Need opinion, lean condition
09-19-2006, 10:04 PM
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Need opinion, lean condition I went out and did some logging tonight since I havent driven the car in 3 months. My LTFT Bank 1 was showing a percieved lean condition and adding %13 more fuel, way high. Bank 2 LTFT was around 2, which is good enough. Now i do have a wideband hooked up in the bank 1 stream. I had it dialed in before so that WOT AFR was at 13.0 actual. Now at WOT it is like 11.0-11.5 due to this percieved lean condition which is making the PCM add more fuel at WOT. If there was a real lean condition then i wouldnt be so rich at WOT so I am assuming the lean condition is percieved and there are no intake leaks.The oxygen sensor seems to be working ok abd switching enough. What are my possible problems? I was thinking there may be an exhaust leak before or right near the bank 1 oxygen sensor. A few months ago I did mess around with the block offs for the AIR and EGR, so maybe thats whats going on, although I cant hear a leak audibly. What do you guys think??
09-20-2006, 08:27 AM
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Even an o2 thats still switching fairly quickly could be showing signs of age and its switchpoint could start to stray away from stoich. I had this happen when one bank was much leaner than the other. Id replace them both just for piece of mind.
09-20-2006, 11:49 AM
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Originally Posted by GuitsBoy
Even an o2 thats still switching fairly quickly could be showing signs of age and its switchpoint could start to stray away from stoich. I had this happen when one bank was much leaner than the other. Id replace them both just for piece of mind.
Anyone else have an idea?
09-20-2006, 01:28 PM
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An injector problem could make a single cylinder lean out
and bump up the whole gang. One that is slow to open
for example, would affect the low end out of proportion
to WOT.
Similarly a small air leak on the intake or exhaust side,
would not be flow proportional but jack the low-flow
cells (0, 1, 4, 5) more than the rest.
As they age they also need more heat to stay working.
Headers can aggravate this big time, a brand new one
can get weak pretty quick if the pipes are shedding a
lot of heat.
and bump up the whole gang. One that is slow to open
for example, would affect the low end out of proportion
to WOT.
Similarly a small air leak on the intake or exhaust side,
would not be flow proportional but jack the low-flow
cells (0, 1, 4, 5) more than the rest.
As they age they also need more heat to stay working.
Headers can aggravate this big time, a brand new one
can get weak pretty quick if the pipes are shedding a
lot of heat.