The exhaust on my car keep on poofing noises at idle. I advanced my timing to 5 degrees before top dead center because it was off by 10 degrees and now the problem has only gotten worse. The engine does'nt feel like it is misfiring because it idles steady as a rock. Could I have an exhaust leak that could be causing this? Tried adjusting the carburetor but it did'nt help any.Open for suggestons.

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

It'll have to be a pretty big leak to poof, usually small leaks are more of a tick or click in my experience.

Have someone bunch up a rag and hold it against the tailpipe to choke it off, if its an exuast leak it will build pressure pretty quickly and make the leak more evident. Then start inspecting from the manifold backwards by ear, or a mechanics stethoscope.

Poofing noises at idle, when you're listening at the tailpipe, are due to engine misfire, not exhaust leaks. The engine mounts will absorb a fair amount of misfire-induced unsteadiness, and you can't always see misfires by watching the engine. Misfires are bad; they waste gasoline and cause pollution, so it's good that you're starting in on looking for the cause.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Sounds like a burnt exhaust valve. One will cause the "poofing" sound you discribe. Hold a rag flat against the exhaust pipe. If the rag tries to suck up into the pipe when the poof happens, than its a burnt valve. Could also be a valve or two adjusted to tight.

Good one!

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

Well...it kind of depends on what kind of poofing noise we're talking about. If it's rhythmic (exhaust sounds like "Pluff-Pluff-Pluff-Pluff-Pluff-Pluff"), then yes, it's likely that one or more cylinders aren't firing. A cylinder may refuse to fire because of a burned or too-tight-adjusted exhaust valve, a pushrod fallen out of its rocker, a faulty spark plug, or spark not reaching that plug, a serious single-cylinder vacuum leak, or a few other reasons.

But, if the poofing is random/irregular and the exhaust sounds like this:

mmmmmmmmPluffmmmmmmmPluffmmmPluffmmmmmmPluffPluffmmmmmmmmmmmmPluffmmmmm

then it's a misfire due to a smaller/cylinder-nonspecific vacuum leak, an ignition or carburetion problem, or other state-of-tune issues.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

My exhaust noises sound like the second description Dan


mmmmmpoofmmmmmmmmpoofmmmpoofpoofmmmmmmmm

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

i love listening "reading" you guys make exhaust noises, I can hear it perfectly in my mind too. You just have to use a larger text size for that dang flowmaster I have on there.

Yes Jeb, I left some rubber behind (I knew you'd ask)

MJ

So Lancerman, how do you like your Flowmaster? I put a thrush turbo on my truck and it is quieter than the stock muffler!

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

OK, then you've got some misfiring going on...time for some systematic diagnosis!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

if it sounds mmmprrrrrtmmmmmpooofmmmmmgrrrfffrrrrtttttrtrrrtmmmm

is time to ease on the beans

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

This thread reminds me of that comedy sketch "Car Noises" by the Frantics....


Jeeez...

I had that same sound you describe, a proper valve lash took care of it, but in your case it might be something else too....



-D.Idiot

Fixed it. Carb was set too lean

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

Wow, thats what my 74 Dart Swinger sounds like...it's kinda eerie to see it spelled out like that...

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We have enough youth, how about a fountain of smart?

BlortaBlortatatatataBlortaBlortatatatata - ignition probs + misfire on Freeflow sytem> or is it the dang beans again

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Regards,
Fanie Gerber
It's never junk, it's just a part you're not currently using

http://www.valiant50.co.za
Just say I own a few Mopars