Heavy fuel fume from newly installed EFI system
 

I recently converted my carburated 383 from carb to the Big STuff 3 single plane EFI with a 1,000 CFM Edelbrock throttle body. Air cleaner is 14x3 K&N filter. The car runs extremely well with no driveability problems normally associated with carburated vehicle especially when starting from cold.
Right now, there is one thing that is really bordering me a lot is the excessive fuel fume coming from the car. I have left my car in the garage for over 3-4 days without driving it, there is still a strong fuel fume lingering in the air. I have checked for fuel leak or anything that could cause the smell but couldn't find anything wrong. Before I takie it back to my shop, can someone please help me to identify the possible culprit. For the record, I have also installed new fuel system including fuel tank, in tank pump and new fuel lines as well.

Please help,

Nelson

Re: Heavy fuel fume from newly installed EFI system
 

Could be fuel in the intake. If it's batch fire you could have some residual fuel left over after you shut it down.

Or you could have a leaky fuel rail that is just enough for a small but no real volume/pressure loss.

-- Joe

Re: Heavy fuel fume from newly installed EFI system
 

If it is the case, can I change the air filter to an enclosed one which hopefully can keep the fume at bay? What type of filter would you recommend?

Thanks,

Re: Heavy fuel fume from newly installed EFI system
 

I had a similar problem on my 86 iroc... Mine turned out to be a bad gasket where the fuel sending unit mates to the tank. Could also be the fuel filler neck is cracked where it meets the tank. You can check for both of these problems by removing the fuel vapor check valve ( small off-white filter-lookin thing on drivers side above rear axle) and pressurizing it with compressed air. this pressurizes the entire fuel system, including the charcol cannister. dont use more than 30 psi as more could damage the system. wait about ten minutes and see if fuel or vapor is leaking. the system should hold this pressure indefinately.
Good luck!

Re: Heavy fuel fume from newly installed EFI system
 

see you,


This might sound a bit basic but did you check your gas cap itself? It happened to me a while back I just replaced the cap and the fuel smell went away. Its worth it to check though. Start checking the easiest/cheapest parts to find on your fuel system then work from there.


Rabi C.

Re: Heavy fuel fume from newly installed EFI system
 

Thank you everyone for all the great suggestions and finally I brought my car back to the garage and have them checking the car out. Their finding was there were two fuel venting lines that they forgot to plug up which cause the heavy fuel fume. I now have my car home the smell seems to have subsided a lot but I am not sure it is totally eliminated. Also I suspected the two tiny cat converters that I have on my car is not doing as well a cleaning job as when they were new.
One further question that I have with my car is, I am running 50 lb injectors in a 383 small block with 10.5 to 1 CR and the engine put out 370 whp in a dynojet dyno, The A/F ratio is a flat 13.4 throughout the whole power curve. it seems like I am using too big an injectors. Do you guys think this will also cause heavy exhaust fume.

Thanks again
Nelson

Re: Heavy fuel fume from newly installed EFI system
 

If your running E10 fuel...probably need to richen it up some unless it made more power at 13.4:1 fuel. E10 fuel likes to be closer to 12.5:1 and I know most states are switching to it.

On my 383 HSR, I run 32s but I need to upgrade to 36s. Orr with his 400rwhp 383 runs 42s but he has a wet shot of nitrous on the car as well so...his was probably more for caution reasons.

Re: Heavy fuel fume from newly installed EFI system
 

I have finally found out the culprit for the gas fume; it wasn't the unplug vent line from the tank, it was because the charcoal canister has been removed previously. When the car was running with the carb, the lower fuel pressure did not cause too bad a fuel smell but when the new EFI system is installed and the fuel lines are now operating at 40 psi, the fuel smell now becomes too much to ignore. We installed a small charcoal canister from a KIA car immediately correct the problem. Once again thank you for all the good advice.

Re: Heavy fuel fume from newly installed EFI system
 

Glad to hear it! I figured it would have to be one of your vapor lines...

Re: Heavy fuel fume from newly installed EFI system
 

I previously thought I had the problem resolved after putting in a charcoal canister, but no, only after a day later, the fuel smell is slowly coming back again. I left with no choice but sent the car back to the shop again.
This is what they had done in the past two week:

1. Replace the brand new fuel tank (under warranty) with another unit, they said they found a crack in the fuel neck;
2. Replace the evap solenoid in the back of the fuel tank because it is not holding pressure;
3. Replacing the fuel cap with a non-vented one;
4. Today, the told me it is the brand new Russell Proclassic Hoses that is sweating out fuel that caused the smell. They called up Russell (Edelbrock) technical support and they told us that they had a few similar complaints from people who used this type of fuel hose and at least they are willing to take it back for a refund. My mechanic is now in the process of bending some new solid fuel lines for replacement.

http://www.russellperformance.com/mc/hose/main.shtml
The black line with blue dots in the middle is the one that I used in my car

Hopefully, next week when I get my car back we have the problem solved. I really miss my car because I only put in very few miles since I had the EFI installed.

Nelson

Re: Heavy fuel fume from newly installed EFI system
 

That sucks man. Hopefully you get it fixed. Nothing more annoying than an ongoing problem. It usually turns out to be something really complicated or really stupid.

Re: Heavy fuel fume from newly installed EFI system
 

I was about to ask you what hose you used. I went through the same problem you were having with their ProFlex two years ago. I replaced it with Aeroquip and "fixed" it. I hate to hear it's not isolated and Russell is still having some problems with the hose you were running also.