AFR/fuel trim randomly going wild during idle?

[kefi]

Got the PRL HVI intake installed along with the inlet pipe and charge pipes. Good lord does it sound like an absolute monster now..

However, I pulled up my datalogs and saw something strange going on with the AFR/fuel trim while I was idling at a light. My AFR started getting rich and the short term fuel trim started dropping, all the way to -16%, paired with a slight change in ignition.

I've never seen this in my datalogs before nor did I notice anything while driving. Not super concerned, moreso curious as I always am, but wondering if someone could chime in why it randomly was doing this with no driver input. Attached truncated datalog but I can't see anything changing other than temperatures.

 

[jasonjm]

Got the PRL HVI intake installed along with the inlet pipe and charge pipes. Good lord does it sound like an absolute monster now..

However, I pulled up my datalogs and saw something strange going on with the AFR/fuel trim while I was idling at a light. My AFR started getting rich and the short term fuel trim started dropping, all the way to -16%, paired with a slight change in ignition.

I've never seen this in my datalogs before nor did I notice anything while driving. Not super concerned, moreso curious as I always am, but wondering if someone could chime in why it randomly was doing this with no driver input. Attached truncated datalog but I can't see anything changing other than temperatures.

Post it on the Hondata forum. This is interesting.

 

[02SilverSiHB]

Got the PRL HVI intake installed along with the inlet pipe and charge pipes. Good lord does it sound like an absolute monster now..

However, I pulled up my datalogs and saw something strange going on with the AFR/fuel trim while I was idling at a light. My AFR started getting rich and the short term fuel trim started dropping, all the way to -16%, paired with a slight change in ignition.

I've never seen this in my datalogs before nor did I notice anything while driving. Not super concerned, moreso curious as I always am, but wondering if someone could chime in why it randomly was doing this with no driver input. Attached truncated datalog but I can't see anything changing other than temperatures.

did you do the same with the factory intake...just to count it out as being normal?

 

[dixie1]

I have an AEM air fuel gauge , at idle it's always 14.7 .....

 

[02SilverSiHB]

I have an AEM air fuel gauge , at idle it's always 14.7 .....

I checked mine with hondata and my injen evo intake...it's flat, right at 14.7 also

 

[kefi]

This issue has gotten worse, it seems. Now it just continuously fluctuates. I think it's a vacuum leak but I can't find it. Tried waving an unlit propane torch around every connection and no dice.

I'm assuming everyone else's AFR doesn't do this at idle? The swings become more rapid if I hold RPMs at 2000-3000 and then goes back to the slow swing after I let off.

I did some more testing this morning and the swings are still there, but the peaks are below AFCMD now instead of the wave being centered on it. This gremlin is driving me nuts.

Maybe an issue with the MAF calibration? Doesn't make sense though, haven't heard of anyone needing to tune for the PRL HVI.

I would think a vacuum leak at idle would also cause it to idle higher.. but my idle is very stable despite all this. It's also having these swings under high boost, just not nearly as noticeable.

Starting to fear an issue elsewhere, like fuel delivery.

 

[kefi]

did you do the same with the factory intake...just to count it out as being normal?

I just found a datalog from before I put on all these parts and it was doing it then too.

 

[BanquoX]

Was this ever resolved?

 

[kefi]

Was this ever resolved?

It's been a long while since this thread, but it's generally believed to be normal to see AFRs swing around at idle or light load. It's only during WOT that AFR swings are a problem.

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