DTA S40-pro idle control using ignition?

This section is dedicated to discussion of DTA engine control units such as the DTA E48 EXP, P8 Pro, DTA S40, S60, S80, and S100, as well as all things ECU related.
firewalk
Posts: 11
Joined: Sun Jun 08, 2014 2:04 pm
ECU Model: S40 Pro

DTA S40-pro idle control using ignition?

Post by firewalk »

I have an MR2 turbo with a DTA s40pro ecu. It runs great. There's just one issue: Idle control. The car doesn't have an idle valve and no matter how I try to adjust it the idle will either be too high or too low, depending on temperature...

I see from the manual that it's possible to use advance instead of idle valve, but I assume that's just on the newer units.

Can I update the firmware on my DTA S40 pro to make it possible to use ignition advance / retard to control idle ? Or is that not supported on the S40 at all ?

I'm considering having my ECU flashed with the latest firmware update. But I need to know if it will be able to control idle using ignition?
PhillipM
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Joined: Tue May 13, 2014 5:30 am
ECU Model: S80 Pro
Distributor: DTA UK
Firmware Version: 73

Re: DTA S40-pro idle control using ignition?

Post by PhillipM »

Should be able to yes, it's been in the firmware a while, how old is your unit?
Alex DTA
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Joined: Fri Feb 28, 2014 1:03 pm
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79

Re: DTA S40-pro idle control using ignition?

Post by Alex DTA »

Yes, the S40 can control idle using ignition.
Yours must be a fairly old unit, as that was introduced in V23.
Rob Stevens
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ECU Model: S100 Pro
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Re: DTA S40-pro idle control using ignition?

Post by Rob Stevens »

I use the ignition idle control and I think it works really well, however I should add that you need to understand that for it to work well you need the ignition to be fairly retarded at your chosen idle speed when hot. i.e. if you want to idle at 1000 rpm when hot without idle control on you need to crack the throttle open enough to require just 2 deg of ignition. this will see loads of air going into the engine, this makes it much more responsive to ignition timing, this helps when cold.
firewalk
Posts: 11
Joined: Sun Jun 08, 2014 2:04 pm
ECU Model: S40 Pro

Re: DTA S40-pro idle control using ignition?

Post by firewalk »

Thanks guys!

I think it's about 7 years old? I'm not exactly sure. I have it set so that when the engine is hot the idle is usually between 1000-1300 rpm. But this cause it to be way too low when it's cold, it would struggle at 4-500 rpm when cold. To try and solve this I installed a solenoid I had laying around, and wired in a relay that's normally open, and connected it to the AUX fan control. So that the solenoid would stay open until the engine hit operating temp and the cooling fan kicked in (about 70degrees). At that time the fan kicking in would cause the relay to close the solenoid.

That helped a lot on the cold start, keeping the RPM up. But the exact moment the fan kicks in and the solenoid switches from open to closed, the RPM drops instantly, and stays down for a few minutes until it crawls back up.
It also varies a lot with how long I drive the car. It can stay perfect on a small trip, but become a bit too high on longer trips etc.

I also tried to help the cold start by adding ignition advance on the coolant temperature map, until the engine was warm.

Ignition is already rather retarded when the engine is warm. About 6 degrees, so that shouldn't be a problem.

This struggle to keep it idling ok has been really anoying to say the least, so I'm really looking forward to testing this out! :)
Rob Stevens
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ECU Model: S100 Pro
Distributor: None-Coil On Plug :)

Re: DTA S40-pro idle control using ignition?

Post by Rob Stevens »

That sounds very complicated for a simple issue! Just open the throttle more on the stop, ditch the extra valve and turn the idle control on. I could do it faster than I can type!
firewalk
Posts: 11
Joined: Sun Jun 08, 2014 2:04 pm
ECU Model: S40 Pro

Re: DTA S40-pro idle control using ignition?

Post by firewalk »

I'm just waiting for a cable that will allow me to flash the unit so that I can try out the ignition controlled idle.
The version I have now aparantly won't let me use ignition based idle, so I have no idle control at all. Just mechanical (adjusting throtle cable and or the screw. But as i said, that won't keep the idle at the same rate when the engine is cold vs warm.
I have adjusted it so that it's near perfect when warm. But it's not ideal when it's cold now. Also, the weather plays a huge role. I live in Norway and we can have days when the temperature is 30 degree celcius, and the next day it's 6 degrees.
This temperature variation is also very noticable on the idle.

I'm running hks 264 cams amd 720cc injectors on a 3s-gte engine, and that will affect idle negatively as well.

I'm looking forward to trying out the Ignition controlled idle. :)

On a side note: How safe is it to flash the unit? Is there any possibility to mess it up and damage the unit so that it becomes unusable if the flashing fails half way, as could happen with some old computers when trying to flash the bios?
Alex DTA
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ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79

Re: DTA S40-pro idle control using ignition?

Post by Alex DTA »

You can't damage the unit flashing it. If it gets corrupted, or interrupted, you can just flash it again.
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ignitionautosport
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Re: DTA S40-pro idle control using ignition?

Post by ignitionautosport »

Alex DTA wrote:You can't damage the unit flashing it. If it gets corrupted, or interrupted, you can just flash it again.
Glad to know I wasn't just lucky when that happened haha.

I have to say igniton based idle control is amazing. I am super impressed with how it works.

Here's the settings I've used, might be an ok starting point. Curiously, I started with way looser settings but the engine was waste-spark and the cam trigger was pretty much on TDC; it kicked back and ran backwards and the broad diel settings meant it started to correct itself and run backwards. That was a brown trouser moment till I turned it off. I let it have massive retard initially though, not like below.
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firewalk
Posts: 11
Joined: Sun Jun 08, 2014 2:04 pm
ECU Model: S40 Pro

Re: DTA S40-pro idle control using ignition?

Post by firewalk »

Thanks a lot! I got this working now. :D
I can't believe how well it actually works! Thanks for sharing your settings. I used them as a template to get mine going, and then adjusted it to better suit my engine.

It now idles at 1200 when cold, and drops to 950 rpm when fully warmed up.
It's like driving a totally different car now! No more worrying about stalling it when stopping at a junction. No more holding the rpm up with the gas when cold etc.

Now I can finally drive and smile at the same time again! :mrgreen:
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