ECMlink AFRatioEst spikes

[barza21]

Hello Everybody,

I am having some funky random AFRatioEst spikes, which in turn throw off the WBfactor. The WB seems to be reading correctly, but is not showing any type of leaning out of the mixture during the spike.

Can somebody review this log. The spikes can clearly been seen when I am going steady speed on the highway. An example of one occurs at time 97.303 seconds, but they continue throughout. Attached is the ecmlink log.

have just switched over to speed density and have been working on the cruise and idle tune (I got it pretty dialed in last night). It even occurs at idle as well. Right before the spike pops up I can physically hear what sounds like a misfire. This has been going on before I switched to SD as well (I was running on 2g MAF).
Any help would be greatly appreciated.

Oscar

 

[Stapl3]

Here's a fat guess. On the SD table, the highlighted value is used AND the cells around it are used, but the amount/importance of the cells around it being used is always changing. I see while you're cruising you are using a cell valued 76, which is at 3000rpm/9.2. Now look at the cells around it. Pretty drastic jumps. My theory is in a matter of no time the ECU could be using 76 and maybe 25% of the the value to the left of it, then it will switch to 76 and 25% of the cell to the right of it.

Basically as an experiment I would put all the cells around 76 to 76. So a small block of 9 cells would have the value 76.

All said and done the values around 76 should be transitioned a lot smoother. It's such a static use of the cell there during cruise, it should't be such a drastic change all in that little spot. You have 68 - 76 - 73.5 going left to right, with 80 below 76. All these values should be way tighter [to 76].

 

[barza21]

Stapl3,

I will look into that. This log was the first cruise log after I was able to get the car to idle correctly on SD. I did a couple of more cruises and used the SD VE adjust tool in link. I think it has become more smooth.

I want to add, that those spikes also occur during idle. Usually it is an audible pop (sometimes not), followed by the spikes you see in the logs. I pulled the plugs, did a compression check and the results came back with about 160psi across the board and a leakdown test had a result 2%-3% leakage across the board as well. I have verified base ignition timing and fuel pressure. I have disabled each injector individually through link to see if the spike goes away, but it does not. It continues to appear in the logs.

Any more ideas?

Thank you

 

[Mello]

I'm on my phone so can't see your log but any ignition misfires will throw off the O2 causing spikes too.