good as new. And thats a ceramic factory one.
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Re: exhaust crackle on deceleration

Post by antus »

The ae and de (accel enrichment and decel enleanment) consist of 2 tables each to know about. One controls milliseconds of injector ms to add/remove when active and one is a multiplier to get the final value. The shapes of the first tables are about right for all applications so to make it add more fuel on ae or remove more fuel on de then the multiplier tabls are the ones I adjust.
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Re: exhaust crackle on deceleration

Post by vlad01 »

whats the AE multiplier called? or is it just that?

Can't recall seeing it when I looked for it the other day. I need to add some as I get a lean spike when I jam the throttle open as fast as I can.
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Re: exhaust crackle on deceleration

Post by VX L67 Getrag »

in most definitions it's called transient - AE Multiplier Vs Engine RPM Table, but it all depends on the definition!

If you have tunerpro open & then press CTRL/F together & search for any of the above mentioned terms you should find it!
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