had a bad day yesterday

[s19243h]

my inspection machanic called me and said harrisburg failed my car for not having heat shields on my mufflers and the front turn signals being to small. the kicker is it has heat shields on the mufflers and two sets of turn signals on the front one set of ron francis gems in the fire wall and one set of rectangle ones on the grill shell. farther in the discussion he told me i need tt bring the car to him so he can take four color pics to send back in . apparently the knucle head sent in four black and white pics how stupid could he be! thats why they cant see anything black and white dont show nothing. back to the engine topic i took the car outside to take pics to send to him after taking the pics started the car up to put it back in the garage the choke was on so i burped the throttle to get the idle to come down and the idle dropped way lower than it ever did and the engine was really shaking i put the car in park and gave it a little rev and it sounded like shit and backfired through the exaust on the right bank i shut the car off and covered it up and said i dont even want to know shut the garage door and went home i hope i didnt break a valve spring or something worse ill pull the valve cover this weekend almost sounded like a crossed wire i dont know just had a real shitty day any ideas?

 

[Corley]

Glenn,
While it's VERY frustrating, DON'T PISS OFF THE INSPECTOR! He can easily decide that about 20 other things have to be addressed. Think of how far you have come and how long it's taken. Another day or two is not all that important, when you are so close to success. Good luck!
Corley

 

[Gerry]

Take a breath, relax and go back when you feel OK again. Easy to say I know but bad tempered attempts at fixing something normally costs me money
Gerry

 

[Wild Mango]

my inspection machanic called me and said harrisburg failed my car for not having heat shields on my mufflers and the front turn signals being to small. the kicker is it has heat shields on the mufflers and two sets of turn signals on the front one set of ron francis gems in the fire wall and one set of rectangle ones on the grill shell. farther in the discussion he told me i need tt bring the car to him so he can take four color pics to send back in . apparently the knucle head sent in four black and white pics how stupid could he be! thats why they cant see anything black and white dont show nothing. back to the engine topic i took the car outside to take pics to send to him after taking the pics started the car up to put it back in the garage the choke was on so i burped the throttle to get the idle to come down and the idle dropped way lower than it ever did and the engine was really shaking i put the car in park and gave it a little rev and it sounded like shit and backfired through the exaust on the right bank i shut the car off and covered it up and said i dont even want to know shut the garage door and went home i hope i didnt break a valve spring or something worse ill pull the valve cover this weekend almost sounded like a crossed wire i dont know just had a real shitty day any ideas?

The choke is there to kill the manifold vaccum while the engine is cold. Chokes usually have a linkage to speed the idle up when the choke is on/engine is cold. Sounds like when you fanned it it dropped onto the hot idle setting and she ran too slow. You may well find the choke is unecessary, and all you need is a hand throttle to set the idle higher when she's cold, and bring her back when she's hot.
Sounds like The Land of the Free has its share of bureaucrats as well, gotta grin and bear it, iffen they got something you need.

 

[s19243h]

sent color pics back to harrisburg waiting to see what happens popped number 8 spark plug by burping the throttle to get the choke off cam

 

[Screaming Metal]

The choke is there to kill the manifold vaccum while the engine is cold. Chokes usually have a linkage to speed the idle up when the choke is on/engine is cold. Sounds like when you fanned it it dropped onto the hot idle setting and she ran too slow. You may well find the choke is unecessary, and all you need is a hand throttle to set the idle higher when she's cold, and bring her back when she's hot.
Sounds like The Land of the Free has its share of bureaucrats as well, gotta grin and bear it, iffen they got something you need.

Mango is right!, it dropped to low too fast. If your motor is blown, you probably popped a blower gasket or a burst plate.....though most these days run a pop=off valve. They sound terrible when they pop off....
If normally aspirated....you might have popped your header gaskets. IF you have a Holley, kiss that powervalve goodbye! You'll have to change it.
What say you, Mike?

 

[Mike]

Well, I'm still trying to get my head wrapped around how manifold vacuum can be "killed" when a choke is set. Since a choke blade introduces an air intake restriction, manifold vacuum should actually improve slightly, shouldn't it? :nod: What happens when you have an engine with a hunt-n-seek vacuum leak idle and you cover the carb with your hand? You close off the largest source of air, manifold vacuum gets closer to where it needs to be and the idle straightens up.

Here's a practical experiment for you - remember those old, paper straws collapsing when you were trying to drink that thick milkshake? The shake provided enough flow restriction that you could create enough vacuum to collapse the straw. Can you create enough vacuum to collapse a larger diameter plastic straw?

Closing a choke merely allows the intake tract to be "wetted" with fuel, rather than trying to maintain something closer to a stoichiometric mixture. Opening a choke too soon can cause a lean backfire, so it certainly is a possibility this is what happened. And yes, if it has a Holley carb, it likely smoked the power valve, which could cause a ragged idle. If that is the case in this instance, the choke needs to be richened up a taste, so it can't pull off so soon.

 

[Ted Brown]

and the possibility of the accelerator pump not working as it should have... causing the back fire, and that can cause all sorts of problems...

 

[2old2fast]

I feel the need to throw this out there , to all you running a holley, for just a couple bucks, there's a power valve "blow out preventer" available. Only takes a few minutes to install, save yourselves alot of grief and look into these. I have them in my dual 450's , after 8 years and a "few" backfires, NO PROBLEMS !!!

P.S Mikes absolutely right, choke on , increase vac.


dave