Thread: Timing question?

So I've been doing some datalogging via ECUtalk and was confused if my ECU is pulling timing and something is wrong or this is normal. Here is a little exerpt from one of the logs:

You can start to see that I go WOT at 3200rpm and timing is at 12* and slowly rises to about 19* when I get higher in the rev range then the throttle closes and timing goes up. Is this correct or is the ECU pulling timing? Base timing is 15* if that matters.

T25, 370cc injectors, DE+T.

Time	 RPM	 Timing	 Throttle

29:55.9	3238	12	3.42

29:55.9	3250	12	3.4

29:55.9	3275	12	3.4

29:55.9	3300	12	3.42

29:56.0	3312	12	3.42

29:56.0	3338	12	3.4

29:56.0	3375	12	3.4

29:56.1	3400	12	3.42

29:56.1	3400	13	3.42

29:56.1	3425	13	3.4

29:56.1	3425	13	3.4

29:56.1	3438	13	3.4

29:56.1	3450	13	3.4

29:56.2	3475	13	3.42

29:56.2	3488	13	3.4

29:56.2	3525	13	3.4

29:56.2	3538	13	3.42

29:56.2	3538	13	3.4

29:56.3	3600	13	3.42

29:56.3	3588	13	3.4

29:56.3	3625	13	3.4

29:56.3	3662	13	3.42

29:56.4	3675	13	3.4

29:56.4	3688	13	3.42

29:56.4	3712	13	3.4

29:56.4	3700	13	3.4

29:56.4	3712	13	3.42

29:56.4	3725	13	3.4

29:56.5	3750	13	3.4

29:56.5	3800	13	3.4

29:56.5	3825	13	3.42

29:56.5	3862	13	3.4

29:56.5	3900	13	3.4

29:56.6	3912	13	3.42

29:56.6	3925	13	3.4

29:56.6	3975	13	3.4

29:56.6	3988	13	3.4

29:56.7	4000	13	3.38

29:56.7	4062	13	3.38

29:56.7	4062	13	3.38

29:56.7	4075	13	3.38

29:56.7	4112	13	3.36

29:56.7	4175	13	3.34

29:56.8	4138	13	3.34

29:56.8	4200	13	3.34

29:56.8	4275	13	3.34

29:56.8	4262	13	3.34

29:56.8	4338	13	3.34

29:56.9	4412	13	3.32

29:56.9	4450	13	3.32

29:56.9	4388	13	3.32

29:56.9	4375	13	3.28

29:57.0	4375	13	3.24

29:57.0	4375	13	3.22

29:57.0	4350	13	3.2

29:57.0	4375	13	3.18

29:57.0	4438	13	3.18

29:57.0	4475	13	3.18

29:57.1	4438	13	3.18

29:57.1	4475	13	3.18

29:57.1	4512	13	3.18

29:57.1	4588	13	3.16

29:57.1	4562	13	3.16

29:57.2	4600	13	3.16

29:57.2	4575	13	3.18

29:57.2	4662	13	3.18

29:57.2	4688	13	3.16

29:57.3	4638	13	3.16

29:57.3	4638	13	3.18

29:57.3	4662	13	3.16

29:57.3	4750	13	3.16

29:57.3	4788	13	3.16

29:57.4	4800	13	3.16

29:57.4	4788	13	3.16

29:57.4	4775	13	3.16

29:57.4	4825	13	3.16

29:57.5	4875	13	3.16

29:57.5	4912	13	3.16

29:57.5	4875	13	3.16

29:57.5	4862	14	3.18

29:57.5	4925	14	3.16

29:57.5	4975	14	3.16

29:57.6	5012	14	3.18

29:57.6	5025	14	3.16

29:57.6	5025	14	3.16

29:57.6	5025	14	3.16

29:57.6	5025	14	3.16

29:57.7	5012	14	3.16

29:57.7	5062	14	3.16

29:57.7	5100	14	3.18

29:57.7	5188	15	3.16

29:57.8	5162	15	3.16

29:57.8	5200	15	3.16

29:57.8	5188	15	3.18

29:57.8	5212	15	3.18

29:57.8	5225	15	3.18

29:57.8	5262	15	3.16

29:57.9	5288	15	3.14

29:57.9	5325	15	3.16

29:57.9	5388	15	3.16

29:57.9	5412	16	3.16

29:57.9	5362	16	3.16

29:58.0	5388	16	3.14

29:58.0	5375	16	3.14

29:58.0	5375	16	3.14

29:58.0	5412	16	3.1

29:58.1	5438	16	3.1

29:58.1	5488	16	3.1

29:58.1	5512	16	3.1

29:58.1	5550	17	3.08

29:58.1	5575	17	3.08

29:58.1	5575	17	3.06

29:58.2	5625	17	3.06

29:58.2	5612	17	3.04

29:58.2	5612	17	3.04

29:58.2	5650	17	3.02

29:58.2	5700	17	3.02

29:58.3	5688	17	2.98

29:58.3	5762	18	2.92

29:58.3	5775	18	2.86

29:58.3	5750	18	2.84

29:58.4	5738	19	2.84

29:58.4	5762	19	2.82

29:58.4	5762	18	2.78

29:58.4	5775	19	2.78

29:58.4	5800	19	2.74

29:58.5	5838	18	2.74

29:58.5	5875	20	2.72

29:58.5	5900	20	2.7

29:58.5	5938	20	2.7

29:58.6	5975	20	2.7

29:58.6	5962	20	2.68

29:58.6	5962	20	2.64

29:58.6	5938	20	2.54

29:58.6	5962	21	2.42

