False Knock or nah?

[airjor13]

If it's doing it on both tunes then you can rule-out the tune, and if it's across the board and uniform then you can rule-out mechanical looseness. The fact that you say it's uniform and repeatable means that you have something wrong with your fundamentals-fuel, air, or spark. Off the top of my head I can't think of anything else.

Verify your plug gap (I stay between .026-.028" though the factory manual calls for .031") and compare your boost/afr/airflow mass measurements along with your fuel rail pressures between your recent logs and the last-known good ones. Obviously you'll want to pay more attention around the rpm range that the knock develops, but looking outside of it can give clues as well.

Good points sir, thank you will be checking the basics

 

[iso100]

I'm seeing that I get negative corrections in 2 and 3 so I'm considering new OEM plugs with proper, consistent gapping.

What made you decide on that tighter gap?

 

[dyn085]

I'm seeing that I get negative corrections in 2 and 3 so I'm considering new OEM plugs with proper, consistent gapping.

What made you decide on that tighter gap?

Generally speaking, most moderately boosted (no specific definition, but I classify it as 15-30 psi) cars run better in that general gap range. Higher boost cars (30+) use less gap while mildly boosted (<15) will run better with more. This is not meant to be 'definitive' information, just my general observations-there are lots of factors to consider.

I haven't gotten around to any general plug testing to have further data, but just like any other aspect of the engine-it's a tunable item. Because of the facts that I'm not trying to extract every possible extra hp and that plugs don't generally yield large gains, it hasn't been a pressing matter yet. Someday I'll get bored enough to do it, but with my datalogging road being so far away...

Tl;dr-For me it's just the most logical starting point. Ymmv.

 

[iso100]

Ahh, I figured the stock gap would be the starting point unless you detect that high boost is blowing out the spark. Then you reduce...

I'm going to order another set of plugs to see if it resolves my issues with #2 and #3.

 

[dyn085]

That's not illogical at all, I just didn't want to get to the point during tuning where we raised boost just to find out that I would need to tighten the gap. I just went the route of possibly leaving a few hp on the table for the sake of consistency as opposed to the possibility of having to troubleshoot.

Jmo, but I would pull your plugs and swap their locations before ordering. If your problem follows the new locations then you have a definitive answer but if it's resolved then you saved a few bucks.

 

[iso100]

Jmo, but I would pull your plugs and swap their locations before ordering. If your problem follows the new locations then you have a definitive answer but if it's resolved then you saved a few bucks.

Ahh, that's a good idea! My new Motorcraft plugs are already on the way but I can put them in my stock parts bin (getting larger by the week) if the corrections don't move around. I can just make 2 and 3 become 1 and 4.

I half expect the issue to be intake oil coming in from the PCV system between the 2 and 3 runners...

 

[dyn085]

That's definitely a possibility, and something worth looking into if you swapped plugs and the problem remained in the 2/3 cylinders. I thought you had an OCC though?

 

[airjor13]

Great information in this thread guys! I am going to pull my plug this afternoon to see the condition of them. I do not current have an OCC which I know is kind of dumb on my part but I been lazy and waiting for an PnP solution haha

 

[iso100]

That's definitely a possibility, and something worth looking into if you swapped plugs and the problem remained in the 2/3 cylinders. I thought you had an OCC though?

No OCC for me yet. I haven't had the time to go through all the fabrication required to cobble together two freaking cans and plumbing. I've been hoping for a kit to be released.

 

[dyn085]

Great information in this thread guys! I am going to pull my plug this afternoon to see the condition of them. I do not current have an OCC which I know is kind of dumb on my part but I been lazy and waiting for an PnP solution haha

I don't have an OCC either, and I don't intend on it. Outside of restoring your octane, which is a null-point on a daily driver that is custom tuned, I just don't see the added cost/time as being beneficial. Obviously that's a completely different subject covered elsewhere, and there's really no 'wrong' decision in having or not having one.

