vapor lock question(update4/10/8 fixed prob.)

[tick68charger]

when its above 75 degree's my 440 after 30 min would loose idle when
cruising below 30 mph. and if i opened her up it's like i ran out of fuel.
she would also heat up to about 210 to 220.

I thought it was because she was running hot. so i got a aluminum becool
radiator, mildon high flow water pump and high flow thermosat, a new temp
gauge. I got the manual trans radiator and the B@M super stack trans cooler.
now she runs at 180 all day but i still have problems with idle and when i open her
up after 30 min of running.

here is my engine specs.

1968 charger with the 440hp 727 trans
1967 closed chambered 915 heads mild port bowl blend with harden seats and port matched
i have the valley pan that blocks off the heat port
holley street dominator intake
850 holley mechanical dbl pumper (jets 80 in front and i pulled the 80 in back and put 84 in no change in performance)
1/4 " paper gasket under carb
hooker super comp headers 1 7/8 to a 3 " collector
3" hedmen x-pipe
40 series flow masters
3 1/2" turn downs dumping out just before the rear end
mopar purple cam 484 lift
3000 stall
b@M 0 balanced flex plate
carter high flow mechanical fuel pump
stainless steel 5/16 fuel line
stainless steel 1/4 return line
7 blade mechanical fan
electric fan pushing air for back up
converted to an 80 amp alternator
mp electronic conversion kit
accel super coil
becool radiator for a manual trans
11"x11"x1 3/4" B@M super stack trans cooler
mildon high flow water pump
mildon 180 high flow thermostat
i insulated the fuel line(no help)
i bypassed the return line(no help seem to run worse)
timing i have the advance plugged off and i run it between 32 to 38 total timing
3.91 gears
b@m larger 4qrt trans pan with fins

i did not want to leave anything out just in case you see something wrong with this combo
im tierd of spend all this $$$ and still having this problem

[dodge freak]

I am guessing now--I have hear that sometimes the gas tank vent gets clog up, and if you take the gas cap off the gas will flow again. Not sure if thats it, cause the heat seems to be the problem. Are you sure its the gas  and not something else ? You should take the fuel level hole screw off on the carb. fuel bowl and see if there is gas in it,the next time it acts up, if so its something else, if theres no gas in the fuel bowl, the gas is boiling away or not flowing. Check it out tomorrow, and let us know. You get this taken care of, even if you have to get a electric fuel pump and maybe re-rout the fuel lines, but it might be something in the ignition.

[tick68charger]

i did forget to mention that it usually starts right back up unless its really hot out
then it takes a few cranks but once she is started i have to use the foot feet to
keep her running, but that is a good idea i will look through the site plug and
see if she has gas. i will try this tomarrow after work and get back to you with the
results. thanks

[grouseman]

I know that the AFB/AVS carbs sometimes had a Hot Idle Compensator built into them, depending on application.  Basically a temperature-controlled vacuum leak.  A small part that fit just above and behind the secondary clusters.  It would allow more air in, which bumped up the idle speed. 

Run a vacuum line into the psngr compartment, and open it when you experience the condition; see if it helps.  Real band-aid, though. 

[tick68charger]

it was raining here yesterday, but today its going to be 86 and sunny. time for a test
i'll report my findings.

[dodge freak]

I hate the rain, wish it would only rain when I don't have time to drive ha ha. Guess out west like in Nevada it would be nice, expect it gets so hot and the girls there would get all my gas money 

[tick68charger]

well its about 85 degrees or better. drove the car for about 45 min when i got to
the big city with all the traffic and lights it wasn't 5 minutes and she wanted to die
so i hit the back streets and waited. sure enough she died i wiped into a parking lot
took out the sight plugs, bumber i still had fuel in the bowls. i did notice that my
accel super coil was very hot to the touch could hang on to it for about 3 seconds
before i had to let go. it took several cranks to get it started, once started i took off
down the road about 1/8 throttle and its like i was running out of gas so i pumped the
foot feet to bout 1/4 to 1/2 throttle and she fired back up and i could keep her running
barley but if i let off the foot feet she would die if i got her up to  30 mph and above
she came out of it? any ideas ill be checking in off and on tonight for replies.

