Spark blowout?

[boost97gst]

So i finally got free time to tune. Dialed in my afrest and lc1wb to match through the whole range up to 20psi(mostly, its close). Problem is, in 3rd gear at 20psi i get this sputter with just a little bit of knock, like a degree or 2 tops of knock retard. afr target and achieved is 11.1. Dropped timing from 7* to 6* in that cell and dropped one all around it, still have what almost feels like fuel cut but its not. Its breaking up possibly like bad spark. I dont know, ill post a log of a 3rd gear pull soon.

 

[bryanwheat]

What plugs and gap? What wires are you using?

 

[boost97gst]

Wires are old, plugs br7es at .028. Less than 1500 miles on plugs. I take back what i said earlier: i need some more maf comp work. Im running too rich in some places and too lean in others. Its gonna take some time to dial it in properly. Then i can focus on why im sputtering.

bryan, dumb question real quick: If my afrest is say 11.1 and my lc1wb is at 10.4 around 2100hz would i move that slider up or down? i know its stupid but i forget and hate playing the guessing game. Im really considering dyno time, this is dangerous on open roads. I sound like an old man now.... god.

 

[compression]

you want to lower the airflow readings, the ecu will see lower airflow numbers so it will give a little less fuel. just until your around the 11:1 mark then you can have a decently accurate airflow reading.

 

[boost97gst]

you want to lower the airflow readings, the ecu will see lower airflow numbers so it will give a little less fuel. just until your around the 11:1 mark then you can have a decently accurate airflow reading.

THanks alot. I actually looked in a recent thread over in tuning section and found my answer. If afrest is lower(richer) than actual, INCREASE for that hz and vice versa. Too tired to tune anymore today tho....

 

[BurrowZ]

What plugs and gap? What wires are you using?

This.

I was getting bad spark blowout at 20psi on my 16G. Pulled the plugs out and regapped them to .026. Problem solved.

Your wires can be a factor if they are old or not of great quality as well. You can always ohm test them if you're not sure.

 

[19BLACKGST98]

Make your plug gap a little smaller and see if that fixes your break up problem.

 

[boost97gst]

Hell, im thinking of gapping to .022 or so from what ive been reading. Im getting a bit of knock after reviewing the log so i gotta fiddle with timing some more. I think on 93 oct 11:1 is a good stable afr, even safe if anything. Possibly the spark blow out is causing a false knock reading? IDK, but im getting a new set of plugs tomorrow. What should i get BPR7es BR7es, or 6's or 8's?? Im confused as to which will be optimum for my setup.

 

[19BLACKGST98]

BR7ES will be better because it the non protruding plug = helps fight off spark blow out. 6's are for bone stock and I know a few guys who suggest the 8's for meth injection equipped cars.

 

[boost97gst]

Cool, i got the right plugs the first time, ill grab another set tomorrow. These are the break-in plugs so i should prob replace them anyway.

 

[compression]

THanks alot. I actually looked in a recent thread over in tuning section and found my answer. If afrest is lower(richer) than actual, INCREASE for that hz and vice versa. Too tired to tune anymore today tho....

Edit: you threw me a curveball there with the afrest first then the actual. Touche! you can ignore all this below then!

Just for clarification, somebody else may want to chime in for confirmation.

I am fairly certain if you are running too rich, you would want to decrease the hz, the lower the hz (airflow) the less fuel the ecu will squirt to compensate for there being less air.

I like to think of it like this - increase for more fuel decrease for less fuel. i believe the safc works the same way that particular method on ecmlink does. The lower the hz readings the less air.

In some cases (probably completely irrelevant) decreases too much ( injector compensation via safc ) could put you in a totally different hz bracket that uses a much more aggressive timing map to compensate for the low airflow.

Ps. Some of the guys at the parts store here are retarded, so just FYI the EVO 8 uses a bpr7es plug. Sometimes they tell me they dont have the plug in stock then i tell them the plug for an evo 8, and they are like " Yea we have some of these , just not the first one you asked for " WTF

 

[Calan]

I am fairly certain if you are running too rich, you would want to decrease the hz, the lower the hz (airflow) the less fuel the ecu will squirt to compensate for there being less air.

The values of the MAFComp sliders represent an increase or decrease in reported airflow to the ECU. If you increase the value of a MAFComp slider, you are telling the ECU that there is more air entering the engine at that point, so the ECU injects more fuel.

MAFComp adjustments should follow CombinedFT in closed loop. If CombinedFT is averaging +5%, it means the ECU is having to inject an additional 5% fuel at that one operating point to keep the AFR at 14.7:1. So you raise the corresponding MAFComp slider +5%, which is in effect calibrating the ECU for that additional 5% of airflow. CombinedFT should then drop to 0% at that slider point since you have corrected the airflow there (once the long term fuel trims are reset to 0%).

It works the same way in open loop using the error between AFRatioEst and your wideband (WBFactor). If WBFactor is showing +5%, then you are 5% lean. Add 5% to the corresponding MAFComp slider, which tells the ECU to inject more fuel...and WBFactor should drop to 0% at that airflow point.

In a perfect world at least...

 

[boost97gst]

New br7es's gapped .024. No more sputtering! Thanks guys

 

[19BLACKGST98]

Congrats on the fix.