Temp related knock

[solidONE]

Originally Posted by Kodename47

The stock O2 loses consistency if it changes temperature and with changes in exhaust pressures. Over 2 different runs its hard to tell which is more accurate.

If the temperature comps are making it worse, just try flattening out the table.

No changes were made to the MAF temp compensation table in this tune. Also, the 'inconsistency' or change in the afr is actually pretty consistent if there is no change in LTFT values. In relatively high temps the afr reading will be leaner than target, and in cooler temps the afr will read richer than target afr. What I'm not absolutely sure about is whether if this change is due to the MAF scale not accurately compensating for different temperatures or if the O2 sensor reading is skewed by temperature changes. Maybe it's a little bit of both?

Everything I've seen so far seems to be pointing at the MAF temperature compensation since I was able to lessen this effect by modifying the MAF temp compensation table in the past, although only in OL operation or the part of the MAF scale below 2.8v. The resolution of that table and the values are pretty coarse, so it's difficult to 'fine tune' it.

[Kodename47]

Originally Posted by solidONE

No changes were made to the MAF temp compensation table in this tune. Also, the 'inconsistency' or change in the afr is actually pretty consistent if there is no change in LTFT values. In relatively high temps the afr reading will be leaner than target, and in cooler temps the afr will read richer than target afr. What I'm not absolutely sure about is whether if this change is due to the MAF scale not accurately compensating for different temperatures or if the O2 sensor reading is skewed by temperature changes. Maybe it's a little bit of both?

Everything I've seen so far seems to be pointing at the MAF temperature compensation since I was able to lessen this effect by modifying the MAF temp compensation table in the past, although only in OL operation or the part of the MAF scale below 2.8v. The resolution of that table and the values are pretty coarse, so it's difficult to 'fine tune' it.

The O2 will only be susceptible to temperatures within the exhaust. Once it's running, external temperatures mean very little.


As I said, just set the IAT comp to 0 (or 1 depending on program). It may be worth keeping it stock at lower MAFv range for low temp idle etc. I doubt it really needs fine tuning anyway, so long as it keeps you roughly where you want.

[solidONE]

Originally Posted by Kodename47

The O2 will only be susceptible to temperatures within the exhaust. Once it's running, external temperatures mean very little.


As I said, just set the IAT comp to 0 (or 1 depending on program). It may be worth keeping it stock at lower MAFv range for low temp idle etc. I doubt it really needs fine tuning anyway, so long as it keeps you roughly where you want.

That's assuming the lower ambient and intake air temps (69f vs 109f) have zero effect on exhaust temperatures. I'm sure the difference is small if there is a difference.

[Kodename47]

Originally Posted by solidONE

That's assuming the lower ambient and intake air temps (69f vs 109f) have zero effect on exhaust temperatures. I'm sure the difference is small if there is a difference.

In theory you can get a rough idea of EGTs if you log O2 current and resistance due to the way the sensor is heated up and kept at a constant temperature. There's a few threads on RomRaider about it. Flatten the IAT comp, you could even try temporarily flattening the WOT area of your fuel map and see what happens to EGTs.

[solidONE]

Originally Posted by Kodename47

In theory you can get a rough idea of EGTs if you log O2 current and resistance due to the way the sensor is heated up and kept at a constant temperature. There's a few threads on RomRaider about it. Flatten the IAT comp, you could even try temporarily flattening the WOT area of your fuel map and see what happens to EGTs.

Can you link to the thread? For what I'm after, it's kind of a roundabout way of testing how 'off' the stock O2 sensor is. But, it would be nice to know for sure if any of this has an effect on stock O2 output. Still waiting on Vishnu Tuning to release the wideband upgrade. Would be nice to get both the stock O2 and wideband on the same log. Now if the stock O2 can be made to work with a legit wideband sensor, that would be ideal.

[Td-d]

http://www.romraider.com/forum/viewt...8134&hilit=EGT

You would need to know what the resistance threshold is for the O2 sensor used on the FT86 is though - best way would be to test with an actual EGT sensor. Who know, maybe Sasha knows as well - he's a gold mine of technical knowledge.

[solidONE]

Originally Posted by Td-d

http://www.romraider.com/forum/viewt...8134&hilit=EGT

You would need to know what the resistance threshold is for the O2 sensor used on the FT86 is though - best way would be to test with an actual EGT sensor. Who know, maybe Sasha knows as well - he's a gold mine of technical knowledge.

Uh... but what would I use to measure and log the resistance of the sensor while it is running? If I cannot get it through OFT or some other device that reads off the OBD port, I might as well just hook up a EGT sensor and gauge.

I guess the safe and easy way to go about it is to just make sure the afr readings from the stock O2 doesn't go higher than 12.5:1 or so at the top end in high intake temp situations either by 1. tweaking the MAF temp compensation or 2. setting the target afr really rich and living with the super rich mixture in cooler temps(which seems to be the strategy employed in the OTS tunes), or a little of both (what I'll probably end up doing.)

[Kodename47]

Originally Posted by solidONE

Uh... but what would I use to measure and log the resistance of the sensor while it is running? If I cannot get it through OFT or some other device that reads off the OBD port, I might as well just hook up a EGT sensor and gauge.

I guess the safe and easy way to go about it is to just make sure the afr readings from the stock O2 doesn't go higher than 12.5:1 or so at the top end in high intake temp situations either by 1. tweaking the MAF temp compensation or 2. setting the target afr really rich and living with the super rich mixture in cooler temps(which seems to be the strategy employed in the OTS tunes), or a little of both (what I'll probably end up doing.)

ECUtek has them as loggable OEM channels so they are there to monitor. If you have access to a proper EGT setup though then obviously that would be better.

There is a reason that it wants to be richer in lower temperatures as it's all to do with fuel atomization. However, you most definitely wouldn't want it to be leaner at higher temps IMO. So maybe you could find a baseline, flatten the higher temperatures to the same as the baseline and maybe reduce the compensations a little in lower temperatures. No need to try and go all accurate but will pull things in a bit.

[Td-d]

Hmm... I thought I had pulled those parameters out, I'll check.

[Td-d]

They are both defined for B01C, and in the text file in the thread that Steve started.

Ram_AF_Sensor_1_Current FFF8932C
Ram_AF_Sensor_1_Resistance FFF89344

[Kodename47]

Interesting read here:
http://www.efi101.com/forum/viewtopi...4ff13b1d222956


Might be worth reading for those of you wanting to add timing at lower temps too....

[solidONE]

Originally Posted by Td-d

They are both defined for B01C, and in the text file in the thread that Steve started.

Ram_AF_Sensor_1_Current FFF8932C
Ram_AF_Sensor_1_Resistance FFF89344

This is for the tacktrix? I'm using open flash tablet currently.

[Td-d]

Ah... I was under the impression you were using the OP2. Guess you could ask Shiv to incorporate the parameters.

[solidONE]

Originally Posted by Td-d

They are both defined for B01C, and in the text file in the thread that Steve started.

Ram_AF_Sensor_1_Current FFF8932C
Ram_AF_Sensor_1_Resistance FFF89344

Originally Posted by Td-d

Ah... I was under the impression you were using the OP2. Guess you could ask Shiv to incorporate the parameters.

@Shiv@Openflash could you add logging for these parameters and also, can we expect the release of wideband sensor add on in the near future?