2004 Ford Rangler 4x4 XLT 4L SOHC @ 93,000 miles:
Back in November I noticed when passing people that my battery light would flash and the lights would dim at high RPM. It only happened if either the Air, Headlights, or both are on and the RPM lingers above 5000RPM+ for some time like it does when accelerating from 50-80mph. In these conditions the battery light will also not be steadily lit, it flickers like a neon light switching on as if it's teetering and unable to decide if it should fully activate or not.
Because I only reach 5000RPM+ once in a great while, I haven't done anything about it since. I have a BlueTooth OBD2 ScanTool that has graphed the issue, The screenshot below was taken on December 1st. Volts(ecu) is the voltage reported by the ECU and Volts(OBD Port) is the voltage measured by the ScanTool at the OBDII port.
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Anyway, I bought the OBD2 BT Scanner in the winter and today it was a 96 degrees outside, so I was curious what the coolant temp and all that jazz would be since I've never seen it before at this temp. The first thing I did notice was that Volts(ecu) seemed to be reading lower than I remembered it has in the past.
On December 1st, 2013, Volts(ecu) was reading 13.3v @ ~2000RPM.
Today May 8th, 2014, Volts(ecu) was reading 12.8v @ ~2000RPM as seen below:
For reference I checked historic data on December 1st 2013 at my location and sunset was at 5:00PM and it was 36 deg F at 6PM. So my lights would have been on and my heater would very likely also have been on.
For today's Voltage the AC was running at full blast.
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In the garage, Volts(ecu) was reading 12.40V at Idle RPM with AC on fully.
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In the garage, Volts(ecu) was reading 12.70V at Idle RPM with nothing on.
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Now, I know for a fact that OBDII BT ScanTool reads low, so I also tested with a multimeter connected directly to the battery with vehicle at idle speed.
So, I'm not sure if the voltage is low enough to call it a bad alternator for certain or what not, it only seems borderline, what do you guys think? Would just a new Voltage Regulator and brushes fix this? Need a whole new Alternator? Belt Slipping?(I'd hear this one wouldn't I?) idk..
EDIT: The battery is the stock MotorCraft battery model the vehicle came with. The original MotorCraft Battery lasted 8+ years and still started the vehicle fine, but on cold days it cranked slow so I replaced it before the Winter Season. I wanted that same reliability so I replaced it with the same model, so the battery is less than a year old.
Back in November I noticed when passing people that my battery light would flash and the lights would dim at high RPM. It only happened if either the Air, Headlights, or both are on and the RPM lingers above 5000RPM+ for some time like it does when accelerating from 50-80mph. In these conditions the battery light will also not be steadily lit, it flickers like a neon light switching on as if it's teetering and unable to decide if it should fully activate or not.
Because I only reach 5000RPM+ once in a great while, I haven't done anything about it since. I have a BlueTooth OBD2 ScanTool that has graphed the issue, The screenshot below was taken on December 1st. Volts(ecu) is the voltage reported by the ECU and Volts(OBD Port) is the voltage measured by the ScanTool at the OBDII port.
Anyway, I bought the OBD2 BT Scanner in the winter and today it was a 96 degrees outside, so I was curious what the coolant temp and all that jazz would be since I've never seen it before at this temp. The first thing I did notice was that Volts(ecu) seemed to be reading lower than I remembered it has in the past.
On December 1st, 2013, Volts(ecu) was reading 13.3v @ ~2000RPM.
Today May 8th, 2014, Volts(ecu) was reading 12.8v @ ~2000RPM as seen below:
For reference I checked historic data on December 1st 2013 at my location and sunset was at 5:00PM and it was 36 deg F at 6PM. So my lights would have been on and my heater would very likely also have been on.
For today's Voltage the AC was running at full blast.
In the garage, Volts(ecu) was reading 12.40V at Idle RPM with AC on fully.
In the garage, Volts(ecu) was reading 12.70V at Idle RPM with nothing on.
Now, I know for a fact that OBDII BT ScanTool reads low, so I also tested with a multimeter connected directly to the battery with vehicle at idle speed.
Quote:
|
Nothing On: 13.36v AC: 13.24v AC + Brake: 13.20v AC + Hi Beams: 13.14v AC + Hi Beams + Brake: 13.10v In Drive + AC + Brake + Hi Beams: 13.02v In Reverse + AC + Brake + Hi Beams: 12.70v Batt. Voltage with Engine off for 5 minutes: 12.59v |
EDIT: The battery is the stock MotorCraft battery model the vehicle came with. The original MotorCraft Battery lasted 8+ years and still started the vehicle fine, but on cold days it cranked slow so I replaced it before the Winter Season. I wanted that same reliability so I replaced it with the same model, so the battery is less than a year old.