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Just bought a 94' F150 with the 5.8 and its been running really rich and I am getting terrible gas mileage. I know it is a 351 but I would like to think I would get better mpgs if it wasn't running so rich. Just tried to pull codes today and I believe the only one I had was a 512 code. Everything I've seen says that the code means a bad PCM. Is that correct? And do the symptoms sound right? I was going to start by changing the o2 sensor and map sensor first until I pulled that code
There are pinpoint test steps for that code 512
I might have them if you need them
They are going to start with "was the battery disconnected "?
Have an I/M test done and see if the CO is within spec (should blow 0.06 or so)
Terrible gas mileage?
Do not just throw parts at it!!!! I just finished posting this comment https://www.ford-trucks.com/forums/1...l#post20851635
on a that thread. The OP started out with a "Bad" IAC, replaced it, then fixed a few other small issues, without fixing the issue. Turned out the new IAC was the issue to begin with.
Spend time on troubleshooting.
Video is how to retrieve codes. KOEO Key On Engine Off codes are first to run you can use a paper clip instead of the jumper he uses. When you see 111 it means all clear. 10 is a separator code between HARD CODES and MEMORY CODES. Memory codes appear after the 10 separator code. The Memory codes mean they happened but are not currently active. When you post your codes after doing it correctly, indicate which codes are HARD CODES and which codes are MEMORY CODES. The 512 code you got is not active as it was in MEMORY and can be ignored for the moment. Let's see what you get.
Do not just throw parts at it!!!! I just finished posting this comment https://www.ford-trucks.com/forums/1...l#post20851635
on a that thread. The OP started out with a "Bad" IAC, replaced it, then fixed a few other small issues, without fixing the issue. Turned out the new IAC was the issue to begin with.
Spend time on troubleshooting.
I'm really half tempted to start throwing parts at it just because I'm getting frustrated trying to get these codes
The only code you listed is 512. That code is usually triggered when you clear the stored codes by removing a battery cable. When you reconnect it the computer many times will flag a false error code 512. Clear the stored codes by initiating the KOEO tests, when the CEL starts to flashout codes or the reader starts to display the test results remove the STI jumper lead. This will clear the stored codes without removing power to the computer. Drive the truck for a drive cycle or two then re-run the KOEO tests and Stored Code display. If Code 512 persists then you may have a Keep Alive Memory (KAM) issue or the computer is bad. It's a process of elimination without turning on the parts cannon.
The only code you listed is 512. That code is usually triggered when you clear the stored codes by removing a battery cable. When you reconnect it the computer many times will flag a false error code 512. Clear the stored codes by initiating the KOEO tests, when the CEL starts to flashout codes or the reader starts to display the test results remove the STI jumper lead. This will clear the stored codes without removing power to the computer. Drive the truck for a drive cycle or two then re-run the KOEO tests and Stored Code display. If Code 512 persists then you may have a Keep Alive Memory (KAM) issue or the computer is bad. It's a process of elimination without turning on the parts cannon.
I got a lot of other numbers once I did the KOER test like a 311916712 but I’m not sure if I’m reading them correctly and if it is 2 or 3 digit codes. I thought about just buying a obd1 scanner before I take it somewhere to let them diagnose it
[QUOTE=rla2005;20855197]Code 311: Thermactor air system inoperative (right side)
Code 712: No such code exists.
Code 916: No such code exists.
I have been wanting to do the smog delete on my truck. If that is the correct code and I have an issue with the thermactor air system would bypassing it fix that? I know when you delete it you put some relays in the tad and tab
If that is the correct code and I have an issue with the thermactor air system would bypassing it fix that?
No, that will cause that code to pop up during the KOER tests every time. On an OBD-I truck that does not typically trigger a Check Engine Light (CEL).
Originally Posted by Obsdanny17
I know when you delete it you put some relays in the tad and tab
No, that will cause that code to pop up during the KOER tests every time. On an OBD-I truck that does not typically trigger a Check Engine Light (CEL).
No, you do not.
Sorry I meant resistors. Could the timing be off? It is a freshly rebuilt motor in it so I wonder if the timing needs to be adjusted