2008 Dodge Caravan Cylinder 1 Misfire

[Mark72]

2008 Dodge Caravan… Over the past two years on and off I been getting a cylinder 1 misfire code. Replaced plugs and wires twice. Still doing it. Replaced the coil pack and fuel injector for cyl 1. Inspected all the wires, they are fine. Had a leak down and compression test done, its fine. Now as a last resort I’m going to replace the camshaft and crankshaft sensors!!! Uuuugh. Anyone else out there with this Make/Model/year of van with this same problem? Oh, and it has 165k on the Odometer.

 

[WobblyElvis]

When you say inspected wiring, this includes the wires to the #1 fuel injector?
An air leak in the intake manifold just near the #1 intake?
When you take out the cam/crank sensors, if you can do this with the engine in position near where #1 cylinder would normally fire, look into the engine at what passes by the sensor. Is there a clump of dirt or a missing tooth?

You haven't stated the engine.

 

[Mark72]

Oh sorry... its the 3.3L

 

[Olas]

Loom plugs are only small thin copper teeth and if a loom plug comes off and goes back on too many times, the teeth can bend and not always make a good contact.
Plus the vibration from the engine can have the circuit make and break at random intervals.

How did the plug for #1 look when you changed it? Compression test results? Leak down?

 

[JLTD]

Is it coil on plug or common igniter? Reason I ask is that I have seen a bad igniter box that gave a misfire on one cylinder. It had corrosion on the post and the misfire improved with a clean up, but the problem persisted until the box was replaced. Tried all you are trying before doing the simple repair...

 

[Mark72]

I have no clue. its a 2008 Dodge Grand Caravan SE with the 3.3L Flexfuel. But I only run regular gas in it.

 

[JLTD]

See if it has a central igniter box that all the plugs wires run to and check the terminal posts there ... the #1 may show some corrosion or buildup of some kind.

On inspection, mine looked totally fine...

 

[Superflop]

Look at the wiring harness on the drivers side where it crosses from chassis to engine where it goes under the intake. inspect those wires inside the loom for melted insulation and damaged wire.

 

[WobblyElvis]

I believe this engine has a waste spark coil system. This means most ignition problems would affect two cylinders as the "spark" take place on two wires and two plugs at the same time. This problem is more likely to be air/fuel related or engine mechanical.
Just my two cents

 

[clinebarger]

Is cylinder #1 actually misfiring? Can you feel a misfire?

Noisy components (Serpentine Belt/Idlers/Tensioner/Accessories/Wrist Pin Knock) can cause false misfire DTC's!!

Unfortunately.....Leak Down & Compression test DO NOT rule out the possibility of a mechanical issue in the engine!! I have seen Valve Guide issues cause intermittent misfire codes but will pass cranking compression & leak down testing.


As Superflop eluded to.....You can have wiring issues without specific codes to point you in the right direction! A oscilloscope is a lifesaver on stuff like this.....Scoping the Injector, Primary Ignition, CMP & CKP sensors will give you valuable data.
Dealer techs that work on these everyday know pattern failures & can usually tell you where to look......Are you a dealer tech Superflop?

 

[Chris142]

According to Identifix carbon can cause this. Its the 2nd most common thing on the list.

 

[mattd]

When does it feel like it is misfiring? On cold start up, when the engine is warm, at idle, on acceleration? Cruising speed? Need some more info

 

[Mark72]

Mainly on cold starts. I can feel the engine running rough/shuttering.

 

[Olas]

A bad coolant temp sensor could cause an over rich condition on startup

 

[Mark72]

I was reading that a bad coolant sensor always reading hot can cause this but the temp gauge is always right in the middle where it should be

 

[mattd]

I would check for an intake gasket leak. Does the engine smoke at all while it’s misfiring?

A bad coolant temp sensor would affect all cylinders not just one.

 

[Superflop]

No not a dealer tech but i have run into similar on a chrysler t&e the wires inside the loom right where it floats across from chassis to engine had melted the insulation off and was causing misfires.

If its an air leak as some have suggested you should see elevated fuel trim on that bank.

 

[mattd]

This would be correct but I doubt the op has a scanner that will read live data.