[Jason Rouillard]

Hi,

I created a previous topic for help on cold start but my problem become from my vr sensor. So i create a new topic for this problem.

When I crank engine, tuner studio show many pics of RPM. RPM raise to 10 000 while cranking.

I read on internet that a shunt can solve this problem. My VR Conditioner (MAX 9926) already have a shunt on it (4.6k). I removed it in order to increase resistance.

So, I put a resistor of 10k (1/4w) between both wires of crank sensor. This did'nt work. I increase resistor many times and this did'nt work.

I don't know what i can try to solve my problem ?

My trigger edge is setup on falling.

Thanks
Jason

[jonbill]

Probably the best thing to do would be find and eliminate the source of noise.
Normally max based vr conditioners use rising edge detection.

[JHolland]

Higher resistance will make it more prone to noise, although it will increase the voltage. if you have access to a scope measure the voltage, maybe you can go to a lower resistance.it is better to have have the resistor across the input to the VR conditioner rather than across the pins on the MAX device.

[Jason Rouillard]

Probably the best thing to do would be find and eliminate the source of noise.
Normally max based vr conditioners use rising edge detection.

It's for a derby car, so there will be noise.

I can try rising edge. I don't understand why some VR Conditioner need rising and other falling ?

Higher resistance will make it more prone to noise, although it will increase the voltage. if you have access to a scope measure the voltage, maybe you can go to a lower resistance.it is better to have have the resistor across the input to the VR conditioner rather than across the pins on the MAX device.

So, it's better to put shunt between wires that on VR Conditioner ?


I also read this web page and they say to put a resistor on the wire ?
https://www.diyautotune.com/support/tec ... squirt-vr/

Putting a 10K to 20K resistor inline with the crankshaft position sensor wire generally clears this right up. Below is a tooth log showing this problem happening to a 36-1 trigger wheel.

[jonbill]

It's for a derby car, so there will be noise.

I can try rising edge. I don't understand why some VR Conditioner need rising and other falling?

Is "derby car" some kind of race car? Many have race cars on speeduino and manage to get good clean crank signals.
A switch to rising won't fix the noise, but it might be correct. Some (most?) max chip configurations invert the signal, others chips and configurations don't.

[Jason Rouillard]

Is "derby car" some kind of race car? Many have race cars on speeduino and manage to get good clean crank signals.

Yes, it's a tournament to death. Last car who make a hit WIN. We put between 4-10 cars in a square of 80 by 80 foots. Winner gets a place in the final. In one day of derby, we have approximately 100 cars.

I know my noise it's from my starter, but i don't know if the next starter i will put on it (because his current one might be broken in a face to face) will be good for noise or no. In the day of derby, it's not time to hunt noise, so the best it's to eliminate more noise i can with VR Conditioner.

[JHolland]

Putting a 10K to 20K resistor inline with the crankshaft position sensor wire generally clears this right up. Below is a tooth log showing this problem happening to a 36-1 trigger wheel.

Don't put the resistor in-line, put it across the wires. Putting the resistor in parallel will give a better signal to noise ratio and retain the differential input configuration.

[Rednaxs60]

We call it a demolition derby over there. Last man standing wins. You wanted to use the rear of the car to hit your opponent - Dad used to put a few cars in the demolition derby at the stock car 1/4 - 1/3 mile race tracks back in the '60s, using the front took out the rad too fast and your car was done. The Demolition Derby Drivers Association (DDDA) in the US banned the 1964–1966 Chrysler Imperial from being used in a demolition derby sanctioned by its association. The Chrysler Imperial achieved near-legendary status for its crashworthiness (couldn't kill it persay), and it is still banned from most derby events. This is IAW the on-line wiki and could still be valid today.

[Jason Rouillard]

Don't put the resistor in-line, put it across the wires. Putting the resistor in parallel will give a better signal to noise ratio and retain the differential input configuration.

Thanks, if I understand, I need to find the best ohm value to put between ? If I put to small no signal will come to VR Conditioner and if i put to high no filter will be done ?

Also, voltage produce at cranking it's smaller than 1 volt ? And at full RPM it's above 50 volts ? So, I need to find a resistor drop small value voltage when cranking (for remove noise) and can resist at high voltage ?

We call it a demolition derby over there. Last man standing wins. You wanted to use the rear of the car to hit your opponent - Dad used to put a few cars in the demolition derby at the stock car 1/4 - 1/3 mile race tracks back in the '60s, using the front took out the rad too fast and your car was done. The Demolition Derby Drivers Association (DDDA) in the US banned the 1964–1966 Chrysler Imperial from being used in a demolition derby sanctioned by its association. The Chrysler Imperial achieved near-legendary status for its crashworthiness (couldn't kill it persay), and it is still banned from most derby events. This is IAW the on-line wiki and could still be valid today.

I am from Quebec and Yes imperial are banned. With ours rules we can swap radiator by an home made radiator. So we keep coolant in it. It's why i want use speeduino. It's cheap and I can adjust it for when engine is very hot. Stock computer cannot adjuste engin for high temperature.

[Jason Rouillard]

I tried somes resistors. I find that a resistor of 330 ohm make a good job. I also tried a 470 and i had noise. I also tried resistor of 230 and some times i was'nt have RPM in tuner studio.

I don't know if my resistor will survive to high RPM. I will try tomorrow.