Rich Idle - Stock Injectors

[JMSMotorsport]

NA+T conversion, merged a BA XR6T map to my ECU in a  XE,

Having trouble to get it to idle at commanded. Starts off fine but then as it runs the AFRs starts going rich, doesn’t matter how much I increase the Slope table at idle there’s no improvement, it’s at a point now that off idle it’s lean. 
 

i gather I’m missing a idle fueling table somewhere? Can anyone point me in the right direction. 

[Yamonda]

Have you forced open loop? 

[JMSMotorsport]

Sure have, if I hadn’t wouldn’t it be trimming back to commanded? 
 

 

[Yamonda]

It'd be trying to trim to stoich. If the o2 sensor isn't working correctly it'll do weird stuff. When you log fuel source it says open loop correct? Just want to make sure its definitely in open loop. 3 or 4 bar fuel reg? Injector scaling correct for your fuel pressure? 

 

[JMSMotorsport]

I shall confirm tomorrow. 4 Bar Reg, copied all data from a Factory turbo tune. Will check again that everything copied over correctly. 

[Puffwagon]

56 minutes ago, Yamonda said:

Have you forced open loop? 

 

52 minutes ago, JMSMotorsport said:

Sure have, if I hadn’t wouldn’t it be trimming back to commanded? 
 

 

 

47 minutes ago, Yamonda said:

It'd be trying to trim to stoich.

 

It will only ever trim to stoich, a narrowband can't trim to a commanded afr.

 

2 hours ago, JMSMotorsport said:

Starts off fine but then as it runs the AFRs starts going rich

Sounds like a similar issue that was somewhat recently posted here and was solved with a new O2 sensor.

[Puffwagon]

 

[JMSMotorsport]

yes so trimming to stoich wouldn’t be .7-.8 Lambda as I’m getting - Idle commanded is 1 once warm so stoich. 

Two different widebands - one on the dyno and another AEM Standalone unit that’s plugged into the laptop. 
 

I will check data merged correctly and check again. I gather there isn’t any idle tables that control fueling VE other then the Slope Table? 

[JMSMotorsport]

7 minutes ago, Puffwagon said:

 

Replied before I seen this. You mean NB sensor. The car does have a large dump pipe, I will confirm it’s forced OL 

[Yamonda]

@PuffwagonCorrect me if i'm wrong i can't remember off the top of my head, but with no 02 sensor or ecu seeing 0v thats lean yeah? So it'll add fuel for no o2 sensor or if its dead, not the other way around? 

[Puffwagon]

Sorry got cranky kids to sort out and dinner to cook. Be back later.

Edited December 30, 2020 by Puffwagon
Not cooking the kids lol

[Roland@pcmtec]

Have you checked your fuel pressure at idle? What pump and what regulator? 

[Roland@pcmtec]

4 hours ago, Yamonda said:

@PuffwagonCorrect me if i'm wrong i can't remember off the top of my head, but with no 02 sensor or ecu seeing 0v thats lean yeah? So it'll add fuel for no o2 sensor or if its dead, not the other way around? 

Yes it will add fuel due to 0v being lean but it will force open loop for a failed O2 sensor fault eventually. 

[JMSMotorsport]

8 hours ago, Roland@pcmtec said:

Have you checked your fuel pressure at idle? What pump and what regulator? 

Factory 4 bar Reg - Brand New, 044 Style Pump- Haven’t checked actual fuel pressure at idle. Would expect a brand new Reg to give me 4 bar. 

[Roland@pcmtec]

044 with a stock reg is most likely spiking fuel pressure at idle as the return flow will exceed the flow rate of the reg or the tank return. 

You MUST log fuel pressure on every single car you tune. You will save hours and hours and likely a few motors as well.