opinions on vapor recovery system please

[GregWeld]

There's no good reason to have a vacuum leak in any motor. A PCV is a CONTROLLED vacuum leak.... and that would be "tuned" along with the car. Plug it with your thumb and your RPM's will rise... but the point is that it's in the mix when the car is being tuned.

Now you have an uncontrolled vacuum leak. What happens to the motor when you plug it up?? Depending on your system (ECU) you may have to go back and redo the VE table as the MAP sensor may (should) see a completely different signal.


The system you describe is overly complicated given our cars - and their "smog" requirements. Lots of people have gas smell in their garages... and nobody likes or wants that. That is the type of HOSE used in the fuel system. Todays gas has all these new formulations and the gas fumes escape the old style hose rubber. This smell can be eliminated by switching the flex lines to Teflon braided hose.... or a rubber style hose that states it's okay for the new fuels.

I'd call DSE and ask if they remember doing this particular job - and why it was installed and maybe you can get a better understanding of what you have.

[69hugger]

Originally Posted by GregWeld

There's no good reason to have a vacuum leak in any motor. A PCV is a CONTROLLED vacuum leak.... and that would be "tuned" along with the car. Plug it with your thumb and your RPM's will rise... but the point is that it's in the mix when the car is being tuned.

Now you have an uncontrolled vacuum leak. What happens to the motor when you plug it up?? Depending on your system (ECU) you may have to go back and redo the VE table as the MAP sensor may (should) see a completely different signal.


The system you describe is overly complicated given our cars - and their "smog" requirements.

Great points. Completely agree.

Lots of people have gas smell in their garages... and nobody likes or wants that. That is the type of HOSE used in the fuel system. Todays gas has all these new formulations and the gas fumes escape the old style hose rubber. This smell can be eliminated by switching the flex lines to Teflon braided hose.... or a rubber style hose that states it's okay for the new fuels.
Most of the lines in the car are either solid steel or newer braided fabric or braided stainless/ teflon hose. EXCEPT some of this evap system is old fashioned rubber fuel line.


I'd call DSE and ask if they remember doing this particular job - and why it was installed and maybe you can get a better understanding of what you have.
I have been trying to contact them as little as possible because they didn't build the car for me, hence, I am not really their customer. I have been trying to not wear out my welcome.... but I think this is worth at least asking. I think it was the previous owner that objected to the smell, and that was probably why the system was installed along with the F.I. system.

The more I think about it, I think the most logical route is to just not run the vacuum line from the charcoal canister to the TB. I will just leave that open to atmosphere, and plug the vacuum port on the TB. It will be interesting to see how much the A/F tuning changes, but as I am changing the heads/ cam/ comp. ratio, and re-ringing the engine, I guess we are starting from scratch anyway. I can always re-connect the last line & see what happens tune up wise if for some reason the need arises.

Thanks for the input!!

Bill