Gas leaking out through exhaust

[rmurray]

To find out if the pump is leaking into the cooling water, disconnect both water lines from the pump and plug or connect them together. Start the motor and see if fuel start coming out of the ports

AllDodge, which two hoses? There are three water lines connected to the fuel pump. Two into the top of the fuel pump, and one at the bottom. I'm guessing two flow in and one flows out? Please let me know and I'll try that today.

 

[alldodge]

I'm only seeing 2, but you could plug all 3, or Y all 3 together. The supply thru the pump is minimal to effect anything on the motor. If its leaking it shouldn't take long to see, maybe 30 seconds if that

 

[rmurray]

I'm only seeing 2, but you could plug all 3, or Y all 3 together. The supply thru the pump is minimal to effect anything on the motor. If its leaking it shouldn't take long to see, maybe 30 seconds if that

I pulled the lower water hose (the one that connects to the thermostat housing), and without even running the engine, a bunch of water mixed with gas poured out of the hose. Is that water entering the pump or draining from the pump? Is it safe to assume that my fuel pump is pumping gas through a bad seal inside the pump and the gas is getting into the cooling water? Is it possible that water is also getting into the fuel lines? I pulled this fuel pump apart on my last trip because it was clogged. I put it back together after cleaning it out and had to re-use all the seals/o-rings. I'm guessing it needs to be replaced or rebuilt. Thanks again!!

 

[alldodge]

Pulling the hose and finding gas and fuel mix, the Scott identified the issue and its inside the pump. I doubt you need the pump rebuilt but do need some new O rings, and not just any, needs ones that are not effected by E10 gas.

My guess is you could take the pump down to NAPA and they would be able to find some

 

[rmurray]

Pulling the hose and finding gas and fuel mix, the Scott identified the issue and its inside the pump. I doubt you need the pump rebuilt but do need some new O rings, and not just any, needs ones that are not effected by E10 gas.

My guess is you could take the pump down to NAPA and they would be able to find some

I'll give it a try. Thanks!

 

[Scott Danforth]

pull the fuel cooler

remove the pumps

inspect the solder/braze joints

repair as needed

re-install fuel pumps with PTFE or viton seals

go boating.

 

[rmurray]

pull the fuel cooler

remove the pumps

inspect the solder/braze joints

repair as needed

re-install fuel pumps with PTFE or viton seals

go boating.

I pulled the pump apart and several o-rings were destroyed. I am ordering a set from man cave mechanic, but I'll probably see if I can get some locally too. I plan to clean it up as much as possible and get it back up and running. Thanks for your help in diagnosing the problem!

 

[Scott Danforth]

I try to keep a few multi-size o-ring kits on hand.

for sizes not in the standard kit, there is always McMaster Carr.

 

[QBhoy]

That just does not seem right....even my ancient 4.3 with the 4bbl Quadrajet doesn't do that with the slow-to-open up auto choke!

I suppose it’s a very different engine from the carb. My old carbs used to black smoke on warm up...the mpi throws raw fuel into the water. I think it’s further worsened with mine because of the cam in mine.

 

[QBhoy]

you have a fuel injected engine. there is a fuel cooler, specifically the module that the fuel pumps sit in is water cooled. it is a few stamped pieces and a few machined pieces that are brazed / soldered together. there are two locations that if there is a seam leak, will leak high pressure fuel into the raw water stream.

pressure test the raw water side with air, 15-20 psi should hold forever.

May be wrong but I don’t think they are all fuel cooled systems. Don’t think mine is. Or it certainly doesn’t have the cool fuel at least.

 

[Lou C]

Mine does neither, but I made sure that the choke pull off works. With a carb engine if it puts out black smoke and runs rough after a cold start often its that the choke pull off doesn't work or wasn't set right in the first place. Cooling water coming out is clear and does not smell like gas. An EFI engine should put out a pristine exhaust flow by comparison. Mine is like a 1966 Chevy! No emissions controls what-so-ever. Even then, back in the day our carbed cars with auto chokes did not smoke.

 

[rmurray]

The O rings from ManCave mechanic came into days. Instead of O-rings for the entire fuel pump for $30 delivered. I cleaned it, assembled it, and got it installed. I no longer have fuel in my exhaust. That was definitely the issue. I’m getting 10 psi on the low side and 50 psi on the high side. Everything seems to be working correctly and I’ll be taking it out tomorrow for a test run.

 

[Scott Danforth]

Thanks for closing the loop on the issue