How to install a Chip on 88-91 OBD-0 Honda ECU
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Here is a step by step guide toward installing a racing chip on 1988 to 1991
Honda OBD-0 ECUs. First, open up your ECU top cover.
Remove Top Cover
- Open the back panel of the ECU. Figure 3 is
a view of the ECU solder side. Trace the Stock ROM Position from the front
to the back. Look for a 28 pins chip with the marking Oki 38128, 38256 or a
gold sticker in the middle and wording like 27C128 or 27C256. It is usually
at the lower left corner away from the ECU Plug (top view). On the
solderside is lower right position.
- Desolder the stock ROM Figure 4 Use a niddle point soldering iron
touching the base of the pin. Do not overheat the Stock ROM, that will
distroy it Hold the solder pump close to the heated pin to pump up the
solder. Be careful on the grounded pin or pin 1 as they are tougher to
Solder side of the ECU
Desolder the Stock PROM
- Removing the Stock ROM. Figure 5 is a
picture from top view of the ECU while the stock ROM chip is being removed.
Take extra care while taking out the desoldered stock ROM chip. Use a tweeze
to check every pin before moving the chip. Figure 6 showing the stock
ROM coming off the ECU. Figure 7 showing the empty slot where the
stock ROM use to be.
- Removed the Stock ROM. Figure 8 show the stock ROM chip after being
removed.The 28 pin IC socket is going to be soldered on the same spot where
the stock chip use to be. Figure 9 is the solderside view of the
removed stock chip location.
The Stock ROM is being removed
The Stock ROM coming off
The Stock ROM location after being removed
The Stock Rom after being removed
The Solderside of removed ROM location
Install the 28 pin IC Socket. Figure 10 shows a
28 pin IC socket installed in the removed ROM position. Solder it in place and
use multimeter to check any short on the pins. Figure 11 Clean up
the solderedside with solvent like thinner or methenol to remove any residue
near the pins.
IC socket install in stock ROM position
Clean up the residue near the pins
Install chip unto the IC socket
- Insert the New Chip or the old stock ROM in the socket.
Figure 12 showing the Racing Chip is being install unto the IC
socket. After that, just reinstall the ECU top and bottom covers. Plug the
ECU back on the car, reconnect back the battery positive terminal and start
the car to check whether the car is runing fine.If you don't any check light
and able to rev pass 4000rpm, you have just successfully chip your ECU.