Changes have made the exhaust pop/bang on start up

[Golflion]

4.0HC.....Had the full ACT induction kit,ACT superflare carbon fibre trumpets and SC Power plenum spacer recently fitted,already had sleeved exhaust.

On a couple of occassions now, there is a loud pop/bang from the exhaust when i first try to start her up??

Any ideas why please

[pjac67]

and your problem is ....?

[SILICONEKID340HP]

That is fuel which as not been combusted.pops and bangs..i can do that with megasquirt but mine is turned off on over run..

Edited by SILICONEKID340HP on Monday 27th June 23:30

[Alexdaredevilz]

Sounds like a air leak some where........

[900T-R]

Alexdaredevilz said:

Sounds like a air leak some where........

I'd say so - how's idling/driving?

[450Nick]

More likely a blowing exhaust joint I'd say. Manifold end probably.. Check the gaskets by running it and putting one end of a piece of hose by your ear and moving the other around the engine bay

[spend]

Cold start or hot start?

Have you checked the ignition advance so that you are definitely getting sparks at the right times under suitable conditions?

[Alexdaredevilz]

spend said:

Cold start or hot start?

Have you checked the ignition advance so that you are definitely getting sparks at the right times under suitable conditions?

Stop watch and protractor?

[neal1980]

SILICONEKID340HP said:

That is fuel which as not been combusted.pops and bangs..i can do that with megasquirt but mine is turned off on over run..

Edited by SILICONEKID340HP on Monday 27th June 23:30

Good job with your fuel consumption

[450Nick]

SILICONEKID340HP said:

That is fuel which as not been combusted.pops and bangs..i can do that with megasquirt but mine is turned off on over run..

Edited by SILICONEKID340HP on Monday 27th June 23:30

Yes but you can have plenty of fuel in your exhaust and not have any pops and bangs (running rich). What you need in addition is spare oxygen and a spark to ignite the mixture. A leak in the exhaust or induction will allow extra air into the system which gives the oxygen, then a bit of flame coming out of the exhaust port can ignite it (if you delay the spark until late in the cycle on overrun then you're more likely to achieve this) - as you do on the MS. So either your spark's off, or you've got an air leak somewhere I'd say..

[Golflion]

Idles and driving is fine although the engine/exhaust seems a lot more raspy for want of a better word.

When you say air leak,just had the manifold gaskets done,could it be from the plen
um or hose connection?
Only does it when its been stood for a while?

Edited by Golflion on Tuesday 28th June 14:10

[Golflion]

Golflion said:

Idles and driving is fine although the engine/exhaust seems a lot more raspy for want of a better word.

When you say air leak,just had the manifold gaskets done,could it be from the plen
um or hose connection?
Only does it when its been stood for a while?

UPDATE
Sat at traffic lights today after running for a while,idling fine but then small pops then loud pop from exhaust,then back to idling fine

Edited by Golflion on Tuesday 28th June 14:10