Power Loss On Downshifts, Bouncing Idle And Slight Hesitation At Specific Rev Point -R34Gtt

[hy_rpm]

Might of skipped a few pages and didn't read it

But did he indeed check the crank pulley ?

My bet is his idle speed was too high when he checked the base timing

[rondofj]

Yes indeed checked the crank pulley - idle speed goes pretty high (didnt check how much) with TPS disconnected and timing goes up +5 degrees on harmonic balancer.

TPS connected goes down to 20 degrees on harmonic balancer and idle becomes softer - havent checked the rpms, but its always fluctuating 800-850rpms on commander after warmup.

[Dose Pipe Sutututu]

it goes up because it's accessing a different cell..

like I mentioned a few posts before, disconnect the TPS & disconnet the IAV and adjust idle to 800 or whatever it is supposed to be at.. then adjust base timing

make the ECU (N01, P01) , (N01, P02), (N02, P01), (N02, P02) ALL 20 degrees.. then sync up your base timing.

[rondofj]

it goes up because it's accessing a different cell..

like I mentioned a few posts before, disconnect the TPS & disconnet the IAV and adjust idle to 800 or whatever it is supposed to be at.. then adjust base timing - this is already done, base timing is 20 degrees

make the ECU (N01, P01) , (N01, P02), (N02, P01), (N02, P02) ALL 20 degrees.. then sync up your base timing. - to be done,.. but why, when this is the main timing map which is only accessed on throttle input (TPS). its not the idle map.

You can see that N02, P02 the idle cell was already set to 19 so CAS at 20 seems right doesn't it? Almost.

Edited September 8, 2014 by rondofj

[Ben C34]

Im not talking about looking at maps at all.

You need to look at the timing the power fc is putting out. For example as yo u said it can show 2 cells at once. It doesn't for examole just jump from one set at 35 to the next one set at 20 either. It interpolates between the 2. So it might be putting out anywhere in between the two cells.

So you looking at the maps is not helpful.

Just like the power fc can display the afm voltage, surely it can display the actual timing it is running at that point. NOTHING TO DO WITH THE MAPS!

[hy_rpm]

That would explain why the timing is going up 5 degrees when the tps is disconnected

As when the idle is higher the timing is advanced more

So you have to either drop the idle to 750rpm then set base timing to 15degrees or match whatever the cell the ecu is using

If you can't get something as simple as that right just take it back to Unigroup

Tell him you changed the belt and need to reset the cas base timing

[Ben C34]

Don't match the cell!

Match the displayed timing in use!

[GTSBoy]

That would explain why the timing is going up 5 degrees when the tps is disconnected

As when the idle is higher the timing is advanced more

So you have to either drop the idle to 750rpm then set base timing to 15degrees or match whatever the cell the ecu is using

If you can't get something as simple as that right just take it back to Unigroup

Tell him you changed the belt and need to reset the cas base timing

No, the reason that the timing and idle goes up when the TPS is disconnected is that the ECU now thinks that it is NOT at idle condition (cannot see TPS voltage) and so now the ECU runs the engine off the main maps instead of the (hidden) idle maps.

[hy_rpm]

Yeah but as the engine speed gets faster

The spark has to get fired earlier to combust at the right time until there is boost and it will decrease back

[GTSBoy]

Yeah but as the engine speed gets faster

The spark has to get fired earlier to combust at the right time until there is boost and it will decrease back

We're still talking at idle or just above, yeah? Do you really think that there's a lot of difference in "required" timing between say 800 rpm an 1200 rpm? Maybe half a degree?

[hy_rpm]

Yes try holding a timing light at the crank and watch the difference between 800rpm and slowly winding out the iacv to 1200rpm

Will be about 5degrees

[hy_rpm]

That's why it specifically says in the nissan manual or under the bonnet to set base timing

Once warm and at idle speed of 750rpm +or- 50rpm

[GTSBoy]

Um......Nistune (for Neo) says in the "After Start Timing Advance vs RPM (TPS off) table that zero extra timing is added until the rpm reaches 2800 (add 2deg) then 4 at 3200 maxing at +15 from 4000 up.

The Nissan manual and underbonnet sticker says to do it warmed up and settled to normal hot idle rpm so that you DON'T do it when it is still cold and working off the "After Start Timing Advance vs Temp" table which adds anywhere up to an extra 20 degrees of timing when coolant temp is below 70degrees. The actual table doesn't make a lt of sense because it scales down to -40 C and I don't think that coolant can even get that cold without freezing, but never mind. At 10C the ECU will add 11 degrees, which is plenty.

So, to reiterate, a high idle is probably more a result of a cold idle, and cold = more timing according to the factory maps. Fast idle in itself should not add timing until 2800 rpm.

[Ben C34]

And nine of that really matters setting the timing when you can monitor what timing the ecu Is running.

For example, a consult cable and ecu talk or nistune, or in Rons case the hand controller.

Hot, cold, tps plugged in, revving higher, whatever.

Match the cas to the timing being used by the ecu. Displayed in monitor mode.

[rondofj]

Some conflicting bits of info here.. Johnny says to change cells to 20 and set CAS to 20, Ben says not to match cell, but match displayed monitor output in commander (15 in my case after warmup hot idle ).

My timing (at harmonic balancer) does jump approx 5 degrees when increasing idle from 800 to 1500 ish....thats how it is.

And how big are the idle maps really - shouldnt be more than 5X2 or therebouts I would think? Covering values from cold idle to hot idle. My normal idle cell on main timing map N02 L02 IS set to 19 btw.

Edited September 9, 2014 by rondofj

[Ben C34]

Well I'm right. it is the timing the ecu Is putting out that you match.

But of course I can't back my self up. Surely someone else can chime in.

For example. The cell says 20. But there is an unknown warmup timing added. So the ecu puts outs say 25. You set it to 25 cos that's what the ecu thinks it is running.

It's not hard.

The reason for disconnecting the tps with the factory ecu is that at the correct idle it WILL default to 15 degrees for setting the timing. It's a maintenance function built into the ecu.

[Dose Pipe Sutututu]

That's what the stock ECU does, from what I remember PowerFC does not have that functionality.

There's no menu for startup/warm up timing.

[Ben C34]

And the "idle" cell in your timing map Isn't used unless the throttle is opened. When the throttle is closed it uses the idle control maps.

For examole. Set 30 into the cell in use at idle and see what timing the power fc reports when the throttle is shut.

[Ben C34]

That's what the stock ECU does, from what I remember PowerFC does not have that functionality.

There's no menu for startup/warm up timing.

Doesn't mean it doesn't exist. Just not adjustable perhaps.

[GTSBoy]

Ok,

I agree with Ben. There's the backup he needs.

Ron - it is very simple - it is exactly as Ben said. See what the PowerFC monitor function says it thinks the timing is. NOT what the normal timing map cell is active - the actual output. Then make sure that the timing light on the pulley says that you are at the same timing. Job done. It has been this simple the whole time. You should have been out to the car and done it weeks ago.