DIY_EFI Digest Sunday, July 18 1999 Volume 04 : Number 420 In this issue: vcc/gnd ECU'S See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Sat, 17 Jul 1999 13:59:00 -0500 From: steve ravet Subject: vcc/gnd > Date: Fri, 16 Jul 1999 20:35:28 -0400 > From: Shannen Durphey > Subject: Pretty Good Protection > > Hi, all. I was attempting to copy a calibration last week, and was > having problems with the files coming up with zeros in all locations. > After several attempts, and much double and triplechecking various > items, I decided it was the memcal. Some investigation, and handy > work with a pick and razor blade revealed that the programmer had > clipped pin 28 of the 27256 chip. A small pin completed the open > circuit, but now I couldn't get a read that would verify. More > investigation revealed another clipped pin, I believe # 14. There's a > pinout here: http://www.twinight.org/chipdir/giicm/27256.txt > which shows the pins as VCC and GND. > > What is VCC > Am I remembering incorrectly about the GND pin being clipped? (they > were cross corner, top right and lower left of chip) > Is there a brief way to explain why this worked, and how the chip was > still able to work in the ecm? > > Shannen > Vcc is power for normal chip operation. Vpp is also power, but only used during programming. That chip would not have worked in the circuit without vcc and gnd, maybe they got broken at some point? Did you ever take it out of the socket? - --steve - -- Steve Ravet steve.ravet@xxx.com Advanced Risc Machines, Inc. www.arm.com ------------------------------ Date: Sat, 17 Jul 1999 17:26:12 EDT From: WLundquist@xxx.com Subject: ECU'S I've got a real dumb question on ecu's. Why can't a gm ecu such as a 16159278, P4 TPI, be reprogrammed with a haltech or other aftermarket program so that you can have real time tuning capability? Is't the hardware already there? Can you dump the factory programing and reinstall? Would an aftermarket program work? Can't a serial port be added for the laptop? Would the aldl connector work as the serial port? Could this be economically feasable? There are alot of gm ecu's out there sure is a shame to let them go to waste. What are the most significant problems to accomplish this goal? Would it work? Wayne ------------------------------ End of DIY_EFI Digest V4 #420 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace "diy_efi-digest" in the command above with "diy_efi".