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Why is one of my banks of cylinders running lean? (2.8) by zkhennings
Started on: 09-03-2013 05:21 PM
Replies: 7 (374 views)
Last post by: zkhennings on 09-05-2013 08:34 PM
zkhennings
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Report this Post09-03-2013 05:21 PM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
The V6 batch fires correct? Does it do the banks separately (at different times)? I know there is 2 fuses one for each bank, but could they cause one bank to fire lean? I deleted the cold start wiring out of the injector harness, I don't think this affected anything. It is just strange as I am firing on all cylinders well, but one bank is running leaner than the other as one of my exhaust manifolds was white on the inside and the other was not. The plugs all look pretty much the same. I only have like 4000 miles on this engine. I just imagine that if one bank is not lean and the other one is that it is either fueling or unequal air, and it is definitely not that much difference in air.
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fierofool
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Report this Post09-03-2013 06:27 PM Click Here to See the Profile for fierofoolClick Here to visit fierofool's HomePageClick Here to Email fierofoolSend a Private Message to fierofoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
I think it's unlikely that 3 injectors on one side would malfunction at the same time. Since you know about the two fuses we can assume you've already checked them. I would lean toward a gasket leak on that side of the upper intake.
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Hudini
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Report this Post09-03-2013 06:30 PM Click Here to See the Profile for HudiniClick Here to Email HudiniSend a Private Message to HudiniEdit/Delete MessageReply w/QuoteDirect Link to This Post
What do the spark plugs look like?
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zkhennings
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Report this Post09-04-2013 12:00 AM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
They look good It is hard to tell anything from them except they look pretty much the same. I am idling at 950 rpms though is the only thing. I actually haven't checked the fuses because I figured the fuse will be blown or not blown, and those cylinders are definitely running the engine is very smooth. Is it possible for the fuse to cause that bank to fire worse ie. higher resistance so they don't open as fast etc.? I Imagined the fuse would either be ok or just not work.

[This message has been edited by zkhennings (edited 09-04-2013).]

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Slowbuild
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Report this Post09-04-2013 10:54 AM Click Here to See the Profile for SlowbuildSend a Private Message to SlowbuildEdit/Delete MessageReply w/QuoteDirect Link to This Post
I had a friend over at west coast fieros have an unbalance like this...he had one manifold glowing red, the other normal.

After a long time troubleshooting, he found that he was losing the odd spark due to leakage to ground...this caused the fuel to be burnt in the manifold, not the cylinder causing the overheat. the misfire, being random and spurious, was not detectable by ear, or the wire pull method. I'm pretty sure he found it at night with a water spray bottle.

Anyway, I'd look at ignition on the bank you are worried about. Perhaps if you have some spark leakage it is messing up your 02 sensor readings, and therefore your lean bank might actually be performing the way it should!

Chay
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zkhennings
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Report this Post09-05-2013 03:08 PM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
Cool thanks a lot! Yea the lean bank's manifold is white inside, and it is time to replace the wires anyways. And this would make sense why the sparkplugs all look identical, and would explain how maybe just one bad wire is causing the entire manifold to get white inside.

 
quote
Originally posted by Slowbuild:

I had a friend over at west coast fieros have an unbalance like this...he had one manifold glowing red, the other normal.

After a long time troubleshooting, he found that he was losing the odd spark due to leakage to ground...this caused the fuel to be burnt in the manifold, not the cylinder causing the overheat. the misfire, being random and spurious, was not detectable by ear, or the wire pull method. I'm pretty sure he found it at night with a water spray bottle.

Anyway, I'd look at ignition on the bank you are worried about. Perhaps if you have some spark leakage it is messing up your 02 sensor readings, and therefore your lean bank might actually be performing the way it should!

Chay


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Dodgerunner
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Report this Post09-05-2013 07:21 PM Click Here to See the Profile for DodgerunnerClick Here to visit Dodgerunner's HomePageClick Here to Email DodgerunnerSend a Private Message to DodgerunnerEdit/Delete MessageReply w/QuoteDirect Link to This Post
The other possibility might be a weak output of the ecm for that bank.
just a thought.
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zkhennings
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Report this Post09-05-2013 08:34 PM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yea I just don't know how to check that except with an oscilliscope
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