I've had this issue for a while, basically it will leak fuel from sources unknown on cold idle on some days without any trace of where the leak is to be found. Other days the fuel leak won't be present but the smell of fuel or fuel vapour will be strong in the air. There seems to be no commonality with each time this happens, just that sometimes it does and sometimes it doesn't leak. Once the engine is warm the fuel leak disappears. So unlike any regular fuel leak (cut line, puncture, etc.) this is coming from the engine bay but I haven't been able to trace it to a source. The fuel line is fine, fuel filter doesn't leak, fuel rail is ok, I thought one of the injector o-rings might have been shagged so I had those serviced a while back but they were fine on inspection, although they were replaced for new units, there seems to be nothing wrong with the fuel return so I'm out of ideas.. where else could a fuel leak or fuel vapour smell come from on cold idle? I thought about the charcoal canister but I've seen nothing wrong with this either. Any useful advice appreciated, thanks..
Next time smell your exhaust, if it's not dripping anywhere I would'nt worry about it I had the same with one of my 3S-GE's but scrapped it before I could find the problem, I suspected idle mixture too rich due to a dud sensor, O2 sensor etc Charcoal canister - I think can buildup vapour/get contaminated and they aren't meant to last 20yrs. Problem there is the TB-canister vacuum line only opens when the throttle opens - maybe you got constant vacumm?
pcv or egr system? canister is also a good guess, i would assume its not there since its a swap. so may be the way in which it was deleted. e.g. might need to vent the tank rather than cap the line? if its capped the pressure in the tank will rise and fall with fuel level and ambient air temp. i had 09's capped and both those would make a massive change in the tank pressure. (as judged by popping the cap off the tank.) sometimes it would blow the cap out of your hand went you went to fuel. NO JOKE!
Hey guys, sorry I haven't been in here for a while and they are some good diagnoses, but I still haven't found the problem. The idle also fluctuates on cold (and also briefly at warm kick-over idle), but the cold start is where the problem is. I've tried replacing the ISCV, I've had the TPS inspected and tested, given the all clear.. someone suggested fuel pressure regulator but I'm not sure. If it helps anyone in diagnosing my problem I've taken a vid of the car at cold idle.. http://youtu.be/gRsqYh9VHFw it seems to leak from two places but I'm fairly sure the leak is in one area only.
That leak looks like the fuel return hose is leaking. You need to pull the injector rail and replace it and I'd suggest new injector O-rings and gaskets as well. Looks to me like she's sucking air at one of the injectors, I've also seen this happen when the AFM flap is set too loose and the motor gets too much fuel and can't adjust the mixture
Thanks stig but the injectors got a full service only a few months ago when I was trying to eliminate problems. Also it's a 3rd gen engine so no AFM to worry about, only a MAP sensor. I'll have a closer look at the injector rail but I can't find any traces of leaks.
