AFR problem

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Posts: 12
Joined: Tue Mar 16, 2010 9:40 pm
Location: Brazil

AFR problem

Post by fhcampos »

Im having a strange AFR problem with 2 cars here in Brazil.
The problem is:
When VTEC is enable, the AFR reading remains stuck in a certain value. 14,2:1 in car one and 13.5:1 in car two.
The strange parts are:
- In a stock ECU datalog, the AFR is correct, it floates and show a true value
- In my shop I have a W02 sensor wich outside mount, so I use it to see if the calibration reading were correct, they weren´t, far from it.

You will see in the 2 different calibrations that the fuel values are very diferent, but the readings in the datalog aren´t and in the stock datalog, looks like that everything is fine.

Any ideas?
Serial numbers are: 12470 and 12471
South America Civic SI - 100% stock
data stock.fpdl
(53.42 KiB) Downloaded 171 times
(20.57 KiB) Downloaded 159 times
data rev 6.fpdl
(98.32 KiB) Downloaded 164 times
(20.56 KiB) Downloaded 171 times
data rev 4.fpdl
(92.73 KiB) Downloaded 160 times

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Re: AFR problem

Post by Hondata »

The fuel tables are near enough the same between rev4 and rev6 - only about 0.5% difference on the high cam.

In both rev4 and rev6 datalogs the AFR changes are you would expect - can you highlight the areas where the AFR gets stuck?

The stock datalog shows the ECU running in closed loop to 3800 rpm, and the going into cat protect mode at 7400 rpm, but otherwise is not that different from the other two datalogs.

Posts: 132
Joined: Thu Nov 12, 2009 11:29 am
Location: South Africa

Re: AFR problem

Post by civicRSA »

Looks very much like your O2 sensor is faulty.

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