TT Plugin Idle Control

[Grant Baker]

Hi Guys,

We've recently done another TT plugin and having some idle control issues...

Set as open or closed loop EThrottle, we get a lot of hunting around the target idle. It's like a pendulum and the amount it swings, or if indeed it swings at all sometimes, is not consistent.

Idle is set at 900RPM and it swings wildly from 700 to 1200. 

Sometimes as you slow the car down to a stop the engine stalls.

I've spent about 5 hours on it now and it's driving me mad!

Can anybody spot an obvious mistake (or many mistakes)?

[Adamw]

Can you post a PC log, preferably showing the oscillation.

[Grant Baker]

Yep - will grab one tomorrow

[Scott]

I think the Idle ignition table will be creating some problems also. Normally the '0' column should be set to an ignition angle at which the engine idles nicely under normal conditions. This is because the idle ignition table is used instead of Ignition table 1, and not as a trim of ignition table 1.

I recommend getting the open loop idle control as nice as possible before switching over to closed loop mode. The closed loop idle control uses the base position table (from open loop) as a starting point.

Scott

Edited January 26, 2017 by Scott
extra info

[Grant Baker]

I spotted that in the Idle Ignition table just now Scott...

Interestingly, the "0" degrees in the "0" Column is what is in the base map supplied by Link

 

[Scott]

Hi Grant, thanks for letting us know. I've checked the base-map from our current release and this problem now seems to be fixed.

Scott

[Grant Baker]

See attached logs - one with closed loop and one with open loop.

TTPlugInIdle.llg

TTPlugInIdleCL.llg

[Simon]

Hi Grant can you put up a copy of the MAP as well makes it much easier to match up then. Email it if you don't want it public

Could you also do the logs in PC link with all parameters logged.

As a bit of a guide I would tend to follow the following when tring to get a stable idle.

Start with all idle control turned off including idle ignition.

Make sure a stable idle can be maintained on a warm engine with no changes in load (power steering, AC, fans etc turning on or off)

Once the idle is stable under steady state conditions I would then turn on the open loop idle control. Adjust figures to make as good as possible idle during warmup.

Then next step will be adjusting the idle ups for AC fans etc.

Then once all good go to closed loop control.

 

Edited January 26, 2017 by Simon

[jannerboy]

Guys,

This issue still exists, and now its time to sort it out once and for all!

Simon, can I ask for a more detailed "idle start procedure" for our car with ethrottle or clarify some points for me please?

I can turn off the idle ignition control, and will wait until the engine is warm and try to adjust the main ignition table 1 to get a stable idle...some AFR adjustments may also be required i guess.

But you mention "turn on the open loop idle control"...but I can't turn it off! there are only four options...none of which are "off".

Did you mean "turn on the idle ignition control" to then release access to the idle ignition table? Then adjust the figures within during warm up...then adjust for idle ups AC fans etc...then go closed loop...

Regards, John

[Grant Baker]

The options for idle control specific to eThrottle are open loop or closed loop.

Open loop should be the one you try first.

Or just bring it over and we will sort it as agreed

[Simon]

If you select open loop Solenoid/stepper it will disable the control on the E throttle as there will be no Aux output then assigned for Idle control.

Getting the idle stable with no external corrections is the first step and this will all be done on the main tune. Think old school carburetor cars that didn't have a idle control other than a choke cable/knob.

 

[jannerboy]

Guys, thanks and I've got the idle set up Open Loop, Idle Control On, and its now stable and does not now stall. The 1.8T needs 20 degs at idle (as per your base supplied map...). 

The key area was the E-Throttle 1 Target table. The e-throttle is very sensitve to changes around the idle areas within this table. At the moment the changes can only be made with 0.5 as a minimum step. Would it be possible to allow a step change at a resolution of 0.1 step?

Column "0" of the Idle Ignition Table is set at 20, with Column "100" to "500" set at 25, and Columns "-100" to "-500" set at 15. I found that adjustments made in this table seemed to make no difference whatsoever...?

I'll endeavour to turn on Closed-Loop and try that out soon, but i just wanted to run the above by you so you can advise if I have missed anything or anything else to check?

 

[Grant Baker]

There is a way around the 0.5 step John.

I can show you.

Same for ignition table... If the error is not much the idle table doesn't do much... Numbers that are too big or too small can also cause it to hunt.