Understanding headlight vacuum lines

[myk]

I'm just trying to make sure that I have the routing and lines correct in my head as I try to sort out my headlight door issues; I've been staring at the FSM page showing the routing but I need more detail.

From the headlight switch:
1. The top, yellow striped vacuum line goes to the top port on the door actuator, with a t-fitting to go to the passenger side.
2. The middle, green striped vacuum line goes to the vacuum canister.
3. The lower, unmarked striped vacuum line goes to the bottom port on the door actuator, with a t-fitting to go to the passenger side.

Now, I'm sure there's a second vacuum port on the canister, so that goes back to the engine for the vacuum source?  What if I wanted to bypass the vacuum canister; how would I go about doing that-just connect the two lines going into the canister together?  

I hooked up a vacuum pump to my headlight actuators to see if they work.  The left one goes up and down, but the right one won't go down-am I missing something here or could the actuator be damaged?  Thanks in advance guys...

[resq302]

Without confirming it by looking at y car, I am pretty sure you are correct.

[A383Wing]

actuator could have a hole in it....you can by-pass the canister, but you would have to have engine running to operate the headlight doors

[myk]

..............Question guys:

If there's a leak of some sort, anywhere in the headlight door vacuum system, be it in the lines, canister, actuators-wherever; could it affect the engine and/or the driveability of the car?

[A383Wing]

yes.....it's a vacuum leak...engines don't like those

[myk]

yes.....it's a vacuum leak...engines don't like those

My God man, are you serious?  I've had this hesitation/off-idle bog for the longest time now: http://www.dodgecharger.com/forum/index.php/topic,104129.0.html.

This afternoon, when I got the "bad news" about my headlight door system needing some work (leaking canister, bad lines, bad actuators, etc), I told them just to cap everything off and I'd deal with it later.  Well you know what, my decades long hesitation is about 90% GONE...

[Mopar Nut]

 

[myk]

Yup, spent the night driving the car all over town with dead headlight doors but a throttle response I haven't felt since I bought the car.  I never would've guessed it.  In any case, I probably won't fix the vacuum system; I've got an option for electric motors and I'd rather just have it that way...

[A383Wing]

well, now that you have capped of probably all of the vacuum leaks on yer engine, it's time to go back and re-adjust the carb correctly because before you had adjusted it to compensate for the extra air that was going into the engine when it was not supposed to

[myk]

well, now that you have capped of probably all of the vacuum leaks on yer engine, it's time to go back and re-adjust the carb correctly because before you had adjusted it to compensate for the extra air that was going into the engine when it was not supposed to

Right.  The car is probably running......too rich?  Will my timing need to be adjusted as well?  I know my idle speed dropped for some reason, unless the 'tech did that and didn't tell me about it...

[A383Wing]

yer timing should still be the same...yes, the idle probably would have dropped, and now it's probably running a little bit rich

[bull]

yes.....it's a vacuum leak...engines don't like those

My God man, are you serious? 

[myk]

yes.....it's a vacuum leak...engines don't like those

My God man, are you serious?  

Lol, man in all of these years I never thought the headlight door system could directly affect the engine.  I've sprayed so much 'carb cleaner around all of the usual vacuum leak sites trying to find leaks that I'm shocked there's any dirt in my engine bay at all.  I'm rejoicing that I don't have to walk the car off the line anymore and pray that I catch up to the Nissan Leaf that just blew me away.

Thanks a million guys!

[Bob T]

The sound of the penny dropping over here too Myk! 
It sounds similar to a dropoff in performance issue on my car, guess I'd better start checking perished vac lines, I did a few when I got it but not them all. The can doesn't hold enough charge to close them when the motor is shut down either.

[myk]

If I resurrect the vacuum system for the headlight doors I'm bypassing the can-I don't see how I need it, and it just represents another possible vacuum leak to contend with...

[Dino]

Nissan Leaf??  Okay, you need to install some cherry bombs so at least it sounds fast.   

Unless you're going to electric, you can't bypass the can as you need a reservoir for the system to work.  To be honest it's a very simple but effective system as is, but yeah there cannot be any leaks, in any vacuum system, anywhere. 

[myk]

I thought there were some guys in here that bypassed the can?    I need to go back and re-read those threads.  Nevertheless, eventually I'm going to have a motor system installed-it's just better with motors IMO...

