Tach & Battery/Alt issue & Whirr

[V8-X]

1999 X 5.0 AWD w/AT

Let me just state the only mod I have is a drop in K&N air filter. Otherwise the radio and all parts are stock with no modifications.

First off it seems as though I have a problem with my Battery, Alternator or charging system. I have just replaced my Battery & Alternator 6 months to a year ago with OEM parts.

I have noticed that the X's Battery gauge will drop in voltage when I am not accelerating. When the X is running and in Park, all is okay and the gauge is right in the middle. Once I drop it into Reverse or Drive, the battery gauge drops down to about 3/4 of the way to the middle. When I run my lights, radio and heater, this drop is even worse. At this time the lights dim and the gauge is about 1/2 the way to the middle. This is while I am stopped in gear, but once I accelerate the battery gauge goes back to the middle of the gauge.

2nd issue related to the Tach and performance is a lot harder for me to explain.

When I am accelerating in 3rd gear the tach seems to get stuck at about 2200RPMs then it will drop to about 1800RPMs. This is all while accelerating and not letting off the gas, and it does not seem to shift into 4th and it's not the TC locking up which is causing the RPM drop. It seems as though the engine just loses power all of a sudden. This drop in RPM's also includes a deep tone type of moan & driveline noise like the X is in to high of a gear.

Now there are times when the X does shift into 4th or the TC locks up and this same situtation occurs. Which when it does shift or lock up, it's like the shift/lock up was to soon and the tranny is in to high of a gear.

Lastly, I get a loud whirring sound from the engine bay/front end. To me it sounds like the MAF/MAS or something with the intake is whirring. This is when accelerating or decelerating at slow speeds, as I am unable to here it when going over 30MPH. I have already replaced the IAC & TPS. Would this be more likely the intake or hubs, from my searches it could be either.

Is there the possibility that these are all related. Could the MAS/MAF be working incorrectly, which causes the erratic RPM problem, early shift points and the whirr.

Last time I got the CEL was 1 1/2yrs ago when I had a bad #4 plug. Since then I've had this problem and the CEL has never come back on.

Replaced: TPS, IAC, all 4 O2's, All 8 plugs & wires, EGR, T-Stat, Fuel Filter, FPR, Air Filter, Battery, Belt & Alternator. The MAS/MAF has been cleaned twice, Once by myself and once by Ford. Neither time did this cleaning the MAS/MAf help, and none of the parts replaced have fixed the problem.

Any and all suggestions would help, as this problem seems to keep getting worse and no one has been able to find the problem. (Ford Service Center, Independent Shop or myself)

 

[Opera House]

This sounds like bad ground straps from the engine block to the car body. Some have even found the bolt of the ground wire from the battery neg never tightened. The engine and battey are electrically isolated from the frame. If the ground connection is bad, the only current path is through the bearings and U joints. This explains the moving and non moving. The alt and battery are referenced to the block nd the volt gauge is referenced to the frame. Run a heavy wire from block to frame and your problems will likely go away.

 

[V8-X]

Opera House: Thanks for the advice, i'll check into this either tonight or tomorrow.

Just to make sure I have this correct, 1st I need to check the Battery/Alt ground connection to insure it's tightened down.

2nd I need to check to insure the block to frame ground is tightened down. Any ideas on where this ground would be located from the block to frame on the 5.0 V8?

Lastly, I may need to run a heavy gauge wire from the Engine block to the Frame of the X. Any suggestions on where I should connect these or what gauge wire I should use?

With all this stated, is it still possible that all these issues are related, or are they most likely seperate issues? Also, could this contribute to the drop in battery voltage when the Trans is put into Drive or Reverse from Park?

Thanks again for the support and advice, it truely helps. Since I've been dealing with this for over a year. I've always found this site to give good suggestions, to bad none of the suggestions have fixed this issue yet. Fingers are crossed that this is the fix.

 

[Opera House]

There is usually more than one seperate ground connections from the "engine" to the body. When one is lost that can cause another to fail. Look to see if there is an additional wire from the neg battery post to the body. The heavy one on the neg goes right to the frame bolt of the starter.

 

[Opera House]

The first couple numbers might help your general understanding of the electrical system.

General Electrical Diagnostics
To diagnose electrical problems, always have the same reference point. Remove the battery terminal from the negative post. Clean the post and the connector. Then reattach and tighten. This will insure that this one connection is good. All voltage measurements should be made from this electrical terminal.
1. With the engine off, turn on the headlights to create a current load of about 20 amps. Bad connections have resistance and a voltage is developed when a current is passed through them. If headlights do not turn on go to step 3.

2.With headlights on and engine off, measure the voltage from the NEG battery terminal to the vehicle body. This should be some place that does not have a wire going to it. If voltage is greater than 0.25 volts then there is a grounding problem..

NOTE: The negative terminal of the battery is normally connected to the engine block. There may also be a smaller wire that connects to the body. Engines are electrically isolated from the frame and body. There are an additional two to three ground straps that connect the engine to the body and frame. These straps can corrode and break. Then the only connection is through bearings that have higher resistance and can be intermittent. There should be always at least two current paths. When you find one that has failed, there is also another one that has failed. Add that extra ground strap to have reliable operation.

3. Measure the voltage from the NEG battery terminal to the POS center post of the battery and record the voltage. Voltage below 12V indicates a discharged battery. If above 11V you can continue testing. Now measure the voltage on the battery connector. This voltage should be exactly the same.

NOTE: The positive terminal of the battery is normally connected to the starter terminal. There will also be a smaller wire that connects +12 volts to a power distribution point. This will be the starter solenoid (relay) on the fender. Power to the fuse block and output from the alternator connects here. Typical battery voltage with the engine off is 12.5 to 12.8 volts.

4. Measure the voltage from the NEG battery terminal to the stud on power distribution point (solenoid). This voltage should not be lower than 0.1V below that measured at the battery.

5. Measure the voltage from the NEG battery terminal to the main (40A) fuse in the distribution box. This voltage should not be lower than 0.2V below that measured at the battery. Measure this voltage on both sides of the fuse. Check the manual for the correct fuse location. Headlights may be turned off if the problem has been found.

NOTE: Fuses have a holes in the top just over the pins. If the probe will not fit in, use a pin or an awl to make contact. Some fuses have switched power. You will either have a normal 12V or nothing. If you see a voltage in between, there is a wiring problem.

6. Measure the voltage (engine not running) from the NEG battery terminal to the stud output of the alternator. Don't slip with the probe, this terminal can supply a lot of current. This voltage should not be lower than 0.1V below that measured at the battery. If no voltage is present, the fuseable link between the alternator and distribution point has blown .

7. Turn the ignition key on but do not start the vehicle. The battery idiot light should be on. The alternator regulator is turned on through this lamp. If the lamp doesn't light there could be a loose connector on the dash. In the dash there is a resistor across this lamp. In the unlikely event the lamp fails, the alternator will continue to charge. Measured at the alternator plug, the lamp LG/R wire should have greater than 0.2V with the ignition on.

8. Measured at the alternator plug, the regulator 12V power Y/W wire should have the approximate battery voltage. This is powered at all times. If nominal battery voltage is not present, check the 15A regulator fuse in the distribution box.

9. Start the vehicle. Measure the voltage from the NEG battery terminal to the POS terminal of the battery. If the alternator is charging the voltage should be over 13.5 volts. Turn the headlights on and verify the voltage is at least 13.2 volts. Even an alternator with a defective regulator can put out small amounts of current from residual magnetism in the rotor. Voltage of over 14.5 volts indicates an overcharging condition.