I am having a problem where #3 cylinder runs rich, and dry fouls the plug
Is is possible for the pcm injector driver for one cylinder be bad?

I found that my #3 plug was sooty black when I was changing plugs.

SO far I have
swapped coils
swapped injectors
changed wires


I believe it is gas related due to this:
I left the injector in the cylinder, but took the wire harness off of it, and put a new spark plug in, and started the car.
I drove the car, and when I checked the plug again it was completely clean.
This ruled out an oil issue, or ring problem

Back to the fuel pulses.
How can I check to see if the injector is pulsing properly?
I called my tuner and explained the situation, and he said that he can not control individual injectors, just banks of injectors.

I read online that I may have a PCM problem, could that be?
Could the fuel injector driver be bad?
Is the driver replaceable?
Where is it located?
Does it sound like I have a bad PCM?

I waited to post unitl I really have exhausted all other avenues of knowledge.
Any help would be great!

Other things done to try to solve problem:
I added a catch can and breather
Pulled the intake to see if it was cracked
Checked pushrods and springs
Replaced the valve stem seals

 

For a cylinder to fire correctly you have to have:

-Correct Air/Fuel charge
-Correct Spark
-Correct Spark Timing
-Compression

All of the other cylinders work properly so we can say your air intake system is good.

You swapped out the:
coil
injectors
changed wires
so, I would have to say that they are good.

For a spark plug to be black and the cylinder to run rich it would have to be getting excessive fuel or not firing the fuel correctly.

Check cylinder compression and see if it is low. Compare it to all of the other cylinders. Are you getting any DTC's or misfire codes??

You can also try this:

Find a DWELL METER and connect it to the wires on the injector. On Cyl# 3 the injector wires are PINK and Pink/Black. Pink is the 12 VDC from the under hood fuse block. It is INJR2 fuse# 18 (15 amp). The Pink/Black wire comes from the PCM which is connected to the coil drivers. It is basicaly the coil signal wire. The DRIVERS are inside the pCM and you can NOT service, alter or change them other than reprogramming the PCM to change parameters that effect all of them.

The injector signal wires are color codes as follows:
-1 BLK
-3 Pink/Blk
-5 Blk/Wht
-7 Red/Blk
-2 Lt GRN/Blk
-4 LT BLU/Blk
-6 YEL/Blk
-8 DK BLU/Wht


If you connect the dwell meter to a chassis GROUND and to the Pink/Black wire, it should give you a value in degrees. It doesn't matter what the value is until you compare it to other cylinders that you assume are working correctly. Check the injectors at SAME idle rpm and then compare them with each as you rev the engine slowly through the rpm band. I would say idle through 4000 rpm to see if the dwell values all look similar. If there is a problem it will probably show up at a higher RPM. The more dwell degrees that you see, the longer the injector is on.

Now,,,,on the other side of the house you have the COIL and the COIL Drivers. Are you getting a GOOD HOT SPARK from coil position#3 ??. You can swap in new coils all day long but if the electrical signals that drive the coil are bad, you will get a weak spark. Compare spark intensity and color between a couple of coils. I would try a couple on each side. You should ge a nice crisp blue spark that should be able to jump a good 1/4" gap.

Here are what the wires on the coils do and their color codes.

Look at the wires on each coil plug. Each coil pack plugs into an engine wiring harness. The color wires on the plug for the the drivers side all match the color wires on the plug on the coil plug. The plug on the passengers side all have the same color wires but have a WHITE STRIPE on the wires on the engine harness side.

- All coils have a BROWN wire which is: "LOW REFERENCE" from the PCM, and a Black wire that goes to a Black/White wire in the engine harness which goes to GROUND G-107 (on the back of the drivers cylinder head) Each coil pack has a ground wire and they both terminate in a ground eyelet that gets bolted to the cyl head.
Each coil has a "CONTROL SIGNAL WIRE" from the PCM. On the coil side, they are color coded as follows:

1- PPL
3- LT BLU
5- DK GRN
7-Red
2- Red
4- DK GRN
6- LT BLU
8- PPL

On the engine harness side they are color coded as follows:

1- PPL
3- LT BLU
5- DK GRN
7-Red
2- Red/White
4- DK GRN/WHT
6- LT BLU/White
8- PPL/White

You can read the voltages on each coil signal wire and see how they compare. I believe that the Dwell meter will work on the coil signal wire just like it does on the injector signal wire. Try hooking it up to a ground connection and the:

1- PPL
3- LT BLU
5- DK GRN
7-Red
2- Red
4- DK GRN
6- LT BLU
8- PPL

See if you can get a reading.

To be able to get the dwell meter connected to the coil and the injector signal wires, I would use a straight pin and try to slide it into the back of the connector between the rubber seal and in beside the wire. If you do it right the pin will come in contact with the metal pin that the wire is attached to inside the connector and you will not damage the wire or the seal. You just remove the pin when your done and it all back to normal.

Give that a try and see what you come up with. If you have questions, let me know.

BC

 

find some one who know O scope. ya can see injector wave ditto on ign