OBD1 Cam/Crank Pins
#1
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OBD1 Cam/Crank Pins
Looking at the OBD1 pin out the relevant pins are B11-B16 I believe. However, can someone explain what pin does what? I'm guessing B11 and B12 are the cam sensor but what is P and what is M? TDC is probably a blip that occurs right when cylinder 1 is at TDC? That leaves B15 and B16 as the crank signal.
B11-CYP P CYP(#1 piston position) -P Orange, CYP sensor input, n/a
B12-CYP M CYP -M White, CYP sensor signal, n/a
B13-TDC P TDC(top dead ceter) -P Org/Blue, TDC sensor input, n/a
B14-TDC M TDC -M Wht/Blue, TDC sensor signal, n/a
B15-CKP P CKP(crank position) -P Blu/Green, CKP Sensor input, n/a
B16-CKP M CKP -M Blu/yel, CKP Sensor signal, n/a
Does anyone know the nature of these signals? i.e. 30-2 teeth wheel/falling edge, etc?
B11-CYP P CYP(#1 piston position) -P Orange, CYP sensor input, n/a
B12-CYP M CYP -M White, CYP sensor signal, n/a
B13-TDC P TDC(top dead ceter) -P Org/Blue, TDC sensor input, n/a
B14-TDC M TDC -M Wht/Blue, TDC sensor signal, n/a
B15-CKP P CKP(crank position) -P Blu/Green, CKP Sensor input, n/a
B16-CKP M CKP -M Blu/yel, CKP Sensor signal, n/a
Does anyone know the nature of these signals? i.e. 30-2 teeth wheel/falling edge, etc?
#2
Honda-Tech Member
Re: OBD1 Cam/Crank Pins
They are all variable reluctance or VR sensors.
Here is a little bit of info;
Distributor Pick-ups, VR-Sensors
Here is a little bit of info;
Distributor Pick-ups, VR-Sensors
#4
Re: OBD1 Cam/Crank Pins
Looks at the wheels...
24 teeth
1 tooth
4 teeth
Its a 24+1 trigger and I'm not sure of the actual cylinder position sensor (4 teeth) or what it does for stock code
24 teeth
1 tooth
4 teeth
Its a 24+1 trigger and I'm not sure of the actual cylinder position sensor (4 teeth) or what it does for stock code
#5
Honda-Tech Member
Re: OBD1 Cam/Crank Pins
The P = Detects the signal (frequency) sent out as related too the teeth on the cranks/cams speed. The M = the drop between/change between pulses. At least that's how I read it.
The manual says that P = signal and M = Ground.
The CYP in most OBD1 & 2 Honda's is a one tooth VR sensor located in the distributor. Where it is located on the cam there would be 4 pulses per complete 720° crank rotation. It detects the position of the No.1 cylinder to determine the sequential fuel injection for each cylinder.
#6
Re: OBD1 Cam/Crank Pins
The signal is transmitted as a pulse of alternating current. It requires an oscilloscope to measure it.
The P = Detects the signal (frequency) sent out as related too the teeth on the cranks/cams speed. The M = the drop between/change between pulses. At least that's how I read it.
The manual says that P = signal and M = Ground.
The CYP in most OBD1 & 2 Honda's is a one tooth VR sensor located in the distributor. Where it is located on the cam there would be 4 pulses per complete 720° crank rotation. It detects the position of the No.1 cylinder to determine the sequential fuel injection for each cylinder.
The P = Detects the signal (frequency) sent out as related too the teeth on the cranks/cams speed. The M = the drop between/change between pulses. At least that's how I read it.
The manual says that P = signal and M = Ground.
The CYP in most OBD1 & 2 Honda's is a one tooth VR sensor located in the distributor. Where it is located on the cam there would be 4 pulses per complete 720° crank rotation. It detects the position of the No.1 cylinder to determine the sequential fuel injection for each cylinder.
Im guessing TDC sensor is the 1 tooth pulse and the CYL is the 4 teeth (to represent each individual cylinders TDC). Im also guessing the reason for both is in the case one sensor fails, the ECU can still do a relatively good job of keeping the motor running nicely.
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Re: OBD1 Cam/Crank Pins
I may try and do some datalogging with my Arduino Uno to see what exactly the signal train looks like on all three pins. My only question is how can I splice into these signals and read them without affecting them? I don't want to pass them through the Arduino for now since I'm not sure that it can react fast enough.
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#8
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Re: OBD1 Cam/Crank Pins
ECU doesnt need all three sensors to do Sequential Injection though...all it needs is a crank (24 teeth) and a cam pulse (could be 1 pulse per cycle or could be 4). Im honestly not sure which the ECU uses and/or why the other is there as well. Has to be a reason, just never needed/bothered to find out.
Im guessing TDC sensor is the 1 tooth pulse and the CYL is the 4 teeth (to represent each individual cylinders TDC). Im also guessing the reason for both is in the case one sensor fails, the ECU can still do a relatively good job of keeping the motor running nicely.
Im guessing TDC sensor is the 1 tooth pulse and the CYL is the 4 teeth (to represent each individual cylinders TDC). Im also guessing the reason for both is in the case one sensor fails, the ECU can still do a relatively good job of keeping the motor running nicely.
• The CKP Sensor determines timing for fuel injection and ignition of each cylinder and also detects engine speed.
• The TDC Sensor determines ignition timing at start-up (cranking) and when crank angle is abnormal.
• The CYP Sensor detects the position of No. 1 cylinder for sequential fuel injection to each cylinder.
So like you said, only two sensors are really used, the CKP and CYP.
#9
FSAE
Re: OBD1 Cam/Crank Pins
I'm not sure if you guys have seen this before, but we've used this to convert 4AG Toyota distributor signals to digital square-wave for standalone EMS conversions.
http://jbperf.com/dual_VR/v2_0#Buy
You could easily use this on the Honda CYP/CKP sensors.
http://jbperf.com/dual_VR/v2_0#Buy
You could easily use this on the Honda CYP/CKP sensors.
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Re: OBD1 Cam/Crank Pins
It is a 24 and 1 cam and crank setup. However the other sensor with 4 is usually used for quick startup. So the stock computer does not have to wait the entire revolution to start the vehicle on the 1 TDC.
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Re: OBD1 Cam/Crank Pins
It all depends on what you are looking for in the manual. If you are looking for exactly how the FI system works than there really isnt a manual for that. If you are looking for some description and wiring diagrams and test procedures you can pick up a factory service manual for the vehicle. Usually you can buy them at any Honda dealer. Alldata also has a lot of the information on their site as well, but it is a pay service.
#13
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Re: OBD1 Cam/Crank Pins
GhostAccord said "Here are the definitions for each sensor straight from the Honda PGM-FI manual."
I was simply asking what this "Honda PGM-FI manual" is.
I was simply asking what this "Honda PGM-FI manual" is.
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Re: OBD1 Cam/Crank Pins
He was most likely referring to the factory service manual. Not the Helms ones, but the actual Honda Factory Service Manual.
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Re: OBD1 Cam/Crank Pins
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