Voltage Issues/No start

Rangerdanger13 · Nov 30, 2014

Hey guys first time posting. Having some issues with my 2000 Ford Ranger. I will start at the beginning. I was driving the truck after having her parked for the majority of the summer. On the Freeway i started to notice a slight miss, loss of power. Pulled off the Freeway, Idle was very rough. noticed my battery light came on and I was able to stumble into a parking lot where she died. I threw a charger on the battery and figured my alternator had died so I replaced that. when replacing I noticed that the main positive wire to the back of the alternator was damaged and the connecting piece was broken and barely hanging on. as I removed it it completely sheered so i replaced that and started the car up. Felt okay, started driving down the road and then after about 5 mins same issue as before. Miss, loss of power. Now the truck does not want to start. Very weak crank, replaced the battery as it was due either way. Still weak crank, voltage on dash showing low, flashing check battery light. wondering if possibly Voltage regulator blew or something along these lines due to the alternator shorting. Long story short. New Alternator, new Battery. Weak crank, no start. Battery light on dash indicating low voltage, but battery reading 12.6 at terminals. Any advice is appreciated.

Thanks

Michael

RonD · Nov 30, 2014

Battery light on while engine is running means alternator is drawing voltage from the battery not outputting voltage, simple as that.
Although if alternator outputs more than 16volts light can come on as well.

As battery voltage goes down fuel pump and spark goes down, engine starts running rough.

You need a voltage meter.
Key off
Check voltage at battery, but..........use the engine as the Ground(-) for the meter, not Negative battery terminal.

Should be 12.5-12.8volts with new battery
If not check Negative battery cable at BOTH ENDS.

Now check for battery voltage at the B+ on alternator, the big wire you said broke
It should have same voltage as battery, if not then check 125amp MEGA Fuse, follow that big wire and you will find it, it may be outside the engine fuse box or inside it.
125amp MEGA fuse connects alternator to battery +, if that wire shorted and blew this fuse then no alternator connection.

If you have battery voltage at B+ then pull off 3 wire connector on alternator and check for battery voltage on the Yellow/White wire
If no voltage check Fuse #14(30amp) in engine fuse box

Now turn on key and check for battery voltage at the Light Green/Red wire on the 3 wire connector, you should have 12v there because battery light is on, if not check fuse #5(50amp)

Rangerdanger13 · Nov 30, 2014

Ron- Thanks for the quick reply. Ran all your checks test and I am getting continuity on all ends of battery ground and alternator mentioned. I may not have been clear in my first post, but the car will not currently start, and battery light is showing on gauge cluster with key turned to ignition. Also for shits and giggles checked spark to the plugs and I am getting spark as well. Not sure of strength but spark none the less.

RonD · Nov 30, 2014

Read voltage at battery while starter motor is turning.
It is a load test but can also tell you if battery cables or starter motor could be the issue.
Should go no lower than 10volts with a new battery

If battery is new then starter motor turning slowly could be bad cable or bad starter motor.

Put some gas in the intake, or starting fluid(ether), and try starting.

Cold engine needs enough RPMs from the starter motor to get compression up enough to preheat the fuel, ether is better for this since it has a lower combustion temp.

If engine starts and dies right away then fuel pump is not working(or you are out of gas, hey it happens, lol)

Rangerdanger13 · Dec 6, 2014

Okay- Wasnt able to work on the truck this week due to it raining. Was able to get the truck started this morning, while cranking and pushing gas pedal. Will only start under acceleration. Once started the idle is rough. I cleaned out the air idle control valve with carb cleaner, replaced and replaced the fuel filter. Still the same symptoms. Some condensation out of the tailpipe, definite miss. The truck will not Rev over 2000 RPM. Unfortunately there arent any codes being thrown. Not sure where to pick up next.

RonD · Dec 6, 2014

You do know with fuel injected engines pumping the gas pedal doesn't do anything.
On a carb engine gas pedal set the choke and pumped extra gas into the intake, but not so with fuel injection.

If you hold the gas pedal down all the way while cranking computer will shut off the fuel injectors, this allows you to clear a Flooded engine.
So if holding down the gas pedal all the way helps to start engine then you have fuel leaking into intake from an injector.

Rangerdanger13 · Dec 6, 2014

Yes, i knew this wouldnt pump gas into the intake but figured that it may have some effect on air fuel mixture ratios. One last update, changed plugs. They were pretty bad, restored some power, but idle issue is still there.

Rangerdanger13 · Dec 7, 2014

Bump/update. Narrowed the issue down to one cyclinder. Pulled the plug wires and number 1 cyclinder wasnt firing. Ruled out spark and wires by switching with 2 cyclinder. Then checked compression. Compression was 60lbs at idle/120 at half throttle. Checked number 2 cyclinder which was 90 at idle and 120 at half throttle. Not sure why the idle compression was off or if that is a factor. My understanding was the compression is usually only measured under throttle anyways. Either way, figured I would move to fuel with the compression being the same under load. I checked voltage at the injector plug and Volts are 14.6. Switched the injectors around, and still number one is not firing. When
The fuel rail is removed there seems to be a pretty good amount of fuel pressure......thinking the issue may lie in the lower compression at idle may be an issue. The problem almost seems to disappear under Higher rpm. May just be less noticeable but thought worth mentionishing.

RonD · Dec 8, 2014

Not sure how you are doing compression test but to get something you can use you need to follow a few simple rules.

All spark plugs must be removed so crank can spin at a decent RPM, i.e. build compression, metal rings on metal cylinder walls and metal valves sitting on metal seats are NOT suppose to be air tight, they are "air restrictive", so air will leak out, the faster you can get the crank turning the less time there will be for the air to leak out so the higher the compression numbers will be, and this is important when you are looking for a cylinder with bigger air leak, it will stand out more.

Throttle plate must be open so air can flow into engine easily, put something on gas pedal.

Test one cylinder at a time and make sure you hear it hit compression stroke 4 or 5 times at least.

WRITE results down!

The actual numbers are only marginally important.
What is important is the difference in the numbers.

3.0l should have 9.3:1 compression ratio, so you would expect 180+ psi at sea level with a good battery and above setup
But not all compression gauges are calibrated weekly, lol, so again actual numbers at 180psi are not what the test is for.
#1 155
#2 165
#3 160
#4 155
#5 120
#6 165

#5 here looks like a bad valve or ring problem
If you put a table spoon, squirt of oil in #4, #5 and #6, then retested you might get
#4 165
#5 130
#6 175

All went up about 10psi so rings are OK it would be a valve problem.

The point is not the numbers it is the comparison of the numbers.

And I have never found a benefit of warm engine testing, compression numbers will average higher, but that really isn't the info you are after with a compression test, you are looking for a cylinder or cylinders that are way off the "average" you just got.

Voltage Issues/No start

Rangerdanger13

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