ditchlewis
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| posted on 30/12/07 at 09:57 AM |
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Back Fireing
I took the car out yesterday and it was back firing lik a machinegun
Im running a 2.1 pinto with twin 45 delorto's.
is the back firing because there is unburnt fuel being pumed into the exhaust?
i turned the mixture up and it ran alot better. i think it needs a good tune up.
the car only backfires under load and not when idleing.
what do you think lads?
ditch
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jos
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| posted on 30/12/07 at 11:09 AM |
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sounds like you just need to sort out the mixture
keep tweeking the screws until yu can get it to a professional or g decent equipment on it
backfiring wheb letting off the accelerator is pretty cool
.: Motorsport / motor racing circuit / track wall art Apex Traxs :.
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NeilP
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| posted on 30/12/07 at 11:32 AM |
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quote:
Originally posted by jos
backfiring wheb letting off the accelerator is pretty cool
Flames out of the exhaust when your next to someone at lights is even better!
If you pay peanuts...
Mentale, yar? Yar, mentale!
Drive it like you stole it!
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ditchlewis
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| posted on 30/12/07 at 12:59 PM |
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it sounded like a machine gun the local dogs were running for cover
i've used colour tune in the past but not with too much success. i'll jus have to get my brother in law (the ferrari mechanic) up to visit
and get him to look at it.
ditch
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flak monkey
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| posted on 30/12/07 at 02:00 PM |
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Is it backfiring (from the carbs?) or just shooting flames out of the exhaust?
If its spitting back out of the carbs a lot then you need more ignition advance.
If its shooting flames out of the exhaust then the mixture is too rich, probably on the main jets. However all tuned engines will pop and bang on the
over run to some extent but if its doing it under power then you really need to get it tweaked up.
David
Sera
http://www.motosera.com
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mookaloid
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| posted on 30/12/07 at 02:12 PM |
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more ignition advance required
"That thing you're thinking - it wont be that."
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britishtrident
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| posted on 30/12/07 at 02:53 PM |
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Assuming the float chambers are filling properly and the fuel is dry (ie no water) and that the carb mountings are correctly tightened.
First of all check the idle, main and pump jets are clean and the accelerator pumps are squirting.
Check the carb butterflys are synched
If nothing found it check the ignition centrafugal advance (if fitted) is working freeely.
If none of the above it sounds like your carb jets are too small.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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blakep82
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| posted on 30/12/07 at 03:13 PM |
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hmmm, how do you make flames come out the exhaust then?
________________________
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don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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ditchlewis
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| posted on 30/12/07 at 03:16 PM |
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it very rarely backfires throught the carbs.
the car coughs and splutters alot untill it's over 4K then it just flies
it's got a fast road cam, and sould put out 160 to 165bhp. the engine was built by vulcan engineering and was set up with K&N pan filters
which did not fit under the bonnet. i therefore swapped to carb socks, which will give me a problem.
does any one know a good tuner near ipswich?
ditch
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britishtrident
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| posted on 30/12/07 at 04:08 PM |
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Take one of the idle jets out and take note of the size code, sounds like you just need to go one or two sizes up.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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flak monkey
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| posted on 30/12/07 at 06:04 PM |
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Ditto what BT says. Is misfiring as its too lean in the progression phase (the point between the idle jets and the main jets). This part of the
mixture is still controlled by the idle jets in the DHLA and DCOE carbs.
You may find you either need to decrease the size of the air bleed or increase the fuel component. Depends what you currently have.
David
Sera
http://www.motosera.com
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