ponyman

So awhile back I had a thread about some slight surging I was getting while cruising down the freeway. Well as a continuation to that I went on a long drive this weekend and noticed that while cruising (literally with cruise on) around 80-85 mph when I would signal a lane change that I would get the slight surging again (almost in time with the blinker). But no codes, no nothing.

Last night I had the surging pretty bad on the way home from work (even w/o the help of the turn signal), but no codes. Fast forward to this morning and I go to leave and didn't even make it out of the neighborhood before I got a CEL. So I went back home and threw my Predator on in and got the following codes:

P0300 Random/Multiple Cylinder Misfire Detected
P0304 Cylinder 4 Misfire Detected
P0307 Cylinder 7 Misfire Detected
P0316 Engine Misfire Detected on Startup (First 1000 Revolutions)
P0340 Camshaft Position Sensor "A" Circuit

So after this weekend I was starting to think alternator, just because of the timing of the blinking and surging occurring. Then after having the surging last night on the way home and the set of codes this morning, I'm thinking it may really be the alternator. But I was curious if I might have other possibilities to choose from too?

Obviously it could be the Camshaft Position Sensor, but it doesn't seem to be all that usual of a culprit for that code. Also if I stop by AutoZone and have them check the alternator and it checks good can I be guaranteed that it really is good and I need to look at other possibilities?

Thanks,

-R

Wally39

I also have gotten the P0340 Camshaft Position Sensor code a few times, but only when cruising down the highway with my air conditioning on. Then when I get home I clear it. I'd also like to know what is going on.

ponyman

Took to AutoZone. Battery tested fine. Alternator tested at 13.1 volts at idle and 13.3 volts at 2000 rpm with no A/C load.

So do I assume it is the alternator and get a new one, or is there something else I can do to verify it is the alternator?

What is normal output for the alternator?

Bmr4life

P0340 is definitely your alternator. Had the ECU pop that code up twice. Both times I ended up getting a new alternator installed under warranty.

tx_zstang

Sounds like the voltage drops as the car runs and the alternator heats up.
A good voltage gauge should show the drop in voltage if that is occurring, and that would cause the misfiring and other issues, especially with the turn signals aggravating it, too.

But as mentioned, others have had that code cured with the alternator, so even though it may 'test ok', that doesn't mean it's not defective.

Art161

According to the Ford Workshop Manual, the voltage measured from the positive terminal of the alternator to the negative lead to ground should be between 13.2 and 15.5 volts at 2000 rpm engine speed. Also, according to the manual, there should be less than a .1 volt drop between the alternator terminal and the positive battery post.

So it appears that you are right about at the bottom end of the acceptable range, but nothing way out of line.

I would have the amperage output of the alternator checked, using a test load bank. You are not just dealing with volts; you are also dealing with amps. You should have a minimum of 80 amps at 2000 rpm engine speed.

Bmr4life

It's the alternator. 2nd time I took mine to Ford, they said it wasn't the alternator. (First time, they fixed it with no problem). Since my car was out of bumper to bumper warranty, they said I'd have to pay $80 to have the car diagnosed to find out what the problem was. The tech kept saying it was my Optima Redtop that was the problem, lol. I told them to do the test, about an hour later they called saying it was the alternator and would be replaced under its own warranty (my previous unit had been in about 10 months, so 2 months warranty left). Also wasn't charged the $80 as that was covered under the same warranty.

Sad part is I think this third alternator may be giving up the ghost soon because I start getting a horrible alternator whine through my speakers very randomly. Happen about 3 times in the last 2 months. Stereo has been the same for over a year so its nothing that I've changed.

ponyman

Codes again this morning. Weird thing is that I am only getting them on initial startup in the morning. Don't get them when I start the car at other times. Seems a little odd to me.

P0300 Random/Multiple Cylinder Misfire Detected
P0316 Engine Misfire Detected on Startup (First 1000 Revolutions)
P0340 Camshaft Position Sensor "A" Circuit

How would I test the amperage output of the alternator at home? Can I do it with a multi-meter? I'm a little concerned with taking it to Ford and spending the diagnosis fee ($50 to just to a charging system check or $100 to do a code diagnosis) when it seems to be only throwing codes first thing in the AM.

Bmr4life

No, you can not test amperage output at home. You'd had have one heck of an ammeter. You're talking about 60-110amps depending on load.

How did they test it at the autoparts store? Did you take it out the car and have them put in one their machine?

ponyman

No, I think they actually just measured the voltage across the battery with the car running at idle and 2000 rpms.