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Unread 04-09-2004, 03:56 PM   #1
Roadrunr
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Injection problems?

My wife's 2000 WJ started throwing an engine code yesterday. I checked and it was P0204. Went for a short drive, shut down when I got home, started it back up and the light didnt stay on.

Today it came on again and she said the engine was 'chugging' on the highway but not all the time. I just went out and now it's coming up P0202, P0204 and P0207. I checked the list on WJJeeps.com but the description doesnt really mean much to me.

Any ideas what could be causing it? I've already had this thing in the shop for a crank position sensor and a faulty power door lock actuator.

We've only had the Jeep since last August and I'm really not looking forward to a third trip to the shop. I've had my Nissan for 7 years and I havent had it in the shop 3 times yet (though I'd like to trade it for a TJ, the way the WJ has been nickel and diming me to death I'll never be able to afford a TJ for me).

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Unread 04-09-2004, 05:49 PM   #2
Meerkat
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Note: The following procedure is based on the assumption that the fuel pressure is adequate.

1. Check all electrical connectors that are related to the system. Check the ground wire connections on the intake manifold for tightness. Loose connectors and poor grounds can cause many problems that resemble more serious malfunctions.
2 Check to see that the battery is fully charged, as the control unit and sensors depend on an accurate supply voltage in order to properly meter the fuel.
3. Check the air filter element - a dirty or partially blocked filter will severely impede performance and economy.
4. Check the related fuses (probably not required in your case). If a blown fuse is found replace it and see if it blows again. If it does, search for a grounded wire in the harness.
5. Check the condition of all vacuum hoses connected to the intake manifold.
6. Remove the air intake duct from the throttle body and check for dirt, carbon or other residue build-up. If it's dirty, clean it with carburetor cleaner spray, a shop towel and a toothbrush, if necessary.
7. With the engine running, place an automotive stethoscope against each injector, one at a time, and listen for a clicking sound, indicating operation. If you don't have a stethoscope, place the tip of a screwdriver against the injector and listen through the handle.
8. Disconnect the injector electrical connectors and measure the resistance of each injector. (Measure the resistance of each injector across the two terminals of the injector.) Resistance should be 11.3 to 15.7 ohms at 68 degrees F.
9. Turn the ignition key On and check for battery voltage at the voltage supply wire terminal of one of the injector harness connectors. If battery voltage is not present, check the ASD relay and related wiring. NOTE: The fuel injector voltage supply wire could be either dark green/black, dark green/orange, or dark green/light green depending on model. The voltage supply wire is always the same color at each injector connector while the injector control wire color is different for each injector. (Again, this is only included for the benefit of others having fuel injector problems.)
10. Install an injector test light ("noid" light) into each injector electrical connector, one at a time. Crank the engine over. Confirm that the light flashes evenly on each connector. This tests the PCM control of the injectors. If the light does not flash, have the PCM checked at a dealer service department or other properly equipped repair facility.

Having said all that, a friend of mine had similar problems with his 96 Laredo. He told me he always used the cheapest gas available. I had him switch to premium, and his problem went away quickly. Apparently his injectors were merely dirty.

HTH
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Unread 08-01-2004, 11:16 PM   #3
The Sad
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Was a solution to this problem ever reached?

My wife's 2000 started doing the same thing, with the exact same codes. And cyl 3 was just added to that list tonight.

I checked resistance on #2, and it was 13.5. Does anyone know how to fix this?
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Unread 08-03-2004, 09:08 PM   #4
The Sad
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Anyone know how to solve this problem?
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Unread 06-06-2006, 09:41 AM   #5
chipflyer
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My 2000 grand - 4.7 is now doing the same thing, any of you other guys figure this out?

Jeff
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Unread 06-06-2006, 10:25 AM   #6
greasefingers
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Injectors rarely malfunction. But coil packs do. If multiple misfires are detected then I would make sure that the ERG valve is functioning and that the vacuum lines to it are connected.

