1997 ranger skip

Hi,
I bought a 1997 ranger with an oil pressure problem. I pulled the engine out and pulled the camshaft position sensor. the gear was stripped in one spot. I put an electric drill to the oil pump and it pumped a steady 60 lbs of pressure.
I put in a new CPS and installed a new set of spark plugs. I installed the engine. After installing the engine I started it up. It now has a skip. I checked all the wires and the ignition coil and they are ok. I pulled all of the wires and replaced them one at a time and when I did the drivers side, there was no difference. But when I did the same to the pass side, it made a little difference.
I then pulled all 3 wires off the drivers side and there was no difference. I replaced the wires on the drivers side and did the same on the pass side. The engine almost stalled. That to me shows that I should have a problem on the drivers side.
Here is what I don't get!!
I checked with a code reader and it shows a reading of P0171.
HELP!!!
Bob

Got new plugs in there?


Sent from my iPhone using Tapatalk

yes, as I have written in the second paragraph.

P0171 is lean. Lean is determined by too much free oxygen in the exhaust. A misfire will leave oxygen in the exhaust because it isn't being used in combustion.

97 was an OBDII year, so if you get a good scanner, no just a basic code reader, on it you should be able to see which cylinder(s) is/are missing in real time.

Coil pack firing order
3 4
2 6
1 5
front

You see the passenger side is fairly easy to get right, 1, 2, 3
Drivers side can get mixed up, 5, 6, 4

This has to do with Ford's Waste Spark system and why pulling off spark plug wires doesn't tell you as much as it did with distributor setups.

In the coil pack there are only 3 coils, not 6
So the spark plugs are wired in series pairs.
1 and 5 are on 1 coil
2 and 6 are on 1 coil
3 and 4 are on 1 coil

That's why the spark plug wires are connected the way they are.
So when #1 fires so does #5, and when #5 fires so does #1
Because these cylinders are "matched pairs" they are both at Top Dead Center(TDC) at the same time, "matched pairs" balance the engines rotation.
#1 will be TDC at end of compression stroke, so spark will ignite air/fuel mix for power stroke, #5 TDC would be at end of exhaust stroke so spark is "Wasted", waste spark system.
Next time #5 would be at TDC compression stroke and #1 would be on exhaust stroke, so #1 spark is wasted.

Same for 3 and 4, and 2 and 6.

Firing order for 3.0l: 1-4-2-5-3-6, when you split any firing order in half and put one half above the other you get that engines "matched pairs" one above the other.
1-4-2
5-3-6

Because the spark plugs on each coil are wired in series one spark plug will spark from center to tip and the other one from tip to center(reverse spark).
And because of this when you remove a spark plug wire you can cause BOTH spark plugs to stop working.

Drivers side is usually the "normal' spark, center to tip, you can tell this by looking at the old spark plugs, worn out tips, on the passenger side you would see the opposite, worn out centers, reverse spark.
This is why you should use regular copper spark plugs OR Double Platinum, not single platinum, because they would wear out on one side just as fast as regular copper.
On some model years you will actually see different spark plug numbers for drivers side and passenger side, instead of paying extra for double platinum Ford install single platinum tips on one bank and single platinum centers on the other bank, you can do the same, but for 1 engine it doesn't save that much, with thousands of engines it do add up

Any way double check firing order on coil pack and at cylinders, especially drivers side.

Hi RonD,
Thank you for the info. I didn't know that the coil pack only has 3 coils. I understand what is going on now. Anyway, I checked the wiring for the 4th time. I checked the continuity on all 6 wires and they are and were in the correct place.
I checked the fuel pressure also and it is all in specks.
I bought new Motorcraft spark plugs from the local Ford dealer.
Now what?

Hi adsm08,
Thank you for the advise. I know someone that has a good reader and I will have to get him to come and read my truck.
Bob

Hi,
So assuming the spark timing and plugs are working correctly, that only leaves fuel and compression that will cause a misfire(skip).

Gasoline engine's big 3 are:
1. Spark, at the right time
2. Fuel, in the correct mix with air
3. Compression, above 100psi, above 150psi is what most engines need to be, but most will still "fire" at 100psi".

