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Running lean after heatshield install

Posted: Thu Jul 13, 2017 11:39 pm
by mr_fb6_626_
I Drive 2013 civic si sedan.
I had my setup on Basemap MAF tune.
Adjusted my AF ratio target to 13.5 and adjusted the lamba tables as well.
Car was running just fine. Great even.
Recently I purchased your heatshield and just finished the install last night. I put everything back together and burped the cooling system. Then I noticed that when it had warmed up to running temp, it would idle rough. So I drove it for 2 hours or so. Then I got a check engine light. So I ran the hondata to see what code came up. p0139 is what came up

Today I removed the throttle body and plastic manifold so that I can tighten up the aluminum piece that is bolted to the block..
I turned the car back on, burped the cooling system and then did a live data log.
I was running lean again. Fluctuating from 20 to 23 AF ratio and stayed there. Never came back down.
So I setup and uploaded the MAF tune base map as is, and hoped it would fix it.
It didn't. Car is still running very lean.
I checked for leaks, and couldn't find any leaks.

Any suggestions? I don't intend on using the car until this is fixed. I don't want to mess up my motor.
Thank you in advance.

Re: Running lean after heatshield install

Posted: Fri Jul 14, 2017 10:24 am
by Spunkster
IT sounds like you have an air leak somewhere. Check to make sure you have not over torqued the Hondata gasket and cracked it. Also check all other gaskets on the manifold and throttle body to make sure they are installed correctly and not leaking.

Re: Running lean after heatshield install

Posted: Fri Jul 14, 2017 10:50 am
by mr_fb6_626_
Will do. Let me take everything off and check the gasket.

Re: Running lean after heatshield install

Posted: Fri Jul 14, 2017 6:13 pm
by mr_fb6_626_
Checked gasket. Don't see any obvious cracks or breaks.
Seems to be doing the same thing. runs at 14-15 when warming up then back to 18-20 when is warmed up.

Re: Running lean after heatshield install

Posted: Fri Jul 14, 2017 6:24 pm
by mr_fb6_626_
update: checked everything and re-tightened the manifold. AFR is now bouncing around at 16.4 to 16.8
It's in the green. Although I do have the target AFR for low set at 13.5.

Re: Running lean after heatshield install

Posted: Mon Jul 17, 2017 9:23 am
by Spunkster
Are you sure you installed the gaskets correctly for the plastic manifold?