Low ignition timing at idle 25DET NEO

[spudtatoe]

Haha one thing that I've learnt from reading all this is to get a timing light and the timing checked properly.. 

I've been trying to figure out what plug the tps is on the NEO but can't seem to find it. Only the suggestion it's the brown one which I don't believe it to be on the NEO. 

Another thing is that when mentioning adjusting idle, that's via the screw on the iac correct?

Cheers fam.

[89CAL]

O.K

Not sure why but I am going to try and help further more

Think of the way ECU's work. Inputs tell it what is happening, ECU makes calculations and controls outputs to change the running conditions of the engine

Inputs talk to the ECU
Outputs are direction from the ECU

The CAS is an Input, so tells the ECU what is happening

When you set the base timing to 15 degrees, that is setting the BASEline for the timing, its point of reference. ECU shows input of 15 degrees
ECU fires coil packs at 15 degrees BTDC using the data obtained from the CAS. The coil packs are an output

As per above, unplugging the TPS on stock ECU is the best way to lock the timing, it is obvious when the ECU is altering the timing as you can see the timing jump around (a couple of degrees only)
If you are getting roughly double the expected value, I believe this is due to setting the timing light using the wire loop and not the plug lead method

Now think about this. Assuming your ECU is locked at 15 degrees output and is outputting signal to fire at 15 degrees, what should the input (reference) be?

A bit like your knock sensor discussion, I feel like you are overthinking it.

[GTSBoy]

3 hours ago, spudtatoe said:

I've been trying to figure out what plug the tps is on the NEO but can't seem to find it. Only the suggestion it's the brown one which I don't believe it to be on the NEO.

It's not too hard.  The throttle is in the obvious place.  The TPS is on one end of the throttle shaft and the plug is attached to that.  You'll soon know if you've got the right one.

 

3 hours ago, spudtatoe said:

Another thing is that when mentioning adjusting idle, that's via the screw on the iac correct?

Yes, but it is essential that the IACV is clean and working too.  If you were to wind the idle down to 650 with the IACV stuck somewhere away from bottomed out, and the weather changed a lot, the idle speed could drop a long way.  Or vice versa.

[Slap]

?

I thought it didnt add timming at idle

?

So i was slapped with

 

Why unplug tps?

 

 

[Dose Pipe Sutututu]

10 minutes ago, Slap said:

I thought it didnt add timming at idle

Why unplug tps?

It adds timing for idle stabilsation - I've said this before
Unplug the TPS so you can accurately set your base timing - which I've also said before

 

 

[Slap]

It adds timing for idle stabilsation - I've said this before
Unplug the TPS so you can accurately set your base timing - which I've also said before
 
 

And even though i was shut down and just cant explain stuff so people understand and theres lots i wanna say.. ill keep it short.

What if the ecu is fooled by setting it at 850rpm ?

Will it stay in closed loop?

Is this what a redneck like myself would call anolog tuning?

I use a narrow band emulator from the plex300te will this make an impact on idle and the o2 readings to the ecu?

I missunderstood the way electricity was manipulated by the knock sensor , now i know it is a switching current is it worth monitoring on the safc as a trace graph?

[Dose Pipe Sutututu]

12 minutes ago, Slap said:

Will it stay in closed loop?

What if the ecu is fooled by setting it at 850rpm ?

The ECU can't be fooled, it uses the CAS to determine engine RPM

2 full rotations of the crank = 1 full rotation of the CAS, i.e. it reads the home slot inside the CAS.

 

It's always in closed loop, until you unplug the TPS (this applies to OEM ECU only)

[Slap]

The ECU can't be fooled, it uses the CAS to determine engine RPM
2 full rotations of the crank = 1 full rotation of the CAS, i.e. it reads the home slot inside the CAS.
 
It's always in closed loop, until you unplug the TPS (this applies to OEM ECU only)

I dont mean fooled with timing.

I mean fooled into stayin in closed loop.

By continualy forcing idle at 850rpm using the idle valve and modifying the maf signal with the safc.

[Slap]

Will it then hunt timing?

[Dose Pipe Sutututu]

1 minute ago, Slap said:

Will it then hunt timing?

If say the idle is dead at what it needs to be and the narrow band doesn't say it's too lean OR too rich (no idea what the voltage range is for the OEM Nissan ECU at stoich because I've never bothered to look), then theoretically the timing should be pretty stable, noting that the car is at operating temperature. This implies there isn't a timing compensation applied for a quick warmup strategy.

