Anyone had any experience of the innovate lc1 wide band lambda? I am sampling lambda with the setting @ instant and was wondering if this is too fast... I am feeding this into a DTA ECU and using closed loop but the lambda reading second digit is just not stable... It is a huge learning curve for me... but I am determined to get to the bottom of the running issues..... I don't think I have an air leak up stream of the sensor because typically the lamda is showing rich.... I am going to check to see if I have a ground offset tomorrow and see if the ground is shifting as I rev th motor but just on idle lambda is not stable.....

Dave B

I think some fluctuations are normal at idle.

I think it comes down to slight imbalance of throttle bodies/injectors/airflow. Slight changes in burn etc.

Does it smooth out once the throttle is opened nice and wide?

For a megasquirt you sample every 29 ignition events.

You should adjust the sample rate to be a bit slower

Earthing needs to be good. On my megasquirt the lc1 earths to an ecu point.

The LC1 is not particularly good with the narrowband simulation, you are better off with a dedicated narrowband sensor then the LC1 mounted behind at a offset angle

thanks guys for the excellent advice... the LC1 is set to instant but the ECU has an idle Lambda sample rate of 1 second and the off idle strangely is set the same... I may need to slow down the idle sample.... plenty of playing for me to get this right....

I can set the LC1 output to flat line so may be able to see if there is a ground offset read by the ECU.....



Dave B.

Just read the last post.... Are you saying it is likley that I am trying to do something that the LC1 wasn't designed to do? I though output 1 was an analogue narrow band output?

Dave B

If you follow the LC-1 instruction and connect directly to it (the LC-1 comes with a cable) then you can compare that AFR with the AFR that you get when connected to it via megasquirt.

I think you can have them both connected at the same time. It is useful to test that you have selected the correct calibration curves (either on the LC-1 or on the MS).

I don't know what the narrow band simulation is, I regularly autotune with good effect, and often collect logs and tune from that. I'm not sure about the 29 ignition events thing, I just plugged and played. It does seem to work well. A bit of high frequency noise makes little difference, but bias is obviously bad.

Post up a screenshot of your Megalogviewer showing the AFR if you are still worried.

Ok so had a look at the lc1 this evening and trying to understand the programming app... I am using the narrow band analogue 2 output which has a linear output from min to max. I need to enter 20 set poinst in my ECU referencing voltage to lambda. The question is how do I get the min max voltages and the relevant lambda so that I can calculate the linear values.... If I Select the factory reset then the values that are currently there change... Is it a free air cal that generates the min max values and populates the voltage and min max lambda in the app? I have read the manual but it is not clear....

Thanks

Dave B

I don't know anything about DTA ECU, sorry for not reading the initial thread as thoroughly as I should have.

I assume you followed the instructions for the LC-1 (quite complicated initial steps). Fresh air calibrate just does that, the sensor knows that the air contains ~20% O2 and so it works out its internal sensor offsets, so that it knows the correct AFR (as shown on the gauge when you connect the LC-1 directly to your laptop).

The output circuit is completely separate, and is basically a mapping between the AFR and the output voltage (actually there are two output circuits, so it controls each of these mappings).
So, for example you can set it such that AFR 10 gives 1V and AFR gives 5V (for example), or any mapping that you want.
Reseting to default will alter this mapping to the original values.


Now the guessing bit. If you want it to simulate a narrowband sensor then I guess you want the mapping to change rapidly from 0 to 5V when the AFR changes from below 14.7 to above, but I don't know what a narrowband sensor puts out. Can a DTA ECU not take a wideband input??? Seems a bit antiquated.

I need to check but I think the DTA ECU has a default setting for using the LC1.. This default has the lambda range 0.5 to 1.5... And has 0 to 5 volts....

Dave B

Most (later) DTA ecu's with firmware within the last few years do have the LC1/LM1 calibration built in as one of the selectable options. But if memory serves, this is for the default calibration Innovate use on the wideband simulated output, not the narrowband.

I believe DTA's intention was for it to be used for adaptive mapping, not as a narrow band emissions control type set up.

There's a host of secondary settings in the DTA software for slowing it's response down; by default the Innovate stuff tends to be a bit too fast really for adaptive mapping - ends up with the ecu trying to respond to transients that don't represent what the engines really doing.

Have a look round the DTA forum at www.dtaforum.com if you haven't already, there used to be lots of advice there for setting the wideband side up.

Thanks will do...