[djed]

http://www.suzistore.com.au/shopexd.asp?id=378

I was just wounder if anyone knows what the bottom gray pipe on the SJ80 fuel pump is? I am guessing it might be a vacum line which might advance the pump rate ???

[bagnkat]

djed wrote:

http://www.suzistore.com.au/shopexd.asp?id=378

I was just wounder if anyone knows what the bottom gray pipe on the SJ80 fuel pump is? I am guessing it might be a vacum line which might advance the pump rate ???

It's a cam driven pump, so rate is directly proportional to rpm, and the line is an overflow in case the pump shits itself internally.

[djed]

bagnkat wrote:

djed wrote:

http://www.suzistore.com.au/shopexd.asp?id=378

I was just wounder if anyone knows what the bottom gray pipe on the SJ80 fuel pump is? I am guessing it might be a vacum line which might advance the pump rate ???

It's a cam driven pump, so rate is directly proportional to rpm, and the line is an overflow in case the pump shits itself internally.

sweet. so what should it be hooked up to? someone has plumed mine up to a vacuum line on the intake manifold

[bagnkat]

Mine was never hooked up to anything I'll try and find you a photo from when I did the engine swap in mine.

Edit: This is the only photo I could find. I definitely didn't disconnect a vacuum line from it. I guess it's possible that it may have had one which was removed prior to my owning it - maybe to return spilt fuel through the carbon cannister. Do any other coily owners have it on theirs?

[djed]

yeah i am trying to suss those hoses on mine.

my fuel pump overflow is plum up to the carbon canister pipe (which someone has cut out for a battery tray). the solid pipe to carbon canister has then been joined back up to a pipe that runs back to a vacuum line on the intake manifold.

while the solid fuel tank breather line has been bolted up ????

[losfer]

if you have a vacuum hose connected to it , thats most likely your problem , it will stop the pump from pumping fuel and make it jerk.

the pipe is just a telltale for oil to escape when the pump seals are screwed

[djed]

hmm very interesting. i was chancing any vacuum leaks as i had a irregular idle some times (1000 rpm dropping down to 200rpm) and i noticed that the intake and exit pipes where the charcoal filter was were just connected together with a rubber hose that was too big. I thought this was my vacuum leak so i sealed it up with two hose clamps.

while i was at it also replace my plastic fuel filter with a finer fuel injected fuel filter to try and stop the idler jet getting clogged.

Then when i took it for a test run it was occasionally leaning and stilling. I just assumed it was the finer fuel filter restricting the flow of fuel .... could have been the vacuum on the fuel pump making the diaphragm jerking

[losfer]

i can assure you that vacuum there will cause a fuel pressure drop problem

[bagnkat]

djed wrote:

yeah i am trying to suss those hoses on mine.

my fuel pump overflow is plum up to the carbon canister pipe (which someone has cut out for a battery tray). the solid pipe to carbon canister has then been joined back up to a pipe that runs back to a vacuum line on the intake manifold.

while the solid fuel tank breather line has been bolted up ????

Also sort this out. Fuel can't get out properly if air can't get in to replace it.

Sounds like the whole set up has been bastardised.

[djed]

bagnkat wrote:

djed wrote:

yeah i am trying to suss those hoses on mine.

my fuel pump overflow is plum up to the carbon canister pipe (which someone has cut out for a battery tray). the solid pipe to carbon canister has then been joined back up to a pipe that runs back to a vacuum line on the intake manifold.

while the solid fuel tank breather line has been bolted up ????

Also sort this out. Fuel can't get out properly if air can't get in to replace it.

Sounds like the whole set up has been bastardised.

yeah definatly mucked around with. Should i plum up the fuel tank breather pipe to the airbox or a vacum line off the intake manifold?

I was think airbox with a one-way value so it only allows air in and not fuel / air out.

[djed]

Does anyone know where i should pump my fuel tank vent pipe to if i do not have a charcoal canister? carbie vacum line, air box or block it off all together?

[steak_knife]

djed wrote:

Does anyone know where i should pump my fuel tank vent pipe to if i do not have a charcoal canister? carbie vacum line, air box or block it off all together?

No, no & no....
get a cheap fuel filter & put it higher than the tank & nowhere near spark's or heat...

Or, get a charcoal canister, safer....