Can a exhaust leak by the manifold cause a misfire?

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Can a exhaust leak by the manifold cause a misfire?

Postby jamezz666 » Thu Aug 01, 2013 10:26 am

well guys had it for a while one very annouying misfire i'll explain everyone tells me to pull one lead off at a time and diagnose it that way but it doesnt work as imagen this is the engine running > run run run miss run run miss run run run run miss like that and i change plugs and just about everything even double checked timing ect and all i can think wouldit be my manifold? as where the exhaust manifold and the down pipe connect the one side of the join i could feel it leaking so i packed it with gum and it blew lil bits out and now it sounds like a flys fart so could a small exhaust leak cause something such like this?

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby jamezz666 » Thu Aug 01, 2013 10:30 am

also if you keep it in any gear at any revs resting you can feel it. the worse is leaving it in first and it misses like poop

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby c.turff » Thu Aug 01, 2013 12:22 pm

i dont know about causeing a missfire but it will fail an mot do my advice is to repair/replace the exhaust snd try it then.

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby rich_jc » Thu Aug 01, 2013 12:40 pm

Try looking at your points.

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby jamezz666 » Thu Aug 01, 2013 1:31 pm

its electronic ignition this is why its stunned me on what it could be :S

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby pbar » Thu Aug 01, 2013 1:55 pm

Have u tried replacing the electronic ignition with points, as a test?

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby c.turff » Thu Aug 01, 2013 4:21 pm

done a little reasearch and yes your misfire will be caused by your exhaust mabifold leak.

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby rich_jc » Thu Aug 01, 2013 4:24 pm

Which other parts have you replaced? Rotor arm and cap would be my next bet, though get your holy manifold sorted as well.

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby stevemarl » Thu Aug 01, 2013 5:38 pm

yes your misfire will be caused by your exhaust mabifold leak.


Always curious, how exactly?

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby fordperv » Thu Aug 01, 2013 7:39 pm

It may sound silly but check your valve clearences

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby jamezz666 » Thu Aug 01, 2013 10:15 pm

ok well next door I know the guy who runs a garage and he has an emissions tester and he checked the emissions to see if the carb is set up right and he said that's all fine and even he had a tinker and couldn't think of the problem as he checked everything I did and the dizzy looks fine and the cap and rotor arm even tried others and I have even tried 4 different sets of brand new plugs and no difference its even had 2 different sets of leads and I did ask the mechanic who I know about valve clearances and what I thought he said and that was if they was gapped more than they should they would be tappy which it isn't its quite and they aren't closed as he said you would have hell of more problems than you do. so its blew me, all I can think of is the manifold but im planning on soon to get a 4-2-1 manifold so il wait until then and hopefully that is the problem but it did always make me wonder how it could cause it to miss.

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby 340truck » Thu Aug 01, 2013 10:29 pm

c.turff wrote:done a little reasearch and yes your misfire will be caused by your exhaust mabifold leak.


What research tells you that ffs? How? :proof:
Image

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby rich_jc » Fri Aug 02, 2013 6:27 am

Sorry, so have you tried another cap and rotor? Nackered caps can "look" fine, but cause running issues.

I also had a horrible misfire once, turned out to be a grain of sand blocking my carb idle jet. This is the little brass screw at the base of the carb. Take it out and check the hole in the end is clear, blow out with an airline to make sure.

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby c.turff » Fri Aug 02, 2013 6:54 am

with the exhaust manifold blowing to the extent.ot is it can cause it to s"suck air" this can change the air fuel mixture in the engine. i know it sounds a bit out there but i recon thats the trouble. if our trucks at work blow an exjaust manifold gasget they will run like a bag of shit.

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby jamezz666 » Fri Aug 02, 2013 8:55 am

i tried a different rotor and cap i even tried my old points dizzy :/ but il get straight on to having a look at my carb and i thought about if the manifold could draw air in but i could only see it making a difference to modern engines as they have c02 sensors and also on youtube and i've done it my self in the past ran an engine without an exhaust what so ever it was just very loud without any missing or problems so i could only see it being something else. only if i lived close to some people off here :(

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby Major_Tom » Fri Aug 02, 2013 9:08 am

c.turff wrote:with the exhaust manifold blowing to the extent.ot is it can cause it to s"suck air"


During the battle of Ypres in WW1 the British planted hundreds of thousands of pounds of explosives underneath the German lines at Messines. At zero hour, when the explosives were detonated... nothing happened. Then the ground started to shake, like an earthquake, and then the whole of the Messines ridge just disappeared in a huge volcano of mud, killing thousands of enemy soldiers in seconds.

This thread has suddenly got like that moment of silence.
My car isn't stupid.... it's MENTAL.

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby jamezz666 » Fri Aug 02, 2013 9:20 am

oh god that just gave me the shits and giggles that bad in work i just had to get my old man to stop working to read that and even he did the same :P haha

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby rich_jc » Fri Aug 02, 2013 1:31 pm

Callum my friend, what you say is true, but only for cars blighted with an O2 sensor. Drawing in any air post MAF with screw around with mixtures and cause all sorts of running issues, but thankfully our beloved pinto engined cars need not worry about such issues.

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby jamezz666 » Fri Aug 02, 2013 3:39 pm

i thought it was the case. soooo it's got to be something else other than the manifold :/ hmmm i've checked the carb and it just leaves me to think that it can only be ignition side of things somewhere i must be missing something :s but it just doesn't make sense as it is not a constant miss miss miss miss just a run run miss run miss run run run miss and it just blows my mind on what it can be. and someone said am i sure its just not me thinking that there is but i've had 3 people drive my car and they noticed it straight away and even at stand still with the bonnet up

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Re: Can a exhaust leak by the manifold cause a misfire?

Postby rich_jc » Fri Aug 02, 2013 4:02 pm

Did you check the idle jet at the base? It could be worth getting some of those light up plug testers and seeing if it is only missing on one cylinder, or on random ones.

If it is just one, then the problem will be ignition or valve related;if on all, then it will be fuel related.

Also, I'm sure Dave mentioned, did you check in the inlet side of things for air leaks?

Rich


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