If I get the 4 pcm harness plugs and sections of wiring can I put together a system to power up and fiddle with pcm’s on the bench?
If so, will the harness and connections from an OBD2 car also work with OBD1 pcm bench setup?
If I get the 4 pcm harness plugs and sections of wiring can I put together a system to power up and fiddle with pcm’s on the bench?
If so, will the harness and connections from an OBD2 car also work with OBD1 pcm bench setup?
Hiya,
I am days away from finishing my bench programming project for sale if you can wait. I have covered ALL the obd2 protocols('96-2021) as well as aldl stuff. Self healing fuses up to 5 amps, CAN termination, nice aluminum enclosure, made in USA, etc etc. I'll be making a post soon with pics and description. Priced for hobby stuff as well as professional :)
-Carl
It sounds nice. I think you probably have more time and resources in it than I was thinking about experimenting with. I basically wanted to just power up, check if CEL is responding correctly, maybe tinker with resistors to see which ones match VATS for the unit. Simple stuff like that
I have built a test bench that permits me to work with a '97 LT1 PCM.
A while back Kur4o suggested using Arduino to build a VPW interface. I had an old test board for 'HC11 and wound up working with that... but I kept thinking about Arduino and looked into it a bit. It's good because it is cheap ($5/copy) and available everywhere. In the end I re-wrote the program to simulate opti-spark on Arduino. In my case I have 17 different RPM settings. The thing runs fast so all rpms can be simulated. The little board simulated Hi res, Lo res, CKP, VATS and MAF. In my case these are all the frequency based inputs to the PCM. I threw in a few switches for other PCM inputs. Sounds like the bench Carl is working on will be much better though.
If anyone would like the details or the code... just ask.
Tom
Tom, that is slick, I'd like to check that out, neato :) I mis-stated...mine is not a programming interface but basically just powers the ecm/pcm for bench programming purposes, has CEL and fuel pump LED and you just change one end cable for different ecm/pcm's or aldl stuff. In my opinion if the fuel pump turns on like normal after programming you can be pretty sure the programming was a success. I also added the 18v FEPS for the ford guys :)
-Carl
I've used a JimStim for years for this. It's marketed to Megasquirt users/builders, but adapter harnesses are easy enough to make. I have several for different OBD1 GM ECMs and even one for a Nissan ECU.
The man who says something is impossible, is usually interrupted by the man doing it.
Hi,
Here is the code I wrote for the Arduino Nano board. There were zero comments, so I added a few not the best but... Code is all C and not done in any fancy manner. Just enough to get the job done.
Commands through the serial port are
0R engine off
1R ~100RPM
2R ~250RPM
3R ~500rpm then up by 500s through to 16R at 6500 (limiter activated)
0M ~1KHZ through to 230M of 12KHZ or so --> note that the MAF is increased then decreased each 0.1S to avoid P0100 MALF code. This is for a stuck MAF, needs to see a delta on the input
0 or 1A turns on/off the air pump
0 or 1C turns on/off the AC compressor
0 or 1E turns on/off the evap switch
0 or 1T turns on/off the traction control/spark retard input
Plan to add analog inputs later...Code:Port D assignments Function Suffix Attribute Arduino D0 Serial RX -- -- -- D Serial TX -- -- -- D2 RPM R 0-15 D2 D3 Low res RPM R 0-15 D3 D4 CKP sensor RPM R 0-15 D4 D5 Scope sync RPM R 0-15 D5 D6 -- -- -- D7 -- -- -- Port B assignments B0 AIR pump A 0-1 D8 B1 Traction Control T 0-1 D9 B2 A/C request C 0-1 D10 B3 MAF M 0-230 D11 B4 EVAP switch E 0-1 D12 B5 VATS V -- D13 B6 Oscillator -- -- -- B7 Oscillator -- -- --
Cheers,
-Tom
Oh, here is the code...
I will move a continuation of 1997 LT1 test bed back to my main thread --> I don't want to hijack this one.
-Tom
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