A/F Ratio very high in Closed Loop!

jsoman · Post by **jsoman** » Sun Sep 18, 2005 4:54 pm

I have the Hondata Racecar Wiring configuration in a engine swaped car running the Cold Air Cal. I have the primary wide-range Lambda sensor connected only. KPro is reading the lambda (because when disconnected, the Lambda reading goes to the default (10.7). On initial startup, the Lambda reading starts at @32.00 and over the next few minutes, will drop as low as 26.00 but only goes lower instantaneously when the throttle is blipped.?There is no difference between these readings in either open or closed loop modes. As you might expect I am also experiencing unbelieveably poor gas mileage. Maybe a bad A/F sensor? Or? Can you shed some light on this situation? Thanks in advance.

John Soman

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Razathorn · Post by **Razathorn** » Sun Sep 18, 2005 5:37 pm

What ecu / motor / af sensor?

jsoman · Post by **jsoman** » Sun Sep 18, 2005 5:40 pm

Kpro, RSX Type S w/stock sensor.

jsoman · Post by **jsoman** » Sun Sep 18, 2005 7:08 pm

I forgot to mention that the ECU is a PRB. Stock Lambda Sensor. I am using this car for street purposes for now which is why I have the sesor hooked up in closed loop. i will be using it on the track once I get the tuning part figured out.
Also, I looked at some old posts here in the forum and it leads me to believe that the high readings I am getting may actually be leaner not richer is this so? Probably a stupid question but this is my first time dealing with a fuel injection car. It still doesn't make sense that I am getting such poor mileage.

Post by **Spunkster** » Mon Sep 19, 2005 12:35 pm

It sounds like you may have a wiring problem or possibly the wrong sensor. We need a part number.

jsoman · Post by **jsoman** » Mon Sep 19, 2005 12:51 pm

The #on the Denso sensor is: 192400-1090
06C19

I folllowed the wiring diagram provided by Hondata very closely but of course that doesn't rule out bad wiring on my part even though I rang them out twice now. I am wondering if it isn't a problem with the ECU itself.

Also, I'm sure a Datalog of my problem would help but I need to get my Laptop w/Kpro (no internet or CD burner) to network to my Desktop so I can send it. Should I do this before I go any further?

Post by **Spunkster** » Mon Sep 19, 2005 3:20 pm

Did you puy the sensor from Acura?...if so what is the Acura part number. You may have the wrong sensor.

jsoman · Post by **jsoman** » Mon Sep 19, 2005 6:09 pm

I got the primary sensor with the drivetrain that was from a stock wrecked car (sensor was physically fine). I also compared the drawnings of both the primary & secondary sensors to make sure I used the right one. This was easy because of the clear/accurate drawings.

I do have a concern that the probe isn't sticking into the exhaust exhaust enough - the bung that was welded on to the custom exhaust is probably too long. Would that effect the reading much?

I fired it up again w/ coldair cal. in open loop and got and got this data:
RPM 844
MAP 30
Lambda 24.57
INJ 2.36
Duty 1
IGN 3
IAT 90.8
ECT 161.4

I'll be able to attach a datalog of the problem tomorrow.

Post by **Spunkster** » Tue Sep 20, 2005 9:58 am

THe long bung could be a problem. Also the sensor could be damaged form the accident.

jsoman · Post by **jsoman** » Tue Sep 20, 2005 11:22 am

I have changed the port that the sensor fitted into so that it now in the exhuast stream but the outcome is no different.

I've attached a datalog that shows what the A/F readings are during engine startup. The sensor could be bad but the engine runs really rich with or without the sensor hooked up in open or closed loop.

Any ideas other ideas? My next step will be to get in touch with Hondata before I make any purchases of sensors or checks of the ECU etc.

jsoman · Post by **jsoman** » Wed Sep 21, 2005 8:02 pm

I've learned from Hondata that the A/F sensor is the most likely problem as far as the strange A/F reading (22.00-32.00) - not the ECU. Spunkster pointed me that way too - thanks.

Hondata also said that the base map that I am using ColdAir.cal could still need further tuning in order to get better mileage/power, etc. even though my engine is internally stock with a cold air intake and modified exhaust without the Cat. - similar to engine used for the Coldair map. I didn't know that the base map would be that far off?

Next step then is a new sensor A/F (primary sensor)and I guess I will have to learn how to tune.

Post by **Spunkster** » Thu Sep 22, 2005 9:55 am

Yes I know Hondata said this...I'm the one that emailed you the answer.

Razathorn · Post by **Razathorn** » Thu Sep 22, 2005 9:57 am

Unless you're running all the rsx type-s plumbing (intake manifold, header, exhaust) -- tuning is a pretty good idea. Here is what adding a big exhaust + tune did for my rsx type-s:

jsoman · Post by **jsoman** » Thu Sep 22, 2005 7:11 pm

That seems like a big HP differnce from stock. Your tuning definetly helped out alot.

Were running nearly the same mods...
Did you start with the Coldair map first? And if so did you have to adjust the amount of fuel down significantly across the rev range/power band to help get these #'s? Were you running really rich prior to tuning like I am now?

I'm not sure where to start as far as tuning goes so I will have to watch the Hondata movies again. Should be enlightening.

Razathorn · Post by **Razathorn** » Fri Sep 23, 2005 7:13 am

The above dyno lists mod differences. Basically the difference between the two lines are the addition of some ES motor mount inserts, custom magnaflow exhaust, and my tuning. You should see the dyno that compares stock to that -- it's even more nuts. With VTC control in kpro, you have the ability to really adjust for the specifics of your air flow setup. That is a very powerful tool. I would always follow up any air flow change up with a tune.