Toyota 20Valve Triggering Problem above 7000rpm

[Cory]

Hi,

We have had a couple of questions about problems with triggering off of a 20 valve above 7000rpm.

We have looked into the situation, and it appears the cause of the problem is a 'bump' on the shaft of the sensor, which when spun fast enough can cause false triggering on the 'reset' inputs.

If you have a 20 valve with this problem we recommend connecting two 1k resistors as a voltage divider to the input on the reset line as shown in the following diagram.

http://www.adaptronic.com.au/Cory/20Valve.JPG



We have tested the circuit on the bench, and it appears to remove the 'bump' enough to stop false triggering up until approximately 14000rpm, and is still able to trigger at below 200rpm, so we do not expect any problems but if there are any please let us know.

Cory

[mecmw]

hehe, we once had the same problem with the original Honda sensors in the FSAE car when using Haltech.  It would only rev to 7000rpm and then start banging and missing.  We couldn't work out what the crap was going on until eventually we noticed the minutest little bump on the cam signal coming from one of the bolts.  It was tiny, probably less than 1% of the main trigger.  

Unfortunately we could never sort it out.  We had a voltage divider on it (adjustable with a pot), but either it wouldn't work while cranking or it wouldn't work at high RPM - the was no happy medium.  Eventually we had to retrofit a hall sensor.  Ahh, happy days!

[Jason Broadhurst]

This sorted out a 3S-GTE I was working on. Top work Adaptronic.

[Andy]

Cheers Jason

[Jason Broadhurst]

Just came across this problem on a 20V again, all sorted now

[charlie_keto]

Hi Cory could i get you to rehost that picture again, as the link appears to be dead.

Cheers Charlie

[rob_k]

Hi Charlie,

If you choose a Toyota/Lexus engine from the list with the 'Change Engine' feature in the WARI software (on the 'Basic Setup' tab), it will show a picture of how to do it.

Cheers
Rob

[charlie_keto]

Thanks Rob!!! Haha i been scratching my head for ages trying to figure out why i couldn't rev past 7.
Thanks for the help cant believe i missed the whole change engine tab in basic setup!

Cheers Charlie

[71meh]

Hi,

just wondering if you could repost this picture as it isnt in the latest version of wari and i need to check because it wont rev past 5000 rpm.

Cheers,
Tim

[rob_k]

Hi,

With recent versions of firmware and WARI, you can select a 'Toyota' special triggering mode which removes the need for resistors on the CAS inputs.

Cheers
Rob

[71meh]

Hi rob_k,

what about if i use custom so i can increase the dwell time on the coils, will this still remove the need for the voltage divider or do i have to use the (toyota/lexus), then 3sgte with wasted spark option?

as the car is running 4x ls1 coil packs configured in wasted spark.

also from what i can tell i need to wire

ne = 24 tooth signal to trigger 1
g2 = cam position signal 720 deg to trigger 2
g1 = cam position signal 360 deg to trigger 3
g- = negative to the CAS negative (white wire).

can you confirm that this will work in the custom option or will it only work in the toyota/lexus 3sgte wasted spark configuration?

Cheers,
Tim

[rob_k]

Hi rob_k,

what about if i use custom so i can increase the dwell time on the coils, will this still remove the need for the voltage divider or do i have to use the (toyota/lexus), then 3sgte with wasted spark option?

as the car is running 4x ls1 coil packs configured in wasted spark.

also from what i can tell i need to wire

ne = 24 tooth signal to trigger 1
g2 = cam position signal 720 deg to trigger 2
g1 = cam position signal 360 deg to trigger 3
g- = negative to the CAS negative (white wire).

can you confirm that this will work in the custom option or will it only work in the toyota/lexus 3sgte wasted spark configuration?

Cheers,
Tim

If you set your engine type and press OK, it will update the triggering settings for that engine, and it will disable the button to change the triggering settings. Then, if you set the engine type back to 'Custom' and press OK again, it will retain the settings from that engine, but it will enable the triggering settings button so you can change things like dwell time, while still retaining the other triggering settings.

Your proposed wiring looks correct too.

[71meh]

Thanks rob,

everything works perfect now, really appreciate the quick reply.

[Sam-Q]

hi guys, sorry to dig up this old thread but could someone put back up the original diagram for the voltage divider?

[rob_k]

Hi,

With recent versions of firmware and WARI, you can select a 'Toyota' special triggering mode which removes the need for resistors on the CAS inputs.

Cheers
Rob