Author Topic: Kickdown pop  (Read 820 times)

Offline na79

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Kickdown pop
« on: October 05, 2017, 03:11:44 PM »
Hi All, I live in London, UK, and have a 74 SWB stepside pickup. It has a 350 motor and 350 trans. The engine has been modified with summit racing heads, an edelbrock intake manifold, Holley 4 barrel carb, straight through exhausts, high lift cams, etc. It is crazy fast. When I first got it the kickdown cable wasnt attached on the carb and it was driving pretty great. Just had a load of work done on it, and one thing was to reattach the kickdown. After full service and a bunch of work it drives even better, BUT, if I floor it the engine/exhaust/cant really tell, makes a popping sound and hesitates slightly. Any ideas why, what is causing it, and what the solution might be?

Thanks, Nick

Offline bd

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Re: Kickdown pop
« Reply #1 on: October 05, 2017, 04:34:59 PM »
You need to determine from where the "popping" originates - exhaust or carburetor.  Does it pop-pop-pop-pop with full throttle or just once?  Until you can be more specific, symptoms could originate from ignition breakdown, lean fuel delivery, or low cam lobe, etc.
Rich
It's difficult to know just how much you don't know, until you know it....
In other words... if people learn by making mistakes, by now I should know just about everything!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline VileZambonie

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Re: Kickdown pop
« Reply #2 on: October 05, 2017, 05:42:19 PM »
and if you aren't running mufflers this is to be expected the way it sounds you are setup
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Offline na79

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Re: Kickdown pop
« Reply #3 on: October 06, 2017, 06:51:16 AM »
Update! Its not kickdown related, disconnected it and still did the same thing. Also, its not a regular occurrence, it happens randomly. Its definitely a pop, coming from the carb, adjusted fuel I to carb and that looks healthy, do you think it could be ignition? And if so, anything in particular to look out for?

Offline VileZambonie

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Re: Kickdown pop
« Reply #4 on: October 06, 2017, 12:06:49 PM »
If it's popping through the carb check your ignition system, check for vacuum leaks, check for anything that would cause a lean condition, fuel restrictions etc. Next check valve adjustment and for camshaft/lifter wear.
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