440 c.i. Charger starting help

[Texas97]

I didnt build the engine, so dont know the cam specs, but pretty aggressive. I have a QF 850 carb sitting on top with 4 corner idle, i have initial timing set at 18 and all in mechanical at 38. 5 speed TKX transmission. 13.5 inches of vac at idle. idle curb screw set at about 1000 rpm, high idle set to 1600 rpm.

recently, i installed a wagner PCV valve, set up per their instructions with vac gauge. and i had noticed when parked, the fuel levels in the window were ALL the way full and i think was contributing to a very rich running car and an off idle stumble (i had set those , so i adjusted the fuel level down to bottom of the sight glass, reset all of my 4 corner idle screws. now when running fuel level looks to be at the bottom 1/4 of the sight glass of the fuel bowls. these are the last two changes i have made and they were done about the same time, the fuel mixture was done first, then PCV.

Here is my problem: the car starts easily enough, initial rpms jump up to like 1200 when you hit the key, and then when it settles down on the initial start, its idling at like 650 rpms WAY too low, engine is shaking and struggling to stay running. If i start reving the throttle for 10-12 seconds, everything evens out and it idles fine at the normal 1000 rpm i have it set at (verified with timing light hooked up).

the car has an electric fuel pump with a regulator, and i have it set at 6.5 psi steady fuel pressure.

now, car starts no problem when warm, starts so fast, and idles great. its that initial fully cold start that is the problem.

1) Do I have the fuel supply in the bowls turned down too far? would that cause my initial idle issue? it runs great otherwise and it doesnt make my eyes water with fuel smell in the car anymore. do i need to raise the fuel bowl level a little at a time and see?

2) do i have a vacuum leak somewhere that i cant find? would a vacuum leak cause this?

3) is the wagner my issue that i dont have it tuned right on the idle screw? the idle screw goes in and out, i guess to control the air sucked through the crack case?


Thanks in advance for any help.

 

[Two Time Signet]

If you or a friend has a different known good (not an old dried out gummed up one) carburetor swap it out as a troubleshooting step.

Electric fuel pumps are great for fuel injection but I'd run a good mechanical for carbureted. Not saying this is your problem but advice several mopar mechanics I know give.

 

[Texas97]

If you or a friend has a different known good (not an old dried out gummed up one) carburetor swap it out as a troubleshooting step.

Electric fuel pumps are great for fuel injection but I'd run a good mechanical for carbureted. Not saying this is your problem but advice several mopar mechanics I know give.

i get it but, the electric fuel pump shouldnt have anything to do with this issue at all, especially with confirming i have the correct pressure at the inlet lines.

its a good idea on the carb swap.

i keep saying this, i have a full-on 6 pack set-up rebuilt, tuned-ish, (need to probably go ahead and swap the PV to a 6.5, currently has a 4.5) and just go that route. it's how i have wanted to go with this car for almost a year.

i just really wanted to get this carb fully dialed in so when i pull it, if i have any big issues with the 6 pack, i can pull it all off and install the 4 barrel set-up again.

 

[Aron Gleason]

Ive been trying to get my wagner pcv valve tuned correctly, the high idle you're experiencing could be from the valve which is a controlled air leak.

 

[PurpleBeeper]

Yeah, the first two things I thought were 1. Try a stock PCV valve & 2. make sure you have FRESH fuel that didn’t sit over the winter

 

[Texas97]

Ive been trying to get my wagner pcv valve tuned correctly, the high idle you're experiencing could be from the valve which is a controlled air leak.

high idle isnt anything of an issue. my carb has a high idle adjustment arm that kicks in when the choke is closed. SUPPOSED TO. and even if the high idle hasnt kicked in with the choke, the lowest it should be going is 1000 rpm where i have the curb idle screw set to.

i may need to go back and check the choke is closing on initial startup and go from there. maybe i accidentally adjusted the high idle too low after i changed the fuel bowl levels and the four corner idle.

 

[Texas97]

Yeah, the first two things I thought were 1. Try a stock PCV valve & 2. make sure you have FRESH fuel that didn’t sit over the winter

no issues with fuel sitting. i am in Texas, i drive this car year round. i have filled the car up twice in the last month or so, and added octane boost every other fill up.

 

[R413]

1 no
2 yes for sure
3 PCV is the same as a vacuum leak. Plug the PCV line and see what it does. Why do people buy this Wagner PCV? Just use one for a old mopar.


