Symptoms of Vapor lock? Return line ??

[timmycharger]

Last night I may have had my first experience with vapor lock but I am not sure.  I have been taking the Charger on short trips around town since I got it back on the road last year without any issues until last night.  I live in MA and it was warmer and more humid than normal but not sure if that even was a factor.  I drove it around for about 5 miles last night while waiting to pick up my son, pulled in the parking lot and shut if off for about 15 minutes.  Went to leave, it started fine and when I went to take a left turn, I got on it a bit and then it started to feel like I was running out of fuel. No power and lots of bogging etc.  I immediately started to pull over and try to crawl it to a side street to get off of the main road and it kept on bucking and acting like it was running out of gas and then Bam! just like that it was back to normal and was fine for the 2 mile ride home.  

I am running a six pack setup on my 440 with an electric fuel pump mounted on frame near the tank, same place I always had it even before the restoration along with a regulator on the firewall.  I am not running a return line, (never did before and again had no issues).  I ran this set up before the restoration and took it to the track where there was constant stop/start situations, but the big difference from then and now is the hood. I used to run a fiberglass sixpack hood with a huge scoop which would allow the heat to escape better in my opinion through the scoop.

Now that I am running the steel hood with the current set up could that be adding extra heat? I don't have insulation on the hood but I would imagine that would make it worse?  I may look into adding a return line over the winter, would that just come out of one of the sides of the regulator back into the sending unit? I capped off the 1/4 nipple that is on the new sending unit I just put in a few weeks ago.  I thought it could be the sending unit causing me problems but not sure how that is possible as I put about 50 miles since installing it w/o issue besides a very small leak (no drips, just sort of wet near the sender).

[68 RT]

My car did that and floats were too low.

[LaOtto70Charger]

I had an issue similar to that and ended up being a distributor issue.  I was going 70 down the high just fine.  About dies all of a sudden.  Kept off the fuel and got it off the highway.  It would drive okay for a bit than start acting up again.  I thought it was fuel related since it seemed like it would run okay, run the bowls on out of gas, stop give it time to refill and than off again.

Any way ended up being the rebuilt points distributor would act up.  I still had the original one so was able to go back and forth between the two and verify.  Should add that at first I only had issues after running awhile.  Took awhile before it would do it all the time.  Like after replacing the entire fuel delivery system including carb. 

When it was acting up I had my timing light on it and the timing would jump all over the place. Something to check for.  Besides the float levels.

[Brass]

It could also be a bad coil on it's way out.  They may show similar symptoms, especially when hot.

[timmycharger]

Thanks guys, I will check out these suggestions. I drove it a few days ago with no issues but it still needs to be looked into more. 

[JR]

 You have a 440+6, with no fuel return line, and a stock steel hood? Honestly I'd be amazed if it didn't vapor lock.  Especially after being parked for 15 minutes and allowed to heat soak.

The boiling point of modern gasoline is so low, it doesn't take much to cause vapor lock.

Is the heat bypass in your intake manifold blocked off or open? What's the running temperature in stop and go traffic?

[timmycharger]

You have a 440+6, with no fuel return line, and a stock steel hood? Honestly I'd be amazed if it didn't vapor lock.  Especially after being parked for 15 minutes and allowed to heat soak.

The boiling point of modern gasoline is so low, it doesn't take much to cause vapor lock.

Is the heat bypass in your intake manifold blocked off or open? What's the running temperature in stop and go traffic?

Correct.  440+6 with no return line and steel hood.  I am using Edelbrock Aluminum heads, no heat bypass. Running temp in traffic is around 195 or so consistently.

Here is a pic of my setup currently.  My plan this winter is to run a return line off of the regulator (arrow in pic) and hopefully that will take care of any potential issues.  I will check out other things mentioned such as fuel levels and coil but I have a feeling that they are fine as I drove it again a few days ago about 5 miles w/o issue.

[cdr]

you have to use a regulator that is made for a bypass ,return.

[timmycharger]

you have to use a regulator that is made for a bypass ,return.

Crap! I need obviously do more research into this before tearing anything apart. This is new to me, I ran with this regulator set up for about 3 years without issues, and probably about 10 passes at the drag strip.  Thank you for that info CDR

[timmycharger]

Hey guys, it's been a while since I posted this but I am going to be messing around with the fuel system in the near future.

