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Digital Input 5 Unresponsive


Johnny

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Hi Folks,

I have a Link G4 Supra plugin hardware version 1.0 in my Single 6 speed MKIV Supra. Recently I wanted to add 2 more digital inputs however I have already used all I can on the expansion connector. I found that in a JSPEC MKIV manual Supra DI4 is an electrical load sensor and DI5 is the start signal. These are not being used so I used DI4 for my clutch switch for the flat shift and had planned to use the DI5 as a switch to enable or disable another function.

I have set both DI4 and DI5 up as GP inputs, toggle type, pullup on, on level low and active edge falling. When I ground DI4 I can see a change, when I ground DI5 there is no response.

I have checked all the obvious things like wires all ok, cable is tight into the loom connector ect but I can't figure out what is wrong.

Can anyone give me a pointer as to what I might have overlooked?

Thanks,
Johnny 

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Hi Johnny,

I've had a look at the schematic for the Supra ECU, there is no difference in the circuits for DI 4 and DI5. I'm unsure why they would be working differently. If you go to Help > ECU Information which top-board do you have?

Scott

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Hi Johnny,

The only complication I can see with DI 5 on the Storm top-board is that the internal pull-up resistor (for DI5) will not function if knock control is being used. Are you using knock control?

Did DI5 work when it still had the start signal coming into it?

Scott

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  • 6 years later...

Hi Folks,

Sorry for the massive thread revival but I never got round to doing this and flat shifting wasn't a pressing need on the road!

I'd like to make use of the launch control / traction control features so I need more digital inputs. The board has a DI 7 and DI 8 on the expansion connector but doesnt show in the software? Is this a firmware thing or limitation of my board?

DI 5 is connected to a pin that when it was the OEM ecu the manual describes its use as -

 'Manual transmission: This pin is connected to battery voltage when the ignition switch is in the CRANK position.  When the engine is not being cranked this pin is connected to Ground via the Starter Relay coil.'

I havent tried connecting it to 12v as DI 4 is wired and configured the same way, switch toggle, pullup resistor on, on level low and active edge rising. It shows as active when grounded. Maybe I should? Pullup off / on level high?

I have double checked wires and ecu connector for anything obvious but I'm not sure what I'm missing on this one.

Is there anything I can try to troubleshoot DI 5 or to get DI 7 and DI 8 working?
Knock Control is disabled
I haven't tried DI 5 back on the original wire.

The aim is to use DI 5 as a non driven wheel speed sensor for the launch control DI speed channel when using the 3D launch control table. Aside from making my AC off the activation switch and using the DI 4 which is my current one the non driven wheel speed sensor I'm out of ideas!

Any help greatly appreciated

Johnny 

 

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Got sorted on inputs, used DI1 which is supposed to be the normal speed input and hooked the FL ABS and calibrated. Working well when set as ground speed.

Trying to smooth out the traction control now. I datalogged a slowish run in 1st to 7k rpm and then took the corresponding rpms at speeds in increments of 10 and added 10% rpm onto the table figures for slip. Its quite harsh / jerky still tho.

Any suggestions to make it more smooth or anything extra I can turn on in the logging to spot points to fix?

Cheers

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Hi Adam,

Sorry I should really be calling it Launch RPM Control.

A few years back I had enabled the launch control function simply to give me the RPM hold so I didnt need to feather the throttle when getting moving. It was using the Mode 1 - 2D table, I have a toggle switch on DI4 for my activation control and DI1 set to speed channel which was fed from gearbox. Disarming speed was 10 as I only cared about getting moving and only -5 degrees of launch ign trim with RPM limits set to 3500rpm. Using ignition cut as my limit mode.

Fancied getting a bit more out of this to counter wheelspin on launch or when passing the 4k rpm mark when the power came in. A bit of slip is ok I guess but most times I needed to fully lift off to catch grip again or I would hit limiter at 5mph.  To use the RPM limit mode I needed to get speed from non driven wheel - sorted.

I have now configured my launch control into Mode 3 - 3D table. DIsarming speed set to 60kph, -10 degrees Ignition trim and initial launch rpm set to 3500.
I logged a few moderate pulls to limiter in 1st to get groundspeed vs rpm. Then added 10%to the rpm values to give a slip %. Then entered these in the Launch RPM table.

The aim is when I launch, the rpm will continue to hold at 3500 until I get to 30kph and then this limit will increase just ahead of the speed vs rpm curve so if I do lose traction the rpm wont run all the way up.

Sounds like it should work in principal but I must be missing something. The car launches ok but shortly after getting moving when I'm nearing 4k rpm it starts to accelerate in rough lurches. Like a forceful off on off on with the acceleration. I can see the log showing percentage Ign cut coming in hard and I would have liked to have seen the 'Launch RPM Limit - Old' logged with Engine speed to see whats going on there but it seems to be unuseable maybe why its flagged as old.

Would you know why its doing this? Not sure if I should have the launch rpm limit closer the what the rpm should be at that speed if you had traction so less than my 10% or if I should give it a higher allowance. Maybe its just struggling to manage the lack of traction. Is there a way to smooth it out?

I have attached log and map.

Thanks,
Johnny

jerky pull 1.llg jerky pull 2.llg 18-03-23 Map - Copy.pcl

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I think it is mostly the limiter settings are far from ideal.  It looks like you only need about 40% cut to hold it at the correct RPM, but the start cut is set to 60% so that drops RPM too much, then it turns off, then RPM shoots up again, too much limiter kicks in again etc...

So, turn on advanced mode, reduce start cut TP100 to about 20%, reduce end cut to 90%, increase the decay rate, the first two adjustments should make the RPM bounce less, the faster decay will make the interval between bounces quicker.  

In terms of launch strategy, you will usually find it better to have the initial launch RPM higher than it needs to be (say 4-4500), this gets the wheels and other high inertia parts moving as quick as poss, it doesnt matter if it initially breaks into slip, as long as its for a short time, but then pull the RPM back down as soon as road speed is seen to allow the car to "catch up with the wheels" and the tyres will bite again.  

7K9xnVm.png

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Hi Adam,

Thanks for this, it makes a good bit more sense now. Am I right in saying then if my launch RPM limit for 40kph was 4400 then the control range is 4200 - 4400. When the ECU saw 4201+ it was jumping in with a 60% cut which was too harsh. Does this mean then the aim is to get this Start Cut TP100 as low as possible without allowing it to overshoot?
I can see that when I am in neutral and TP is 100% it needed 79% Ign cut to hold my RPM and during the acceleration to maximum speed in 1st gear it didnt need more than 60%. Could I drop the End Cut value to 80% then to decrease this control range gradient?

How close should I be making my RPM limit for each speed entry in the Launch RPM table? I know 40kph is 3960 so basically 4000. I added 10% when filling in values. So no more than 4400 at 40kph but control range starts at 4200 so I have 200rpm of allowed slip. Is this about right? If its too close I guess it will begin cutting when there is next to no spin.

Final question, whats the best view or what parameters should I be watching for me to fine tune this?
I have been looking for a smooth RPM line, no ups and downs like the before photo
Not sure what to be looking for in IGN cut now but I knew the before picture of it basically showing it jumping between 60% and 0% wasnt right
RPM rate/sec either flat as groundspeed catches up and I get grip or smooth in the positive as I speed up, no up down action

Thanks,
Johnny 

After.PNG

Before.PNG

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