[dodge freak]

Well it sounds like its in the ignition. Maybe bad coil or the pick up coil inside the dist. Something when hot is giving out, and when you turn it off its starts to cool off. I doubt if its vapor lock. No , you have gas-you must have a weak spark. Sorry but its maybe swap time until you hit it. New coil and then the pick up coil in the dist, not sure if the spark box goes bad like that- I have MSD, just a Moper dist , then its all MSD. Thats all it can be. Once you fix it, it be fine, forgot about trying to lower the temp. something is going bad on you. You could have a shop look at it for you but you could change everything for the same $.

[tick68charger]

I thought about picking up a new coil today when I felt how hot it was.  I think I'll pick one up tomorrow and mount it in a cooler spot. 
I wonder if I should relocate the orange box for the mopar performance electronic ignition conversion kit?  It's right on the fire wall above the header.  I wonder if that can go bad?  I'll try changing the coil first, and see what happens.  After it dies I can hit the throttle and the accelerator pump pushes gas into the carb, so I am getting gas.  I think you are right, it's probably electrical.  I'll give an update in a couple of days.  I'm going to order a phenolic 1 inch carburetor base gasket, and a new coil.

[dodge freak]

Swapping parts stinks, its always the last thing you change. Coils , boxes , etc. CAN get hot, just that sometimes when they get old they start breaking up, then it cools off and is ok again. That pick up coil in the dist can be a pain to change but MIGHT be it, its only $20 or so but you have to pry the reluter off and take a few screws on the side of the dist off and un hook the vacuum advance. I think the box too can go but it might not be as old as that dist. pick up, nobody ever change those until it goes bad. If you got the bucks, you could just get a brand new dist.- about a $100 or so. You know, I had a bad plug wire one time , when it was cold it was fine , then when it was hot it "leak" the spark to the header- turns out the boot was spilt-Guess what ? It was the LAST thing that I changed.

[firefighter3931]

  I'm going to order a phenolic 1 inch carburetor base gasket, and a new coil.

That's a good place to start. Make sure your fuel lines and filter aren't leaning up against any heat sources ( rad/heater hoses or the block/heads).


Ron

[dodge freak]

Would it still be vapor lock if there was gas in the carb. ? Seems to me even if the gas was very hot so long as it did not boil away it would be ok.

[NYCMille]

DUDE!

Had the same EXACT symptoms as you - my engine combo is simliar as well with the exception of that I have 906 heads punch .030 over and I went exact same steps you did. A big one was going back to the original 18/.5 7 blade clutch fan set-up. I drop 25 degrees and now I idle 180 all day long.

The problem was the 850DP I had on the car - I swapped it out for my buddies 750 Barry Grant and the car ran fine... no problems whatsoever. I just ordered a Holley 750 3310 with Vacuum secondaries as my motor is a pretty mild build. I should have it tomorrow.

Try swapping out the carb with a buddy and run the carb... my bet is your 850DP is to much for the motor. Give it a shot...

Mike

[tick68charger]

friday i hit the road to heat up the car and try and figure out what was going on in 30 min she
died when slowing down. i put her in neutral and shut it off pulled over pulled the sight plugs of
the carb full of gas, next i put a spark plug on the #1 wire no spark then i started to get a
spark after about a minute but it was very week. I'm going to try the new coil and wires.

Saturday well its 90 out today and i got my new coil and spark plug wires in. i got the msd blaster 2  coil
and accel high temp 8mm plug wires. i mounted the coil on the outside of the radiator support
to keep it cool. took her out for a test same thing happend after 30 min it died when slowing down at
a stop sign on a highway  . well i tried to start her back up, nothing, all i was doing was flooding it.
so i sat there for about a minute or two and she fired back up and i headed for home. she did run a little rough until
i got going. when home i felt the coil and she is nice and cool. but the electronic conversion kit orange box was very
hot i think i will mount the box inside the car under the dash and see what happens. if that don't work.
i was thinking of getting the msd 6 box and the msd distributer. by the way after she died i pulled the
sight plugs on the carb again and she was full of gas.

any ideas? also what do you think about the msd set up would you get it.  if so what one would you recommend?

[firefighter3931]

Tick, before you go and scrap the whole ignition system...try swapping out that POS orange box. Those are notorious for going bad. If the MP conversion kit is less than 3 years old.....the box is junk. The older orange boxes were much higher quality....whoever is producing these for MP now (low bidder) isn't doing a very good job. Mine was leaking resin (melting) on the firewall 

I luv MSD stuff....the 6A or 6AL with the built in rev limiter would be all you need. If you decide to stick with the MP stuff....upgrade to the Chrome Box...those are much more reliable.

