echappe
Well-Known Member
before I start removing interior pieces, can anyone tell me where the vent line from the fuel tank goes after it leaves the grey expansion tank next to the wheel well?
Thanks,
Ernest
Thanks,
Ernest
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fuel tank vent
- Thread starter echappe
- Start date
tank , fuel, vent
Try this: http://www.e9coupe.com/forum/showthread.php?t=5480&highlight=fuel+tank+vent
Try this: http://www.e9coupe.com/forum/showthread.php?t=5480&highlight=fuel+tank+vent
pamp
Well-Known Member
Evap
I am always amazed to find out new things regarding the coupe on a near daily basis...thanks to all who post, especially those who work in the field. OK...now my coupe is a CS with a D-jet transplant and I have been wondering since my purchase about the trunk expansion tank as well as the charcoal can. I do get intermittent vapors noticeable while driving, no leaks. The charcoal can is still hooked up to the vacuum line that feeds the distributor. Near as I can tell, the can is also still hooked up to the line back to the trunk. Also my gas cap appears to be of the non-vented type. If I understand Mr. 61 properly, I should disconnect the canister as well as the lines to the expansion tank from the tank. What is still unclear is what style of gas cap should be used with EFI? I kind of figured that this emission stuff on my car was a remnant of it's carb'ed days and was not addressed properly at the time of conversion by the PO Thanks before hand if we can get some instruction in this regard. Oh, I also get a intermittent "breathing" sound while braking that I am sure has to do with how the car is plumbed, vacuum - wise at present. Probably pulling vacuum on the tank?
I am always amazed to find out new things regarding the coupe on a near daily basis...thanks to all who post, especially those who work in the field. OK...now my coupe is a CS with a D-jet transplant and I have been wondering since my purchase about the trunk expansion tank as well as the charcoal can. I do get intermittent vapors noticeable while driving, no leaks. The charcoal can is still hooked up to the vacuum line that feeds the distributor. Near as I can tell, the can is also still hooked up to the line back to the trunk. Also my gas cap appears to be of the non-vented type. If I understand Mr. 61 properly, I should disconnect the canister as well as the lines to the expansion tank from the tank. What is still unclear is what style of gas cap should be used with EFI? I kind of figured that this emission stuff on my car was a remnant of it's carb'ed days and was not addressed properly at the time of conversion by the PO Thanks before hand if we can get some instruction in this regard. Oh, I also get a intermittent "breathing" sound while braking that I am sure has to do with how the car is plumbed, vacuum - wise at present. Probably pulling vacuum on the tank?
pamp
Well-Known Member
Evap +
Back out from the shop to review...the liquid/ vapour separator...one line to the filler neck and one line forward to the engine bay to the charcoal canister. I have suction and return lines on the tank itself. Should I disconnect the vacuum line forward and then delete the canister from engine vacuum? This line then routed from the trunk to say the rear fender (sunroof drain line hole) to be vented to atmosphere? Not very P.C. but there you go. The manuals are as clear as mud on this one...blue book shows carb picture only. Haynes shows a picture with the evap. stuff used for EFI. I would bet the old char. can is toast at this point and would be tough to change. My battery tray is welded to the chassis. Dying to get feed back...
Back out from the shop to review...the liquid/ vapour separator...one line to the filler neck and one line forward to the engine bay to the charcoal canister. I have suction and return lines on the tank itself. Should I disconnect the vacuum line forward and then delete the canister from engine vacuum? This line then routed from the trunk to say the rear fender (sunroof drain line hole) to be vented to atmosphere? Not very P.C. but there you go. The manuals are as clear as mud on this one...blue book shows carb picture only. Haynes shows a picture with the evap. stuff used for EFI. I would bet the old char. can is toast at this point and would be tough to change. My battery tray is welded to the chassis. Dying to get feed back...
Pamp,
My charcoal canister is left in place but plugged on the vacumn side. ( I don't have any emissions eq. ) While the battery tray is welded, below the battery are two bolts that hold the cannister by a strap.
With a motronic... some hook it up, some don't. There's a provision for a purge valve though. But If you have vacumn hooked up full time then , no: disconnect it. That's not how it works.
At some point ( late 72,,,) carbed cars also had a return line. Don't know why or what for.( stupid emissions)
Since you haven't collapsed your tank yet, you're probably golden on the gas cap vent. It's hidden behind the gasket or seal anyway. I know mine is vented ; it's one way though, only into the tank.
Gas smells can come from a lot of places... loose hoses/ clamps, sender ring gasket, cracked rubber at the filler, loose neck, bad overflow hose. I once saw a car with 4 gas filters on it.. guess the owner thought more was better untill he didn't get gas because of the restrictions.
if I didn't answer everthing- try again. Always glad to help.
My charcoal canister is left in place but plugged on the vacumn side. ( I don't have any emissions eq. ) While the battery tray is welded, below the battery are two bolts that hold the cannister by a strap.
With a motronic... some hook it up, some don't. There's a provision for a purge valve though. But If you have vacumn hooked up full time then , no: disconnect it. That's not how it works.