If only one cylinder is constantly misfiring then disconnect the coil pack for that cyl and see if the engine starts to run worse. If it does then the injector and coil pack are fine.
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94 Black Laredo 4-Liter with QuadraTrac (42RE trans & NP249 TC) 200,000 + miles purchased new

88 Cherokee 2-door with 5speed manual 139K miles(deceased) purchased new
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Unread 07-05-2006, 08:20 PM   #7
zaq123
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Ok folks
When I was stock in the sand the other day I got my MIL on and then it went away and no MIL light since.
However, I just decided to pull codes and codes are still there. I guess it takes 40 warm ups for them to go away.
Anyway, any idea why I got those P0203 and P0206 codes (injectors 3&6 don't respond properly to the control signal.)

Did any of you guys ever figure them out?
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Unread 07-05-2006, 08:34 PM   #8
zaq123
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could it be heat related? Is there any TSB on that or something, injector heat shield etc?
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Unread 07-05-2006, 08:40 PM   #9
greasefingers
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Someone recently(today or yesterday) posted a TSB about injector #3 needing heat shielding. It does not explain injetor #6 but it is interesting.
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94 Black Laredo 4-Liter with QuadraTrac (42RE trans & NP249 TC) 200,000 + miles purchased new

88 Cherokee 2-door with 5speed manual 139K miles(deceased) purchased new
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Unread 07-06-2006, 07:22 AM   #10
impossiblethat
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regarding 'injection problems', with engine running wiggle wiring harness to injectors and fuse box and pcm and see if missfire occurs. if problem persists and is somewhat predictable, and if the autoshutdown relay has same part number as any other relay, switch the relays and drive again. if problem goes away condemn the relay that came from the asd position
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Unread 07-06-2006, 08:15 AM   #11
greasefingers
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The codes could have been an anomaly? You should plug the #3 & #6 plugs for a visual inspection. See if they are fouling. I assume the engine runs fine and your gas mileage has not gone down?
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94 Black Laredo 4-Liter with QuadraTrac (42RE trans & NP249 TC) 200,000 + miles purchased new

88 Cherokee 2-door with 5speed manual 139K miles(deceased) purchased new
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Unread 07-06-2006, 08:21 AM   #12
greasefingers
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Quote:
Originally Posted by The Sad
Was a solution to this problem ever reached?

My wife's 2000 started doing the same thing, with the exact same codes. And cyl 3 was just added to that list tonight.

I checked resistance on #2, and it was 13.5. Does anyone know how to fix this?

The injectors are solenoids. So the resistance across the coils should all be the same for each injector. I do not know what the specific ohms should be, but they should all be the same.

Either the trigger signal from the PCM is bad, or the harness has an intermitant issue, or the soleniod valve itself is electrical unstable, or the mechanical movement of the soleniod is worn and sticking.
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Cheers Steve

94 Black Laredo 4-Liter with QuadraTrac (42RE trans & NP249 TC) 200,000 + miles purchased new

88 Cherokee 2-door with 5speed manual 139K miles(deceased) purchased new
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Unread 07-06-2006, 08:28 AM   #13
zaq123
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Quote:
Originally Posted by greasefingers
The codes could have been an anomaly? You should plug the #3 & #6 plugs for a visual inspection. See if they are fouling. I assume the engine runs fine and your gas mileage has not gone down?
Yeap, the engine runs fine. It actually first accrued right after I filled it up with gas at some gas station in NC. Literally 1 min after. I put some plus in it after and light never came back, so far anyways.
I think injectors/pcm on WJ are very heat sensitive and gas picky

Last edited by zaq123; 07-06-2006 at 09:17 AM..
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Unread 07-06-2006, 09:01 AM   #14
greasefingers
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I just got back from NC ... the Outer Banks for a week at the beach. The gas was cheaper in NC, VA, & DE than NJ

Actually this morning regular jumped to $ 2.93/gal
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94 Black Laredo 4-Liter with QuadraTrac (42RE trans & NP249 TC) 200,000 + miles purchased new

88 Cherokee 2-door with 5speed manual 139K miles(deceased) purchased new
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Unread 07-06-2006, 09:21 AM   #15
zaq123
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Quote:
Originally Posted by greasefingers
I just got back from NC ... the Outer Banks for a week at the beach. The gas was cheaper in NC, VA, & DE than NJ

Actually this morning regular jumped to $ 2.93/gal
It actually where I was. Does it look familiar http://jeepforum.com/forum/showthread.php?t=289769 ?
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