No fire in 4 of 6 cyl

[BrokeRanger]

Ok new here and completely stumped. Need help. Ok truck is an 02 3.0 v6 not flex fuel. It's my Father in laws Truck. Truck has had a hard start issue for months now about 2 weeks ago got to where just had no power at all. Did fuel pressure check and key on engine off it ran up to 45psi same when running. Replaced fuel pump now trucks @ 65psi key on and running or not running same psi. Well FIL had relative change coil plugs wires ECT b4 fuel pump was done. Apparently when truck lost power it was due to lost spark. Test plugs for spark only get spark from plugs on cyl. 1 & 5. Tested the spark directly @ coil same thing only getting spark from that one coil bank. Used test light and have power @ wires 1-4 on coil ( type 2) key on engine off tried putting test light on battery + and tested wire 1 @ coil harness and it flashed wires 2 & 3 I got nothing. Altho wire 3 has signal bc it controls plugs 1 & 5. Everything iv read online so far says if test light flashes its bad coil and if nothing happens then its not reciving signal and could be bad PCM Now I put the old coil back on and tested it and got same results as the new one. MAF replaced a well as the TPS. I tested the crank position sensor and got ohm readout of over 600. Haven't done voltage test yet on anything havent tested the cam position sensor at all. Just completely stumped as to how it can get fire to only 2 posts on the coil and run on 2 cyl only. Tried to be as detailed as possible. Help is appreciated very much

 

[RonD]

Welcome to the forum

You have a Waste spark system
This means each cylinder is sparked when its at TDC(top dead center), so one spark is "wasted"
In a V6(any engine really) the cylinders are in matched pairs to balance the engine
3.0l pairs are:
3 4
2 6
1 5

Look familiar?
hint: coil pack spark plug wires

Cylinders 3 and 4 are at TDC at the same time so they both get spark at the same time
Same for 2 and 6, and 1 and 5

So there are only 3 coils needed in the coil pack

So only 4 wires are needed, one 12volt wire, and 3 Ground wires, just like in the old days coils get 12volts all the time, then grounded to power up and when that ground is CUT, they send out a spark

Two Spark plugs are wired in series, what that means is its hard to test spark
But if your tester was working on 1 and 5 then it should work on the other 4

If you have changed coil packs and still have no spark on 2/6, 3/4, then your computer is bad
That all there is to the spark system, coil pack and computer
If you have spark on 1/5 and engine fires that means crank sensor is working, and that's the only sensor that can cause no spark and no injectors

If you want to test coil's 4 wire connector, put test light on Red wire, thats the key on 12volts
Then the other test light wire on one of the 3 ground wires, yes it should flash when cranking
The ground wires run directly to the computer
The transistors they use to cycle the ground for coils can "blow", so no spark, not common but if there was a bad batch I can see 2 or 3 ending up in one computer

 

[snoranger]

If you have changed coil packs and still have no spark on 2/6, 3/4, then your computer is bad
That all there is to the spark system, coil pack and computer

Ron... I normally agree with everything you say, but not in this case.
There’s also the chance of damaged wires from the computer to the coil. This time of year there are critters looking for a winter home, and we all know they love wiring harnesses.

 

[RonD]

Certainly possible

 

[BrokeRanger]

Thanks. I was worried it was the pcm. It's been doing the hard start for a long time now. Idk why I said few months b4 guess was just tired. No critters have been under hood and untill it lost power @ coils it was daily driven. I'll check signal wires again to see if get any response from them. Online says attach probe clip to + bat side so I did that maybe should try the ground side and see if I get any flickers? It's storming today so as soon as it lets up I'll get out there on it again. My wife has even been trying to help read up on every thing about it and all I could think of was eother bad ecm or cam sensor and syncro

 

[RonD]

You can use battery+ instead of the red wire at the coil pack, either would have the 12v needed to detect 0v/ground on the other 3 wires at coil pack
And since 1 coil in the pack works the Red Wire must be OK

There are some different coil packs, with different connector

2002 3.0l wiring should be like this: https://www.justanswer.com/uploads/lostrider/2009-06-16_231324_1.gif

Spark plug wires like this: https://ww2.justanswer.com/uploads/jsorell/2009-12-29_143422_2009-10-16_003611_Picture_4.png

As said above 1 and 5 are on the same coil, so wires can be reversed, 1/5 or 5/1 wouldn't matter
Same for 2/6 and 3/4

 

[BrokeRanger]

Key on engine off probe clip @ ground of battery I get power @ all 4 wires of coil pack power plug when I connect clip to Batt.+ I have wife start truck and I probe each wire 1-3 and only wire 1 makes the test light flash. the first link wouldn't loaf maybe bc I'm using my phone but 2nd did n that's how iv got it wired up. Thanks so far for all help everyone

 

[RonD]

I would say computer is the problem, unless the connector for the coil pack is damaged, which should be obvious??

Needs to be for a 3.0l with 5R44E automatic trans, 2wd or 4x4 doesn't matter, Ranger or Mazda B3000 will work
So 2001-2003, but.............................You do have PATS(passive anti-theft system) inside the computer
So not a simple plug and play
You need correct keys to come with a used or new computer and then you need those to be cut to fit your locks

2001-2003 Ranger computers have PATS inside computer and thats where it stores the PATS key IDs
2 or 3 key numbers are stored in PATS memory at the factory and those keys are sent out with the new truck
More keys can be added, or deleted, using laptop connected to OBD plug in, with proper software
Most locksmiths can do this

But if you get a used computer WITH at least 1 working PATS key you will be able to start engine
A New computer should come with 2 blank PATS keys who's numers are in that computer's memory, you can take these to locksmith and have them cut to match your current key, so they fit ignition and doors


2000 and earlier 3.0l used 4R44E automatic trans, so can't be used
2004 and up have HEC instrument Cluster with PATS in the cluster, so won't work for you

 

[BrokeRanger]

Yeah I was thinkng about that too bout going to junk yard n grabbing a new pcm, key, ignition switch n door locks n just swap it all out and see what happens