Just because you are building a hot rod doesn't mean you need the trick of the week part for every system. You spend countless hours, days, weeks, months fussing over these temperamental parts, do you wonder of the other guys are chasing their tails like you are?useless aftermarket junk?

 

[Texas97]

1 no
2 yes for sure
3 PCV is the same as a vacuum leak. Plug the PCV line and see what it does. Why do people buy this Wagner PCV? Just use one for a old mopar.


Just because you are building a hot rod doesn't mean you need the trick of the week part for every system. You spend countless hours, days, weeks, months fussing over these temperamental parts, do you wonder of the other guys are chasing their tails like you are?useless aftermarket junk?

i can agree to a certain extent. and the point is well taken. but i was trying to even out what i felt like was a wandering idle issue.

i will go back to a regular PCV valve ASAP.

 

[Bird 426]

I have the Wagner on two cars with no issues. Fuel level should be the same as your 6-pack, bottom of the sight hole. I would check the choke settings. Also sounds like some fuel pooling in the intake at start up. That's a double pumper right? You can dump a lot of fuel in at start with a pump and the engine is too cold to atomize it? Built engines can have their quirks! I stay down at 6 psi, but shouldn't be your problem.

 

[R413]

i can agree to a certain extent. and the point is well taken. but i was trying to even out what i felt like was a wandering idle issue.

i will go back to a regular PCV valve ASAP.

Yes, Just try it and see what it does for the idle.

 

[Doorkicker]

Silly question... slightly related to post #8...

Are guys running PCVs (Wagner or stock, etc.) because you have to for state emission inspections or for some other reason?

 

[Aron Gleason]

1 no
2 yes for sure
3 PCV is the same as a vacuum leak. Plug the PCV line and see what it does. Why do people buy this Wagner PCV? Just use one for a old mopar.


Just because you are building a hot rod doesn't mean you need the trick of the week part for every system. You spend countless hours, days, weeks, months fussing over these temperamental parts, do you wonder of the other guys are chasing their tails like you are?useless aftermarket junk?

For many reasons. 1 its supposed to help eliminate oil leaks, keeps the combustion chamber cleaner, better throttle response, keeps plugs cleaner. And can be tuned for idle and cruise. Can a stock pcv valve do all that? No it cant.

 

[PRHeads]

The QFT instructions show the correct float level is 1/2 way up the sight glass………with the engine running.

 

[Texas97]

The QFT instructions show the correct float level is 1/2 way up the sight glass………with the engine running.

and that was how i was running the engine. BUT, every engine is different and it resulted in the bowls being overfilled at times when the engine was off. i dont know why. but it seems to run better at the bottom of the sight glass.

 

[Aron Gleason]

and that was how i was running the engine. BUT, every engine is different and it resulted in the bowls being overfilled at times when the engine was off. i dont know why. but it seems to run better at the bottom of the sight glass.

Just a thought, but maybe the needle and seats are sticking or there could be junk in there causing the floats to overflow.

 

[Texas97]

Just a thought, but maybe the needle and seats are sticking or there could be junk in there causing the floats to overflow.

it would do it currently, with the floats lowered, if that was the case. but that is not the case.

 

[Bird 426]

When you get your Sixpack on, if you were to follow more than one set of instructions, they say bottom of the hole. The QFT is basically a modified Holly, not sure why the float levels would be different. I had rich conditions with high fuel pressure, 7.5, and high float bowl levels. I'll get out, way smarter people here than me.

 

[PRHeads]

I installed some replacement bowls that had the sight glasses on one of my carbs.
I took a measurement on the old style Holley bowl from the inside floor up to the bottom of the site plug hole, and compared that to the site glass bowl.

The bottom of the plug hole on the old bowl was about 1/2 way up the much larger diameter of the site glass.

As always……. Ymmv.

 

[Geoff 2]

The factory PCV has a limit to much minimum vacuum it will work with. When the vac is below the minimum, it opens & lets a LOT of air in. I would expect the PCV would work ok with 13.5" of vac. Is the vac reading accurate? Quick test to see if the PCV is working is to put your finger on it at idle. If you feel pulsation, it is not working.


And 18* of initial timing is NOWHERE near enough for an aggressive cam. Try this 5 min test: engine idling, timing still at ~ 18, slowly advance the dist until you get the highest rpm. Then check the timing; my prediction is 30-45* & that is what the engine WANTS for best idle quality, & tip in response. Giving the engine the correct idling timing will often fix an off idle stumble. One method to increase idle timing is to use vac adv connected to manifold vac.
Examples below.