fuel leak> evaporative canister

May 3rd, 2003, 07:02 AM

<240 fuel leak> evaporative canister
1990 240sx hatchback, 160k miles. still a1. 2nd owner for last several years..
after hard drive, 1/2 hour+, fuel streams out of evaporative canister,
engine stalls/floods. relive pressure on tank, restart and it runs fine again for a week or so.

had evaporative canister, valve and gas cap replaced.
in past has blew a few fuel lines and pin hole in tank filler, all replaced/repaired.
still happens, repair shop/local dealer(haha) mystified.
overpressure?,
pressure seems ok, but is intermittent fault so never happens at shop, even after them driving it for a week.

love the car[not as much as my '86 300z], help please!!! peter in Ontario.
sailer291@hotmail.com

aaronford
Nissan Enthusiast

Registered: Mar 2003
Location: Morgantown, WV
Car: 95 Nissan Pickup E
Posts: 101
I take it you did install a vented cap? A nonvented cap will cause a problem, but its usually due to the fuel pump pulling a vacuum on the tank, not the other way around. Try running it with the fuel cap removed and see if it does it... Hopefully this does not cause a condensation problem... It is obviously an overpressure problem, but I do not understand why. Check the line running parrallel to the fuel filler and see if its blocked/clogged/kinked as this is how vapor escapes the tank. Has there been any mods to the car, any quick fixes, any known problems? Has the gas tank been replaced before? Write back and tell us more. You might also try to post this on the truck page as you have the same setup that my 95 PU does. Aaron

sailer291
NissanForums Newbie

Registered: May 2003
Location: ontario canada
Car: 240sx 1990 hatchback se
Posts: 3
thx, its a help.
no mods, quick fixes. all started when fuel line had hole and local cowboys snapped the sender pipes when replacing fuel lines.
new nissan sender, then nothing but continual leaks, and overpressure. tank subsequently removed after pin hole leak by new shop
l will have local shop remove sender and check lines, even drop tank.they will do work for nominal charge as new canister/valve/cap etc, did not fix prob.
could the return line be too far into the tank, or is it a fixed factory steel line?

aaronford · May 3rd, 2003, 10:07 AM

There should really be no way for the fuel to get back up the evap line unless the sender was installed incorrectly (ie the vapor recovery line was submerged.)
If I remember correctly, there are three lines going to the fuel sending unit. The pressure (feed) line, the return line, and the vapor recovery line going to the evap cannister. If the latter two were mixed up, it might cause the problem you suggest. This is from my experience with GM cars, let me go out and check my pickup and I will get back to you. Aaron

aaronford · May 3rd, 2003, 12:15 PM

Hey, I looked at my PU and I was right. There are three lines that run side by side. One 1/4 inch fuel line and 2 3/16 lines. Of the two smaller lines, one goes to the cannister and the other is indeed the fuel return. Now to map them out. The vapor return line starts at the cannister and goes to the tank stopping at a fitting on the side of the tank (?) and continues to the top of the tank. The last stretch of hose on my truck is red for some reason. The fuel return line starts at the fuel regulator (on the fuel rail, opposite the feed line) and runs with the others to the tank. It enters the tank right beside the fuel feed line as opposed to the vapor line which enters the tank seperately from the others. Check to see if the yahoos might have crossed these up as they are the same diameter hoses. I will include pictures if you need them. Aaron

May 4th, 2003, 08:09 AM

thx Aaron, should nail it. have car booked am mon for sender/tank/line inspection and will post results, thx again.
peter

May 6th, 2003, 04:23 PM

thx Aaron.
shop found vent line off its clip inside the tank and submerged in the fuel, thats why the probs were inconsistent, depends on fuel level.
internal clip broken, best fix:new tamk [wow]
his fix; 10cent fuel proof tie to sender body. this clip/line resides in a hump in the tank so was missed the last go around.
this at no charge as the fuel canister did not need replacing.

thx for guidance.
the great Nissan Guy will reward you for your good deeds.
peter

aaronford · May 6th, 2003, 09:58 PM

Cool, glad you found it. I have taken it as a rule to always question the work prior, as this is the case in about 9 out of 10 where work has recently been done. I have seen it all: brake pads installed backword, vacuum lines left off, bearings/joints not greased, components miswired, etc... You always see the one where the guy put a stereo in and now his dash lights do not work... Or the mysterious extra part. Aaron