Ron

[dodge freak]

It still could be the pick up coil inside the dist. but it sounded like you may have gotten a new dist a few years ago when you swap over. If so its might be ok, good chance. Its either one of those now-the box or the pick up in the dist.

I like -make that love-MSD but if you have no smog checks where you live you may want to get a 7 al unit at Jegs or Summitt before they are all gone-MSD has a 7 al plus now for $575 , thats too much. I know everybody says the 6 unit is fine and all you need, but I have a 9-1 compression motor and did notice a nice improvement over my 6a box that I had in there, it had no rev limiter so thats why I change. I think the price difference is like $145 or so WELL worth it. You don't have to swap coils. I had a Mopar chrome box and thought the 6 unit MSD was way better. Marroly , Crane make boxes too but don't know how they are. You could just go to Auto zone and get a $15 well's box to check if thats it, if it is great ,take it back to Auto Zone for a refund, they may give you one. If its not , its in the dist. I have the Mopar dist. with light springs in it and a Accel cap and rotor, works great.

[tick68charger]

i think i will get the msd 7 box and the distributer since i have such high compression. i thought i had 11.5 to 1
but in a recent mopar mag it said my combo was 13 to 1.
does the msd box automaticly adjust your timming for the best performance?
i live in iowa so ther are no smog laws here

[firefighter3931]

i think i will get the msd 7 box and the distributer since i have such high compression. i thought i had 11.5 to 1
but in a recent mopar mag it said my combo was 13 to 1.
does the msd box automaticly adjust your timming for the best performance?
i live in iowa so ther are no smog laws here

The MSD box just supplies the spark....timing is controlled by the distributor. If this motor is an actual 13:1 compression build, you would have to be running 110 octane race fuel in the tank....are you ?

Ron


Ps. The 6AL is all you need. The digital series boxes are for Race type applications with a lot of features that a street car would never use. 

[tick68charger]

thanks for the info time to save up some more $$$ for an msd box.  i want to get both
distributer and box so i have the complete msd set up. i think i might put the msd box
under the dash so i wont have to worry about engine bay temps and maybe it will
last longer.
i don't know how long it will take to get.  but when i do i will post my findings.
first i will put in the distributor and test, then the box to pin point the problem.
thanks for the help all

[dodge freak]

The box CAN get hot and work fine might last longer in the trunk or pass. area but I ran a MSD 6 for 8 years no problems. On the digital boxes Firefighter is right its race only no street only the 6 digital can be use on the street. The 7al box is NOT digital and with most coils can be used everyday on the street, the 6 might be all you need but it does not hurt anything by having a stronger spark then needed. Your plugs might wear out a Little sooner but I had my in for a year-5000 miles- and when I changed them last week they were all clean, very clean, when I was running the 6 box a few were brown-to black with a little oil , now all I did was to get the MSD 7 al box and the 7251 coil and all the spark plugs were clean. The gaps opened up from .038 to .045 so I am glad I changed them. I think FF might be right about that mopar box being bad but its not the heat-well it is but it should not be. That MSD stuff is a lot of money but it is good and the way I see it if you are going to spend $230 for a 6 al you might as well go for the 7 al at $380, you get $20 summitt bucks off your next oder too. Like I said everybody told me I was throwing away $150 but I did notice a difference-when the motor is cold after a few days of not running it still will not stall in gear, with the 6 al box it would until it ran for a min. And now my plugs stay super clean. Its your money maybe its not needed but so is a lot of stuff we have on our cars, right?

[firefighter3931]

when I was running the 6 box a few were brown-to black with a little oil , now all I did was to get the MSD 7 al box and the 7251 coil and all the spark plugs were clean.

From what you're describing, a new coil was installed at the same time as the 7 series box....is this correct ? The reason i bring this up is because the coil likely helped more than the switch in boxes. The 6al works well, even better with a high voltage coil.  I have a buddy who ran 10's for years with an old 6A box and no rev limiter....he tried a digital box and went back to the old 6a because of electrical gremlins. The digital boxes are very sensitive to electrical interference from other wiring. The distributor feed wires need to be shielded & isolated from all other wiring or the box can act wierd. 


Ron

[dodge freak]

Thats true I never said get a digital box! The 7 comes both ways-the 7al is not digital-the digital one should never be use on the street only the 6 can be. I seen the horror story's too on those digital boxes-might be why it comes both ways. The coil I just change this spring the box I changed last summer, before I was using a Morroso plasm coil , cost $80 , maybe it was cause my MSD 6a was 8 years old. Maybe I am not be fair comparing a brand new 7al to a 8 year old 6a box, but like I said for $150 I would just get the stronger box even if is over kill.

