Hi, I have a 2004 Ford ranger edge 170k miles. It abruptly quit starting, replaced coil pack, CPS. It's not getting spark to plugs. Cam position sensor tests 0.1 when cranking and can be seen spinning. Checked grounds and fuses. Any helpful info would be appreciated. Fuel injectors are working which suggests computer is still good.thanks

 

 

ranger will crank but will not start, ruled out timing belt ( my understanding is it would still run just not well.) Spark I'm getting off plugs are little to none, they're relatively new as well. Next course of action is to replace port to read codes it doesn't work according to AutoZone, will it throw code to narrow down my search or just read that it's not firing

 

Welcome to the forum

2004 Ranger
What engine?
2.3l
3.0l
4.0l
(none had timing belts, just FYI)

Anytime you have a crank but No Start, first thing you do is 50/50 test
Pull off intake's big air tube
Spray some gasoline or Quick start(ether) into the intake and try to start engine

If it starts and dies, you have spark but no fuel
If it doesn't start then you have no spark
50/50

And it is pretty much impossible to test for spark on newer engines, just FYI, 50/50 test will do that, but spark testers or the old screwdriver in plug wire won't show much, lol, coil can detect something is off and won't spark that wire

No sensors can cause a No Start, well one can but it never ever fails, Crank sensor.
Usually it is no fuel, fuel pump quits working, especially if is sudden

Have you checked all the fuses in the engine fuse box?
Pull them out 1 at a time and test them or give a very close look

Also there are some in the cab fuse box that could cause a no start or a no read for OBD2 scanner

Get your Owners Manual here, it will have fuse panel diagrams: https://www.ranger-forums.com/genera...1-models-3747/

 

3.0L did 50/50 test with starter fluid, nothing. Checked fuses in both can and under hood with ohm meter. Pulled spark and grounded it to block to check for spark and nothing. Thanks for quick reply I'm not very savvy with vehicles but guy working with me knows his way around them and is stumped. Anymore questions I'd be happy to answer if it gets any kinda feedback. Thanks

 

Ron, sorry about such an ambiguous post I'm at work lol, checked for fuel in line via pin valve also plugs have fuel on them so I'm not sure about a fuel issue

 

Coil pack will have 1 Red wire on the 4 wire connector, it should have 12volts with Key on

That power comes from PCM Power relay in engine fuse box
PCM relay should "click" closed each time key is turned on
But this relay also powers fuel injectors and PCM(computer) so if plugs are wet PCM relay is closing, and computer is getting CKP sensor pulse to open injectors

In the early 2000's Ford moved the PCM to the upper center of firewall, its 104 wire connector can be seen there, at that location it could get water intrusion
Unhook battery and remove connector, check for moisture

I think in '04 the 3.0l also had the big connector on drivers side of engine, open it and check for corrosion

 

We have got 12v on 4 wire connector also the relay clicks as well we checked computer for any sign of water damage and nothing, next I checked for corrosion on unit in front of driver's side and found nothing. Still stumped.

 

Spark system is pretty simple, on all gasoline engines.

An ignition "coil" is just what it says, but there are two coils of wires inside
Primary coil has say 100 windings around a core, so 100 'coils', this is the 12volt coil
Secondary coil will have 80 times more windings, coils, so 8,000 in this case

Primary coil gets 12volts, and that creates a magnetic field around BOTH coils.
When the 12volts is cut the magnetic field collapses and that causes a high voltage low amp current in the Secondary coil, 12,000-15,000 volts, which looks for a Ground, and that is on the other side of the spark plug, so this voltage jumps the gap to get to a Ground.

To get the coil to spark you need to power up the Primary coil then cut the power to the Primary coil.
This was done with Points in the old distributors, points closed powered the coil points open cut the power.

Because of all the metal parts in a distributor it was easier to connect Points to the Ground(-) on the Coil, cutting the Ground is the same as cutting the 12volts, just less chance of a short using the ground, lol.

So coil gets 12volts when key is on and the points connected and disconnected the Ground on the coil causing it to spark.

When things went electronic, they stayed with using the ground, just used a Transistor to connected and disconnect the Ground .

And with a Coil Pack it is still the same.
One 12volt wire powers all 3 coils in the coil pack
Then there are 3 Ground wires, one for each coil in the pack

Transistors in the computer connect and disconnect each coil from Ground to spark it.

For all 3 transistors to fail would be unusual, same as for all 3 coils failing at the same time.

Possible but very very unlikely

You could test if computer is grounding one coil while cranking, hook up test light or meter to battery + and the other wire to one of the 3 ground wires on coil pack
Crank engine and you should see flickering voltage, as it is grounded and ungrounded by computer

 

Really appreciate it Ron. I will try this test tommorow. On the plus side I found faulty fuse so I can finally get a scan on obm and maybe narrow the playing field. One more question should a crank position sensor have continuity when removed ? I've heard from a few people that those sensors are renowned to fail, wondering if maybe I got a bad one out of the gate

 

Cam sensors fail, and on the 3.0l that can cause a no start, but it is usually the housing part, synchro tower, that fails

Crank sensors rarely fail, not never but rarely

In '04 both would be VR(variable reluctance) sensors so both will output AC volts.
Not sure an OHM test would help with a VR sensor.
A VR sensor generates its own AC voltage when a piece of metal passes near it.
The Metal is called a tone wheel and the spacing between its teeth is "known" so the AC voltage pulsing can be a "known" distance, crank sensor spacing is 10deg
Not sure on Cam spacing

But when cranking the engine crank sensor should show .5 to 1volt AC, the faster the crank turns the higher the voltage

 

We took housing cover off of cam sensor and it was spinning inside during cranking. Is there a better test that can be performed ?

 

Ron, figured I'd do my due diligence. Replaced PCM and truck fired right up after being programmed!!! After further inspection we found a single transistor on the board with a burn spot. Appreciate all the help hopefully this thread will help someone in the future. I'll be sure to recommend this forum to anyone down the line I meet... Thanks again.

 

Thanks for posting the update and the fix


Very odd to lose a PCM on any vehicle