Subject: Re: Running rich and hunting for idle by bogus on 2014/9/5 17:48:03
Quote:
lunytnz wrote: Quote:
Schrade wrote: Maybe get the tune diagnostic BEFORE putting in a new O2.
Rich burn might foul the O2 element. It WILL foul cats...
That's *exactly* what I was hoping to do, Schrade. But, I'm not able to figure out, so far, what the cause might be. I have heard that the O2, itself, might be the cause.
The part that has me most confused is that I'm getting the 45 code (running rich), but the MPG on the dash (which I believe is based on pulse width) is high, indicating that the engine is running lean. But, *actual* (calculated) MPG is lower than normal.
I'm also wondering about the Evap Emissions system... I think it may be pumping air into the exhaust full time, but can't figure out how that would cause a rich condition.
Any help will be most appreciated!
what comes first? chicken or the egg?
A bad O2 most certainly can and will cause this... it's the logical place to start.
Setting the IAC... meh, it might help with the idle, but I would be more inclined to clean up the throttle body first. If it's all coked up, well, all bets are off.
Whatever you do, do NOT oil the IAC. It can be cleaned, just don't oil it.
Evap emissions? Well, the air pump technically runs all the time, but it will, if anything, lean out the mix, not richen it... sure, the injectors will compensate to a degree... The valves could be out of sorts, it's easy enough to test. Pull off hoses, feel for air.
Also check the exhaust check valves... they can be sticky and cause all sorts of secondary issues. And not throw a code. These valves are on the air pump lines near the manifolds, Round things that are inline with the rubber lines... 2" round, silver or black... 1" long... line in, line out. They open with the higher air pressure hits them, but if they are jammed open...
A little too much air, computer adjusts, now running a bit fat...
