S2000 Speed Sensor Erratic

[Mario Schneiderbanger]

I dont think I can use DI1-8 for an ap1 s2000 speed input since the frequency is much higher than that of other sensors. Here is a chart i found. At very low speed it works fine but anything faster than 20 mph the reading goes erratic reading as high as 1500mph at times.  Any suggestions? I already tried to switch from rising to falling. I have not tried the pullup resistor since it does read speed.

 

EDIT: I just checked the runtime values on DI3 and it reads up to 1600hz reliably before it starts to drop out. Unfortunately 1600hz is only 34ish mph which coincides with the chart below. 

 

VSS Signal:

speed(MPH) S2000(hrtz) Integra(Hrtz) 
0    0-100 0 0
10    500 15
20    940 26
30    1340 38
40    1800 48
50    2230 59
60    2640 70
70    3090 80

80    3500 91
90    3910 101
100  4310 112
110  4810 123
120  5240 134

 

[Richard Hill]

What ecu are you using? if its a thunder then yes the differential digital inputs are fine to use with high speed inputs. 

All other ecus are restricted to lower speeds, so a divider circuit would need to be used. 

[Mario Schneiderbanger]

Thanks Rich, i realized after asking about DI11+ that my Fury doesn't have them.  Any idea where I might find a divider circuit that I can configure to divide by 39?

 

Edit: It only needs to divide by 6 or 8 to get the full resolution 

[cj]

You can build one using these chips for a few $ https://www.jaycar.co.nz/4024-7-stage-ripple-carry-counter-divider-cmos-ic/p/ZC4024

Depending on which output you take the signal from it will divide by 2/4/8/16/32/64/128

I've used these in the past to adapt high frequency gearbox outputs down to something that can be fed to a DI at lower frequency and they have worked fine. Only thing to check is whether you need a pullup on the input & output circuits - input you need to add a pullup resistor to 5v or 12v, output side (ECU input side) you do in the ECU config for the DI.

[Mario Schneiderbanger]

my circuit building knowledge is very slim. 

can i feed 12 into the VDD (14) or must i feed it 5v?

ground goes to VSS(7)

My sensor signal goes to pin (1) and my output i’ll have to try Q3(9) 

i’m also not quite sure how to calculate the pull-up resistor value for the VDD side

[Adamw]

Q3 gives you a divide by 8, Q4 is divide by 16.

[Mario Schneiderbanger]

thx adam! 

[Mario Schneiderbanger]

Gonna give this guy a go 

[Mario Schneiderbanger]

Were in business! 

 

[1320MINI]

Adam,

It worked for me also, 

[Mario Schneiderbanger]

Can’t say enough good things about Link tech support!