LSJ E85 Tuning car runs fine then ramdomyl goes rich

Here's the deal, making the switch to e85 (E68ish for now 3gal 93/e10 10 gal of e85) , car runs fine , did some pulls then will randomly goes pig rich, it didn't do this on gas and the only thing i'v changed is the stoich value and timing. Its only done it twice since filling up with e85 and i cant figure out why. If i turn the car off and back on everything goes back to normal. its kinda driving me nuts because i cant make it happen it just happens randomly...its really a :banghead: situation but im hoping its just something I'v missed or over looked so it can be a :doh: situation

File 7 is a capture of the event, along with a few minuets of driving and a 1-3 gear pull before it happened. 8 is driving after i turned off and restarted the car.
my 02 is a innovate mtx-l configured to read stoich as 10.83 for e68 the transfer-function for hp is volts:0.452488688 + 5.4 (switching to lambada so i don't have to dick with it when switching fuels.)


http://farm6.staticflickr.com/5530/1...df1438bc_b.jpg

Did you notice how much the VE Airflow jumps in the log? It's already higher than the MAF reading to begin with, but then it jumps about 35% even though there are no jumps close to that in your VE table. Stranger yet, you have the dynamic airflow disable set at 300rpm, so it shouldn't matter anyway. Either way, your ECM believes that there is a sudden increase in airflow when this happens. It's also interesting how the cylinder air mass does not increase, yet the timing advance drops a bunch at the same point.

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Originally Posted by Matt M

Did you notice how much the VE Airflow jumps in the log? It's already higher than the MAF reading to begin with, but then it jumps about 35% even though there are no jumps close to that in your VE table. Stranger yet, you have the dynamic airflow disable set at 300rpm, so it shouldn't matter anyway. Either way, your ECM believes that there is a sudden increase in airflow when this happens. It's also interesting how the cylinder air mass does not increase, yet the timing advance drops a bunch at the same point.

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yeah i noticed that , but it its like the ECM decided to dived by zero or something... starting to wonder if the e85 has nothing to do with it, and there might be something wonky with the ecm. Maybe a flash entire might be good idea...until then i'll just keep logging until it happens again.

I'd try a full write if you haven't already. Sometimes it is required to get all of your adjustments to flash correctly.

lol, good call.

it almost looks like your 02 is sticking at the highest voltage, maybe its grounding? or lost its ground

that's because its going real rich

Yeah I don't think its o2 issue because my wb pegs rich,and the ecm starts to trim -25 but it stays pegged rich. if the o2 was falsely reading rich and the ecm trimmed that much then I would think my wb would read lean ?

not if it was delivering the high voltage constantly and not dropping its voltage down.

It's not the o2 sensor. The injector duty cycle jumps significantly at the same time the O2 starts reading rich. It is a real reading.

i know exactly what this is. Give me a few minutes to grab my notes.

Add individual cylinder misfires into your scanner.

Next time you're scanning, have the dtc tab open. When it dives afr, click dtc reset even though there aren't any. Should come out of it if it's what I think it is.
Watching misfires will give you a hint.

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Originally Posted by armcclure

Add individual cylinder misfires into your scanner.

Next time you're scanning, have the dtc tab open. When it dives afr, click dtc reset even though there aren't any. Should come out of it if it's what I think it is.
Watching misfires will give you a hint.

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Thanks I'll Give that a shot.