73 challenger 440 smells like gas, hard to start

[Kuruton]

Hello all,

Quick update for anyone who saw my intro, suspension is mostly squared away now and new torque strap installed. Ended up ordering new upper control arms cause my drivers side one is pretty bent and I wasn't able to replace the ball joint anyways without the socket. (In Japan, would have to order one anyways)

Onto my current issue! Lately, the car has been wreaking of gas but mostly from outside and even when it's been sitting for a day or 2. If it sits for more than 30 mins there's a 50% chance it will take tons of cranking to get it to finally turn over. Other times, it might fire right up. I'm not sure if my electric choke is acting up, but it definitely has a high idle when first starting so I don't think that's it. Also, I don't see any wetness or anything coming from the fuel pump/hoses after its sits so I don't think it's leaking. Timing is fine at least for idle, have it at about 14 degrees initial if I remember right when I set it a few months ago. Vacuum advance is turned way down but I still get a knock at higher rpms but I suppose that's a different question.

Anyways, any ideas on my gas smell and difficulty starting? Thanks on advance!

 

[DetMatt1]

What carb are you running? I guess the first thing I would check is that the floats are still good and are set at the right level. Are you running a stock mechanical fuel pump?

 

[Kuruton]

What carb are you running? I guess the first thing I would check is that the floats are still good and are set at the right level. Are you running a stock mechanical fuel pump?

Thanks for the reply! I rebuilt the carb (edelbrock performer 750) a few months back and hadn't had any issues until recently but i could definitely give it another look over. It's a mechanical pump but upgraded to a carter 7.5 psi. I know it's a little high for the edelbrock and I have a regulator I'll eventually install.

 

[Challenger RTA]

Check your oil for gasoline.

 

[Kuruton]

Check your oil for gasoline.

Will do. Have been putting off an oil change anyways so I'll just do it this weekend.

Would you suspect that it would be related to difficult starting or 2 unrelated issues? Bad piston rings?

 

[Chryco Psycho]

the heat from the engine is evaporating the fuel in the carb , the heat crossover in the intake should be blocked to reduce heat under the carb , you can also add a a heat blocker such as Cool carb to reduce heat , it iiiis hard to star because it is flooding with the fuel boiled out of the carb

 

[Kuruton]

the heat from the engine is evaporating the fuel in the carb , the heat crossover in the intake should be blocked to reduce heat under the carb , you can also add a a heat blocker such as Cool carb to reduce heat , it iiiis hard to star because it is flooding with the fuel boiled out of the carb

I didn't have these issues back in summer and I'm running a lot cooler now too since I swapped to electric fans and a 160 thermostat. Although when I swapped to my edelbrock performer intake I took out the wood spacer for clearance. With my current filter I can probably get it back on though.

Wondering if running that 7.5psi might be related too after Challenger RTAs comment. I also only using it to get to and from work at the moment. Which is only 10 minutes below 40mph the whole time so I'm wondering if it's just not burning off gas introduced to the oil?

Either way, I'll put a fuel pressure regulator on, get that spacer back on, check my floats and change the oil this weekend. Hopefully some of that combination produces some results!

 

[heminut]

I had pretty much the same issues (also running an Edelbrock 750) and figured out that my float levels were too high. It was sucking fuel in through the boosters when it was sitting and just idling.

 

[moparleo]

Remove the air cleaner so you can look into the carb for leakage. You should be able to pinpoint the fuel smell source.
For safety do all your checking outside away from the house/garage/carport etc.. A handy fire extinguisher should be part of your tool kit anyway.
Always go back to the basics and don't assume anything. Recheck all clamps and connections with a screw driver or wrench.
Check for leaks especially on the flex lines from the frame line to pump, tank to frame fuel lines. Fuel filter. Etc..
You can just pull the oil dipstick to check for fuel smell. This would indicate either fuel leaking down the intake manifold or a faulty fuel pump. Always use extreme caution when working with fuel fumes. Highly explosive.
160° Thermostat is too low. Factory was in the 195 ° range. The engine needs heats for proper combustion.
1966-1974 Mopar Bendix Master Cylinder, 1.125 Inch Bore
Most experts agree that a vehicle's engine should run between 195°F and 220°F.
The OEM t/stat was a 195 degree F thermostat, although by 1972, Chrysler had gone to a 185 degree F thermostat OEM, although this was a short-lived item. So, pick your choice of temps, either 180 degrees F or 195 degrees F, although most would probably choose the 180 item

 

[Challenger RTA]

The reason I say check oil, is one of the reasons is the fuel pump can leak into the crank case.

 

[DetMatt1]

You definitely need to reign in that fuel pressure down to around 3 psi and the 160 stat is too low. It probably never shuts and that doesn’t allow the radiator to do it’s job which is cool the coolant.

 

[Kuruton]

Remove the air cleaner so you can look into the carb for leakage. You should be able to pinpoint the fuel smell source.
For safety do all your checking outside away from the house/garage/carport etc.. A handy fire extinguisher should be part of your tool kit anyway.
Always go back to the basics and don't assume anything. Recheck all clamps and connections with a screw driver or wrench.
Check for leaks especially on the flex lines from the frame line to pump, tank to frame fuel lines. Fuel filter. Etc..
You can just pull the oil dipstick to check for fuel smell. This would indicate either fuel leaking down the intake manifold or a faulty fuel pump. Always use extreme caution when working with fuel fumes. Highly explosive.
160° Thermostat is too low. Factory was in the 195 ° range. The engine needs heats for proper combustion.
1966-1974 Mopar Bendix Master Cylinder, 1.125 Inch Bore
Most experts agree that a vehicle's engine should run between 195°F and 220°F.
The OEM t/stat was a 195 degree F thermostat, although by 1972, Chrysler had gone to a 185 degree F thermostat OEM, although this was a short-lived item. So, pick your choice of temps, either 180 degrees F or 195 degrees F, although most would probably choose the 180 item

You definitely need to reign in that fuel pressure down to around 3 psi and the 160 stat is too low. It probably never shuts and that doesn’t allow the radiator to do it’s job which is cool the coolant.

Will do, thank you guys. Going to get it on the lift tomorrow at the base shop and check everything as well as the work I mentioned. Will report back after!

I actually i just double checked my old summit emails and it was a 180. It originally had a 195 and I went down to 180 with the new water pump, my bad. Numbers are hard, haha.

 

[Kuruton]

Update: oil indeed reeked of gas. Replaced all soft lines, did oil change, installed regulator, dialed down to 5.5 psi and it seems to be starting great now! We'll see if it stays that way.

 

[Ricks72Chlgr440]

Will do, thank you guys. Going to get it on the lift tomorrow at the base shop and check everything as well as the work I mentioned. Will report back after!

I actually i just double checked my old summit emails and it was a 180. It originally had a 195 and I went down to 180 with the new water pump, my bad. Numbers are hard, haha.

Update: oil indeed reeked of gas. Replaced all soft lines, did oil change, installed regulator, dialed down to 5.5 psi and it seems to be starting great now! We'll see if it stays that way.

Great! Check the oil smell after a few drives to ensure it is not smelling of gas again. If it does, then the fuel pump diaphram is likely leaking and the pump should be replaced.