Got a continious memory code 512(Keep Alive Memory), no hard faults showed up, just 512 on the KOEO test I have not run a KOER test though. This sounds fatal to me computer shot?

 

QB1 - Check KAPWR to PCM

Continuous Memory Diagnostic Trouble Code (DTC) 512 indicates the Powertrain Control Module (PCM) has experienced a power interrupt in its Keep Alive Memory (KAM) circuit.

NOTE: If Keep Alive Power (KAPWR) is interrupted to the PCM, for example when installing a breakout box, or when battery is disconnected, DTC 512 may be stored in Continuous Memory.



Key Off.
Disconnect Powertrain Control Module (PCM) . Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.
Install breakout box, leave PCM disconnected.
Measure voltage between test pin 1 and test pin 40 or 60 at the breakout box.
While observing Digital Volt/Ohm Meter (DVOM) , grasp the EEC-IV harness and wiggle, shake or bend a small section while working from the PCM to the dash panel.
Does DVOM indicate less than 10.5 volts?
Yes -- Service open circuit. Remove breakout box. Reconnect PCM. Rerun quick test.
No -- Reconnect PCM. Go to QB2. See: QB2 - Inspect Engine Compartment Wiring For Proper Routing

 

humm unless you got a breakout box that post was usless

 

Not useless at all. The only difference would be actually probing the pins of the computer connector instead of points on the B.O.B. All of the tests can be performed without a BOB.

 

PCM is another way of indicating the MAIN COMPUTER? This is a 1992 4 banger mustang with the gay 8 spark plug setup. Young kid's highly abused vehicle that I got stuck working on Shade tree mechanics you know how this goes.

Basically his car was running ****ty(go figure) I checked his plugs and wires all were gross one plug not firing at all too gummed up.
So new set plug wires and plugs went in. Upon further inspection the timing belt tensioner pulley had rusted/froze up allowing timing belt to become really slack. New timing belt installed -tensioner fixed and timing mark lined up.

Discconect batt for 15 mins to clear codes I then run car(runs not bad) I have a cheap Equus code reader so shut off car and do KOEO test get code 512. We start car go for a test drive , car runs like crap. Come back almost on FIRE lots of unburnt fuel in the exhaust--get that under control(garden hose)

Wait a while start car and put timing light on it timing is jumping all over the place at idle. Kid tells me he has slid this car into curbs at speed a few times(Could this have messed the computer?)

Also the fuel pump in this car is the loudest thing I ever heard, but no codes indicated this as a problem. I'm stumped I think I'll send him to real mechanic.

 

I think the computer is inside the car on the passenger side, either under the dash or under the front seat. 512 may be coming up due to disconnecting the battery. Check for 12V on pin 1 of the computer connector on the harness to be sure.

 

If there wasn't 12 volt to the pin 1 it wouldn't be running at all though right?

 

That sounds right.

 

If it was my own vehicle and time was no option I'd get it fixed. Oh well he's young he can spend some coin. I'll post later when he gets it fixed though, just so the problem and solution adds to the tech on the board. As for 12 volt at the computer must be there cause it runs. Like poo, but it runs.

 

Actually inside the engine bay on the passenger side strut tower is a large black metal box , a very thick wire harness is plugged into this. I thought this was the computer. Althought this was the first time I've ever looked at a Mustang(92) from that era.

 

I'm not too familiar with them, but the harness I have from a mustang had a big grommet where it looked like it passed through the firewall. I don't know for sure, so you may have found it. It should have a big flat grey connector going to it.