[rgvtx]

OK, here is the background. 01 Wagon with 40K miles. Battery light would come on while driving for last few months. Today I replace the alternator, whew what a job that was. Put everything back in place and she fires up and runs and no more battery light. So I decided to change oil too. Change oil, added a little power steering fluid and added a little antifreeze as it was near the low level line on the tank. Also install new air filter. Start it up, runs a minute or so and dies. Yellow light on dash comes on, looks like exclamation mark. Book shows it's a multi function light for Automatic Transaxle / cooling system. Starts back up, runs for a few minutes and sputters and nearly dies and light again comes on. Continues running for another minute or so, sputters again but continues to run fine. Step on gas peddle, sputters again but continues to run. Each time the yellow light comes on for just a moment. Then suddenly it dies, yellow light comes on and now won't start. Turns over fine but never hits. Don't have a code reader and now that it won't run can't get it to the parts house to have them check it. I can buy a reader I suppose if that will help find the problem. Thought I would ask here first to see if this has happened to others. Thanks, Geo. [???]

 

[Blurvfocus]

I'm curious about why you added power steering fluid. Was it actually low?

The reason I ask is because there is a power steering pressure transducer connected with the ecu. I always thought it was there to stabalize the idle speed, but- and I'm guessing here- what if you didn't leave enough head room in the reservoir? would the pressure go too high and maybe the pressure transducer >> ecu shuts the whole thing down? Are you sure the PS res isn't overfilled?

 

[rgvtx]

The PS fluid was a little bit low and the pump was howling a little bit. I added some fluid and don't think it's overfilled but I will check to be sure. The pump did quit howling after adding the fluid by the way. I had it parked on some ramps when I added it and it's down on level ground now so I'll check it. BTW, I bought this car new and it's been trouble free other than the recall on the fuel pump. It died several times back then and the check gas cap light came on. After some reserach I discovered the recall that Ford had failed to notify me of and I took it to the Ford dealer and they took care of that problem.

 

[rgvtx]

I'm curious about why you added power steering fluid. Was it actually low?

The reason I ask is because there is a power steering pressure transducer connected with the ecu. I always thought it was there to stabalize the idle speed, but- and I'm guessing here- what if you didn't leave enough head room in the reservoir? would the pressure go too high and maybe the pressure transducer >> ecu shuts the whole thing down? Are you sure the PS res isn't overfilled?

OK, I just checked. The PS fluid level is just above the minimum line, far below the maximum line. I guess that shoots down that theory, but thanks for the idea!

 

[Blurvfocus]

Damn! And I was proud of that one!

There is a way to read codes off your odometer, but I forget how it's done- lemme see if I wrote that down someplace...

 

[rgvtx]

A better day...

Last night I pulled both battery cables off the battery and hooked up a battery charger and left it on overnight. The battery read good but I did this anyway. Within a half hour or so it showed it was fully charged last night, but again I did leave it hooked up. This morning I took the charger off and hooked the cables back up. Now she fires right up, no dash light messages, no hesitations, nothing.[woot] Have not driven it yet, but it sat there idling for 15 minutes with no issues. Maybe I just needed to unhook the battery to reset the computer? The only other thing I can think of is when I was putting antifreeze in the reservoir some spilled since the wind was blowing 40 mph. A little splashed up toward the coil pack and I wonder if maybe the plug there got wet since I had that dismounted and out of the way for the alternator replacement. I just hate this electronic stuff, I'm from the old school and can tear apart and fix anything from the 60's.[?|] I drive the old stuff and the Focus if the wifes car although I must admit I've driven it a few times on road trips and really like to drive it. Here is a picture of SOME of my older easy to understand rides.

 

[iminhell]

Here is my take on it.


In the ECU there is a table for something called "battery voltage offset". It's a voltage compensation table for the fuel injectors, they operate on 12 volts but as we all know the voltage in a car is not actually stable. Hence the table.
Now lets say that the voltage regulator was on the fritz. That table would change and compensate for the opening times of the injectors with a goal of making the car run as optimal as possible.
You put a new and correctly working alternator in the car, one where the output was more stable/higher voltage/etc. Now the car has to relearn the proper voltage offsets to idle properly and drive at optimal conditions.
Maybe resetting the ECU was just what it needed.


I do have to scold you for leaving the battery hooked up while change the alternator though, shame on you. lol (if that was the case)

 

[rgvtx]

I do have to scold you for leaving the battery hooked up while change the alternator though, shame on you. lol (if that was the case)[/QUOTE]

No scolding necessary, I did indeed have the battery disconnected. Had a buddy once almost loose a finger, seems he had his hand around an alternator to put tension on the belt and his wedding ring shorted and almost melted his finger off. Hospital cut off the rest of the ring and a lot of skin came with it, took a long time for that to heal.

Anyway, I have now driven the Focus around for about 20 miles and all is well. I bought a scanner too just to be safe (figure I'll need it again one day) and it shows no codes. Life is good! [cheers]