2013 XSport Tuning

[SHOdded]

Fuel pump percentage > 100???  Weird ...  Load is also weird ...

[StealBlueSho]

When you see positive knock numbers it is pulling timing because it is sensing incipient knock..

When you see negative knock numbers it is adding timing until it senses incipient knock...

The knock sensor just searches for the beginning or the start of knock... It adds or removes timing accordingly..

Negative knock reading  = good
Positive knock reading = bad

[MiWiAu]

Fuel pump percentage > 100???  Weird ...  Load is also weird ...

Ha, yeah, can't answer the question on the fuel pump percentage. It has been consistently reading over 100 ever since I started data logging with the SCT. I thought that was strange, too.

Is one load particularly weird over another? For the 0-100 pull I was on a stretch of road that wasn't very flat. I'm thinking that variation might be the uphill/downhill. I've since started running just 0-60 on a flatter road section for improved consistency. I can re-run the 87P1 tune 0-60 on a flat stretch, if that will help.

When you see positive knock numbers it is pulling timing because it is sensing incipient knock..

When you see negative knock numbers it is adding timing until it senses incipient knock...

The knock sensor just searches for the beginning or the start of knock... It adds or removes timing accordingly..

Negative knock reading  = good
Positive knock reading = bad

This was my impression based on the reading I had done, which is why I was confused that it was recommended to run the 87P tune over the 87P1 tune, since the 87P1 has much less KR at 60 mph.

Is there something else I'm missing on the 87P tune that would make it preferred over the 87P1? Thanks for the feedback, guys!

[StealBlueSho]

Lots of knock in both tunes... Like through the entire run..I wouldn't be happy with either tune...how are your plugs?

[MiWiAu]

Lots of knock in both tunes... Like through the entire run..I wouldn't be happy with either tune...how are your plugs?

I just went out and re-ran the 87P1 tune from 0-60 on a flat section of road (removed the 0-100 87P1 datalog). Under WOT, I peaked at +2.5.

Plugs are brand spanking new NGK (1 step cooler) that I received from Torrie. gapped at 0.030" per his recommendations.

[StealBlueSho]

It's a bit normal to have some knock readings... At least on the stock tune.... Dunno.. you guys already on winter blended gas? Might be some of it...

[MiWiAu]

It's a bit normal to have some knock readings... At least on the stock tune.... Dunno.. you guys already on winter blended gas? Might be some of it...

Hmm, good question. I'm not sure. It's about that time of year.

[sholxgt]

Does 87P mean you are tuning for 87 octane?  I don't think there's been much success tuning with 87.  The car from the factory is pretty close to on the edge for cheap fuel.

If 93, what brand?  There are significant differences between top tier and no-name.

[MiWiAu]

Does 87P mean you are tuning for 87 octane?  I don't think there's been much success tuning with 87.  The car from the factory is pretty close to on the edge for cheap fuel.

If 93, what brand?  There are significant differences between top tier and no-name.

Yeah, the 87P is an 87 octane "performance" tune. I'm also working with Torrie on an 87T "tow" tune. I have a 93P "performance" tune on deck once I finish up with the 87 tunes.

I primarily buy my fuel at Costco (87 and 93 top tier, high volume) or BP.

[MiWiAu]

It's a bit normal to have some knock readings... At least on the stock tune.... Dunno.. you guys already on winter blended gas? Might be some of it...

It looks like September 15 was the eligible sale date for winter blend fuels in 2016, and being in Wisconsin, I'm guessing that's what's been in my tank for some time.

I went back and looked at a 4th gear WOT pull on my OE tune with 87 octane and I went from +7.5 KR down to +5.0 over the course of the pull. Yikes. The stock plugs looked pretty good when I pulled them out @ ~32000 miles. No signs of peppering.

I'm going to pump in some 93 and see if that eliminates the knock, so I can try to get confirmation that fuel is the culprit.

[SHOdded]

If 93 doesnt help on an 87 tune, boy o boy   You should PM AJP to see what he thinks.  You said you normally get Top Tier fuel right?  Might also occasionally run a bottle of HEET through to absorb any malingering moisture in the gas tank/fuel lines.

[MiWiAu]

If 93 doesnt help on an 87 tune, boy o boy   You should PM AJP to see what he thinks.  You said you normally get Top Tier fuel right?  Might also occasionally run a bottle of HEET through to absorb any malingering moisture in the gas tank/fuel lines.

Good suggestions, SHOdded, thanks.

I always go for top tier. Usually (85% of time time) I get it at Costco, since they are very high turnover. If not there, I use BP that has decent turnover.

I've been running 87 exclusively since I bought it in mid-August, and I was planning to start working on the 93 tune once I got these tunes sorted.

[SHOdded]

I forget, but have you checked for a possible chafing knock sensor wire issue?  Do you feel any loss of power when these knock events are happening?

[MiWiAu]

I forget, but have you checked for a possible chafing knock sensor wire issue?  Do you feel any loss of power when these knock events are happening?

I have not checked for chafing wires yet - didn't realize that could be an issue. Does the chafing generally occur near the knock sensor and/or is there somewhere else specific in the harness to check?

With the OE tune, I recall some flat spots under WOT where power would level out, then pull again, but I'm not sure whether or not it coincided with a knock event. I haven't noticed this power delivery hiccup as much with the custom tunes, but I will mess some more this weekend and start paying closer attention for sure.

EDIT: Just found this thread regarding knock sensor chafing. I will check it out! http://www.ecoboostperformanceforum.com/index.php/topic,554.45.html

[sholxgt]

If 93 doesnt help on an 87 tune, boy o boy   You should PM AJP to see what he thinks.  You said you normally get Top Tier fuel right?  Might also occasionally run a bottle of HEET through to absorb any malingering moisture in the gas tank/fuel lines.

Good suggestions, SHOdded, thanks.

I always go for top tier. Usually (85% of time time) I get it at Costco, since they are very high turnover. If not there, I use BP that has decent turnover.

I've been running 87 exclusively since I bought it in mid-August, and I was planning to start working on the 93 tune once I got these tunes sorted.

Fuel turnover was always my barometer when choosing diesel for my cars/trucks, but it's not a measure for me with gasoline.  I go for ones that have the best rated additive packages.

I'm a Costco fanatic, but I don't buy their fuel.  I go for Chevron, BP, and Shell.  Many on here swear by Shell giving them significantly different datalogs.  If you have one nearby, it might be worth a tank to see if you get different results.