Speedracer

As some of you have read, my Service Engine light came on about 1 week and 150 miles after I replaced my broken HKS supercharger with a new unit. The confounding factor is that I added Redline Water Wetter to my coolant and I think it has affected my coolant temps significantly. The underhood temps are WAY lower than before. The car is running rich....REALLY rich. Don't know what the A/F is yet but my exhaust tips are jet black and my milage has dropped to about 14-15 mpg. The upside is that the car is running super smooth and making gobs of power.

My question is for all people with FI set-ups. Does anyone know at what A/F ratios, both rich and lean, the MIL will go on. Basically, this will be the point at which the ECU will no longer be able to compensate for a rich or lean condition as sensed by the oxygen sensor.

I'm getting this all formally checked out at the end of the week, but I want to see if anyone know this info. Thanks.

Sharif@Forged

iTrader: (92)

Hi Speedracer. At WOT, your ECU will never trigger a CEL regardless of how rich you are running...unless you misfire or something.

If you are running too rich at idle or cruise, then the CEL will activate, and tell you left/right bank running rich. I dont kow the exact point. But since the car is tuned to bump around 14.7:1 at idle and cruise...I imagine anything below maybe 13.5:1 would trigger the light.

Have you dynoed your car yet? How about installing a wideband and see how your car idles and cruises? It should be close to stoich....unless you go WOT.

Speedracer

Well this is interesting. Apparently model 2004.5 on have actual A/F sensors, not plain old "oxygen" sensors. I am throwing codes 1271/1281 indicating the A/F is out of spec range. I am getting the coolant system flushed and getting rid of my water wetter and the cold temps coming with it. Beyond that, I'll have to re-dyno to see what my actual A/F is running. Now, the real problem is that I don't know what the "spec" A/F ratio needs to be in order to not throw an SES light, and my Nissan dealer didn't have this info either. I'll keep everyone posted. I may end up getting the HKS Graphic control computer...a piggyback for the piggyback that allows fine tunign of the A/F. I'll be contacting HKS as well.

westpak

iTrader: (19)

I believe there is a bulletin for those codes.

Speedracer

please explain further. Basically it looks like on 2004.5 cars onwards, any significant change in the A/F will trigger a SES light. Possibly this has something to do with tighter emissions??

Znitro

I have the Stillen SC STG3 / Aluminum radiator W/ water wetter and a nismo cold t stat My temps are around 170-175 on the freeway down from 180- 185 W/ stock equip.

Never any problems ......... Just MORE power less heat = more power The ECU will compensate timing and fuel above 187*F

Please use accurate data when making these types of claims.

I have a consult 2 that I plug into my OBD2 ....I know my temps and I really doubt that water wetter would make that much difference.

My .02cts

etx

Agreed. So when are you going to lend me that Consult2?

Sounds to me like something else. Your temps could be way down because your car is running so rich! It's not the water wetter. Hook up a datalogger and verify that your car is adjusting the STFT and LTFT with the data from your o2 sensors. If it's not there is your problem. Most likely a bad o2 sensor, or someone blew the o2 sensor fuse when installing something.

Funny how you say you put in water wetter, and a new supercharger. And then say you think it's the water wetter that's the problem. LOL The blower mabye? Wild guess.

Speedracer

[QUOTE]Originally posted by etx
Agreed. So when are you going to lend me that Consult2?

Sounds to me like something else. Your temps could be way down because your car is running so rich! It's not the water wetter. Hook up a datalogger and verify that your car is adjusting the STFT and LTFT with the data from your o2 sensors. If it's not there is your problem. Most likely a bad o2 sensor, or someone blew the o2 sensor fuse when installing something.

Funny how you say you put in water wetter, and a new supercharger. And then say you think it's the water wetter that's thTe problem. LOL The blower mabye? Wild guess. T

The supercharger had over 200 miles and about 10 start-ups with no problems. The problem started only after I added the water wetter. Obviously it is most likely something with the SC management, but there is chance it is not. The cooler temps may be interpreted differently by the HKS F-CON computer. What I am really trying to figure out is that my dealer specifically said that on 2004.5 models onwards, an out of spec A/F ratio will throw an SES light. Also, the DTC is coming from BOTH pre-cat sensors and neither post cat sensor, so I doubt it was an install or damage problem. I'm just trying to figure out what to do about it.

So while it may appear that I am "blaming" the water wetter, I am not. I am just hoping it is something that simple.

In any case, what is the STFT and LTFT that you are referring to? I know a lot about some things, but absolutely NOTHING about others. Thanks.

Speedracer

Please use accurate data when making these types of claims.


My .02cts [/B][/QUOTE]

What data is inaccurate. I DON'T KNOW what the problem is. I am simply stating what I did, and what problems I have, and how I am starting to try and eliminate the possibilities. The info I am getting is that the A/F is out of range beyond the ECU's ability to compensate on both pre-cat sensors, and on neither post-cat sensor. Any more ideas? I don't know if when HKS developed their engine management for the SC, the SES light was being triggered by an actual "out of spec" A/F ratio. That ratio could be 12.5 for instance, and if I am running 12, the light would trigger. Supposedly this was not the case on pre 2004.5 cars.


It does look like I need to head back to the dyno for some more A/F testing.

westpak

iTrader: (19)

Sorry different codes but similar subject:

NTB04072

IF YOU CONFIRM: A MIL "ON" with the following DTC(s) stored: · P1031 / P1051 (A/F Sensor Heater), and/or · P1148 / P1168 (A/F Sensor Closed Loop Control), ACTIONS: Step A: Confirm this bulletin applies: · Check the Current ECM Part Number. ·Compare your Current ECM Part Number to Chart A. If that part number does not match one in Chart A, this bulletin does not apply. Go back to ASIST for further diagnostic and repair information. Step B: Reprogram the ECM. Step C: Perform A/F Sensor test to confirm proper air fuel operation. See this bulletin for further detail.

Speedracer

So....I take out the water wetter, flush and change the coolant. Have started the car 8 seperate times. Have let it idle for twenty minutes 4 seperate times. Have taken two drives of about 20 miles each including several full throttle blasts and......NO SES LIGHT!!!!! Go figure!!!! Still looks rich on the exhaust side, but not quite like before.

Z1 Performance

iTrader: (564)

Remember what we talked about yesterday? Well I did some more research on it today

As you know, OBD2 codes are a universal thing among car manufacturers - they all mean the same things. One of our very good customers, who also has become a good friend over the years, works for Honda, writing ecu code. We talked for awhile, and he said the ecu checks for a variety of things including the thermostat opening relative to when the car is started. Since its been so cold here lately, and you put water wetter in, we got to thinking it must be the ecu thinking the thermostat is stuck opened. This becomes a hard code that is stored in the ecu.

On my car, as we discussed, I had a CE light come on the other night, when it was very cold for no apparant reason. Scanned it yesterday and it was for low thermostat operating threshold. This code came on about 10 mins into my drive on Friday night (it was around 30 degrees out). Since I have the aluminum radiator and the NISMO t stat, it makes sense that the t stat opens up quicker than normal. Now, I know you did not install the NISMO t stat yet, but I think whats happening, in light of the really cold weather we have had in the NE, is your ecu is reacting to the watter wetter like mine did to the t stat. I also cleared the code last night and it has not yet come back

Get that code scanned VJ and let me know what you come up with. Clean your exhaust tips, get a fresh tank of gas in there and let me know what you find in terms of mileage, etc