I have a cold start issue thats been going on. I changed nearly everything and It still won't start right.You can look at my other post to see what I already have done. This only happens when it's cold outside. today it is 55 degrees and the truck started great. when it was 20 the other day it ran like it was on 2 cylinders out of 8. Oh, I got the 5.0 V8 and E4OD trans. So anyway, I ran codes. the first time after running it for about 5 minutes I got Codes 625 (EPC Driver open in PCM) and 512 (EEC processor Keep Alive Memory test failed). I looked them up and I'm concerned mostly about 512. the 625 is probably because I changed the MLPS and didn't put on grease for the connector. I had a hard shift issue, I cleaned it and that fixed that issue. But why do I keep getting 512?? I never unhooked the battery to cause this except for one time! I was told you can get this if you unhook the battery. and when I ran that I DID NOT get a 111 code. so I turned it off, checked it again and got 111 only. I did the engine running test and got 111. So what should I look for getting 512 all the time? I keep getting it. Thanks in advance! If you wanna know all I have done to it so far I guess you can look up my post and see. I'm newer here so I'm not smart with it haha.

 

The 512 means that power was lost to Pin #1 of the computer.
Not starting cold could be the IAT or ECT sensors, the EGR valve stuck open or week battery.
The truck could also have low compression or bad timing chain.
Have you checked the slop in the chain to see how much it is.
I would change the chain if it is over 3 or 4 degrees.

 

I already checked all of that. The timing chain I believe was replaced but I checked it anyway. It's got a new ECT (Original was fine but I still changed it anyway because you never know) EGR has been blocked off a long time ago so it's fine, fuel system tested great, IAC is new and working properly, timing is at 12* now, O2 has been changed, ignition coil, spark plugs (motorcraft), wires, cap and rotor, and I believe more things but I can't think of them lol. But I did just find out my exhaust is leaking. It broke bad from the motor shaking due to this cold start problem. Maybe it's been broke and I just didn't notice. I do know from experience that these engines need back pressure or they don't like starting in the cold. Like yesterday it was 55 outside and it started very well. but when it was 30 outside, well it scarred me lol. So how can I test that pin #1? Can I test without a breakout box? I should probably check for dirty and loose connections by the computer shouldn't I?

 

That would be a place to start.
How are you clearing codes?
You may be getting the same 512.
To clear the 512 ground the STI wire and when the MIL starts flashing codes remove the ground from the STI wire.
Never unhook the battery to clear codes, only unhook it to reread the sensors if you change an input sensor. Not for solenoids or other actuators.

 

I check the codes just like you described and remove them the same. Sometimes while they are flashing I just turn the key off and they go away. But usually I just unhook the jumper. And I know they're clearing because I had the EPC circut one and after I removed the jumper to clear codes, EPC (i think it was 626) was gone and I got 512, and 111. So they're clearing but I think the recent 512 was a continuous code. I'm not sure what difference that makes though.

 

512 is only a Continuous Memory code.

Continuous Memory DTC 512 indicates the PCM has experienced a power interrupt in its Keep Alive Memory (KAM) circuit.

NOTE:
If 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 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?

 

Is there a way I can test it without a breakout box? I can't afford one or even find one. I cleared them by pulling the jumper while the codes were flashing. I then checked it again and all I got was 111. I took it for a drive, came back, checked them again, i got 512 and 625 again. If I do engine running test I get 111 so I guess that's good! I thought about pulling the PCM out to see if there is any damage or corroded wires. I seen another guy say he couldn't find out why his kept coming up and he changed the negative battery cable and it went away. It's all new so I'm not sure. He also said something about the EEC relay but I don't think mine has it. I guess 1992 trucks a different from the old ones.Does this sound like a good idea and is there anything I should look for if I do pull it out?I changed all the battery terminals and checked every wire that I could with out ripping things completely apart. .

 

The EEC Power Relay will not cause a 512.

 

That's good to know! I'll take pictures tomorrow if I see anything weird. I doubt it though

 

I've checked all that I seen with wires, cleaned connections and still have 512 and "Sometimes" 625. Does anyone know which wire does the KAM at the PCM? Can I measure for voltage at it to see if it's getting any power? I don't know how to find the pin nor do I have a diagram of it.

 

It is pin #1 of the PCM computer connector.
A diagram of the connector is in this link:
Ford Fuel Injection » EEC Computers

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Ok Thanks. Should there be 12 volts at the pin? And when testing should the ignition switch be on or off?

 

It should have battery voltage (12.5-13.5) on pin #1 of the PCM Computer at all times if the ignition switch is on or off.

You can use a 9 VDC adapter plugged into the cigar lighter while changing the battery to maintain the memory in the computer and the radio.

 

Im getting the same two codes but i have a hard shift problem know how to fix that?

 

jonathan642,

I can not say much more about the codes then what was posted above.
You might want to check the wires going into the Solenoid Pack plug on the transmission, they some times will break off at the plug. You have to pull the back of the plug cover off to see these wires.

Speedometer working OK?