1969 camaro Z28 backfiring

[wisemanz28]

What would cause my 69 Camaro Z28 to backfire? First time it happened when I was starting the car and today it happened when I was accelerating on the highway. The car is backfiring thru the exhaust
.

[69VN]

*Source Wikipedia: Exhaust system backfires occur in engines that have an emission system malfunction, like an air injection system diverter valve problem, or an exhaust leak. In some high-performance vehicles, when a driver shifts up and lets off the accelerator, the engine has a moment of running rich. This causes an incomplete burn which causes the fumes to explode in the exhaust system along with an audible pop or bang sound. This is a result of working equipment, and is unlikely to cause damage. Also, poor or unregulated engine timing is often a cause of intake backfires, but can also be responsible for exhaust backfires. Improper wiring in the ignition can also lead to timing issues and backfires. Low fuel pressure, clogged fuel filters, and weak fuel pumps could cause a severe lean air-to-fuel ratio during fuel injection. Hope this helps.

Sal <<GRAEMLIN_URL>>/biggthumpup.gif

[Dicky]

I was taught that &quot;After fire&quot; was out the exhaust and
&quot;Back fire&quot; was out the intake...

Just a nomenclature FYI

If it is consistent could be ign. timing. <<GRAEMLIN_URL>>/dunno.gif <<GRAEMLIN_URL>>/dunno.gif

DH <<GRAEMLIN_URL>>/flag.gif

[m22mike]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dicky</div><div class="ubbcode-body">I was taught that &quot;After fire&quot; was out the exhaust and
&quot;Back fire&quot; was out the intake...

Just a nomenclature FYI

If it is consistent could be ign. timing. <<GRAEMLIN_URL>>/dunno.gif <<GRAEMLIN_URL>>/dunno.gif

DH <<GRAEMLIN_URL>>/flag.gif </div></div>

Thank you, The way I learned it too.... <<GRAEMLIN_URL>>/grin.gif

[napa68]

Sounds like the points and or condenser may have s#it the bed if it came out of nowhere.

[wisemanz28]

The car also backfired last week when I started it.

[PeteLeathersac]

A few more thoughts;
Bad fuel, failing coil, intake leak?
Good luck!
<<GRAEMLIN_URL>>/beers.gif
~ Pete

[Plowman]

One or more bad or open spark plug wire,sound's like one bad plug wire for now.

[Mr.Nickey Nova]

Hope you don't have a worn camshaft...

[firstgenaddict]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mr.Nickey Nova</div><div class="ubbcode-body">Hope you don't have a worn camshaft... </div></div>
X2
I assume it is a flat tappet cam, how many miles does the cam have on it?

[Plowman]

Pull the distributor cap off and check for tracking.

[al8apex]

it is a bad condensor in the distributor

[Salvatore]

I would start with:
a plug change
check wires for any arching or wrong firing order
check point dwell
check timing.
may just be a simple plug change.

[wisemanz28]

the cam has under 30,000 miles on it.

[scuncio]

Does the car have the original smog system? I was getting a lean backfire on my old 69 Z until I gutted the original pump.