evap valve

[pff]

'99/-00 V70 NA
ECU gives me a code for long term fuel trim hitting upper limit.
I read off the long term fuel trims and sure enough long term fuel trim 1 is 1.2something, 2,3,4 and 5 are all 1.0x~.
My understanding is that LTFT 1 corresponds to the engine at idle, where vacuum is high, and so this corresponds to a vacuum leak.

Second problem i have is that the car won't start after refuelling.

So putting on my detective hat i clamped off the hose from what i think is the evap valve on top if the radiator fan into the intake manifold, LTFT immediately dives down to ~1.0 and stays there. also a change in engine note.
I was watching also the evap valve value which should have been closed.

I took the clamp off the hose again but the LTFT value stayed at ~1.0, but the ECU was reporting that it wasn't in adaptive fuelling mode (not sure of the term) for whatever reason (?!) and so i think i shouldn't have expected the LTFT value to change again?

I have checked the parts diagrams and for my VIN emission code (F) it loks like i should have just one evap valve at the front, a round carbon cylinder (somewhere?) and thats all there is to it.


So my question really is, are there any other parts/valves of my evap system I should check? Also the hose i clamped is pretty badly deteriorated, if this is carrying fuel vapours do i need to be cautious about what material it is made of? finally is it safe or a good idea to leave this hose clamped off until the valve is replaced?

thanks.

[Clan]

Originally Posted by pff

'99/-00 V70 NA
ECU gives me a code for long term fuel trim hitting upper limit.
I read off the long term fuel trims and sure enough long term fuel trim 1 is 1.2something, 2,3,4 and 5 are all 1.0x~.
My understanding is that LTFT 1 corresponds to the engine at idle, where vacuum is high, and so this corresponds to a vacuum leak.

Second problem i have is that the car won't start after refuelling.

So putting on my detective hat i clamped off the hose from what i think is the evap valve on top if the radiator fan into the intake manifold, LTFT immediately dives down to ~1.0 and stays there. also a change in engine note.
I was watching also the evap valve value which should have been closed.

I took the clamp off the hose again but the LTFT value stayed at ~1.0, but the ECU was reporting that it wasn't in adaptive fuelling mode (not sure of the term) for whatever reason (?!) and so i think i shouldn't have expected the LTFT value to change again?

I have checked the parts diagrams and for my VIN emission code (F) it loks like i should have just one evap valve at the front, a round carbon cylinder (somewhere?) and thats all there is to it.


So my question really is, are there any other parts/valves of my evap system I should check? Also the hose i clamped is pretty badly deteriorated, if this is carrying fuel vapours do i need to be cautious about what material it is made of? finally is it safe or a good idea to leave this hose clamped off until the valve is replaced?

thanks.

the tank breathes through that hose , clamp it off where it goes into the engine but leave the end which goes to the tank open ...