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Lean AFR spikes @ WOT w/ LC-1 WB

EfiniX

Well-known member
Joined
Oct 18, 2012
Messages
647
Location
portland, or
Just when I think I've got this car nearly there...

I'm seeing AFR lean spikes from my LC-1 @ WOT. Now I just had an aeromotive FPR installed a few weeks ago, so that's my absolute first thought, but there's not much to an FPR, so after verifying the pressure and that the hose is zip-tied down, I'm not sure what else it could be. Fuel pump? Calibrate the LC-1? Burned-up sensor?

here's what I'm seeing (links to logs at the end)

AFR is the thick, red line in all images.

Before (smooth):





After (lean spikes):





Now the odd thing is that I would think that if the FPR was acting up, I would see a correlative spike in the fuel flow (thick blue line), but I don't. And the O2 sensor output looks good as well.

I'm kinda stumped...

Logs:
click (VE's were a bit all over the place since I didn't do smoothing after my last adjustment)
click (smooth VE's, same issue)
 

EfiniX

Well-known member
Joined
Oct 18, 2012
Messages
647
Location
portland, or
A bit more info... I did another couple pulls and I didn't see the problem at all. I had lunch, then came back out and drove home and saw the issue again. This time, i was logging while paying attention to the gauge. I'm seeing the same crazy fluctuations on the gauge as I am in the logging. Since Link see's 0-5v from the DAC in the Innovate gauge, but the gauge shows raw input from the WB sensor, I'm thinking this is a sensor issue. If it was mechanical, I figure I would see it all the time under similar conditions. If it was a loose wire, I figure I would see a voltage drop (rich spike). If it was the DAC in the gauge, I would expect to see the gauge output look normal.

Seems like sound reasoning to me, and with a WB sensor that is 2+ years old, heck, I just ordered a new sensor. We'll see if that gets the job done...

Of course, if someone thinks I'm a loon, do say something, please. /ubbthreads/images/graemlins/smile.gif
 

jepherz

Staff member
Joined
Aug 8, 2004
Messages
7,877
Location
KC, Missouri
I am confused. You have the analog output of the lc1 hooked to the ecu, and the other analog hooked to an innovate gauge? And when you see the spike, what's happening? If the sensor is at fault, you should see the same behavior on the gauge/ecu. Are you sure the analog output is configured correctly? And the input is set up right within link?
 

EfiniX

Well-known member
Joined
Oct 18, 2012
Messages
647
Location
portland, or
The sensor provides an analog signal to the wideband gauge. The gauge shows exactly what the sensor is telling it. the gauge has a DAC that converts the analog sensor input to a user-defined voltage range. So I'm sending 0-5v to the ECU, with 0v being totally rich, and 5v being totally lean. This is all confirmed with innovate.

I'm seeing 5v (max-lean) spikes in both the logs, and on the gauge, which tells me that I'm likely having a sensor problem. if I didn't see the spikes on the gauge, I would suspect the DAC was having issues. I wouldn't suspect a wiring problem because I would expect to see voltage drops, not spikes if that was the case. I've actually seen that condition before, when I discovered English Racing installed my WB using a butt-connector instead of solder and heat shrink. it would occasionally go 100% rich in instance.

make sense?

oh, and thank you for replying /ubbthreads/images/graemlins/smile.gif
 
Last edited:

EfiniX

Well-known member
Joined
Oct 18, 2012
Messages
647
Location
portland, or
I forgot to put a bow on this thread.

I installed a new WB sensor and everything has been fine since.
 
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