Engine knocking

[Beetlejuice]

Im getting codes 31,32,33,34,41,43,51,52,54, and 55. No matter what the timing’s set at it knocks but it wasn’t doing that before I tweaked with the timing. I’m wondering if my ECM’s bad or something I know that’s an easy thing to blame it on but the motor’s only got 99k miles on it I’ve been checking wire diagrams, looking for shorts the whole nine. Please help y’all. I gotta big drive ahead of me coming up in 3 days and would really like my truck to be goin’ with me.

 

[tpass]

More info needed, year of truck, engine info, stock or modded? what was done before all the codes were started?

TBI motors need a wire disconnected to set timing, but unsure if thats what you have.

 

[Beetlejuice]

More info needed, year of truck, engine info, stock or modded? what was done before all the codes were started?

TBI motors need a wire disconnected to set timing, but unsure if thats what you have.

Its bare bones stock. I’ve replaced stuff like TPS, fuel pump, fuel filter. ICM, spark plugs, IAC, all those little guys on the TBI i’ve also rebuilt the TBI with new gaskets and regulator. New oil sender unit the one above the oil filter.

It’s an ‘88 Sierra 2500 5.7l 99k miles Imm the 3rd owner previous owener was older and had passed away they’d only put about 15k on it, with a 700r4. I’ve crossed as many T’s and Dotted many I’s on this girl. New dist. and new cap/rotor. New rad cap. Tryna think of anything else but I think thats it.

Bouta do a compression test will update this thread when it’s over with

 

[tpass]

I googled ODB1 codes... these are interesting:

51 Prom incorrectly installed
52 Electronic Control Module malfunction (ECM PCM)
53 Electronic Control Module malfunction (ECM PCM)
54 Carburetor Mixture Control solenoid
55 Sensor Circuits

GM OBD I Diagnostic Trouble Codes¦ Complaints Possible Causes,Corrections

Diagnostic flow chart for GM OBD I Diagnostic Trouble Codes, Complaints, Most Probable Causes, and Corrections

straighttalkautomotive.com

i would start checking all grounds and connections... hopefully others can help, i'm not much good on electrical other than I add grounds and clean existing ones zealously.

I had a GMT800 that looked like a discotech on the dash with all the flashing lights, crazy gauge activity and codes.. until I added one new ground wire from engine to the cab and it cleared everything.