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The mkiv Supra Owners Club

Racelogic Blues


ttsupra97

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Hi all,

 

I've been running with a Racelogic TC system for a few months now, and it's been running really well. Last weekend I installed a HKS EVC EZ and HKS Super AFR, and now when I am driving hard enough for the TC to kick in, the engine just cuts off. When I have the Racelogic dial in the 'off' position and do the same, everything is then fine.

 

Can anyone suggest anything I should check? Currently, I have done the following:

 

- I have used Graham Rudd's Win95 software to monitor the wheel sensors and RPM (all of which are registering correctly)

 

- I am tapping into 12V at the trac ECU harness (I have removed the old trac ecu completely)

 

- I have checked that my outputs (the striped wires) are going to the injectors, and the solid wires are coming from the ECU.

 

- The RPM line is connected correctly.

 

- I re-loaded my datafile (using Graham's software), and also went through the full calibration procedure (which was successful).

 

I was thinking of next trying the launch control to see if the rev limit cut is working.

 

Cheers,

Tony.

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I've sorted things out, but there is something inexplicable going on...

 

If I disconnect the AFR from the RPM line, the racelogic works perfectly. So, it looks like they won't coexist, from the racelogic's point of view anyway, the AFR has no probs at all and happily displays the correct RPM. With the AFR connected, the Racelogic mesures a constant RPM of around 1900. Anyone have any ideas??

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Ah ha, cheers you've just solved why mine displayed a constant RPM! :) I'll have to go play with it now. It's not just AFR's it seems if there's any device close on the RPM wire it 'defaults' to 1900 RPM. Mine didn't cut the engine, but I got one hell of a misfire for a bit.

 

Matt Harwood suggested for me that tapping it from the back of the rpm guage could be another way of getting the rpm. Looks like the RLTC might have to be moved to that.

 

Thats not going to be pretty, though.

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Theres a couple of RPM inputs to the ECU anyway arent there? I know Martin tapped in to one wire and the Racelogic didnt do its self test properly, we tapped in to the second one and it did the same so we test drove the car and it calibrated up properly so it seems both RPM signals would have been okay.

 

JB

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Guest Martin F
Originally posted by Branners

Theres a couple of RPM inputs to the ECU anyway arent there? I know Martin tapped in to one wire and the Racelogic didnt do its self test properly, we tapped in to the second one and it did the same so we test drove the car and it calibrated up properly so it seems both RPM signals would have been okay.

 

JB

 

Yep there is more than one RPM signal at the ECU, you can probably connect the AFC and RLTC to different lines.

 

I would guess that having the two devices on the one line is causing too much of a load.

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Neither device if designed correctly should present enough of a load to affect one another. (But clearly they do)

 

 

Best bet is to use the alternative RPM signal or buffer the RPM signal yourself and then feed this buffered signal into the two external units.

 

Most of my units use a simple FET transistor input stage with high input impedance, which means you'll need a lot to present anything significant as a load.

 

My RLTC and my own AFR are wired in on the same line so it can be done.

 

 

It's when people start tapping into the shielded Knock sensor wires that worries me ;-)

 

Pete

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Hi Pete,

 

That's an interesting point about the knock sensor lines. I wonder if having a Fields harness has any affect on the knock sensor signal, as the knock lines on the Fields the harness certainly does not appear to be shielded at all... weird.

 

Cheers,

Tony.

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I do intend to develop knock sensor in the future, using digital signal processing techinques to distinguish the knock from real crank noise.

So not the crummy £100 jobs you get now which are worse than crap. Sorry if you have one, but I found they aren't very good at distinguishing normal engine harmonics from true knock and most (if you read the small print, or know anything about them) are only affective at low RPM. Which is bloody stupid as you want it to work at high RPM as that's where the high power is. Be careful relying on cheap knock sensor products. Just like using your stock O2 sensor. They are all O.K. up to a point, so long as you know their limitations.

 

I've got the design planned out.

It will use my graphical system and could flash a big warning graphic up and sound a buzzer.

 

Just don't ask for it yet. It'll only happen if the next generation TRL stuff is received reasonably well at the shows this year. Got to get some money back for all the development.

 

Pete

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