Engine was hesitating/surge, Lack of Power with CEL on.
Took it in and they put in a new fuel pump.
That Didn't fix the problem. DH changed plugs, plug wires & fuel filter.
Lots of black soot stuff came out tailpipe like a week after and
Drove worse. Smelly exhaust.
Replaced Throttle position sensor
Replaced Mass Airflow sensor (fixed some of the codes)
Now fault code 543 left
Fuel pump circuit failure
Fuel pump secondary circuit failure: Battery to PCM
How do we fix this?Where do we start?
We want to do it and not take it in.
Any advice would be appreciated.
Thank you

 

Is it a KOEO code (comes out before separator pulse in KOEO test) or a continuous memory (CM) code (after separator pulse)?

A KOEO code (hard fault) indicates that the computer detects a break in the fuel pump circuit or in the fuel pump monitor circuit during the KOEO test. A CM code indicates that at some point during normal operation, the computer detected a break in the fuel pump circuit.

Diagnosing a KOEO 543 shouldn't be that difficult: Get a wiring diagram and a voltmeter and work through the fuel pump circuit until you find the break/short to ground.

If you have a CM 543 without and accompanying KOEO 543, I would clear the CM code, drive, and see if it comes back. I wouldn't be surprised if the CM 543 is left over from replacing the fuel pump. A common way of depressurizing the fuel system prior to repair is to disable the fuel pump by unplugging the fuse or relay or inertia switch and starting/attempting to start the engine. Such an act is effective at depressurizing the fuel system, but also leaves the code in the computer's memory.

 

Is it still running bad though? Or is it now running OK after a week of blowing crap out the exhaust? It's always a good idea to look at the plugs if the engine is running bad. This will tell you what is actually going on inside the cylinders. It's actually easier to read a new plug and just because you just replaced them, doesn't mean you fixed anything if they weren't the problem to begin with.

If everything is running OK and you have a memory code only, I'd follow Mrshorty's advice. If it is a KOEO code then something is still wrong. This particular code can show up as either a KOEO or a memory code that is detected when the car is running, as MR S noted.

 

The Mass airflow sensor helped... But it is still running bad. DH going to clear codes and do what was suggested on this forum. I'll keep you posted.

 

OK - check the plugs so we know what the engine is doing. Without that, a fuel pump circuit code doesn't really help us know where to look.

 

DH cleared codes and we took a drive. After bout 10 miles CEL came on...turned off.... came back on..
Got home and check codes again. Same 543.. Now 542 and o2 codes.
He is going to check the plugs tonight. What is he looking for?
Do you think that there is a wiring diagram on line?
Thanks for all your help

 

The 542 indicates an "open circuit - ECA to motor ground." When you solve this one, the other codes will probably go away. I'm not sure where the ground connections are on your model, but you likely have a poor ground wire connection somewhere.

This is just a hunch, but try removing the negative battery cable where it attaches to a starter bolt, clean/spray with WD-40, and reattach.

(This ground connection has given trouble on many different Ford models in the past.....)

ROE

 

Wiring diagrams on Autozone web site. This would be under chasis, not enginge, I would think. Not a surprise to see O2 codes. There's a problem in the fuel delivery system so the A/F mixture is going to be off. The PCM does not compensate for variations in fuel pressure. Pressure is not monitored. The O2's can only affect +/- 20% on the A/F mixture. If pressure is too high or low, you'll run rich or lean since the injector's pulse width stays the "same". if the pressure problem is greater than the 20% that the O2's can affect, it'll run bad and you'll get O2 codes.

Looking at the plugs tells everything! It tell's you what's really happening inside the engine. You don't have to try and figure out what's wrong form a limited set of computer codes. You'll know if it's 1 or 6 cylinders being affected. You'll know if it's the right side or left side - which are affected differently from the O2's readings. If all plugs show the same condition, rich, then Pressure is too high - vice versa....

Not sure who DH is. But this is pretty basic stuff. If he's charging you for this I'd be a little leary. The key to troubleshooting is getting as much hard data as possible. If I do this, this happens...When you can get to the point of affecting the issue - make it go away and come back in a controlled fashion, then you have the root cause.

 

DH = dear husband, And he better not be charging me for this lol........

 

HA! That's great! So where the hell is DH now? Monday night football perhaps?

Trust me, you wives get charged in all the mysterious ways! So you can take this new found knowledge and eductate dear ole hubby about what a spark plug can do. Then come back and tell us if you are rich or lean and where and we'll get this thing fixed in a DH heartbeat!