Why do the coversion?

From what OBD2 stuff I deal with, I have a couple of thoughts. If the system you're controlling is missing components, you may have insurmountable issues. If you're expecting full OBD2 performance out of a 1996 unit, you're NOT gonna get it. It was only slightly more sophisticated than the OBD1 unit it replaced, and lacks a LOT of functions. If you were to change the entire induction/exhaust system to go with the ECU, and you had all the other monitoring components in your car, you might have SOME of the functions you seek, but they might also be pretty basic. Later OBD2, which is pretty well developed after 12-13 years, has hundreds, probably even thousands, of functions, and would be ideal for your use. Remember, however, that there's no such thing as a free puppy, and this puppy could end up costing you a TON.

From what OBD2 stuff I deal with, I have a couple of thoughts. If the system you're controlling is missing components, you may have insurmountable issues. If you're expecting full OBD2 performance out of a 1996 unit, you're NOT gonna get it. It was only slightly more sophisticated than the OBD1 unit it replaced, and lacks a LOT of functions. If you were to change the entire induction/exhaust system to go with the ECU, and you had all the other monitoring components in your car, you might have SOME of the functions you seek, but they might also be pretty basic. Later OBD2, which is pretty well developed after 12-13 years, has hundreds, probably even thousands, of functions, and would be ideal for your use. Remember, however, that there's no such thing as a free puppy, and this puppy could end up costing you a TON.

The Cap'n

What you are looking for, you need standalone. Forget error codes, take control of the car and know what it is all doing 100% of the time.

Are we reading the same posts?
Andy

OBD-II Diagnostic connector
Connector

The OBD-II specification provides for a standardized hardware interface—the female 16-pin (2x8) J1962 connector. Unlike the OBD-I connector, which was sometimes found under the hood of the vehicle, the OBD-II connector is nearly always located on the driver's side of the passenger compartment near the center console. SAE J1962 defines the pinout of the connector as:

1. -
2. Bus positive Line of SAE-J1850 PWM and SAE-1850 VPW
3. Ford DCL(+) Argentina, Brazil (pre OBD-II) 1997-2000, Usa, Europe, etc.
4. Chassis ground
5. Signal ground
6. CAN high (ISO 15765-4 and SAE-J2284)
7. K line of ISO 9141-2 and ISO 14230-4
8. -
9. -
10. Bus negative Line of SAE-J1850 PWM only (not SAE-1850 VPW)
11. Ford DCL(-) Argentina, Brazil (pre OBD-II) 1997-2000, Usa, Europe, etc.
12. -
13. -
14. CAN low (ISO 15765-4 and SAE-J2284)
15. L line of ISO 9141-2 and ISO 14230-4
16. Battery voltage

The assignment of unspecified pins is left to the vehicle manufacturer's discretion.

[edit] Signal protocols

There are five signalling protocols currently in use with the OBD-II interface. Any given vehicle will likely only implement one of the protocols. Often it is possible to make an educated guess about the protocol in use based on which pins are present on the J1962 connector:

* SAE J1850 PWM (pulse-width modulation - 41.6 kbaud, standard of the Ford Motor Company)
o pin 2: Bus+
o pin 10: Bus–
o High voltage is +5 V
o Message length is restricted to 12 bytes, including CRC
o Employs a multi-master arbitration scheme called 'Carrier Sense Multiple Access with Non-Destructive Arbitration' (CSMA/NDA)
* SAE J1850 VPW (variable pulse width - 10.4/41.6 kbaud, standard of General Motors)
o pin 2: Bus+
o Bus idles low
o High voltage is +7 V
o Decision point is +3.5 V
o Message length is restricted to 12 bytes, including CRC
o Employs CSMA/NDA
* ISO 9141-2. This protocol has a data rate of 10.4 kbaud, and is similar to RS-232. ISO 9141-2 is primarily used in Chrysler, European, and Asian vehicles.
o pin 7: K-line
o pin 15: L-line (optional)
o UART signaling (though not RS-232 voltage levels)
o K-line idles high
o High voltage is Vbatt
o Message length is restricted to 12 bytes, including CRC
* ISO 14230 KWP2000 (Keyword Protocol 2000)
o pin 7: K-line
o pin 15: L-line (optional)
o Physical layer identical to ISO 9141-2
o Data rate 1.2 to 10.4 kbaud
o Message may contain up to 255 bytes in the data field
* ISO 15765 CAN (250 kbit/s or 500 kbit/s). The CAN protocol is a popular standard outside of the US automotive industry and is making significant in-roads into the OBD-II market share. By 2008, all vehicles sold in the US will be required to implement CAN, thus eliminating the ambiguity of the existing five signalling protocols.
o pin 6: CAN High
o pin 14: CAN Low

Note that pins 4 (battery ground) and 16 (battery positive) are present in all configurations. Also, ISO 9141 and ISO 14230 use the same pinout, thus the connector shape does not distinguish between the two.

Perhaps I can clarify it more for you if need be?

Andy,

the system will be monitoring fuel, emmissions, throttle position, air flow (inbound), head temps, ambient air temp, and probably a few more I cant think of.

It will need two 02 sensors, on on each side of the cat.
They are different, so research that.
the front one gives a variable signal, the rear one has a target of a constant signal.
Its in a range of 0-1 volts...
Its pretty well documented.

Each ECU is different and each car uses simple basic sensors that send 0-1 volts in a specific window...like 300 milli volts to 350 millivolts if the car is at the perfect operating temp.

As long as you have all the right sensors, it should work.
You can fool the ECU with resistors to get the reading in the right range.

Maybe it would be easier to figure out how to convert the engine output from OBD1 to OBD2 and feed that into the data logger ...

Andy

Well, you did just clarify that you didn't get what i want at all. Which is why i asked if you had actually read my posts. So, thanks for clearing that up.

Like i stated above, i already have the data logger. It connects to OBD2. It can read Porsche specific data.

But the real interest lies in the fact that it can transmit data wireless in realtime and has build in GPS and can measure G-Force, acceleration and braking.

The actual data coming from the engine is just a added bonus. So no, i don't "want to know what is going on 100%" ...
Andy

PS: Nice copy & paste. Is that from Wikipedia?

How much would and ECU/brain/harness etc cost from Easy?
Just to play with?

Looks like i found a solution!


They have a version for older cars that let's you bypass the whole OBD2 stuff and just run GPS, Speed, Heading and G-Force.

It uses a Driveshaft/CV sensor to get good Speed sampling and the satellite link works just as in the more modern cars.


I'll be installing the kit tomorrow. We'll see how that goes ...
Andy

If you wanna install here, you're welcome! And we can have a delicious burger lunch, and share secrets.

which unit do you have?