[george kujanski]

Not quite, Monkey.....6000 RPM =600 RPS (revs per second) X 36 teeth = 3600 teeth per second. each tooth gives you 1 cycle of the signal so that's equal to 3600 cycles per second, = 3600 Hz @6000 RPM.

In fact, if you had 60 teeth, at 6000 RPM you would get 6000 Hz., a nice 1-to-1 number.

George

[TheMonkey]

d'oh. you're right. goofed up the minutes -> seconds.

anyhow, i'm not sure if the HEI module could speed up by a factor of 9 (9 teeth on 36 tooth wheel is the same as 1 tooth on distributor reluctor).

[george kujanski]

You will probably need to connect a 1Kohm resistor or so from BAT to the module terminal that normally connects to the coil since that terminal is probably a open collector transistor, and then take your output signal from there, (negative-going square wave edge when a tooth is present).

I'd say you definitely need to move the Vr sensor to a radial position with the tooth to mimic the input signal to the HEI module.

george

[TheMonkey]

you're right on with the resistor. prior to the internal conditioning circuit, that is exactly how it was done. i have read 470 ohm, 1/2 watt resistor.

i was re-reading a post about crank sensors that i was participating in (i just bumped it in street section today) and HIS had indicated that he had tested the HEI module to an extraordinary frequency. i'm thinking that the sooner the circuit is conditioned, the better.

[Jack Gifford]

If nothing else, this thread reinforces my choice of hall-effect trigger (ignition only, no FI)- so nice to know that triggering is strictly crank-position-sensitive, with no concern for signal slope or frequency-dependence. Plus the nicety of being able to statically play with tweaking the sensor position, etc. The Crane sensor is neatly packaged with just three leads- power, ground, and square-wave 12v trigger output- even has an LED tied to the output. If I were ever to play with EFI, I'd look into adding a fifth magnet (separate track from the other four) and a separate sensor to a setup like mine, to substitute for your missing-tooth deal.

I doubt that a filter capacitor at your fuel pump will accomplish anything. It looks like power to your ECU is already pretty "clean". Yes, the pump could also be radiating (broadcasting) RFI, but in that case, only shielding would help- or filtering out the RFI wherever it's being received.

[TheMonkey]

yes, i think you're right about the hall-effect trigger being more reliable, because they are less susceptible to noise. although, many people and many cars have done fine with VR sensors. i reckon it just requires some fooling around with a custom setup.

when you do go with EFI, prob just leave the Crane as it is, and use an HEI distributor with only 1 reluctor tooth to reference not only crank position, but firing order.

i updated the crank trigger thread last night; i tested a 4-pin HEI module i had in the garage, and it converted a simulated signal fine up to 10kHz, or 16,500 RPM. that's as fast as my simulator would create a signal. simulated signal is a bit different, in that it looks like a square wave that goes +/-, but at least it seems that it can handle the frequency. i suppose if i use that module, i should protect it from the elements if i mount it by my VR sensor. do any type of arrangements come to mind for that?

[TheMonkey]

i have pinned down the source of RFI. i used an AM radio. it's the o2 sensor. when the fuse gets pulled from that, everything is super quiet, even the fuel pump. when the o2 sensor get powered up, the radio screams when the antenna gets near the o2 sensor. if the o2 sensor is powered up, the radio screams from the fuel pump too. the fuel pump and sensor share the same power source, but different grounds. the base of the break-in stand seems to broadcast a bit too when sensor is powered. this is all with the motor off, but 'key on'. when i get rid of this o2 sensor RF, i might find some broadcast from my ignition system... we'll see, but one step at a time for now.

how do i get rid of this? there is a lot of AM radio noise right next to the VR sensor which has a couple inches of unshielded wire before it gets shielded. should the sensor have it's own power supply from the battery?

it seems to be from the wideband brainbox rather than the actual bosch sensor with the heater in it.

thx for the help.

[TheMonkey]

i thought i would find some sort of quirky way that i had this setup that was causing the lambda sensor to radiate. boy, was i trying so many different arrangements.

and then.... i hooked up the lambda sensor directly to the battery without anything else hooked up. bottom line.... this thing is too noisy. check out the attached video of the RF noise coming through an AM radio. when sensor is first powered, the LED blinks during warm-up, and then when it goes steady, it is reading o2. in the video, i powered it through the whole warm-up cycle. it screams the moment power is applied, and as soon as power is pulled, you can hear the RF noise go away.

also- as for the noise in the power line as read by the scope.... it's still there when connected directly to the battery. the closer i probe to the sensor, the louder it gets, and it shows up in other items like the fuel pump when everything was hooked up.

perhaps i could hook up the sensor directly to the battery and shield the power line as that seems to be what is radiating. a 0.01mF 500v capacitor at the sensor did not clean up the power at all. is there anything else that could absorb some of these power shocks?

i suppose it could be a faulty unit... after all... this thread started because this unit was restarting itself, but i suspect those restarts might have been due to voltage drops through cranking that i fixed through using battery cables instead of jumper cables, and then i was having probs with noise infiltrating my tach signal, which was coming from this RF.

VIDEO: http://youtube.com/watch?v=k0FXdOOHYtM
Scope shot of power at sensor (when sensor is powered off, the power looks perfectly flat): http://img136.imageshack.us/img136/3...batterywf1.png