[Slap]

If say the idle is dead at what it needs to be and the narrow band doesn't say it's too lean OR too rich (no idea what the voltage range is for the OEM Nissan ECU at stoich because I've never bothered to look), then theoretically the timing should be pretty stable, noting that the car is at operating temperature. This implies there isn't a timing compensation applied for a quick warmup strategy.

Ok getting there.

 

Warm up isnt involved with what im discussing...atm lol (different maps).

 

Now my cam gears are set ex advance 7°

In retard 2-3°.

 

Cas corrected manualy 7°

 

Will the o2 readings be wrong?

 

Will ecu do fuel trim?

 

Will ecu compensate timing based on fuel trims if needed?

 

Car is at 850rpm. closed loop?

This is still an idle off idle maps (atm) wanting to correct?

 

I use a narrow band gauge on the emulator to ensure the ecu sees readings according to plx300

 

[Dose Pipe Sutututu]

Will the o2 readings be wrong?
No, if the combustion took place - if there are slight misfires then yes

Will ecu do fuel trim?
It always does, different IAT, different ambient temperature, different altitude 

Will ecu compensate timing based on fuel trims if needed?
No, the stock ECU doesn't care

Car is at 850rpm. closed loop?
It's always on closed loop, if the closed loop conditions are met, i.e. TPS 0%, within idle RPM range, etc.

This is still an idle off idle maps (atm) wanting to correct?
Not sure what you mean, sorry

[Slap]

I would have thought that because of the advance on the ex cam it would make o2 rich. Because the valves are opening earlier and the burn processes has been compromised.

The car idles at 850rpm. The ecu isnt in an idle map. Does that mean my car truly isnt idling? Or is it still at an idle ?

How much can it correct +/- advance to try get back to idle map?

[Dose Pipe Sutututu]

When your TPS position is at 0% you're essential on the zero throttle timing table like I posted up before.

I think you're understanding it differently, the car idles because it is commanded x amount on the IACV, and y amount of injection and z amount of timing. 

[GTSBoy]

Gents,

When Slap is asking about closed loop, he's talking about closed loop fuelling.  I suspect when Johnny Dose is talking about closed loop (in above posts) he's talking about closed loop idle speed control.  So, talking at cross purposes.

As has been posted before;

At idle (ie, TPS closed, ~0.45v) the ECU is definitely in closed loop idle speed control.

At idle, provided the O2 sensor is warm enough, the ECU will be in closed loop mixture control.  But this often fails and the ECU will just revert to the idle fuelling map.

At idle, the ECU does not change timing based on O2 feedback.

At idle, the ECU adds AND subtracts timing from the base 15° according to its needs for idle speed control, but is aiming to run 15° and control speed with IACV wherever possible.

[Slap]

Yes i was meaning closed loop fueling.

And still. At 850rpm is my car idleing?
And no i dont care about what map its on.

And i do use an upgraded wideband o2 sensor that converts it to a narrow band reading through an output to the original o2 pin wire on the ecu.

Its 850rpm.
The idle control isnt working to its programed function due to interference.
The car will?

Was it reving at 850 or idling.

Im no professor and have learned some stuff here but have you?

[Ben C34]

11 minutes ago, Slap said:

Yes i was meaning closed loop fueling.

And still. At 850rpm is my car idleing?
And no i dont care about what map its on.

And i do use an upgraded wideband o2 sensor that converts it to a narrow band reading through an output to the original o2 pin wire on the ecu.

Its 850rpm.
The idle control isnt working to its programed function due to interference.
The car will?

Was it reving at 850 or idling.

Im no professor and have learned some stuff here but have you?

What are you trying to learn here?

If the car is Idling too high ecu will pull timing, too low will add.

I have learnt nothing from this thread, I am also not a professor. 

[Slap]

Hahaha best post you have done.

Im trying to show you and... you all confirm that it does add and minus timing just not if its in its idle map.

[GTSBoy]

I will now quote myself.

3 hours ago, GTSBoy said:

At idle (ie, TPS closed, ~0.45v) the ECU is definitely in closed loop idle speed control.

And thus, yes it is idling.  It is not running on the main maps.

And the original argument was whether the ECU added 15° to a static 15° for a total advance of 30°BTDC, which is not the same thing as the ECU using delta control to manipulate the idle speed.

[GTSBoy]

And Slap, RB20s have an actual TP switch, not just a sensor.  Idle is a binary input to the ECU.  You can prove it to yourself.  When it is idling, as you open the throttle (by hand, with your head above the engine), very slowly, you will hear the ECU double pulse the injectors just once.  That's the ECU seeing the idle position switch input disappear, and is actually a good way to adjust the idle position switch on an RB20.

The RB25s rely on the analogue from the TPS.