I guess my point with this and related threads is that, especially for AP3 users, addressing possible issues is less-difficult than it looks or sounds most of the time. I don't claim to know everything and can't look at a single log and come to a legitimate/correct answer, but anyone can rule out possibilities one step/test at a time and should be able to reach resolution. Sometimes it's a bit time-consuming and each fault may require a different overall approach, but it gets easier the more you look at and analyze your data. A lot of times in aviation that is the only way to correctly diagnose a fault that isn't directly covered in manuals-process of elimination.

No OCC for me yet. I haven't had the time to go through all the fabrication required to cobble together two freaking cans and plumbing. I've been hoping for a kit to be released.

Cool, thanks. I'm definitely interested in your outcome.

 

[airjor13]

Okay I pulled my plugs, they honestly don't look to bad, about 10k miles on them, Motorcraft SP532. I cleaned my panel air filter. Last thing, I drove around until the gas light came on, then drove another 20 miles to make sure I am almost empty, pumped 1gal of E85 and the rest 93oct Costco gas and what do you know, the car gods smile down upon me and negative corrections are gone for the most part! Saw +3* this morning on some pulls and had a small hiccup of -.65* on Cyl.1 No more Sunoco gas for me

 

[crankin]

Okay I pulled my plugs, they honestly don't look to bad, about 10k miles on them, Motorcraft SP532. I cleaned my panel air filter. Last thing, I drove around until the gas light came on, then drove another 20 miles to make sure I am almost empty, pumped 1gal of E85 and the rest 93oct Costco gas and what do you know, the car gods smile down upon me and negative corrections are gone for the most part! Saw +3* this morning on some pulls and had a small hiccup of -.65* on Cyl.1 No more Sunoco gas for me

I hope the car gods smile on me fairly soon when they are done with you as I am working through a similar problem right now.

 

[srg3037]

Okay I pulled my plugs, they honestly don't look to bad, about 10k miles on them, Motorcraft SP532. I cleaned my panel air filter. Last thing, I drove around until the gas light came on, then drove another 20 miles to make sure I am almost empty, pumped 1gal of E85 and the rest 93oct Costco gas and what do you know, the car gods smile down upon me and negative corrections are gone for the most part! Saw +3* this morning on some pulls and had a small hiccup of -.65* on Cyl.1 No more Sunoco gas for me

Airjor13 - I live in Chantilly/South Riding and I have had similar issues with Sunoco. I stay away from them now. I only use the TopTier gas brands (which Sunoco is not part of) and have had no issues since.

 

[airjor13]

Airjor13 - I live in Chantilly/South Riding and I have had similar issues with Sunoco. I stay away from them now. I only use the TopTier gas brands (which Sunoco is not part of) and have had no issues since.

No kidding man, I just always assumed Sunoco is top tier. Hey you are really close man! Hit me up if you want to grab a beer or wrench on the car lol

 

[iso100]

Wait, which brands are top tier?

 

[BoostBumps]

Wait, which brands are top tier?

http://www.toptiergas.com/retailers.html

 

[iso100]

http://www.toptiergas.com/retailers.html

Cool. So the BP right by my house should be fine.

 

[srg3037]

No kidding man, I just always assumed Sunoco is top tier. Hey you are really close man! Hit me up if you want to grab a beer or wrench on the car lol

For sure, I'm quite often at the Whole Foods in Fairfax on Thursday for their $0.39 wings. Haha I'm always wrenching on my car or cleaning it. My neighbors think I'm crazy because I actually use the garage to park my and my wife's car in there or are usually working on them. 90% of people around here use it to store junk.

I have had actually better luck with Sunoco elsewhere but for some reason in NOVA it does work well with my car and apparently others as well.

 

[airjor13]

For sure, I'm quite often at the Whole Foods in Fairfax on Thursday for their $0.39 wings. Haha I'm always wrenching on my car or cleaning it. My neighbors think I'm crazy because I actually use the garage to park my and my wife's car in them or to work on them. 90% of people around here use it to store junk.

I have had actually better luck with Sunoco elsewhere but for some reason in NOVA it does work well with my car and apparently others as well.

Lol that's so close, you don't btw have an silver one do you? Cause I saw a silver one at whole foods on Thursday...

 

[srg3037]

Lol that's so close, you don't btw have an silver one do you? Cause I saw a silver one at whole foods on Thursday...

If it had Florida tags that was me.