hello everyone i just recently bought a 1992 GMC 3500 SRW it has the 5.7 liter gas motor in it. the truck was running good up until the other day. the ruck blew a check engine light and then started running rough and the would die. but i noticed while it was running rough i got a real strong smell of gas out the exhaust and the it would just die. so i would go to start it back up and the truck wouldnt start unless you have your foot on the gas pedal all the way down. the code that came up was a code 51 which is a ECM PROM ERROR. need help please. thank you for you input

anyone got any ideas

This may not help but...
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

but what would cause the truck o run really rich before it will die?

The ECM is dumping fuel due to the prom error. think of it as the hard drive in your home computer taking a crap, how well does the computer work if the hard drive is shot?

ok i wasnt sure. i didnt want to go putting a computer in the truck and have it not be that

i should have just stuck with the diesel. thats all i have ever used to plow and never had any trouble. these damn gas motors suck

you will not replaced the whole ecm just the prom or "chip"

here are the tests

1992 Chevy Truck C 3500 P/U 2WD V8-350 5.7L

Vehicle Level (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741) http://library.alldatapro.com/images/a_003366.gif Powertrain Management (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029) http://library.alldatapro.com/images/a_003366.gif Computers and Control Systems (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/34857030) http://library.alldatapro.com/images/a_003366.gif Testing and Inspection (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/34857030/34857663) http://library.alldatapro.com/images/a_003366.gif Diagnostic Trouble Code Tests and Associated Procedures (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/34857030/34857663/122915129) http://library.alldatapro.com/images/a_003366.gif Manufacturer Code Charts (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/34857030/34857663/122915129/134328064) http://library.alldatapro.com/images/a_003366.gif DTC 51 (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/34857030/34857663/122915129/134328064/134371654) http://library.alldatapro.com/images/a_003366.gif Powertrain Controls - ECM/PCM (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/34857030/34857663/122915129/134328064/134371654/134371752) http://library.alldatapro.com/images/arrow1.gif With 4L80E Automatic Transmission (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/34857030/34857663/122915129/134328064/134371654/134371752/136046524) http://library.alldatapro.com/images/arrow2.gifhttp://library.alldatapro.com/images/blnk_spc.gifWith 4L80E Automatic TransmissionFAULTY PROM (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/56221396) (MEM-CAL)


Check that all pins are fully inserted in the socket.
If OK, replace PROM (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/56221396) (MEM-CAL), clear memory, and recheck.
If CODE 51 reappears, replace PCM (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/34857030/101367478)http://library.alldatapro.com/images/blnk_spc.gifhttp://library.alldatapro.com/images/g_angle.gifhttp://library.alldatapro.com/images/blnk_spc.gifConversion Calculator (http://javascript<b></b>:calcWindow()) http://library.alldatapro.com/images/blnk_spc.gif1992 Chevy Truck C 3500 P/U 2WD V8-350 5.7L

Vehicle Level (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741) http://library.alldatapro.com/images/a_003366.gif Powertrain Management (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029) http://library.alldatapro.com/images/a_003366.gif Computers and Control Systems (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/34857030) http://library.alldatapro.com/images/a_003366.gif Testing and Inspection (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/34857030/34857663) http://library.alldatapro.com/images/a_003366.gif Diagnostic Trouble Code Tests and Associated Procedures (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/34857030/34857663/122915129) http://library.alldatapro.com/images/a_003366.gif Manufacturer Code Charts (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/34857030/34857663/122915129/134328064) http://library.alldatapro.com/images/a_003366.gif DTC 51 (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/34857030/34857663/122915129/134328064/134371654) http://library.alldatapro.com/images/a_003366.gif Powertrain Controls - ECM/PCM (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/34857030/34857663/122915129/134328064/134371654/134371752) http://library.alldatapro.com/images/arrow1.gif Without Electronic Transmission (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/34857030/34857663/122915129/134328064/134371654/134371752/136046526) http://library.alldatapro.com/images/arrow2.gifhttp://library.alldatapro.com/images/blnk_spc.gifWithout Electronic TransmissionPROM (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/56221396) Problem


Check that all pins are fully inserted in the socket.
If OK, replace PROM (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/56221396), clear memory, and recheck.
If CODE 51 reappears, replace ECM (http://library.alldatapro.com/alldata/LIB~C7123~R0~OD~N/0/34870055/42417603/42418766/42418767/34853741/34857029/34857030/101367478)

sorry there is not a better test but this is it, if you ever thought about chipping it this is a sign to do it.

no i dont do that stuff to my plow trucks. its bad enough the guys i have running them break the without any mods

you wouldnt think a fuel pressure regulator would be bad also?

well i replaced the ECM today and the truck seems to be running fine. thanks for all the input