Bank one lean @ 79 MPH

firepaw · 05-18-2006, 08:36 PM

Got the "light" today and checked it out when I got home. Code triggering the light (drivetrain) was "Bank One Lean". The snapshot said it happened @ 79 MPH. Never exceeded 55 MPH in the last week! Wha? ('98 4WD, standard)

Tom

BlazerLT · 05-18-2006, 09:54 PM

What year?

firepaw · 05-18-2006, 10:05 PM

LT,
'98, 4WD, standard. It's in the post. Good to see you back around.

Tom

BlazerLT · 05-18-2006, 11:14 PM

Lean sensor signals are usually linked to a dirty MAF sensor.

dmbrisket 51 · 05-19-2006, 01:39 AM

depending on mileage it could also be a sticky o2 ... was the only code a lean or was there more? what secer detected the issue and set the code?

BlazerLT · 05-19-2006, 02:01 AM

Quote:

Originally Posted by dmbrisket 51

depending on mileage it could also be a sticky o2 ... was the only code a lean or was there more? what secer detected the issue and set the code?

You have to watch it there, it is sensing something which doesn't mean it is defective.

I worked on a 1997 that was having lean problems and codes and it came back to a faulty dirty MAF screwing up all the fuel trim values.

Cleaned the MAF and all went back to normal. Had one guy that had to change the MAF completely in order to get the fuel system right again.

dmbrisket 51 · 05-19-2006, 02:30 AM

but its only detecting it on one bank and not both, thats the only reason for my though of a bad o2, could also be a vaccume leak (severe)

firepaw · 05-20-2006, 07:45 PM

I dumped the code, but remember that an O2 sensor was out of range. I watched it run and noticed that one was "spikeing" (but didn't register as a code or "pending code). I should have saved a graph to post . Then again, 170k miles!

I just thought that the 79 MPH was wierd.

Tom

dmbrisket 51 · 05-20-2006, 10:56 PM

they should run between low 100 ish to 200 tops, and 7 or 800 on the top end when under a load

firepaw · 10-30-2006, 07:11 PM

I know it's a late reply, sorry I had some problems. I took your advice and cleaned up the MAF sensor this past weekend. I also cleaned up and tightened the duct connections downstream of the sensor. No more lean burn! Passed inspection today - thanks for the tips.

Tom

Now it sounds like it's bearing/hub time again!

BlazerLT · 10-30-2006, 07:57 PM

Quote:

Originally Posted by firepaw

I know it's a late reply, sorry I had some problems. I took your advice and cleaned up the MAF sensor this past weekend. I also cleaned up and tightened the duct connections downstream of the sensor. No more lean burn! Passed inspection today - thanks for the tips.

Tom

Now it sounds like it's bearing/hub time again!

Glad to have helped you.

And thanks for letting us know how things went.

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