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I'm trying to learn here in this next question and if I get this wrong please explain it to me. But the way I understand it is.... The timing is based off a combination of Rpm & Voltage from what the Map sensor is putting out. The voltage is set by the KPA / Hg vacuum. So if I got this correct?? Do you happen to have the voltage reading and the KPA or Hg reading to go along with those timing numbers??
The MAP sensor output is frequency based to the ECU, I would think the X axis in that table is a calculated number based off of VE/Load, which uses MAP vs RPM.
I know my 95 has a data +, and data -, would that be where you could gather that info?
Yes, ForDiag, Czech program and hardware $100US, works great if you have DCL data+ and data-.
You can tell if you have it, by the wires on the OBD1 connector, and or the specific chips installed in your hardware.
The timing is based off a combination of Rpm & Voltage from what the Map sensor is putting out. The voltage is set by the KPA / Hg vacuum. So if I got this correct?? Do you happen to have the voltage reading and the KPA or Hg reading to go along with those timing numbers??
The MAP sensor outputs a frequency, not like a voltage like EGR(0-5V). Voltage measurements can be made directly from the analog to digital(AD) converter within the CPU.
Frequencies need to be detected, then converted to voltages within the PCM/EEC, and then those voltages can be counted by the High Speed Inputs(HSI) within the CPU.
Once all that is done by the hardware, the software then computes the value.
The row values for MAP are:
8
10
13.50
16.50
19.625
22.75
25.875
29.00
in "Hg.
It's quite complicated:
MANIFOLD ABSOLUTE PRESSURE (MAP_WORD and MAP) OVERVIEW
The MAP_WORD calculation is a conversion of the SCAP (Silicon CAPacitance) sensor output. The sensor outputs a digital frequency modulated signal in the 89 to 162 Hz range. Each edge output from the sensor is the equivalent of the integration of the pressure seen at the sensor since the last edge. The conversion of SCAP edges into frequency and then into a MAP_WORD value in inches of mercury is carried out during one of two foreground routines. If the sensor is determined to be not operating properly, a background routine (CNVERT) will substitute a value for MAP_WORD. The value of MAP is a less precise value of MAP_WORD that is contained within a byte.
The end game. Well it started off as... Just out of curiosity. I have been trying to learn more of how these PCM's and related components work. Now I am very interested in real time data. You lost me on Data + and Data - ??
Yes, ForDiag, Czech program and hardware $100US, works great if you have DCL data+ and data-. You can tell if you have it, by the wires on the OBD1 connector, and or the specific chips installed in your hardware.
How can you tell if you have it by the wires on the OBD1 connector?? What you are showing is Very cool.
The DCL output can be sampled from the OBD connector, is that the location you're referring to?
Originally Posted by wwhite
Yes, ForDiag, Czech program and hardware $100US, works great if you have DCL data+ and data-.
You can tell if you have it, by the wires on the OBD1 connector, and or the specific chips installed in your hardware.
Originally Posted by Zrt1200
The only thing I have is a Innova scan tool. Would you care to tell us more about the Ease diagnotics??
Now I am very interested in real time data. You lost me on Data + and Data - ??
I remember Subford saying you could see live data(if scanner was capable) his was, we have pin 9 data bus(-), and pin 28 data bus(+), in our PCM 60 pin connector, and wondered if that was how he got it, I think 1990 started having that in PCM's, I think y'all for wanting to tell/teach us some of what y'all have learned, sorry Zrt1200 didnt mean to clutter.
I remember Subford saying you could see live data(if scanner was capable) his was, we have pin 9 data bus(-), and pin 28 data bus(+), in our PCM 60 pin connector, and wondered if that was how he got it, I think 1990 started having that in PCM's,
That is correct. Take a look at the Truck Computer pin-outs at the old FFI site: Truck Computers
There is a note in there "90-95" for the Data (-) and Data (+) pins.
How can you tell if you have it by the wires on the OBD1 connector?? What you are showing is Very cool.
ForDiag, on 1994 F150 EEC-IV OBDI, 351w Speed Density. Works perfectly, reads all PIDS, and displays all gauges correct values. All I had to do was the following: OBDI – Pin# 1 – Data (-) PK/LB(pink/lightblue) to OBDII – Pin# 11 OBDI – Pin# 3 – Data (+) T/O(tan/orange) to OBDII – Pin# 3
Pin #3 and #11 Vendor Option is FORDs DCL Protocol.
I remember Subford saying you could see live data(if scanner was capable) his was, we have pin 9 data bus(-), and pin 28 data bus(+), in our PCM 60 pin connector, and wondered if that was how he got it, I think 1990 started having that in PCM's, I think y'all for wanting to tell/teach us some of what y'all have learned, sorry Zrt1200 didnt mean to clutter.
Just looking at wires, and just looking at pin 9 & 28, may not be enough to have Data Communication Link(DCL) going.
The PCM must have the following chip on board: 81C62
Also, the calibration must have it enabled: (LINK_SW = 2, 3, 6 or 7)
DATA COMMUNICATION LINK (DCL) OVERVIEW
The EEC communicates with other vehicle microcomputers through the 81C62
RAM/CART chip. The RAM/CART is a special microchip which contains a serial
I/O port. This port performs serial communications on the data communication
link (DCL). The communication link consists of a twisted pair (DATA+ and
DATA-). The EEC treats the RAM/CART as read/write memory. The RAM/CART is
identical to the 81C61 RAM-I/O chip, with exception of the serial port.
The RAM/CART chip may operate as an UART (Universal Asynchronous Receiver
Transmitter), or a CART (Custom Asynchronous Receiver Transmitter). In UART
mode, information is sent character by character, requiring large software
overhead. In CART mode, information is sent in frames with minimal software
intervention.
Chip identified in the following image and labeled in red 81C62:
I remember Subford saying you could see live data(if scanner was capable) his was, we have pin 9 data bus(-), and pin 28 data bus(+), in our PCM 60 pin connector, and wondered if that was how he got it, I think 1990 started having that in PCM's, I think y'all for wanting to tell/teach us some of what y'all have learned, sorry Zrt1200 didnt mean to clutter.
No problem at all. I am glad you jumped in and asked. I am learning from it all and if you can that's great as well.
[QUOTE=wwhite;20311715]
Heading out to check now. Update. Yes I have the Data + & Data -
Just looking at wires, and just looking at pin 9 & 28, may not be enough to have Data Communication Link(DCL) going.
The PCM must have the following chip on board: 81C62
Also, the calibration must have it enabled: (LINK_SW = 2, 3, 6 or 7)
Chip identified in the following image and labeled in red 81C62:
I'm not sure what's in my truck at the moment and its 24* and blowing outside so I am not pulling it right now either. But here is what's inside my 460 PCM. I noticed the 460 PCM does not have the knock sensor chip.
I will pull my stock 351w PCM once it warms up a little and have a look.
here is what's inside my 460 PCM.
I will pull my stock 351w PCM once it warms up a little and have a look.
Your 460 has the 81C62 chip, which will work with DCL.
If the PCM has 81C61 chip, that does not have the serial port data lines for DCL, and will not work. That is the difference.
Your 460 has the 81C62 chip, which will work with DCL. If the PCM has 81C61 chip, that does not have the serial port data lines for DCL, and will not work. That is the difference.
OK, You lost me here. Are you talking about the 2 red caps in your pic??