[dodge freak]

The MSD 7220 is the one thats not digital --The 7530t,-75301,-7535,-, 7531 7520 are all digital and will burn up on a street motor-and be a pain to work with. Why do MSD even make them IDK but I would never get one. MSD has the 8 units and the 10 unit boxes if you need more spark and those are not digital also. But that would be a waste and you might start getting in to crossfire problems with that strong of a spark.

[tick68charger]

I like over kill! I'll look at all the boxes and coils, but I think I will do the over kill. I'll report my findings. Thanks All!

[grouseman]

Next time it happens, pour water on your mechanical fuel pump and report back. 

[XXSpiralXX]

  I have a very similar problem now. The only difference is that mine is a BONE STOCK 72 318!  And it does it without getting too hot either. I had big distributor problems with my old points setup and swapped it out. No more starting issues. At the same time I had stalling problems that I associated with the distributor but its still doing it. If I jump on it ( Cant really go too nuts its only a 2bbl ) after a few seconds it starts to stumble and spit. And if I stop the car quickley it cuts out completely. Sometimes it will start again right away but mostly I have to wait for a few seconds. Also, when the car gets hot ( stock gauge has the needle about halfway up ) it starts to stumble and cut out.
Now, this happens sometimes when im on the gas. I could be cruising down the highway and it will just start spitting and stumbling. When this happens I have to put it in neutral and keep pumping the gas. Sometimes this works sometimes it doesnt. Im the king of restarting my car at 60 mph....   
    Anyway. Since the plugs wires distributor and coil are new I was thinking it had to be a fuel problem. The timing chain is a milodon double roller about a year old so I don't think its that. I have alot of rust buildup in my tank from sitting. I was goign to get it boiled out but I wanted to cover all the other bases first. Could this have messed up my fuel pump? Maybe the lines/filters are clogged? ( I changed the filters not that long ago, maybe a month or two ) a friend said it could be the ballast resistor?  Im going to try to change that tomorrow. Thinking of doing the pump today. 
   Any suggestions? I dont know where else to look.

[tick68charger]

well it is the 7/28/6 just got done working my charger . I'm going to back track. I thought my car was getting vapor lock
when she got up to full temp it would die. when it died i shut her down and pulled the sight plugs and the bowls where full of gas, so
that ruled out vapor lock. so then i put a spark plug on the #1 wire and no spark, so i waited a few minutes for it to cool down.
turned it over and she started.  but my spark was week. so it must be in the ignition.

things i have replaced since my last post.

new msd coil replaced the accel super coil
msd 6 box replaced the mopar performance orange ecu box
new accell high temp wires

no help it still dies when she gets up to temp(no spark). when it died today i put a meter on the wire that connects to the the red wire on
the msd box in run position and i had 12v i have replace everything but the distributer, maybe the mag pickup is going bad in the distributer?
but wouldn't it just go out, i can't see the magnetic pickup in the distributer working fine until she gets up to temp then no spark until she
cools down. i don't know

and this only happens when over 75 degrees out, it only happens faster the hotter it gets out

i will check back tommarrow

[dodge freak]

Yes the pick up CAN go bad only when it gets hot. I did say to get a Wells ecu box from Auto Zone to see if thats was it. Its ok, the MSD stuff is better but like you say its still there. If you never change a pick up coil in the dist before and it has the vacuum advance it can be a little hard. You should pull the dist to do it. You might as well change it, it could be it, if not and you are sure the voltage is not dropping when hot the ignition is fine. Not sure what else it could be . Its happen to me, the last thing I change is the one thats it.

[tick68charger]

after it died i put a volt meter on the red wire comming off the msd box to the run wire and i had 12v, well
close i always get a reading of about 11.8 hot or cold. i have pulled the distributer before and changed the
springs in it. the mag pickup has 1 screw and some type of pin pinched in the point where it swivels that
looks like a major pain to get that pin out and to put in another unless the kit comes with something different
that installs easily. but i was thinking about getting an msd distributer. undecided yet.

