Fuel leak/fuel vapour smell on cold idle 3S-GE

[Andrew162]

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..

[thechuckster]

disconnect the cold-start injector wiring and/or fuel line and see if problem goes away?

vacuum line from charcoal canister to manifold (via VSV on hot water outlet) OK?

[Andrew162]

Thanks Chuck, the vacuum line from charcoal canister to the manifold gives me another avenue to explore, and actually I've had a few suggestions alluding to the same thing for another problem (lumpy cold idle) which isn't a TPS or ISCV issue (I've changed the ISCV over already) and the TPS values are all normal... the hot water outlet could just be the problem that ties these issues together. I haven't had a cold start injector since I ditched the Gen1 3S.. it's a Gen3 (1996) in there now. Cheers for the info, I'll have a look at it.

[thechuckster]

fwiw, I haven't had a look at a Gen3 wiring diagram, but some models use an electric solenoid instead of temp-switched valve to connect the canister up to the inlet manifold. Just trace the thin vacuum line leaving the canister. If it's OK, then I suggest standing back from the engine bay and spraying it with a loud and angry stream of invective. Might not achieve much but it helps relieve stress.

[Andrew162]

Vac line leaving the canister appears ok..

Got video of the leak from late last year, might make things clearer, might not.. this leak was bad enough that it seemed to be coming from two places in the engine bay. It's not hunting at cold-idle as bad now either.

https://www.youtube.com/watch?v=gRsqYh9VHFw

[jonathan yee]

I wouldve thought fpr, due to it actually affecting idle.