The fuel injectors get 12volt power when key is turned on, the Red wire is daisy chained from one to the next.
On your year each of the 6 injectors will have a Ground wire running to the Computer(PCM), so 6 Ground wires, the computer will Ground each injector to open it at the right time and open it long enough to let in the calculated amount of fuel(pulse width).
Each injector will make a distinctive "tick" noise when it opens and closes.
I would get a longer vacuum hose, or similar, to use as a stethoscope while engine is running, and "skipping", listen to each injector for steady "tick, tick, tick" to make sure it is working.

P0171 means Passenger side exhaust is too lean, and as adsm08 said that can be caused by a steady misfire.
So I would check injectors on that side first.
Could be one just didn't get plugged in, or connector not pushed down enough.

Another issue while you are on that side of the engine is the lower intake manifold.
If there is a gasket leak on lower intake it will usually only effect the closest cylinder to that leak.
Injector o-ring could be the leak or the intake gasket itself.
Put "stethoscope" down close to bottom of injectors, listen for the hiss of a vacuum leak, same along the edge of intake gasket on that side.

Hi RonD,
I checked the injectors on the pass side with a long screw driver. I got the tick tick on all three. I only could check # 6 because the upper manifold is in the way. #6 is ok. I guess I will have to remove the upper manifold to get to #4 and 5 injectors to check them. I will also check for a manifold leak. I have a friend that has a real good code reader. I will see if I can get him to check with his reader.
Thank you for the help.
Bob

I would stick with the passenger side because of the P0171 code.

And yes read codes again.

You can get Bluetooth OBDII readers for under $40, they plug into the OBDII port and get power from that port, they use Bluetooth wireless signals to send data to a Smartphone or Laptop/tablet that has Bluetooth.
Beside codes you can also see Live data while driving or idling, which can be helpful.

Make sure the APP for the device is free.
Since OBDII is an industry wide protocol, and requirement, these work on ANY vehicle sold in North America after 1995, so well worth the investment if you planing on owning a vehicle or vehicles in the future.

RonD said:

I would stick with the passenger side because of the P0171 code.

And yes read codes again.

You can get Bluetooth OBDII readers for under $40, they plug into the OBDII port and get power from that port, they use Bluetooth wireless signals to send data to a Smartphone or Laptop/tablet that has Bluetooth.
Beside codes you can also see Live data while driving or idling, which can be helpful.

Make sure the APP for the device is free.
Since OBDII is an industry wide protocol, and requirement, these work on ANY vehicle sold in North America after 1995, so well worth the investment if you planing on owning a vehicle or vehicles in the future.

Click to expand...

Yeah, there is a brand called Konnwei that makes decent BT scanners for $20 or so on ebay. The construction is OK and they make it so you can take it apart and flip the front panel (otherwise the front panel will be upside down). Works with the Torque app, The full version is $5 well spent IMHO. Avoid the "slim" clear blue scanner for under $10 a pop... they're CAN-only, which means they only work on newer vehicles. The "fat" ones do work with the PWM signaling pre-2012 Fords use.

Hi RonD and ratdude747,
After your suggestions, I looked on E-bay and now I am confused. I looked for Bluetooth and the adds state that I need something else to us with it.
Here is what I bought. Actron CP9125.
Here is what I have here. A desk top computer with Windows 7 and a ground line for a phone.
I do not have a cell phone or any of the other things people walk around with in there hands.
So what is a good code reader that would work that is cheep and do all the things that the ones that you gays say are good.
Thank you both.
Bob

wa1vvs said:

Hi RonD and ratdude747,
After your suggestions, I looked on E-bay and now I am confused. I looked for Bluetooth and the adds state that I need something else to us with it.
Here is what I bought. Actron CP9125.
Here is what I have here. A desk top computer with Windows 7 and a ground line for a phone.
I do not have a cell phone or any of the other things people walk around with in there hands.
So what is a good code reader that would work that is cheep and do all the things that the ones that you gays say are good.
Thank you both.
Bob

Click to expand...

The Actrons are special and use their own proprietary software that IIRC is Android/iPhone only.

The off-brand ones (BT, wifi, or USB) can be used with a variety of software. There is Torque/Torque lite that is for Android (and maybe iPhone too). There are a few for Windows on laptops. There also is some software that is cross-platform (I run Arch Linux on my laptops and tried to make it work, no dice).

Hi ratdude747,
I was confused before, now I am completely lost!