#4 misfire

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Jun 16, 2013 | 03:58 PM

JPfromClovis

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#4 misfire

Well my service engine soon light came on and my truck started running like ****. Got the code scanned at a good guys they said #4 is misfiring. I popped off both valve covers the driver side plug on the inside was loose but I did the 25 cent fix to both sided. Service engine light still on. Where to go from here?.btw I'm a new member this is my first post. Thank you for the help in advanced.

Jun 16, 2013 | 04:30 PM

Shake-N-Bake

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From: Mesa AZ

Start the engine with valve covers off and see if all injectors are discharging oil about the same way.

Jun 18, 2013 | 11:55 AM

JPfromClovis

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Ok so I did that and # 4 was not shooting any oil. I jumped the gun and replaced it. New number 4 still not shooting oil. All the wires seem fine, how can I test them

Jun 18, 2013 | 12:05 PM

cps

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From: coquitlam,BC

You can go to GB Remanufacturing web site and it will tell you how check the wiring harness of our trucks.

Jun 18, 2013 | 01:58 PM

Shake-N-Bake

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From: Mesa AZ

You replaced the injector or just the solenoid?

Here is the testing documents mentioned above

Attached Images

IDM_Module_Replacement.pdf (710.5 KB, 57 views)

Jun 18, 2013 | 05:35 PM

JPfromClovis

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I replaced the injector. So I undid the idm plug and checked the ohms and all is well except the reading for the 23 and 7 pin which of course is for the #4 injector that is misfiring. 8.9 ohms on that one. The rest all pretty much the same where they should be. What does this mean ?
Btw thanks for the link shake n bake

Jun 18, 2013 | 05:47 PM

Shake-N-Bake

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From: Mesa AZ

Quote:

Originally Posted by JPfromClovis

It means you have a fault in that circuit. Normal suspect is the solenoid but your new injector probably came with a solenoid so we will assume it's fine for now.

Here is when Rich's photo comes in super handy. (Thanks Rich!)

Open up the engine wiring harness connector on the top of the left valve cover and measure resistance between D+ and #4.

If your reading is around 2.8-3.6 ohms then your fault is somewhere between the IDM and the 42 pin connector.....most common place is where the wire bundle rubs on the valve cover.

If your reading is still high...then your fault is somewhere between the 42 pin connector and the injector. Work your way towards the injector until you find the fault.

Good luck!