OK, this is almost freaking me out, it's so weird.

Seriously, though... after some recent scanning, I can see that the short term BLMs in cell 15 are MOVING at WOT! The long terms stay at 128, but the short terms are going up to around 140-150 (on the nitrous).

And, the O2 sensor values are pretty much proving it, as they were sub .100! Crazy!

The only thing I can think of is that this started when I finally finished wiring in my timing retard module (an Accel, connected to my 300+ ignition).

It has never done this before the install of the module. My BLMs locked at 128 like normal and the O2 values on the nitrous were normal (~.920).

So, what do you think is going on here?

 

Anyone have any ideas?

I've never seen this before. My MAP enable for WOT is set at the stock 15, so I know I am entering PE mode.

The crazy thing is the long-term BLMs never change at WOT, even though the short-terms are going up past 140!

 

Now this is only a guess, but there may be a protective algorithm within our programs that allow the computer to add fuel through the ST modifiers when it reads an extremely lean condition.

I went back through my old WOT run files and did not find where my computer did this.

Give us some more info to go on as this interests me. You have a Datamaster file?

Ben

 

I'd like to see the datamaster log too, if available.

Are you sure that the ignition is really pulling the timing out it's supposed to?

Can you disconnect the retard module and run the car again so that we can verify or eliminate your newly installed retard module as the culprit?

What is fuel pressure doing on the nitrous? Hopefully it's not dropping.

 

sounds like you need more fuel or less n2o. ive never observed the S terms but are they constant to in cell 15 for everyone else?

 

FP is fine.

As I mentioned, I have been running nitrous before this module, and everything was normal back then.

I was getting O2s in the range of .920-.950 and FP was staying constant.

I was only getting an occasional increase in knock count (a few hundred, around 3800-4000 RPM).

My BLMs were locking at 128 then too.

So this seems to be connected to the timing retard.

Yes, I know it's working. I tested it by engaging the n2o circuit with the bottle closed (so only fuel sprays), and I could see the timing retard value flash on the module. I also tested it by touching it to a regular 12V switch at idle, and could hear the idle go down when the number flashed (I set it to 10* so it'd be apparent).

I will try disconnecting the timing retard switch wire and log, and let you know what's happening.

In the meantime, here is my last log (Freescan CSV) of some short 150-shot bursts with I think 7 or 8* of timing being pulled. My stock tune is somewhat aggressive above 4000, but it gives no knock N/A.

 

Ok edit your log and show it referencing your cell first then the related BLM's then your related ST's Then timing.

Also can you reference where it is on this log where you actually apply juice?

I think we would have much better luck that way.

Wowzers that took a bit to dig into

 

ha ha, yeah, I guess that was a big log file.

Here is a snippet of a run of the spray... it comes on at 3000RPM. You can see things start to go weird there.

Here is the new log. It's CSV format. The column names are at the top.

I noticed something else weird... sometimes the ST BLMs would go below 128 too.

And, they also went higher with the timing retard not engaging. It is still connected between my coil and the Accel 300+ though.

 

Well, I think I have it figured out.

I changed the fuel filter today thinking I might have been starving the fuel solenoid/system. No change.

So, I'm thinking that the fuel solenoid needs rebuilt, and isn't opening all the time. I noticed in my logs that sometimes the ST BLMs will return to 128 with normal O2 values (high 800s/low 900s) during the spray. Like it's cutting in and out.

It doesn't do this N/A; I always have steady O2 values and BLMs stay locked at 128.

So I'm going to talk to NX and see what they say.

At the least, I think I've discovered a built-in safety device in our PCMs--it would seem they DO monitor O2 values at WOT/PE mode, and if they get extremely lean, will try to fix things...

Solomon

 

I have a buddy that got his base file from one of the popular LT1 tuners and it was sooo lean at wot that the O2 voltage would drop into the 100's at wot! Wideband O2 data showed the a/f ratio in the very high 14's. The st fuel trims would go up but apparrently not enough to help. Also, this was with the cell 15 blm stock/unlocked.
Once it's locked at 128, I'm not sure if that still applies?