At some point ( late 72,,,) carbed cars also had a return line. Don't know why or what for.( stupid emissions)
Since you haven't collapsed your tank yet, you're probably golden on the gas cap vent. It's hidden behind the gasket or seal anyway. I know mine is vented ; it's one way though, only into the tank.
Gas smells can come from a lot of places... loose hoses/ clamps, sender ring gasket, cracked rubber at the filler, loose neck, bad overflow hose. I once saw a car with 4 gas filters on it.. guess the owner thought more was better untill he didn't get gas because of the restrictions.
if I didn't answer everthing- try again. Always glad to help.
Last edited:
pamp
Well-Known Member
OK
As I understand, go ahead and delete, then vent the separator can to atmosphere vs the engine. Of coarse I can see how the char. can is mounted, yet it looks to me as the alternator would need to get out of the way...
As I understand, go ahead and delete, then vent the separator can to atmosphere vs the engine. Of coarse I can see how the char. can is mounted, yet it looks to me as the alternator would need to get out of the way...
echappe
Well-Known Member
the thing that puzzles me is that my fuel tank gets pressurized to the point that when I remove the cap the accompanying rush of air and fumes out of the tank is noteworthy. Mine was originally a 70' 2800CS which now has an 89 M30 B35 with carbs. It did this with the original mech fuel pump and still does with an electric pump. there is no return line.
Any thoughts on this/
Ernest
Any thoughts on this/
Ernest
pamp
Well-Known Member
Evap
This is a great thread as I am quite certain the "set up" as per stock is sucky...as to say a source of trouble. I am in the hot rod group and do not worry about judges, unless busted for excessive speed. Would love to hear what sfdon would say. I am of the notion to keep the trunk can in place, connected to the filler neck and then vent this out the right rear fender. This would keep the tank close to atmospheric regardless of fuel return. Delete the char.can and vacuum lines associated with this. Simple. Again, I do see that the blue book warns against getting the fuel tank caps mixed up, explanation is nebulous.
This is a great thread as I am quite certain the "set up" as per stock is sucky...as to say a source of trouble. I am in the hot rod group and do not worry about judges, unless busted for excessive speed. Would love to hear what sfdon would say. I am of the notion to keep the trunk can in place, connected to the filler neck and then vent this out the right rear fender. This would keep the tank close to atmospheric regardless of fuel return. Delete the char.can and vacuum lines associated with this. Simple. Again, I do see that the blue book warns against getting the fuel tank caps mixed up, explanation is nebulous.
When I converted from carbs to D-jet, I had to do something with the evap line so I drilled a small hole in the lower half of the air filter box and hooked up the evap line to a tapped piece of copper tubing I installed. The vacuum in the air intake takes care of any vapors. No charcoal canister used either (removed and discarded by the PO anyway.) Not PC, buts it seems to work OK.
It seems to me that if there is no evap. line from the tank or it is clogged (or blocked with a ball bearing as mine was!), gas expansion/contraction due to temperature changes would be very problematical, and would explain the build-up of pressure in the gas tank.
It seems to me that if there is no evap. line from the tank or it is clogged (or blocked with a ball bearing as mine was!), gas expansion/contraction due to temperature changes would be very problematical, and would explain the build-up of pressure in the gas tank.
pamp
Well-Known Member
Fuel Tank
I went ahead and did some re-plumbing...Renewed the hose from the filler neck nipple to the liquid/vapour reservoir (lower connection) as well as the hose at the upper connection. This I ran out the right rear fender hole alongside the sunroof drain hose just behind the right rear wheel. The blue plastic hose is now disconnected, yet still in place. No more vacuum connection to the charcoal can. Took her for a test drive and bingo...no more "eau de petrol" Still have a strange sound coming from the right rear of the car under light braking.
This I am starting to think is being caused by a possible bad brake hose and hydraulic in nature, no pulling though...new stainless hoses are on the bench and will go in when I replace the springs with the LaJolla pieces. To those that have a pressured tank, I would be concerned. It takes very little pressure to rupture a tank. Vent the tank to atmosphere if you can get away with it, as I did. Otherwise, I like what Bill did. Yet I would be inclined to run a new line outside of the passenger compartment. Seems like kind of a design flaw to run a line with fuel vapours through the interior of the car, as BMW did. I now have no worries in this regard, thanks to all who posted.
I went ahead and did some re-plumbing...Renewed the hose from the filler neck nipple to the liquid/vapour reservoir (lower connection) as well as the hose at the upper connection. This I ran out the right rear fender hole alongside the sunroof drain hose just behind the right rear wheel. The blue plastic hose is now disconnected, yet still in place. No more vacuum connection to the charcoal can. Took her for a test drive and bingo...no more "eau de petrol" Still have a strange sound coming from the right rear of the car under light braking.
This I am starting to think is being caused by a possible bad brake hose and hydraulic in nature, no pulling though...new stainless hoses are on the bench and will go in when I replace the springs with the LaJolla pieces. To those that have a pressured tank, I would be concerned. It takes very little pressure to rupture a tank. Vent the tank to atmosphere if you can get away with it, as I did. Otherwise, I like what Bill did. Yet I would be inclined to run a new line outside of the passenger compartment. Seems like kind of a design flaw to run a line with fuel vapours through the interior of the car, as BMW did. I now have no worries in this regard, thanks to all who posted.