Evap issue? Vacuum leak?

[timboku]

Ok so I have a pesky vacuum leak I think I cannot locate....stfts at idle are +10 and ltft maxed at +16..when driving stfts get more normal while ltfts stay pegged..at more than 70 percent throttle they both go to 0 and stay up there untill i let up.
Anyway, had car running and was pumping gas and looked at stfts and they were perfect at idle with gas cap off..ltfts still maxed..finished pumping and put gas cap back on they go back to +10 stft. What would cause this? I have a top swapped l26 with a gen v and ssic with gen 3 tb tapped for pcv..utilizing the gen 3 evap solenoid..any thoughts..no ses except good ol 171.

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[Scottydoggs]

try spraying some carb cleaner at the vac lines and sensors with a vac line to them. if the idle jumps up you found the leak area.

if you get no results try moving the lines while spraying them.

the fat evap vac line off the side of the TB likes to break in the curl/bend so it can get to the back vc to the evap solenoid.

[timboku]

Oh ya I know..went thru 2 bottles of spray..no luck..replaced many lines incliding one under sc...heat control one..map sensor..pcv valve..checked and sprayed egr pipe..not sure where it is..either ssic is warped..I spray all around it no change in idle..or maybe the sd headers leaking..they are wrapped in header wrap so not sure...just thought it was weired when u take cap off trims run better...and evap line is good and even zip tied

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[Scottydoggs]

thats odd for sure. maybe somethings up with the canister tank or one of the solenoids.

[timboku]

Think I got a spare senoid so may swap that out just to see.

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[Scottydoggs]

crazy as it sounds i had a evap code that a new map sensor fixed lol

i got a egr and a evap code as we speak, they are both getting deleted, this is the 3 rd time ive had to fix both. im done.

[timboku]

I put a new map sensor in when I swapped the new vac lines in...Im gonna delete my 0171..lol...gotta dig up that evap seniod and try it...thing runs great just missing out on some mpgs im sure.

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[231FUN]

Evap directs fumes/vapour from fuel tank to the intake instead of venting them to the atmosphere like old school cars...hardly a mpg gain worth worrying about IMO.
I deleted that crap long ago... more trouble than it's worth!