code 51

[tclark1722]

hi, i just installed a casper chip set up for my we-4 stock with 60# injectors now i have a code 51 and the car won't start. it ran rich with stock injectors and old casper chip but it ran. i know there's a lot i need to learn. i'm ready.

 

[SouthernCal GN]

hi, i just installed a casper chip set up for my we-4 stock with 60# injectors now i have a code 51 and the car won't start. it ran rich with stock injectors and old casper chip but it ran. i know there's a lot i need to learn. i'm ready.

Malfunction Codes Reference

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CODE 51
Trouble Code 51 indicates that the ECM sensed a fault in the PROM.
When the PROM was initially created, a checksum number representing the total of all the cell values was also stored. The ECM uses this checksum as one way to determine if the contents of any cell has changed. A Code 51 causes the ECM to enter Back-Up mode which uses the CALPAK for default sensor values.
The conditions for setting this code are:

• power has just been applied to the ECM, and
• the calculated checksum does not match the stored checksum. - or -
• the engine was just started, and
• either of two specific PROM locations do not contain the expected value. (One location should have 1's in the odd numbered bits and the other has 1's in the even numbered bit positions.)

Typical causes for this code include:
1) Incorrectly installed PROM module
2) Defective PROM module
3) Defective ECM

The chip and injectors are matched, yes? Did you reset the ECM? Look by the battery- you'll find an orange wire with a weatherpak connector. Disconnect it for a minute, then reconnect it. Try starting the car........

 

[tclark1722]

yes the injectors and chip match. i'll try to disconnect the orange wire this weekend. thanks.