Barksavon
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| posted on 26/4/10 at 08:03 PM |
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Engine Popping on Over Run....
My 2.0 Pinto is 'popping' on over run, or when i lift my foot off the accelerator. Its not backfiring or spitting back under load, is
there a remedy for this...i have been told its cos the exhaust is so short it sucks air in on over run (Its a Tiger avon) Thanks
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RichardK
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| posted on 26/4/10 at 08:04 PM |
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I would check ign timing first!
Cheers
Rich
Gallery updated 11/01/2011
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Danozeman
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| posted on 26/4/10 at 08:05 PM |
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are leak in exhaust system??
Id leave it though sounds nice!!
Dan
Built the purple peril!! Let the modifications begin!!
http://www.eastangliankitcars.co.uk
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DRC INDY 7
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| posted on 26/4/10 at 08:10 PM |
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might be running weak mine used to do this till i set the carbs up
https://www.facebook.com/groups/462610273778799/
Puddle Dodgers Club
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flak monkey
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| posted on 26/4/10 at 08:25 PM |
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Its just simply running lean on the overrun nothing more, nothing less.
Basically fuel is cut on the overrun which means it never fully burns in the combustion chamber and a lot gets pushed into the exhaust. Eventually
enough builds up to ignite from the hot exhaust and it pops.
Too much can be annoying, a little is nice though.
If you have mappable injection you can adjust the effect quite easily from no popping, a little burble up to spitting flames and all sorts 
Sera
http://www.motosera.com
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Barksavon
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| posted on 26/4/10 at 08:51 PM |
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Thanks. I aint got mappable injection, the cars on Twin 40DHLA's with electronic dizzy, it is popping a bit excessive so if i can cut it down a
bit would be ggod,i might have a tinker, thinking about megajolt over the winter can it be reduced with a suitable map for this system?
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Werner Van Loock
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| posted on 26/4/10 at 09:10 PM |
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dont bother, i've got a 4age with twin dellorto and megajolt and its also popping and banging all over the place, sounds more like a WRC
rallycar with ALS (anti lag system)
last time i went to the petrol station i switched off the engine and then a loud bang, people jumped
http://www.clubstylus.be
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iscmatt
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| posted on 26/4/10 at 09:16 PM |
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quote:
Originally posted by Werner Van Loock
last time i went to the petrol station i switched off the engine and then a loud bang, people jumped
I'm on a pinto with bike carbs and get a lot of popping too. I love it when that happens in petrol stations!! 
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Dave Ashurst
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| posted on 26/4/10 at 09:22 PM |
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You might still want to check for air leaks in the exhaust system though 
My crossflow (twin dcoe's, electronic dizzy) pops and bangs like that whenever there's an air leak in the upstream end. Loose manifold
nut, delaminated gasket, loose fit between sections or a cracked weld for example.
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coozer
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| posted on 26/4/10 at 09:26 PM |
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Hmm, I love a bit of low banging in the exhaust..
I have slightly better/worse situation whereby coming off the throttle to change up when accelerating, the thing backfires when I push the pedal again
then takes off!.
1972 V8 Jago
1980 Z750
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Dangle_kt
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| posted on 26/4/10 at 09:36 PM |
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Worth checking your not running seriously lean though, that's how you hole a piston.
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ashg
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| posted on 26/4/10 at 09:46 PM |
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mine pops a little on overrun i know its setup spot on as it was done on a proper rolling road. if your mpg is ok and its pulling fine then i
wouldn't fiddle with it. best bet is to take it to a rr and just pay to have it checked. shouldn't cost too much and they may be able to
eek a bit more out of it.
Anything With Tits or Wheels Will cost you MONEY!!
Haynes Roadster (Finished)
Exocet (Finished & Sold)
New Project (Started)
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bi22le
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| posted on 26/4/10 at 10:09 PM |
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i want my car to pop, just a little to put a huge grin on my face. My car has been meticulously set up though so it just sounds nice and goes like
stink!
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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