29:58.6	5975	21	2.26

29:58.7	6050	21	2.06

29:58.7	6025	21	1.82

29:58.7	6025	21	1.54

29:58.7	6062	21	1.18

29:58.7	6000	21	0.58

29:58.8	5800	21	0.28

29:58.8	5575	22	0.28

29:58.8	5512	23	0.28

29:58.8	5438	27	0.28

29:58.9	5425	34	0.28

29:58.9	5350	38	0.28

29:58.9	5288	39	0.28

29:58.9	5250	40	0.28

29:58.9	5212	40	0.28

29:58.9	5200	40	0.28

Firstly, your TPS is way out of spec for closed and WOT. It should be 0.45-0.55 closed and over 4.00v at full throttle. This could effect what 'cell' the ECU is using for the timing, i.e you might not be getting right to the end of the load cells in the ECU map which would result in different timing values.

Generally speaking though...

high load & low rpm = low timing
low load (cruise and off throttle at higher rpms) = high timing

That's not to say that your timing at high load isn't too low or conservative, but that's just the rule of thumb. As RPM rises, the timing will increase and that's normal.

If the throttle data that you are reporting is the TPS voltage, I agree that that looks out of calibration.

WRT to the timing readings, they are more or less consistent with the WOT specs in a stock B13 timing map. Selected specs are listed below:

4200RPM = 14*
5200 RPM = 15*
6000 RPM = 18*
6400 RPM = 24*
6800 RPM = 26*

The ECU averages across cells based on the data it is reading, and things I don't fully understand can influence how it reads the timing map, but this is pretty close.

When you let off the throttle, the ECU reads portions of the map where the advance is as high as 38*, so this looks normal as well.

These readings will not change when you change your base timing (but the actual advance that the engine experiences will), so where your base timiing is set does not matter.

Can you pull your bin file and view it? You just need a cable to access you OBD port and some free software to do so.

Bill

Actually on the 200sx+ TPS's it's 0.36-0.65v. I think the range is so much higher is because Lowports don't adjust how far the throttle opens at WOT, they adjust at how open the throttle stays when gas pedal is released.



Your WOT TPS is definitely too low, get it adjusted to be around 4.0V.

First off thanks for answering my question, I know it's noobish but it helps me understand how all of this works. All this stuff is a little confusing but after reading more of it it's all becoming clearer.

As for the TPS being off, the FSM says I am able to adjust it by moving it. So I just put the car in the 'ON' position and adjust it until I get the right specs in ECUtalk? Could my TPS be bad? Also if my car is not seeing the right timing can it be low on power?

I've never used ECU Talk (I used Nissan Datascan), but what you are saying sounds correct.

Timing specs definitely affect the power you are putting out -- the timing map and the base timing setting have to be coordinated to get the best power and aviod detonation.

So I adjusted my tps to 0.48 and now I have an idle of 1,400rpm. Still can only get 3.6v out of it when the throttle is all the way open. Bad tps?

T25 or T28?

EDIT I meant to say Low Port or high port?

? T25

I don't know about whether your TPS is bad, but would recommend that you try to adjust your base idle down to spec using the air idle control valve. You probably know this, but to set base idle, you have to put the ECU in "set idle" mode. Double check your base timing while you are doing this.

Then see how it runs.

Bill