Does anyone have a recommendation for a bypass style fuel regulator? I was looking at Summit and they range in price. I found the Holley 12-887 for about $50 but it had mixed reviews.

[cdr]

300-899 Quick Fuel is the one I have on my car, works great, I would recommend wrapping the fuel lines going to the carbs.

[BSB67]

You have a 440+6, with no fuel return line, and a stock steel hood? Honestly I'd be amazed if it didn't vapor lock.  Especially after being parked for 15 minutes and allowed to heat soak.

The boiling point of modern gasoline is so low, it doesn't take much to cause vapor lock.

Is the heat bypass in your intake manifold blocked off or open? What's the running temperature in stop and go traffic?

Correct.  440+6 with no return line and steel hood.  I am using Edelbrock Aluminum heads, no heat bypass. Running temp in traffic is around 195 or so consistently.

Here is a pic of my setup currently.  My plan this winter is to run a return line off of the regulator (arrow in pic) and hopefully that will take care of any potential issues.  I will check out other things mentioned such as fuel levels and coil but I have a feeling that they are fine as I drove it again a few days ago about 5 miles w/o issue.

Very nice looking set-up under the hood.

Your problem that day was very likely vapor lock.  Considering how long you've gone without it being a problem and that it only happened once, sort of, I would consider just letting it go to see what happens.  Maybe it was the first batch of winter blend fuel.  Also make sure that you are running at least 6 psi.

Or if you just like working on stuff, add the return.

What she run in the quarter mile?

[timmycharger]

300-899 Quick Fuel is the one I have on my car, works great, I would recommend wrapping the fuel lines going to the carbs.

Thank you! I will take a look at that one 

[timmycharger]

You have a 440+6, with no fuel return line, and a stock steel hood? Honestly I'd be amazed if it didn't vapor lock.  Especially after being parked for 15 minutes and allowed to heat soak.

The boiling point of modern gasoline is so low, it doesn't take much to cause vapor lock.

Is the heat bypass in your intake manifold blocked off or open? What's the running temperature in stop and go traffic?

Correct.  440+6 with no return line and steel hood.  I am using Edelbrock Aluminum heads, no heat bypass. Running temp in traffic is around 195 or so consistently.

Here is a pic of my setup currently.  My plan this winter is to run a return line off of the regulator (arrow in pic) and hopefully that will take care of any potential issues.  I will check out other things mentioned such as fuel levels and coil but I have a feeling that they are fine as I drove it again a few days ago about 5 miles w/o issue.

Very nice looking set-up under the hood.

Your problem that day was very likely vapor lock.  Considering how long you've gone without it being a problem and that it only happened once, sort of, I would consider just letting it go to see what happens.  Maybe it was the first batch of winter blend fuel.  Also make sure that you are running at least 6 psi.

Or if you just like working on stuff, add the return.

What she run in the quarter mile?

Thank you! 

I may as well go and add the return line anyway to take it out of the equation completely just in case it happens again this year. I did confirm that I was getting good pressure, actually experimented with a few different gauges as the liquid filled ones kept giving me bad readings once hot.

I have not run it at the track since converting to a 4 speed/Dana 3.54 and adding the aluminum heads but in its old configuration with the same motor and a 727/ 4.10 set up it ran a best time of 12.82 @109 mph on street tires

[BSB67]

Nice

[Kern Dog]

What happened with the belts for the A/C pump? I'm looking to add A/C to my car.

[timmycharger]

What happened with the belts for the A/C pump? I'm looking to add A/C to my car.

The belt was not installed yet so the pump is just along for the ride for now. Everything has been connected for almost 2 years now but I never had it filled with refrigerant as I was still working out some issues.  Went with the setup from Classic Auto Air which was pretty nice and easy to install but I did a complete tear down to the shell.

[timmycharger]

Back on this issue,  getting ready for driving it again and I don't have the funds for a new regulator so I am trying to solve this without buying one.  For factory cars, didnt they just use a filter near the carbs with an extra nipple for the return? If so will it work if I just run a return line off of the fuel rail back to the tank? As suggested I may just wrap the lines and call it done but if its easy to run one I will.  Thanks

[Dino]

They used to have a vapor separator with a return line to the tank. I have both removed from my car, if you're close to SE Mi come pick them up!

[timmycharger]

If i were closer!

What does the separator look like?

[Dino]

http://www.dodgecharger.com/forum/index.php?topic=90084.0

Repros available anywhere