Jump to content
PeterHay205

Storm - ST205 GT4 - Unusual 'limit' behaviour

Recommended Posts

We have a Toyota GT4 (model ST205) fitted with a Link G4+ Storm ECU that we use for short course tarmac rallysprint events. The car is largely stock, with just a few upgrades (rebuilt stock turbo with steel wheels), coilovers etc. The car has been tuned in Perth by one of your major dealers who are well experienced with your ECUs.
The car has been a lot of fun, weve been chasing an issue where the car feels like the ignition system (which is single coil with a distributor) is 'breaking down' at certain (random) times. To eliminate the ignition system, we replaced the cap, rotor, and gapped the plugs smaller during the last event, but the issue still occurred.
We enabled ECU logging during the last event, and at the particular time we felt the issue occurring, I have examined the logfile in detail, and it seems to be the ECU applying a limit to the ignition timing. 
I have attached the logfile and the ECU tune.
I have spoken to our tuner about what may be causing it, but as it is not easy to repeat it is difficult to pin it down.
The specific questions I have are:
1. In the logfile, at file time 16:34.46 through 16:37.76 the logged parameter 'Limit Ign Trim' goes from 0 to -2 degrees a number of times. We actually felt this in the car - felt like a misfire of some sort. I've looked at the various limits setup in the tune, and discounted:
a) MAP limit. MAP only gets as high as 212kPa. MAP limit is 260kPa, with a Limit Control Range of 15kPa, so nothing should happen until we hit 245kPa
b) RPM limit. We are well under the RPM limit
c) I don't think it is a trigger error. The Max RPM recorded in ECU Statistics is a 'normal' number
Maybe it is a Engine Coolant Temp limit (the ECT is 102/103 degrees at the time)? Looking at the ECT Ign Trim 3D Table, I'd expect some sort of limit (goes from 0 limit @ 100 degrees to -8 limit @ 110 degrees), but I'm not sure why it is so 'sporadic' in the way it is applied?
Can you please have a look and advise if this is what you'd expect, or if we need to look at some other settings/logging?

Thanks

190314-Rallysprint Rnd 5 - ignition limit.PNG

06-Angelina - enabled ECU logging.pclr 190314-Rallysprint Rnd 5 - run 1 thru 4.llg

Share this post


Link to post
Share on other sites

the MAP limit table values are linearly interpolated between the entreies you define. So at 103 degrees you are 30% between your 100ECT value (260kpa MAP) and your 110ECT value (150kpa). This gives you an effective MAP limit of 227kpa at this temp. Minus 15 for the start of limit engagement number and you are at 212kpa for the limit to kick in, which is exactly what you see. 

I suspect that ECT is recorded in whole numbers internally, so you are either at 227 kpa limit, or at 238kpa limit (102ECT), and so it seems to come and go randomly, because its only 1 deg ECT difference.

Quick fix is add in a row at 105ECT which still allows 260 MAP.

Also, whats up with your IAT sensor, it seems to read a constant 75C for that entire last run - it doesnt change with boost level even 1 deg, but 75C is kind of high to be ambient?

If you want to make the limits a little easier to tell apart without changing what you are logging, change one of them to -3 deg instead of -2, so its more obvious in a log. Really you should just change your ECU logging to include more parameters if you know there is an issue hiding in there somewhere though.

Share this post


Link to post
Share on other sites

Thanks cj - what you say makes perfect sense. I had forgotten about the rapid drop in MAP limit at 110 degrees.

I take your point about the IAT readings. The IAT sensor seems to be accurate at ambient temp (always close to ECT when car is cold), but the response time seems way too long. I'll see if we can get it out without too much trouble and have a look at the response time.

cheers

Peter

Share this post


Link to post
Share on other sites

I've done some more 'internet research' about the stock IAT sensor on the GT4, and it seems that it is very prone to heat soak and very slow response time. I know its a long shot, but does anyone happen to know of any 'open element' type IAT sensors that will easily fit in the Gen3 3S-GTE?

The IAT sensor in these cars is squeezed in just after the throttle body, so it is quite difficult to get at.

Share this post


Link to post
Share on other sites

I have a ST185 and since the Link ECU is installed, everything works great and I have deleted the Cold start Injector. There is now a hole that I can put an Audi Bosch open type element

in there that will catch the air stream coming in. In ST205, they probably got rid of the cold start but I am sure you can drill a small hole and tap a 6mm threaded hole that can expose an open element temp sensor from Audi A4 or VW vehicle. Nice thing is that sensor is listed on the software to use.

 

Cheers

 

Share this post


Link to post
Share on other sites

Thanks Crackerjack - as it turns out, we are also building a ST185, and have done exactly the same thing (stolen the hole left by the Cold Start Injector) and stuck a Bosch open element sensor in it. Unfortunately, we haven't yet got as far as starting it up, so I'm not sure how well it will work in practice.
With the 205, there is no cold start injector, and the stock Air Temp Sensor is even further 'into' the manifold, and is a M16 screw-in design (difficult to adapt the Bosch sensor to fit, given its mounting arrangement). I have spoken to our tuner and we will probably weld on a boss on the rear wall of the Intercooler core (right next to the outlet) and stick the sensor there. We will then be able to compare those readings to those of the stock sensor.
Have you logged any data from your setup? I'd be interested to see how well the sensor performs there. 

Share this post


Link to post
Share on other sites

Hi Peter,

I have been using the new setup now for about a week. so far there is only one issue that I noticed with the open element sensor. That is Heat soak.

I find that on a hot 29C day, the heat soak causes the car to not idle. I have since adjusted the base idle to slightly higher but the minute you drive,

the issue went away. I have not logged any data yet as we have distracted driving law and if the cops sees a laptop running in the passanger seat, its

a $250.00 fine.

I do have a AEM X series wideband gauge that sends CAN info to the link for closed loop operation. I also have the stock narrow band O2 removed.

judging from the readings, the open air element is working out really well.

Cheers.

Share this post


Link to post
Share on other sites

Hi Guys,

Regarding heat soak, you can add some values into your IAT table to compensate for this. Even on modelled fuel mode where IAT correction isnt normally needed you can enable it, set one axis to TPS and the other to IAT, and then just add in some ~+5 to +10%  values in the 30C+ ranges, but only at <10% TPS. Leave the rest of the table zero'd out as you arent looking to use this for IAT correction during normal load.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...