2002 WJ Misfire on 1,3,5 - JeepForum.com
 
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post #1 of 12 Old 11-14-2019, 09:58 PM Thread Starter
D-R0CK
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2002 WJ Misfire on 1,3,5

Well folks, I did what I could, but I've come crawling here to see if someone with more brain cells than me can suggest a solution.

I have a 2002 Jeep WJ Grand Cherokee with the 4.7 V8 and the California emissions package. Since August, I've been intermittently getting the following errors. An issue would occasionally crop up over the summer - especially after longer drives on the freeway - but clearing the OBD2 codes always resolved the issue for several weeks, so I figured it was probably just an O2 sensor failing.
  1. P0171 - (Fuel Bank 1 Sensor 1: Lean)
  2. P0202 - (Injector 2 Control Circuit)
  3. P0208 - (Injector 8 Control Circuit)
  4. P0300 - (Multiple Cylinder Misfire)
  5. P0301 - (Cylinder 1 Misfire Detected)
  6. P0303 - (Cylinder 3 Misfire Detected)
  7. P0305 - (Cylinder 5 Misfire Detected)

Well, when I got the P0300 and the cab started shaking at idle, my butt started puckering and I decided to get the O2 sensors taken care of. I went ahead and replaced all four. No dice. I also have run injector cleaner with no success.

The fact that it's cylinders 1,3, and 5 is suspicious. Do they share a bank? Is that Bank 1, hence the P0171? Is there something wrong with a fuel rail?

Thanks all!

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post #2 of 12 Old 11-14-2019, 11:58 PM
jtec
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YOU ARE USING A SCANNER TO GET all CODES ?

did you get a p0302 or a p0308 with the injector codes?

I would start with P020x codes.

You did use NTK o2 sensors ?

Before erasing codes use scanner to look at freeze frame.

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #3 of 12 Old 11-15-2019, 06:58 AM
Danny_Hurst
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I ran into a problem just like this on a Chevy engine 1357 throwing multiple miss fires all on one head tried every thing finally cut the catilatic converter open and it was plugged up, I gutted it and welded it back up it ran fine just throws oxygen sensor codes now.

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post #4 of 12 Old 11-15-2019, 07:50 AM
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INFO
It is illegal to remove or render inoperative emission devices - FEDERAL nothing to do with State regulations.

So throwing a o2 code was chosen over just replacing CAT?
What is the PCM's "action taken' when a cat code appears? Would be interesting to know.

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #5 of 12 Old 11-15-2019, 10:45 AM Thread Starter
D-R0CK
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Yes, I'm uaing a scanner.

I'm using Bosch O2 sensors. They're all reading the expected voltages.

No P0302 or P0308


I'll grab a freeze frame tonight.
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post #6 of 12 Old 11-15-2019, 11:21 AM Thread Starter
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Should I be worried about the head gasket?
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post #7 of 12 Old 11-15-2019, 11:34 AM
jtec
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Bosch sensors are problematic.

The injector codes and NO misfire codes - rings a bell I will look into that in TSB;s and my notes.

Try this - next time it 'acts up' read the freeze frame, if the p020x codes are there use a noid light on those cylinders.

Is your AIRBAG light on and your cruise control and horn operate ok?

Check your fuel pressure with a gauge and post PSI.
You are using correct plugs?
No exhaust leaks?


Yes 1,3,5 are same bank #1 driver side.

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #8 of 12 Old 11-15-2019, 12:11 PM Thread Starter
D-R0CK
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Thanks jtec! I appreciate the time you're investing to help me figure this out.

funny you should ask. My airbag is throwing a code (37) which I figured was just related to some bumper damage from when a spring perch bushing quit on me... do you think it's related?

Never checked fuel pressure or used a noid before, I'll look into that and get back to you.

As for plugs, I haven't changed them in a while, but the nature of the problem (three cylinders, all same bank) seemed to disqualify something as simple as plugs, no? I think they're either NGK or Bosch Iridiums.

No exhaust leaks.

Do you think it could be head gasket or catalytic converter? I do have the California emissions package, so I have one smaller cat per side before they join up for the bigger cat.

Thanks again!
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post #9 of 12 Old 11-15-2019, 12:18 PM
jtec
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why would you suspect head gasket?

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #10 of 12 Old 11-15-2019, 12:22 PM Thread Starter
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Whitish exhaust, seems to all be cylinders along one bank. Would imply a crack in the gasket running from cylinders 1,3,5 through the odd bank?
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post #11 of 12 Old 11-30-2019, 03:44 PM Thread Starter
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Quote:
Originally Posted by jtec View Post
Try this - next time it 'acts up' read the freeze frame
Here's a video of the datastream: https://photos.app.goo.gl/k8oJk3p2AuExNajD7

So after clearing the codes and letting the engine warm up, it seems to be running somewhat better. Maybe the cats and O2S' weren't warm enough last time?

In any case, it now idles and drives around the block without throwing a code, but it still shows huge amounts of fuel trim. Any thoughts on why?

Thanks!
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post #12 of 12 Old 11-30-2019, 07:04 PM Thread Starter
D-R0CK
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Update: after a bit more running, it's improved some. May have been the O2 sensor after all?

https://photos.app.goo.gl/htmjytPgRsbcHh2R7
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