Automotive Electronics
| Automotive | Mopar ECU |
After on-and-off experimentation with the ECU calibration on my 1987 Shelby CSX, I have finally made some progress. Much of it is due to the efforts of those on the Mopar ECM mailing list. I am making the calibrations available below.
Disclaimer: The projects described in these web pages may use dangerous materials, and components. This material is intended for advanced electronics experimenters only and may cause your vehicle to be suitable for off-road use only. The author assumes no liability for damages incurred through the use or misuse of the information provided herein. This information is provided "as is" and without warranties as to performance of or any other warranties whether expressed or implied. No warranty of fitness for a particular purpose is offered.
To use any of these calibrations, you will need to get the necessary equipment and modify your Engine Control Unit (ECU). There are basically two ways to go about putting a calibration onto an ECU. You can either use a socketed EEPROM (electrically erasable programmable read-only memory), which must be removed and programmed outside the ECU, or you can modify the ECU so that the EEPROM can be erased and programed remotely ("flashed"), which requires the necessary software and cables. The ECUs actually come from the factory with EPROMs, which must be erased with ultraviolet light. The ability to flash the ECU is especially useful if your ECU is a SMEC (single module engine controller) or SBEC (single board engine controller), which are located behind the battery and have electronics that are buried is potting material. If you have a logic module (1987 and earlier), it is located in the passenger compartment behind the passenger-side kick-panel and is not potted.
If you intend to use removeable EEPROMs, you will need an EEPROM programmer. If you intend to use EPROMs (which I sometimes do), you will need an EPROM eraser. I own a Needham's Electronics EMP-10 programmer and a Datarase II EPROM eraser. If you plan to flash your ECU, then you will need a cable and interface, as well as somewhat more extensive modifications to the ECU. The interface is available as a kit from Chad Clendening. The modifications needed to flash a SMEC were documented by Graem Schmidt in his very useful document.
There is a nice variety of software forming around this effort. They are listed below:
Obviously, some modifications are needed to your ECU to facilitate installing custom calibrations. If you plan to use the removeable EEPROM method, you will only need a 28-pin socket and some extra EEPROMs (or you can just reuse the EPROM you already have if you have an eraser). You will then need to desolder the EPROM from the ECU board and solder in the socket. If you are not skilled with a soldering iron, then I would recommend finding someone who is. The boards are double-sided and can be tricky to work on without damaging the traces. If you are planning to flash the ECU, then you don't necessarily need a socket, but I would recommend one just in case the EEPROM gets fried. See Graem Schmidt's document for additional details about the modifications needed to flash a SMEC.
For the socket, you should at minimum get a low-profile, machined pin socket such as Digikey ED3628-ND or A409-ND. Preferably, you should get a low-profile ZIF (zero-insertion force) socket, such as Digikey 3M2803-ND or A347-ND. The ZIF socket makes extraction and insertion much easier and safer for the chip and the ECU board, though probably isn't necessary if you plan to flash. If you have one of the Mopar Performance ECUs, then you might get lucky as they are sometimes already socketed.
The EEPROM you need depends on the model year ECU that you have. The 1984 electronics are probably not suitable for custom calibrations. They apparently use bipolar PROMs (similar to PALs) and little has been done to understand them at this point (though that doesn't mean it is not possible). The 1985-1986 electronics use a pair of 16kx8 EPROMs (one for the code and one for the calibration tables), but they do not have a hardware timer and it doesn't take much to upgrade to the 1987 electronics, which were the best from the Logic Module era. These are the devices used on the various modules:
The 27C/87C series EPROMs require an ultraviolet eraser to clear them. The 28C series EEPROMs are erased by the programmer itself. The 128 kilobit size has been obsoleted by most manufacturers but it can be replaced by the 256 kilobit parts, which have the same number of pins. Therefore, the part you want to get for 1987-1989 electronics is the 28C256, 150ns, industrial temperature (-40 to 85^C) EEPROM, Digikey AT28C256-15PI-ND. If you don't plan to flash your ECU and have an ultraviolet EPROM eraser, you can get the 27C256 EPROM equivalent for about one third of the price (Digikey FM27C256QE150-ND). Since the 1987 logic module only uses half of the 256 kilobit part, you can connect the A14 pin (pin 1 on 28C256 or pin 27 on 27C256) to a switch that either grounds or raises it to 5V and program two, seperate calibrations in (i.e. street vs race or new vs previous cal).
This calibration is based off of a cleaned-up version of Geoff Allan's "Blueberry" calibration. My 1986 Dodge Daytona is currently using this calibration. Many of the table modifications were rolled back to stock Turbo II specs to get a clean starting point. The fuel tables were then scaled for 58pph injectors and spark advance tables were aligned close to MP CSX Stage II specs. Some fuel was removed from the WOT fuel baseline to get better performance with my laggy turbo and a lot of time was spent getting the startup and cold weather fueling tuned. It is a work in progress, but has been working well all year round. This should make a good starting point for most people with 1987 electronics and it tuned better than the legacy cal below. Use at your own risk!
08/30/2007: Version 60.14 (based on "Blueberry60") - bump FuelFullThrottle point 2 down to 5800uS. Too lean during decel still, so move point 1 of FuelNoThrottle right and up 2 ticks to -14.2psi @ 10.00uS. Move ColdEnrichmentFuelCurveA point 4 from 58.8^F @ 1.19 to 58.8^F @ 1.21.
11/11/2006: Version 42.02 (based on "Blueberry42") - this was an initial attempt to tune Blueberry42 for the Daytona with the same tune as the legacy calibration below. With winter approaching, this calibration was abandoned and the legacy calibration from the CSX was used instead.
See the revision history in the above archive for information about previous changes.
This calibration is based off of a very early (circa 2002) disassembly of the stock 1987 Turbo II software (not the MP Super 60). My 1987 Shelby CSX is currently using this calibration. It has been modified to use the Super 60 3 bar MAP sensor and +40% fuel injectors while still making use of closed loop and other features of the stock cal. The spark curves were left stock. It is tuned reasonably well, but it's not perfect. It has worked well for me for the past few years, however I don't plan to make any new revisions of it. Use at your own risk!
09/28/2004: Version 1.4 - had some mechanical issues that had me chasing my tail. Ended up undoing a lot of changes and putting them back. The accumilated changes include an unscaled AISBaroCompensation table, some changes to the AIS off idle position, changed all the boost tables to 21psi, took some fuel out of the fuel baseline, added some fuel to cold start table C, grabbed the non-MP no throttle fuel table and fine-tuned it to reduce exhaust popping and funny behavior in high vacuum, slight tweaks to starting fuel, and kicked the whole PEFTBL up by 10%.
11/07/2003: Version 0.6 - made a slight adjustment to the partial throttle curve to try to address what seemed like a lean spot. It seemed to take care of it. This calibration seems now to get similar gas mileage to the stock calibration.
See the revision history in one of the above archives for information about previous changes.
Updated on 06/04/2008
Copyright © 1996-2008 Russ W. Knize