[A383Wing]

If I resurrect the vacuum system for the headlight doors I'm bypassing the can-I don't see how I need it, and it just represents another possible vacuum leak to contend with...

if you want to by-pass the can, that's fine...just couple the 2 hoses off the can together....just remember, you will have to have the engine running to operate the headlight doors open & close

Bryan

[resq302]

I think the reservoir can was for two reasons.  First was to act as a buffer so the high vacuum demand wouldn't open / close the headlight doors too fast and cause a slamming action.  Secondly was to provide a reservoir to be able to close the headlight doors if the engine was shut off prior to turning the headlights off.

[A383Wing]

the can is gonna hold whatever the highest engine vacuum was when it was running.....bypassing the can will not make the doors "slam" when connected to intake manifold vacuum.

And yes, the reason for the can is so you can open & close doors without engine running....but maybe only 2 or 3 times

Bryan

[Dino]

the can is gonna hold whatever the highest engine vacuum was when it was running.....bypassing the can will not make the doors "slam" when connected to intake manifold vacuum.

And yes, the reason for the can is so you can open & close doors without engine running....but maybe only 2 or 3 times

Bryan

3 on mine but only the ps closed on the last try, lazy ds door...   

[1974dodgecharger]

Can I connect the PCV line to the canister build pressure that way?  My carb does not have a vacuum line (race carb) only a vacuum testing port.  I do have a PCV off my valve cover and 3ft of tubing from there I was gonna hook it to the canister and hopefully that buils pressure enough to open the lights.

[fy469rtse]

Or you can do away with the vacuum and get the kit from charger specialitys and convert doors to electric , plugs in head light harness for similar operation

[Ghoste]

Ah man, that's cheatin'. 
Besides, the vacuum setup is kind of cool.

[Fred]

Ah man, that's cheatin'. 
Besides, the vacuum setup is kind of cool.

 

[myk]

Or you can do away with the vacuum and get the kit from charger specialitys and convert doors to electric , plugs in head light harness for similar operation

That's EXACTLY what I plan to do.  The headlight doors are part of an electrical system-why it's tied in to engine vacuum makes no sense to me.  The fact that they used motors for the headlight doors in the 1st Gen and the '70 just tells me that the vacuum system was just destined to suck, pun intended.  Personally, I would NEVER design an accessory/system that could affect engine performance if it had a problem...

[Dino]

Or you can do away with the vacuum and get the kit from charger specialitys and convert doors to electric , plugs in head light harness for similar operation

That's EXACTLY what I plan to do.  The headlight doors are part of an electrical system-why it's tied in to engine vacuum makes no sense to me.  The fact that they used motors for the headlight doors in the 1st Gen and the '70 just tells me that the vacuum system was just destined to suck, pun intended.  Personally, I would NEVER design an accessory/system that could affect engine performance if it had a problem...

I don't know man, $500 to replace something that never fails as long as you keep it in good shape.  I don't see me doing this mod, my headlight doors work just fine.

Design wise...well, I try not to wonder why they did what they did.  They hit the ball out of the park by making the car look as it does and I'll gladly take the faults with it!   

[fy469rtse]

Wouldn't have to cheat if there were re pops including block to head light switch , always annoyed me one operating before the other, until I found out that's original, yeh I like the vacuum too,
There's no cheating on these cars,

[fy469rtse]

Post photos when you do Myk , be good to see the install and maybe a video of them operating .

[Ghoste]

yeh I like the vacuum too,
There's no cheating on these cars,

Don't you love the little hissing sound when you pop the headlight switch?

[Bob T]

yeh I like the vacuum too,
There's no cheating on these cars,

Don't you love the little hissing sound when you pop the headlight switch?

Yeah, exactly. I took a early 20's couple for a birthday cruise around town and the waterfront the other weekend, when I told them about the vacuum head light operation and showed them the baked beans tin they just looked at me like I was from Mars  .....at least I think thats why 

[myk]

Post photos when you do Myk , be good to see the install and maybe a video of them operating .

I will, assuming I get the kit; like Dino says $500 is a lot to spend on something that I could fix for relatively free, but...the whole vacuum thing just annoys me...

