Idle AFR and temp

[0081(2)]

I installed a cooler thermostat quite a while ago and now im doing some logging i have noticed that the coolant temp will tend to site between 75 and 85 degrees is this range too cold??
it is only 10 degrees outside tonight so on a summer day it might run a bit warmer plus the low speed fan is always on while logging which i guess would not help.

I have also noticed that when the temp is under 80 degrees there must be an offset table as the AFR commanded will stay at 14.7 but the actual AFR will always drop lower than this it sits around the 13.xx mark

If the temp is ok what table would i adjust the offset in? is it Open loop - Mulitiplier for Coolant Offset Table Vs Coolant

Peter

[vlad01]

iirc when in idle the AFR is 13.4, but if your target is saying 14.7 and its lower, then yes most likely a offset vs coolant temp.

I had a problem with all aftermarket thermostats running running from 70-80ºC instead of the 91ºC like suppose to. Had the same issue, was running richer than it suppose to run, basically the engine never reached operating temps.

you could adjust these offsets if you wanted, but I'd opt for higher running temps to be honest.

[Holden202T]

there two things here .... if its in idle fuelling mode (usually 20 seconds after coming to idle) it will be using the Idle AFR v's Coolant Temp Table. But if its not in idle mode it could be getting offset by cold engine AFR table ...

[0081(2)]

I can see the Open Loop - Coolant Offset AFR Vs RPM & Cylair but this table must reference another table as it has cylair across the top and rpm down the side then the data in the middle which i would take it is off set amount but there is no temp.
Im thinking its looking at the Open Loop - Mulitiplier for Coolant Offset Table Vs Coolant

Open Loop - Coolant Offset AFR Vs RPM & Cylair table has no offset anyway so it cant be this one causing the issue
but the Open Loop - Mulitiplier for Coolant Offset Table Vs Coolant one has a multi value of 0.40 as 56 degrees C, Im thinking this one is having some affect but im not too sure how.

[Holden202T]

oh sorry didn't realise your referring to a MAF system .... in that case I have no idea how much of what I said above is relevant at all!

[VX L67 Getrag]

If you can see the PCM is commanding 14.7 but the wideband is showing 13.xx then there is a problem there!
No matter what offsets come into play it will show in the commanded afr in the log so if it's out then it's just an area that needs to be tweaked in the inj mul tables.

As far as it being cool, there's no way around that once cooler thermostat is fitted nearly every man & his dog believe it's a bad idea to put a different thermostat in other than stock, but if it's tuned correctly it does help with power!
It just depends on what you want power or fuel economy, as far as low speed fan being on & you don't want it on then raise the enable/disable temps!

[0081(2)]

If you can see the PCM is commanding 14.7 but the wideband is showing 13.xx then there is a problem there!
No matter what offsets come into play it will show in the commanded afr in the log so if it's out then it's just an area that needs to be tweaked in the inj mul tables.

As far as it being cool, there's no way around that once cooler thermostat is fitted nearly every man & his dog believe it's a bad idea to put a different thermostat in other than stock, but if it's tuned correctly it does help with power!
It just depends on what you want power or fuel economy, as far as low speed fan being on & you don't want it on then raise the enable/disable temps!

Thanks VX, it will go get to around the 14.7 mark when warm but not so much when cold so i was at a bit of a loss to what to adjust. might have to do another log and check it again

Im not too fussed about the temp just wondering if 75 degrees was too low as a lot of settings are around the 90 mark and just wanted to check if dropping them would be a issue

My low speed fan comes on when the ALDL cable is plugged in, that's normal i thought.??

[VX L67 Getrag]

LMAO, oh yeah about fans that is normal when logging because of BCM comms is disabled (I think).

There would be a table to adjust for AFR Vs coolant temp seeing it is working in a different range with cooler thermostat, but would make sure the fuel trims are zero when at thermostat operating temp & if not adjust the inj mul, if they are at zero then you'll need to adjust the coolant offset afr for that range but in reality it should be the same as it was it just means it's working in that range more than usual!

[0081(2)]

Im looking at these tables

Coolant afr.PNG

I don't really understand the top table and im guessing the bottom one is 0.40 more fuel between 56 and 80 degrees ??

[Dylan]

Could that be less between 56 and 80 deg? If you multiply a figure by .4 it will be less than half?
100 X 0.40 is 40 for example?