Weird AFR and fuel trims P1170 P0171

[Tonypepatone]

Originally Posted by Tonypepatone

Also worth mentioning when I changed the spark plugs their was some oil inside and on the little electrical connectors for the coil packs. None on the spark plugs or inside the ignition coil itself. Should I give those a good cleaning with electrical cleaner?

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Could this actually be there source of my problem?

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[theadmiral976]

Originally Posted by Tonypepatone

Could this actually be there source of my problem?

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Oil on the spark plug threads? No, that isn't a big concern. If you see carbon tracking on the plug ceramic or frank oil on the coils, I'd start to worry. Regardless, I wouldn't necessarily suspect a lean condition from that.

High trims on low throttle while moving (semi-engine braking) is indicative of a vacuum leak, particularly if the trims are closer to normal on throttle. Have you checked the PCV and EGR systems? Using your OFT, I would check the "Boost" value at idle and I would check the MAF voltage on and off throttle. If those seem out, it might help point you in the right direction. Worst case scenario, I'd do the following:

1) Pull the MAF and clean it with an isopropyl alcohol-based cleaner, let dry completely
2) Pull the PCV valve and clean/replace it (they're stupid cheap and kind of a pain to clean). Check the hose from the PCV valve assembly to the intake manifold for damage.
3) Check the EGR return tube into the intake for damage. Trace it back to the engine and determine if it's loose (it's hard to see without pulling the manifold).

If nothing changes with all of that, find a friend with a smoke machine and go to town. Personally, I have found that the exhaust manifold gaskets are susceptible to serious corrosion in the cold north where I live. I just finished tracing my own issues with high trims and it led me to completely corroded manifold gaskets which didn't even sound like they were leaking. Replaced those and my trims improved by >10%.

Edit: After reading the past posts more carefully, I see you said there was oil on the outside of the electrical connectors to the coil packs? That sounds like you have an oil leak, possibly coming off of the timing cover at the head or one of the camshaft sensor plates. There is a TSB for this. I have this same issue - my oil leak is not terrible and I think it's coming from the timing cover (instead of just the cam cover bolt/s), making this job an enormous pain. I'm waiting until I see oil on the ground to mess with it.

[Tonypepatone]

Alright so o2 sensor fixed it. Pheww thanks for all the help everyone! That was an epic stressful one. If anyone lives in KC I highly recommend kc auto worx. They helped a lot. Sometimes it's just the little things and FYI OFT sometimes will not show all codes thrown.

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[Tonypepatone]

Originally Posted by theadmiral976

Oil on the spark plug threads? No, that isn't a big concern. If you see carbon tracking on the plug ceramic or frank oil on the coils, I'd start to worry. Regardless, I wouldn't necessarily suspect a lean condition from that.

High trims on low throttle while moving (semi-engine braking) is indicative of a vacuum leak, particularly if the trims are closer to normal on throttle. Have you checked the PCV and EGR systems? Using your OFT, I would check the "Boost" value at idle and I would check the MAF voltage on and off throttle. If those seem out, it might help point you in the right direction. Worst case scenario, I'd do the following:

1) Pull the MAF and clean it with an isopropyl alcohol-based cleaner, let dry completely
2) Pull the PCV valve and clean/replace it (they're stupid cheap and kind of a pain to clean). Check the hose from the PCV valve assembly to the intake manifold for damage.
3) Check the EGR return tube into the intake for damage. Trace it back to the engine and determine if it's loose (it's hard to see without pulling the manifold).

If nothing changes with all of that, find a friend with a smoke machine and go to town. Personally, I have found that the exhaust manifold gaskets are susceptible to serious corrosion in the cold north where I live. I just finished tracing my own issues with high trims and it led me to completely corroded manifold gaskets which didn't even sound like they were leaking. Replaced those and my trims improved by >10%.

Edit: After reading the past posts more carefully, I see you said there was oil on the outside of the electrical connectors to the coil packs? That sounds like you have an oil leak, possibly coming off of the timing cover at the head or one of the camshaft sensor plates. There is a TSB for this. I have this same issue - my oil leak is not terrible and I think it's coming from the timing cover (instead of just the cam cover bolt/s), making this job an enormous pain. I'm waiting until I see oil on the ground to mess with it.

Thanks for the epic write-up man. But it was just some electrical greese that had gotten a little darker overtime on the connectors. And anyone that has this problem such as mine should definitely check o2 sensor first in the future. But I guess this problem kinda forced me to finally do the spark plugs lol

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[theadmiral976]

Originally Posted by Tonypepatone

Thanks for the epic write-up man. But it was just some electrical greese that had gotten a little darker overtime on the connectors. And anyone that has this problem such as mine should definitely check o2 sensor first in the future. But I guess this problem kinda forced me to finally do the spark plugs lol

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No problem! Glad you got your issue figured out and fixed!

Out of curiosity, which O2 sensor died? I ask because awhile after I got my OFT and replaced my header with the OFH (catless), my secondary O2 sensor fouled and started trending my trims positive. I have always suspected the lack of the primary cat was the culprit; however, I have no way of really knowing. If your secondary died, since you don't have a header but have been running OFT maps, that would be really interesting as it might suggest something about the maps is accelerating the demise of the narrowband sensors. Then again, I've been running my new secondary O2 sensor for over 50k miles without any issues, and without a front cat, so maybe there was a bad batch at the factory...

[Tonypepatone]

It's definitely possible the more aggressive tunes will do this. And it was the front AFR sensor that failed bank 1. And I'm sure tunes don't help cats either. So I'll definitely be keeping an eye on them.

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