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For full features; Go to 98 chevy venture: bank one lean
starting at the begining.
A few weeks ago, my dad started getting a cylinder 1 misfire on his van. He
knew the plugs and wires had ~60k miles on them, so we assumed it was them,
and replaced them. this fixed the problem for a day or two, then the
problem came back. At the same time it started to overheat at city speeds.
Took it to a local repair shop which found a visable coolant leak aroung
the intake gasket. so he brought it home and replaced the intake gasket.
After replacing the intake gasket, he goes to get gas, and it starts
overheating again. So he decides it is probably the head gaskets going as
well, as the exhaust smelled of coolant. so, tear the engine apart, get the
heads planed, (there was an obvious leak) and replace the head gaskets.
puts it all back together and backs it out of the driveway with no
problems. Goes to get gas again (never made it last time) and takes it out
on the highway to see how it does, and New problem: when he lets off the
gas, it stalls, and the computer is now throwing the code: bank one
lean.
Any suggestions/ideas of where to look? could it be as simple as an O2
sensor that is not connected right?
Just trying to get some ideas of where to start diagnosing.
dvdrose18
Simply this means the O2 sensor servicing the #1 bank is reading lean. (I
could go into more details but don't want to complicate the issue)
One needs to check the O2 sensor response (test procedures can be found in
many shop manuals or Haynes tech books) and verify the O2 sensor is good
and giving accurate information.
Once you verify the information is accurate from the O2 sensor one must
look for the cause of more air entering the combustion process then the ECM
can trim out. Usually, the culprit is a vacuum leak of some sort
downstream of the throttle body (vacuum hoses, leaking intake manifolds,
fuel injector O-rings, etc). Unfortunately, there is no magic bullet -
you are going to have to hunt for the leak and fix. One way to do this is
to squirt oil or carb cleaner at the gaskets and suspected leak areas while
the car is idling and listen for changes in the idle characteristics. Your
shop manual can provide additional details.
tbaxleyjr
After searching high and low for a vacuum leak and finding none, we decided
it was the upstream O2 sensor. It was just about impossible to get it out
as it is right up against the fire wall. Ended up rolling the engine
forward and reaching up from below, but it was still terribly cramped
getting it out. Seems to have fixed the problem, for now at least. Does it
make sense that between the leaking head and intake gaskets and the
cylinder misfire that we just totally fouled the sensor?
dvdrose18
yes - O2 sensors can be fouled
tbaxleyjr