[dodge freak]

To change it you have to pull the whole plate out. Remove the rultor -the thing that looks like a wheel right under the rotor- then take 3 screws out on the side of the dist. The plate lifts out then, might help if you had the new one in your hand. Think Napa might sell just the pick up coil alone but you are right it be a major pain. 11.8 should be fine, you have the MSD unit going right to the battery now so I would think thats all ok. You could just buy a rebuilt dist. from Auto Zone or somewhere, not sure how much, if its around $60 or so its cheaper than MSD. I wish I could help you out but you are not by Detroit , right ? Its really not that hard once the dist is out, if you can change the springs you can do it.

I hate to see you keep throwing money at it, but I would think thats it, but I could be wrong. Its not right though, its in the low 90's here and I have no problems running my small block and I even have the exhaust cross over open in the intake, motor gets good and hot, runs great too.

[tick68charger]

I  hope i get this taken care of soon i want to take my charger to the woodward dream cruise in Detroit
the week of aug 19. i live in iowa and its been in the 90's.

in the mopar performance distributer is the mag pickup the same as a stock unit. could a stock pickup
work with the msd box and coil with out any problems?

do you use the ballest resistor on msd set up? i am using mine.  could that be a problem.

my battery is in the trunk so i hooked the msd 6 red battery line to my starter relay, the positive
line from the trunk and starter then i took the ground and mounted it to the motor and
firewall ground on the back of the motor. do you think that there is to many wires in line of the
starter relay for the msd + wire to be hooked up there? do you see any problems with the way i
hooked the + and - on the msd box?

do you think i might be getting Resistance from my 8mm high temp stainless steel coil wound accel super stock wires,
and cause the pickup in the distributer to kick out?

[dodge freak]

I am using the MSD 7al and before that the MSD 6a with a Mopar dist. with no problems. If you ask MSD they tell you battery only not how you have it, but I doubt thats the problem. Its doing the same thing as before so the bad part or wire is still there. No you do not use the ballast resistor.

You know I read your old post again and you said you changed the dist. springs so you have pulled that pick up coil out before. It comes all in one unit the plate and the pick up coil and cost no more than $25 or so and thats for the standard brand, which I use. I would change it and make sure the gap is very small ,they call for .008 but I just set it as close as poss. with out it touching when you spin the shaft.

See I don't think the wiring is the problem cause it would always do it, unless the starter is get hot and messing it up but I would change that pick up plate first, no guartnees but it might very well be it. If the singal is getting weak when its hot the MSD box or any box won't fire.

[dodge freak]

Hold on those ballet resistors do go bad too, get it out of there. Its heavy black to ground, heavy red to battery post. or 12 volts allways and small red to 12 volts only when key is on start or run. and the two pick up coil leads. make sure the white wire does not touch ground.

[tick68charger]

i will get rid of the balest but i have the small red msd wire going to the brown and blue wire on one side of the balest .
so i will take out the balest, but on the other side of the ballest is another blue wire should i connect that to my
wires that i have my red wire going to or do i just tape it off?
if the mag comes on the plate then that would be a cheep and easy fix. i will order one tomarrow.  also i will run
my wires back to the battery i have to many hooked up to that relay now my electric fan etc..

so what do i do with the other wire on the balest?

by the way thanks for all your help

ill check back tomarrow

[dodge freak]

You know it sounds like it -the ballet resistor- is not hurting anything cause the MSD small wire is right to the 12 volt wires and you have 11.8 when its hot and acting up. That pick up plate should be easy to find, most auto stores should have one in stock, it was used from early 70's till early 90's I think. I would just change that before I start ruining new wires everywhere. Heck you can crank the motor over when its hot. Won't hurt to change that pick plate, that tells the spark box when to fire and they do sometimes give out when hot.

[tick68charger]

i will change the mag first. then i will update in a few days.

[steves66]

I know this is an old topic, but what the heck. Did the new magnetic pickup work? If not, have you fixed the problem yet?

[tick68charger]

I know this is an old subject but I found the problem, My fuel pump was bad it finally gave out.  It started to die on me going down the highway
at 55 so I got a fuel pressure gauge let the car get nice and warm and the fuel pressure started to drop then it finally died.
  I went with a carter strip mechanical fuel pump with fuel regulator. She has ran great ever since, But i
would still get detonation on hot days.  I have a dual snorkel air breather,  I ran some piping from the air breather to the fenderwell
so i could get cool air instead of hot under hood temps. Problem solved. I sent my hooker headers to jet-hot to get ceramic coated
inside and out this winter, that should knock down some of the under hood temps. Thought I'd update my findings just incase somebody else has this problem.