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Timing questions: logged timing does not reflect map

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Old 12-05-16, 11:18 PM
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Timing questions: logged timing does not reflect map

Hi, my RTEK 2.1 is set up and running pretty well in my s4 tII, but I've found some issues with my ignition timing. The first thing I noticed is that the leading timing values in my logs don't match the timing values that are programmed into my map. The map I'm using is (for the most part) arghx's conservative timing map.

The logged numbers seem to be 7 degrees or more behind the map, maybe more like 10 degrees. It's hard to tell if it's a linear thing, like if it's always the same amount behind, but what would cause this? My base timing seems to be set correctly, the car idles at -5* leading and -20* trailing, but somewhere along the line something is off. Where does the log get its numbers from? Directly from the CAS, or is it processed by the ECU first?

The other problem I noticed is that when I first start the car up, cold, it misfires quite a bit when it's idling up before it settles into its 750 rpm, -5* and -20* idle. I found that dialing the timing back in those low load cells (first 2 or 3 load cells and first 3 or 4 rpm cells) fixed the problem, but the timing has to be set around 6* or lower to keep it from hiccuping. I'm guessing this has to do with the first problem, but the solution almost seems like it's backward. Is it normal to taper the first few cells like that so the car isn't jumping from -5* to 16* or so when it's in and out of idle?

Thanks for any help.
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Old 12-05-16, 11:34 PM
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not really sure about your first question. with a haltech, it could be a correction map (like timing vs air temp, or coolant vs air temp), although i'm not really sure how the Rtek works. the stock ECU does have temp corrections, and i'm not sure where the timing map you program is in the chain.

for the second, i've noticed the same thing. its jus how the engine is, it wants to misfire at a high idle.
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Old 12-06-16, 03:10 PM
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Thanks for the reply. So for the first question, what you're saying is that it's possible that timing is being corrected (in this case, dialed back) because of coolant or air intake temps? I haven't been logging air temps, maybe I should to see if there could be an issue there. If I remember correctly there are two, one in the AFM and one in the IC tubing to TB connection. I'm guessing the one at the TB would affect ECU calculations most.

And that's good to know about the misfire at high idle, the car has always seemed to tend toward doing that no matter what I do. I guess I'll taper the cells down slightly to compromise, it doesn't seem to be affecting drivability at all.
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Old 12-07-16, 11:17 PM
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Anyone encounter a similar issue? I'm still working on the first one I mentioned. At idle, I moved the CAS forward a few degrees to see if the RTEK would log the change, and it did not, so I'm really not sure where the discrepancy could be. Seems like the log must get its numbers from what the ECU has programmed into it... If anyone has experience with this I'd really appreciate any input. Thanks
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Old 12-16-16, 01:18 AM
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Quote:
At idle, I moved the CAS forward a few degrees to see if the RTEK would log the change
that's not how this works. if you want to test advance at idle, do it by adjusting it in the software, not moving your TDC alignment at the CAS. the only time moving the cas will directly move the timing is when you are setting timing and the jumper is connected that makes the ecu keep 5 and 20 timing.
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Old 12-16-16, 05:48 PM
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Ok, I've been overlooking the initial set coupler... since I have Rtek I assume I can use the jumper built into the software? Also, does Rtek 2.1 have the ability to adjust idle advance? I've been through the program a few times and don't see the option. Not that I have a problem with where the car idles, it's just that anytime it's in closed loop idle, the logger is going to read -5 and -20. Not a problem. My main problem is that I don't have any reliable way of telling what the ignition advance actually is, particularly under load and off idle.

When I installed the motor, I had a little trouble determining if the marks on the pulley were correct. I ended up finding TDC myself by lining up an apex seal in the trailing hole of the rear rotor, and then the leading hole, marking both on the pulley and then finding the halfway mark between the two. In my understanding this is a surefire way of finding TDC for the front rotor. The TDC mark I made is about 20* advanced from the -5* stock mark (and about 35* from the -20* trailing mark). The only explanation I have come up with for this is a mismatched pulley and front cover (I did not put the motor together and don't have contact with the guy who did)

When I was first tuning the motor, getting it all to just run smoothly, I played on the safe side and lined up the stock leading mark with the front cover pin. Now with the RTEK logging extremely low advance numbers and performance seeming a little sluggish especially at low RPMs I have moved it up to 5* after my TDC mark, I believe this is where it should be at idle. However, so far I have overlooked jumpering the initial set coupler (or enabling it in the RTEK) when setting base timing so I suppose that could be the issue. It has run better since I advanced the CAS, and the logged numbers maybe rose a bit, but I'm going to try jumping the coupler and setting it that way and see if the logged numbers match those on my map a little more closely. Thanks for the help lastphaseofthis, cool name by the way. If you notice any errors in what I'm saying about TDC, let me know.
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Old 12-16-16, 08:27 PM
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I think the software version for setting the tps and A/f ratio at idle doesn't do the same as hard wiring the jumper in the the engine bay.
I can confirm that you do need use the jumper in the bay to set initial timing.
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Old 12-28-16, 02:49 PM
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For anyone else who is encountering a similar problem, I think I stumbled upon the solution today. I went to make a change to my leading map and realized that most of the values were all over the place, not where I had set them at all. Went to the settings and found that "boost based timing" was unchecked, when it had been checked before. I re-enabled it and went to load my maps in again. When I was loading them in the program froze about 3 times but when it eventually came back around, the timing load graph was in PSI and inHg, which it had never been before, and I realized that the Rtek had never before fully gone into boost based timing mode. Needless to say the car runs far better now! So the solution to this problem would be to check if boost based timing is selected, and if it is but your Y graph in your timing maps doesn't show actual PSI and vacuum figures, toggle it a few times until it catches.
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