My friend has a 1996 Integra with a B20 swap. I did the swap over a year ago and just recently his check engine light has been coming on.

It is throwing code P0171 - Bank 1 System Too Lean.

I changed the fuel pump, cleaned the fuel injectors and reset the ECU. It is still coming on. My next thought is the fuel filter.

Anyone have any idea as to what else could be the cause of this problem?

 

What ecu is being used? Any modifications?

 

change the primary o2 sensor and it may help. but if you are running a stock LS ECU on the B20 i dont know if the code will clear up. the 2.0l engine requires a bit more fuel which is probably why the code keeps appearing.

 

an LS ecu is being used. It has not had any problems in the 1 year it has been installed. This is the 1st check engine light in 1 year since being installed to come up. Why would it come up now if the ECU wasn't supplying enough fuel?

Something has to be causing it to run lean.

Like I said, I've cleaned the injectors, replaced the fuel pump. The only thing left is the fuel filter.

 

bad gas can cause that dtc to set. You could also try a valve adjustment.

 

somone in the thread said change the o2 sensor, so change it. but then again, if it was a bad o2 sensor it would prob. be a bad 02 sensor code, next


a inline 4 cylinder has difrent banks? i thought that was only in V style engines?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by wannakno &raquo;</TD></TR><TR><TD CLASS="quote"> You could also try a valve adjustment.</TD></TR></TABLE>

why would that cause it to run lean?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by x_doug-x &raquo;</TD></TR><TR><TD CLASS="quote">somone in the thread said change the o2 sensor, so change it. but then again, if it was a bad o2 sensor it would prob. be a bad 02 sensor code, next
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ya my thoughts exactly. if it were the O2 sensor, it would throw an O2 code.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 92integraVTECgsr &raquo;</TD></TR><TR><TD CLASS="quote">

why would that cause it to run lean?


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If the valves aren't in proper spec, and the valves could be letting more air or not enough air into the combustion chamber, causing your short turm fuel trim to run either too rich or lean.

But Hey what do I know, I just work on Hondas for a living...

not saying that'll fix your problem but its possible and I've seen tis before. Just trying to help ya out.

 

ya i was checking the acura manual last night and it says, fuel pump, fuel filter, FPR, O2 sensor, valves.