That's right. Coasting fuel cut on our cars shuts off the injectors until your reach around 1500 RPM. So, our engine is just pumping a ton of fresh air right on through.

Actually, on a sidenote, it would be good to eventually find this in disassembly, so it can be adjusted.

Also, the fact that the LC-1 starts flashing 20.9 shows that this is working. The 20.9 no longer is an AFR...it is the percent O2 in the air.


Eric

 

yup - i've already looked for it hehehe

 

check for boost leaks.......they can really mess up the afr. It will cause the afr to stay rich while you keep taking more and more fuel out of the map.

 

Have you checked you're spark plugs?

Their condition can tell you alot...rich/lean,detonation & spark timing.

Just a thought

 

Tephra,

You mentioned leaky exhaust. This could cause incorrect o2 readings me thinks,especially if it leaks in front of the sensor. just a thought

good luck

 

x2

Return your fuel map to stock and try this formula if you havnt already:

Desire AFR X Map AFR / Actual AFR, that should help to get started.

Try making smaller adjustments as well after each log until you get your desire afr

good luck

 

I have done the calibration method that Lr299 posted, it works. It is no different than free-air calibration, afiak.

You can also re-calibrate the sensor after 6 hours of the car being off, and it seems to calibrate the same.

but as mentioned, if you have any exhaust leaks it can throw off the calibration. I ahd a friend with a Saturn that had a leaky front O2 that would throw everything off, took him a good month to figure out why there was all this black soot collecting around his O2 sensor, and why his LC-1 was saying 13:1 at WOT...lol.

 

the only thing is wouldn't a leaky exhaust read the same at WOT, ie the pressure in the exhaust would push exhaust gases OUT not suck air IN?

 

I believe the answer is no because of the individual cylinder pulses could create a vacuum. As an example .... My resonator had a pinhole leak and to find it the muffler shop used a modified doctors stethoscope. He let me use it and I could actually hear pulsing sounds coming from the exhaust. As RPM increases the likelihood of sucking air in probably decreases and if anything would make your o2 reading more accurate especially if your leak is before the o2 sensor mounting location

I also believe that somewhere in Innovates documentation they mention exhaust leaks and the effects they have on Wideband performance.

PS Is your leak upstream of where the o2 is mounted?

 

upstream, yes I need to fix it before doing any more tuning hehe

 

taken from the lc-1 manual ......

"7 Tips, Tricks and Troubleshooting
7.1 General measurement requirements
The LC-1 measures the air-fuel-ratio by measuring the amount of oxygen in the exhaust (for lean
conditions) or the amount of unburned or partially burned fuel (for rich conditions). You should
correct for the following in order to get optimum results from the LC-1
1) An exhaust leak will allow oxygen to enter the exhaust stream and therefore will
measure leaner than the engine is actually running. For correct measurement, airleaks
in the exhaust MUST be prevented under all circumstances.
2) Missing ignitions (where the air-fuel mixture does not ignite) also pump unburned
oxygen into the exhaust and cause the LC-1 to measure lean.
3) The only circumstance where the LC-1 will measure richer than the engine is running
is if the pressure in the exhaust tract is excessive (and the engine is running on the
rich side to begin with).

 

I know you are discussing other issues to maintaining your desired AFR of 11.7 and possible causes for why its not where it is...but for everyone elses benefit I would like to point out that the fuel you use is going to affect the map as well.

This car is one I street tune and have dyno tuned.

The first is on Turbo 104 Unleaded and it was maintaining an 11.5-11.6 on the dyno. Lean spool is off, the timing was much higher on the 104 (average of 7*) but it was still the same AFR...only difference was fuel other than that.

The second map is pumpgas from the street for a 11.2-11.3 AFR, it was 11.5 on the dyno

 

right, well I am using the stock catback - could this cause the excessive pressure talked about in the manual.

interesting those maps JB - basically reitterates the map difference required on the dyno vs street right?

 

JB,

I would also like to point out that, yes every fuel is different, but also every car is different. I also find it interesting the big change you see in 104 and pump gas, as I found 104 burns much quicker so the fuel map doesn't change as much compared to how much more the actual AFR is.

Brands of gas change thing as well, with race gas at least...

 

I'll also note my maps are leaner than JB's with lean spool off to get it in the 11's.

I now use Pro to iron out the rest. But I had to take it alot leaner than I thought I would without lean spool on or I was super rich. I think I went up a point and a half almost to make up for lean spool being off. It surprised me. I kept going up in small increments and it didn't do anything. So I finally just went up like .5 point and I was back where I was before kinda.

93 octane 10% ethanol Sunoco.