You can see my mods in my signature, essentially I'm working further into my tune to improve it. I just have a few basic questions. Originally I kept the timing tables completely factory after the cam and headers. I have slowly added timing across the table (3 degrees across the table, but never exceeding 46 degrees, while WOT conditions max out at 33 degrees (95-100kpa). So, I had my BLMs ±1%, now that I adjusted timing I am +5% rich across the board. Does this mean that I was not burning all of the fuel it injected since my timing was too retarded and now that I advanced it (giving more burn time) it is showing that too much fuel has been given? In other words I was pumping our raw gas through the exhaust? I have a firm grasp of the concepts of tuning and the structure but this is a relatively new venture for me. The car really seems to like the additional timing, throttle response and drivability both clearly increased. Lastly, where do you find the limit with max part throttle timing and closed tps timing? I currently have my closed tps timing at 27 degrees @ 800 rpm (idles at 750) and this smoothed out my idle quite a bit compared to the factory 23 degrees. Also, with my current timing setting I am not getting any spark retard.

Thank you!
-Colton

 

In general you increased Timing across the board and are now 5% rich?

 

Correct

 

retarded timing requires more fuel and has a higher egt due to fuel burning in the header rather than in the cylinder. What are you using for a target AF ratio and what fuel not brand as that is of much less importance

 

^^^ he's on the money, I've found that more timing requires less fuel. It would make sense that you are now a little rich.

 

Right or wrong, anytime I wanted GLOBAL change in timing, I did so using percentage increase vs static amounts across loads/rpms.

Knock counts is part of what you look at to determine if too much timing has been added. When you get close (within a degree or two), a roller dyno can dial in precise tuning. Assuming later years are similar, it's almost a necessity since the car goes into open loop during WOT.

If it helps, I like this page for an overall summary of EFI tuning considerations.

 

My wot timing was set at 33 from the dyno tuning so that’s why I haven’t changed it. For some reason I didn’t want to go over 46 so when adding to the timing table I didn’t add to the value if it was already 46. My wot AFRs are still good around 13.1 (wide band in car). Thanks for the replies everyone, it seems like I’m on the right track as to why it pushed it rich. I’m running 93 octane fuel but sometimes have to run 91 if I travel.

 

Given the same fueling, a motor with retarded timing will run rich; advanced timing will run lean. Not sure why yours reads opposite.

 

That's what I would have assumed.

If the mixture is "lit" late (and as ddahlgren mentioned exhaust temps (egt) goes up), you HAVE to assume too much fuel is present to be burned in time. Too much fuel in the exhaust would register as rich by the O2.

The intuitive conclusion is what's stated by 383vett above.

 

I couldn't figure out from your sig what heads you are running? If FE1, I'm not familiar with that acronym?

I wouldn't think you'd NEED more timing than stock...even in the lower ranges with performance changes. When making an engine more efficient, less timing is often the case....unless you LOWERED compression with your build?

My instinct is you should returning timing back to what you had before this recent attempt/iteration.

 

FE1 is a reference to my factory suspension package, although I should probably take it off. I raised my compression a hair with a slightly thinner head gasket but nothing major. I have completely factory heads. Essentially the only true changes to my engine in reference to air in and air out is headers and a cam that is similar to a hot cam. I have had no retard due to the knock sensors yet. I adjusted my VE tables and got it back to + or - 1% on the BLMs.

 

Just to clarify....Did your BLMs get higher or lower with the advanced timing? If they went higher, that means it got leaner and needed more fuel...which is what should happen.

Lower BLMs mean it's running rich. I decided it might be worth while to make sure you weren't thinking backwards.

 

It was definitely running richer, I could see it on my wideband and I had to lower the VE values to correct it. Its been running great with no knock codes at all. The only thing I can think of and its far out is that due to the retarded timing I was continuing to burn into the headers. By time it gets to the O2 (long tube headers) sensors it might read it as a good mixture. When I advanced the timing it changed how that burn occured (ie no longer burning while in the headers after it was pushed out). This is super far fetched in my opinion but its the only reason I can come up with

 

It may have already been said but in my experience more retarded ignition timing will create richer conditions at the o2. Seems yours is the opposite which is odd??

 

What about the possibility your KS is retarding timing BECAUSE you advanced it? Plus, knock sensors seem to pull a bit MORE timing than you need to...which is why having the correct timing is better than letting the KS do the work. Knock sensors aren't setup to "instantly" recover either. To me, this COULD add up to (at least regions of RPMs) where you're seeing runs register as rich.

Are you certain, the additional advance you programmed in isn't triggering your knock sensor?