Hondata

I've had the Comptech Supercharger on my 2006 Civic Si since it was released: 10/2006

I installed AEM wideband A/F gauge soon after.

Since then, the car has been at around 12.5 at full throttle @ 4-5psi.

Within the last month or two, I've noticed that the car has been as lean as 13.5-14+ at full throttle @ 4-5psi. Partial throttle is anywhere from 10-12 usually.

I'm concerned that this may be too lean, and not sure what could cause it.

At first I thought it was because it was starting to get cold here in Denver (25-40? most nights) but during the day it is still 65? or so, and the A/F is still pretty high.

What could be the cause? And what should I check/fix if anything?

Colder temps?
Injectors? Fuel pump? FPR? Plugs?
"Winter" Gas?
Something wrong with wideband? Sensor?

So... is this dangerously lean? Should I stop driving until I find a solution? Any help is appreciated, Thanks!

13.5-14:12 at 4 lbs won't kill it, but if something has changed then you need to find out what it is. 10-12:1 part throttle sounds wrong too.

What has been changed on the vehicle? Fuel pump, fuel pressure regulator, injectors?

What does the wideband read when the car is cold and not running, but wideband powered up?

I have the same set-up. With the SC I have a AEM CAI, Comptech Header and Greddy EVO 2 Catback (Stock Cat still intact).

I use a PLX Wideband A/F. We installed a new bung, just past the Cat for the A/F sensor (not the best place, but closest we could get).

My A/F runs around 14.6 at idle and normal, non agressive driving. Whenever I shift or add throttle, it drops, but then returns to around 14.6.

Under hard throttle, the A/F drops off the gauge, goes below 10, but returns to hold at around 11 / 12.

Not sure if you concider it rich, but I have not had any problems. I was concidering trying the stage II pulley with this reflash (I REALLY want to get to 300hp to the wheels) but my mechanic at Dynospot strongly advised against it.

Btw, I got my Pillar pod at GlowShiftDirect.com.

Hondata wrote:13.5-14:12 at 4 lbs won't kill it, but if something has changed then you need to find out what it is. 10-12:1 part throttle sounds wrong too.

What has been changed on the vehicle? Fuel pump, fuel pressure regulator, injectors?

Nothing has changed since I installed the SC, which is why I'm so stumped... I was planning on adding a race header soon, but not sure if I should find out what's going on first.

Spunkster wrote:What does the wideband read when the car is cold and not running, but wideband powered up?

Gauge reads 14.9-15.0 with the car off but gauge powered on. I started the car and it was 14.5-14.8 and upon turning off the car it read ---. Most of the time, if I turn the car off and leave the gauge powered it will read --- but then start reading like 17.2 with the car off still.

What brand Wideband is this?

Spunkster wrote:What brand Wideband is this?

AEM

http://www.aempower.com/ViewCategory.aspx?CategoryID=67

Any ideas? :(

Something soemwhere in the car has changed...You will have to start going over everything.