MattR

OK unique problem, or I atleast I think so. On my 96 Runner with the 3RZ It has developed a loud click that I thought was coming from behind the gauge cluster...yeah I know. Well turns out the noise was under the hood, At first glance and listen I thought it was a VSV making that noise but its not it is a Vapor Pressure Sensor for the EVAP..here is the diag, its circled in red Well when I first start it up in the morning its fine, then when you drive it around warm it to normal ops temp. this little bugger starts clicking, or ticking and its loud sounds like an old fashioned alarm clock ticking, but loud enough to be heard in the cab with the engine idling. Shut the engine off and start it up again it goes away, drive it around a little and it comes back. No vaccum lines are disconnected, no CEL or anything like that. It has been damn cold here the last two weeks like single digits to -10, dont know if its cold related or not, but as soon as this showed up I have also experienced another problem, occasionally on cold days the 4Runner lacks power, big time like you have to floor it to maintain 75, Hmm is this Vapor pressure sensor clicking like mad and the loss of power related?? Anybody know what this pressure sensor does exactly?? Anyway to bench check it?? Im not buying a new one just for the hell of it until I figure out what the whole story is. Thanks in advance.

Matt Rogers

MattR

Anybody, got some "idears" Im still stumped.

SLOYOTA

I'm by no means an expert on this. However, my first action would be to replace the PCV valve (it's cheap). The diagram seems to be showing that the PCV valve allows the entry crank case vapors into the circuit. Maybe its plugged and restricting the proper flow through the circuit and causing the vapor switch to go wacko. The intermittent poor acceleration you mentioned could also be tied to the PCV valve.

BustedTaco

This is just during start-up, in the cold weather?
Mine does it too. I'm told is just some valve noise and is normal in cold weather for the 2.7L.
Seems less noticable to me 1) after an oil change. 2)with 5w-30 instead of 10w-30. Seems more noticable when I use Mobil1 synthetic. Could all be unrelated, but thats what I've noticed.

MattR

Hey thanks, thought I checked that already, but Ill check it again, and maybe replace it, cheap insurance. Any other ideas??

Matt

towotaguy

Was the PCV the problem?