ok guys here you go . got a 2000 model ranger 3.0 v6 this one is a stumpier. i acquired this headache thinking it would be a simple and quick fix so i am now fubared. i first inspected engine and found misfire on number three and found no compression due to broken valve spring fixed still no activity on cylinder. inspected further and decided to remove heads and inspect were a ok. now i inspected cylinder walls and motor had been replaced with this wonderful piece of crap long lock bored forty over and looked as though metal shavings had been run through the whole entire engine. threw it away heads and all very nice truck so i decides to round up donor short block and build one i knew would be good. did this replaced heads also bored engine all new components every piece thinking i would have a great engine and ready to roll. well installed this new long block and fired it off cylinder three misfire changed fuel injector still no good ,spark great and noid light showing computer firing injector still misfire on cylinder three . checked all connections and backtracked over entire engine still same issue i had with the junk motor happening to this fresh long block. if i had not seen it i would not believe the issue i am having. any ideas cause i am fresh out. thanks in advance.

 

Wires and plugs; just because there is spark doesn't mean to say that there will be proper spark when the engine is running ?
Coil pack could also be the problem, but because of the waste spark system, that may be unlikely, but something to consider.
If 3 is the problem with spark, then cylinder 6 should also be affected.
Change number 3 and 6 spark plug wires around at the coil pack and see if the misfire doesn't move to number 6.
If it does, you have a bad plug wire.

What is the compression on #3, should be checked just to rule that out even if it is an new engine.

And Merry Christmas BTW.

 

compression on three is 150 and all others are the same. coil is new , plugs and plug wires are new. changed plug wire to see if faulty wire same result. rechecked all plugs to check for defect or broken. all gaps are right. fuel is new with no water. fuel rail checked for obstruction , coil will absolutely knock your package in the dirt trail and era accidentally got a full blast from no three. number six firing good. as well as all other cylinders. funny this was the same thing happening before i threw all complete engine away and went new. ???? thank you and Merry Christmas to you. checked all voltage on map and maf . checked all voltage on o2 sensors i checked the pulse with no id light but i am going to check sure voltage to make sure it has the right amount to operate correctly.

 

I think you mean swapping spark plug wires 3 and 4, not 3 and 6, 3/4 share same coil in the coil pack, as do 1/5 and 2/6

And #3 misfire is not just a code number like P0303, you can actually feel the engine misfiring?
Misfire codes come from Cam Sensor(CPS), so it may detect something thats not there

Spark
Fuel
Compression
1 or more are missing when a cylinder misfires

With compression at 150 then its spark or fuel
swap 3 and 4 at the coil pack
If 3 still misfires then swap spark plugs in 3 with and other cylinder

This is where you need to test if Computer will allow engine to run without CPS, some 3.0l computers will others won't
Unplug CPS
See if engine starts, if it does you will get a CEL(check engine light), but computer should also be in Batch Fire mode, this fills the lower intake with fuel and cylinders just suck in what they need, if misfire goes away then #3 injector is the issue OR..........its ground control in the Computer is
Injectors all get 12volts with key on, the computer Grounds each injector to open it, in Batch Fire it grounds 3 injectors at the same time, then the other 3 the next time

 

Ron, I looked up which coil was shared with number 3 from this, so that's where I got 3 and 6.
I guess the article is wrong.

Or may be you're thinking that I was suggesting the firing order was wrong, in which case the article is correct.
The coil is firing number 3 and 6 at the same time, number 3 being on compression and number 6 on exhaust.
So in theory one should be able to switch those wires around and still have the engine run as normal, right ?
Same goes for "1 and 4" and "2 and 5", assuming the article is correct.

Or there are different firing orders for the V6, just like a straight 6 ? 153624 OR 142635

DISTRIBUTORLESS IGNITION SYSTEMS

 

You may have looked up the wrong 3.0l V6, Rangers use the Vulcan V6

Info here: https://therangerstation.com/tech_li...formance.shtml

Firing order is 1-4-2-5-3-6, the second one

To get the PAIRS you split firing order in half and put one below the other
1-4-2-
5-3-6

So 1/5, 4/3 and 2/6 are the pairs at TDC at the same time to balance the engine
On the coil pack they just use
3 4
2 6
1 5

or
1 5
2 6
3 4

depending on orientation, they don't put 3/4 in the middle

Works the same for V8 engines, say firing order is 1-5-4-2-6-3-7-8
1-5-4-2-
6-3-7-8

So pairs are 1/6, 5/3, 4/7, and 2/8
Coil packs would reflect that pairing on a Waste spark system

 

I figured as much, looked up the wrong firing order. Not very familiar with V6's.
At any rate it will be interesting to see what the OP's problem will be _ eventually...

 

want to thank everyone for their input. update to 2000 ford ranger 3.0 v6. started over last night drove truck to bring up exhaust temp did a infer red test converters where 500 degrees at entrance and 260 exit. this was two converters the secondary not as bad. even though i checked these with exhaust down had issue with with injector after driving vehicle again noticed tremendous loss of power and surge .that is when i decided to check converters asap. this test told me the converters were restricted causing back pressure and all the while heat damaged all the new plugs to the point they had to be replaced and not much running time to do this. this is another reason for valve seat damage also to heads with one prolonged to excessive heat. so i checked fuel filter which was newer replaced by original owner and was installed wrong. so the moral of the story is check recheck because i knew it was something i was overlooking that did not make sense. so all the small issues added up to major headaches but got it taken care of after stepping back and regrouping for the second attack.

 

This is why a vacuum gauge is still the second best tool you have for gasoline engines, brain being the first

Thanks for the update, glad you found the problem

 

have to have a cut wire some place. Only thing that makes sense