2008 grand caravan misfiring, :( thoughts?

[steffen707]

Well now i'm lost.

Still only having misfiring on #2. I looked up online that looking at the engine from the front bumper, the closest, far left cylinder is #2. The plug wire running to this said #2, and on the coil pack it ran to the #2 spot. So i'm thinking i've got the right cylinder.

I changed plug and wires on 2,4,6 yesterday.
I sprayed all around the #2 cylinder intake manifold with a spray bottle. Didn't notice anything. Pulled the #2 new plug, smelled a bit like gasoline, so i'm assuming the injector is working.

Did a compression test on #2=160psi, #4=155psi, #6=158psi.

I don't know if a leakdown test is needed if you have decent compression. And i don't know if this is a thing, but i tested #2 again, 155psi. Then i went to buy beer, came back 20 minutes later, the gauge was at 153psi. So it didn't lose hardly any pressure. Is this the same as a "poor mans" leakdown test, or is this horribly not accurate and doesn't mean anything?

I should have a new coil pack tomorrow from Amazon. I'll swap that out and see. Maybe only #2 isn't working, even though its wasted spark and has 3 coils for 6 cylinders?

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[steffen707]

Here's a pic of the coil pack

 

[DMoney]

I would check the fuel injector that goes to cylinder #2. You can test this by putting the tip of a metal rod to your fuel injector then put the other tip near your ear and and listen for a clicking sound through the rod. Of you hear a clicking that means it is working.
(While the engine is running)

 

[steffen707]

I would check the fuel injector that goes to cylinder #2. You can test this by putting the tip of a metal rod to your fuel injector then put the other tip near your ear and and listen for a clicking sound through the rod. Of you hear a clicking that means it is working.
(While the engine is running)

any metal rod? I can do that. I don't own a stethoscope, but i'm guessing harbor freight has one for cheap i can buy tomorrow.

 

[DMoney]

any metal rod? I can do that. I don't own a stethoscope, but i'm guessing harbor freight has one for cheap i can buy tomorrow.

A screwdriver could even work.

 

[steffen707]

A screwdriver could even work.

yeah i should be able to tell if i compare the sound coming from injectors 4 and 6 compared to 2.

 

[DMoney]

yeah i should be able to tell if i compare the sound coming from injectors 4 and 6 compared to 2.

Yes, if you can't hear it from 4 and 6 then you are doing it wrong or need a different rod.

 

[steffen707]

Yes, if you can't hear it from 4 and 6 then you are doing it wrong or need a different rod.

AHA! I found an 18" threaded rod and the sound from 2,4,6 are all the same. YOU SAVED ME A TON OF WORK. I was looking up how to take the upper intake manifold off to get to the injector, lmao.

So, we have compression, presumably fuel, air........missing spark with new spark plug and plug wire. I'll swap plug wires and plugs with a known working cylinder next in case the new one is shot (not likely).

My new coil pack should arrive tomorrow. If that doesn't fix it.....ECU problem?

 

[DMoney]

AHA! I found an 18" threaded rod and the sound from 2,4,6 are all the same. YOU SAVED ME A TON OF WORK. I was looking up how to take the upper intake manifold off to get to the injector, lmao.

So, we have compression, presumably fuel, air........missing spark with new spark plug and plug wire. I'll swap plug wires and plugs with a known working cylinder next in case the new one is shot (not likely).

My new coil pack should arrive tomorrow. If that doesn't fix it.....ECU problem?

I'm stumped... Usually an ecu failure doesn't cause constant misfire, when it causes misfire it is USUALLY only occasionally. But then again it this could be an unusual cause. I will ask what my co-workers think on Monday.
For now unwind, drink a beer and relax and enjoy life. Stress is unhealthy.
God Bless You.

 

[steffen707]

I'm stumped... Usually an ecu failure doesn't cause constant misfire, when it causes misfire it is USUALLY only occasionally. But then again it this could be an unusual cause. I will ask what my co-workers think on Monday.
For now unwind, drink a beer and relax and enjoy life. Stress is unhealthy.
God Bless You.

Thanks for the diagnosing. I got a hockey tournament for my 5 year old tomorrow. I'll swap out the coil pack between games and report back.

 

[steffen707]

Well I don't know why only one Cylinder was misfiring from a bad coil pack, but that did the trick.

 

[DMoney]

Glad you got it taken care of. I was w/o reception this weekend and was hoping you didn't need any help. As far as why only one cylinder, I have no idea, my car has one coil per cylinder, on some I know they share a coil per 2 (looked like yours was two cylinders per could), but I actually am a diesel mechanic so I'm not very experienced in sparkplugs and etc. Although I have done some on my car.

 

[RedTRex]

Yes , I have seen that as well. Thought I saw early on you had already swapped it. For as cheap as they are, swapping plugs wires, coils is usually a good start

 

[steffen707]

Yes , I have seen that as well. Thought I saw early on you had already swapped it. For as cheap as they are, swapping plugs wires, coils is usually a good start

Yeah I swapped plugs and wires immediately, ordered a coil and got it yesterday. Problem was my buddy led me to the idea that if it was the coil, then I should have two cylinders with issues. Guess that was wrong.

Anyway fixed now and got good compression here's to the next 230,000 miles.

 

[steffen707]

With the temp hitting the 30s and new plugs, wires and coil I'm getting 50% better fuel economy! From like 13-20.5mpg all highway. Yay!

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