BlvdKreeper

Been getting a P0302 code for a few months now. Can't seem to get it right. I did a complete tune up and I bought a brand new mopar gas cap. But it still turned on a few days later. Can it be the injector itself? Also which one is injector #2? I read on here about putting heat shield around the injectors. Well....I tried that also and it didn't work. Any advice ???

BlvdKreeper

It's a 2001 jeep Cherokee xj. 161 k

BlvdKreeper

Anyone?

joeyv44

I would check the coil, especially if they it is the OEM coil. You could always try changing around an injector and see if the misfire cylinder changes.

Cheddarnut

That code could mean any of the following, some of which you've hit already. Start working down the list:

- Faulty spark plug 2
- Clogged or faulty fuel injector 2
- Faulty ignition coil 2
- Fuel injector 2 harness is open or shorted
- Fuel injector 2 circuit poor electrical connection
- Ignition coil 2 harness is open or shorted
- Ignition coil 2 circuit poor electrical connection
- Insufficient cylinder 2 compression
- Incorrect fuel pressure
- Intake air leak

CCKen

It's pretty hard to have the coil rail be defective to the point where it only affects one plug.


My guess it's the #2 cylinder fuel injector, or its wiring, giving the problem.

Dumajones

The 2001 has the coil rail. take a look at the underside of the coil and check for cracks around #2 mine had a crack I didnt see and would give me miss fire on 4 all the time. I tried to fix it with Epoxy stuff that didnt work.. new rail all gone..

Here is a pic of where the crack was





And about the heat shield,, that's for injector #3. It called heat soak 2000-2001 have bad heat soak on #3 with the stock fuel injectors. when I upgraded my injectors that issue has stopped. I also warped my injectors with heat shield tape that might as well helped also.






Here is the #3 injector fix

Parts required:
56028371AA Ignition Wire Shield or just some heat shield tape.

Repair procedure:
1. Cut insulator sleeve, p/n 56028371AA, to make two (2) insulator sleeves about 25-30 mm (1 in.) in length. See diagram.
2. Install one sleeve around injector #3, with the slit on the upward facing side of the injector. Install the other sleeve with the slit on the downward facing side of the injector.
3. Confirm sleeve is flush to intake manifold surface around injector.
4. Check injector #3 wire and ensure that the injector is rotated to a 2 o'clock position (from driver’s side of vehicle).

But listen to what others have said and try to rule out the injector not being bad or wire.

cruiser54

Those years also had an issue with weak valve springs allowing carbon to build up under the exhaust valve.

Do you ever rev this thing up good or do you drive like a grandma?

A simple try is to add a can of BG44K to a full tank of fuel. Drive til it's down to 1/2. fill it up with gas and drive til down to 1/8 tank. This will clean the injectors and remove carbon from the combustion area.

Dumajones

Really? I did not know that, Info locked away in my head, thanks Cruiser.

cruiser54

You sure that qualifies as safe keeping? LOL.

After the 44K, I would de-carbonize with water. That's what finally fixed my buddy's.

BlvdKreeper

I sound dumb for this but which is injector #2?

Dumajones

Start counting from the front to the back,front of motor> 1,2,3,4,5,6<back of motor.

CCKen

OP,


Congrats on the Blackhawks winning the Cup.


If you have a mind to, you can test your coil rail...to a degree.


Follow the instructions in the below pic...even with the typo (TE=The)

BlvdKreeper

Thanks. I wasn't sure if it was the opposite. That's why I asked

BlvdKreeper

Are the coil rails from autozone any good?