[el dub]

I'm kind of surprised there hasn't been more written about this. I would like to know how many people on here have changed their intake and carb for more performance and still have their headlight doors work. I know when I changed to a single plane intake, street dominator, and a holly 750 my doors quit working. So how many people here have doors that work with intake and carb change. Just curious. I know if your running a stock set up they work fine.

[Dino]

I'm kind of surprised there hasn't been more written about this. I would like to know how many people on here have changed their intake and carb for more performance and still have their headlight doors work. I know when I changed to a single plane intake, street dominator, and a holly 750 my doors quit working. So how many people here have doors that work with intake and carb change. Just curious. I know if your running a stock set up they work fine.

Plenty people have a vacuum issue once upgrading some parts.  Most of those have a bigger concern than grille doors though as their power brakes will no longer work properly. 

Depending on the end goal of the car, it may or may not be worth doing away with vacuum anything and upgrade grille doors to electric and brakes to a hydroboost.  For me, I want to cruise around and roast the occasional tire and I don't need anything more than stock to do so.  Funny enough, my car felt as if it got a boost in performance when I replaced the Edelbrock 'performer' carb with a truck's thermoquad!

[A383Wing]

you may have felt an increase...primaries on a T-quad are smaller than Carter ones...bigger ain't always better in the carb department

[Dino]

you may have felt an increase...primaries on a T-quad are smaller than Carter ones...bigger ain't always better in the carb department

Also the eddy is a pain to tune all the time while the t-quad is a pain only once.   

I noticed the much crisper throttle response as soon as I fired up the car with the t-quad.  When I put it in reverse and backed out of the garage I noticed I had more power because the tires were spinning, something that never happened with the eddy.  On the road I could feel loads more torque which I cannot explain.

I had my floats set too high at that time so to make sure it was the carb and not something else, I put the eddy back on.  Just as before the car got slower again.  I'm sure that the eddy can be made to work just fine, but I don't have the patience for it anymore.  Besides, the T-quad gives me better mileage and cooler fuel to boot!

[myk]

Ugh.  Does anyone WANT my 'Eddy 750?  I'll even pay the shipping, lol. 

Anyway, I remember when I first got my Charger it had a ridiculous 'cam in it and the car wouldn't idle properly, let alone open the headlight doors in less than 3 hours.  At some point I will start heading back in that wild 'cam direction, but I'd like to know that my headlight doors with electrical motors won't be compromised by the 'cam.  Conversely, I want to know that my motor won't be compromised by the headlight system if there's a problem it.

Dino, what intake are you running?

[A383Wing]

I have never had any issues with the Edelbrock Carter series AFB or AVS carbs..very simple design...but on the other hand, I have never been able to get a Thermoquad to run right either...or a Holley....

Bryam

[Dino]

Ugh.  Does anyone WANT my 'Eddy 750?  I'll even pay the shipping, lol. 

Anyway, I remember when I first got my Charger it had a ridiculous 'cam in it and the car wouldn't idle properly, let alone open the headlight doors in less than 3 hours.  At some point I will start heading back in that wild 'cam direction, but I'd like to know that my headlight doors with electrical motors won't be compromised by the 'cam.  Conversely, I want to know that my motor won't be compromised by the headlight system if there's a problem it.

Dino, what intake are you running?

Edelbrock performer (non rpm).  Basically a lighter version of the stock intake.  I have the 71 only intake which is supposedly better but never did the swap because for my day to day driving I will never know the difference anyway.

Bryan, tuning the TQ was a challenge at first.  The sequence of adjustments has to be followed to a T and I'm still surprised I pulled it off!

The eddy always runs rich at idle and gets lean when you put your foot in it.  I've heard from several people that they are great carbs, but not on a 440.  What that means I do not know but I thought it was funny.   

[Lord Warlock]

Sure, i'll take your Edelbrock 750 I'll give you an address to ship it to.  I haven't had any problems tuning mine, then again i don't drive the car, just start it and let it idle a while with an occasional rev to clear out the pipes.  Wish i'd installed the electric choke on it when i bought it, now i can't find all the pieces for it. 

How many here have installed the electric door actuator system available?  thought that was a nice unit but like you said, 500 for headlight doors seems a bit much to me, my doors have never worked since i got the car, the vacuum lines in the grille seem to be fine as I'd switch the lines to open and close the doors, the coffee can cannister seems to work.  Maybe the lines from the switch to the can are bad.  I'll use the breakdown in the first post to check them out one day.