Help With 2012 5.7 Ram 1500 - Cylinder Misfire

[Mrbutt]

Hi All,
I was hoping for some assistance.

Im in the UK and have a 2012 Ram 1500 5.7l Hemi but have been struggling with an issue for over a year now.
The Engine Management light is on with a fault of multiple cylinder misfires amongst other codes for single cylinders reporting misfires.

Looking at recent invoices, we have changed;
Valve Spring
Valve Spring Retainer Keeper
Valve Cover Gasket
Rocker Arm
Push Rod
Cylinder Deactivation Solenoid

Its still got he issue.

Is next step changing the ECU?

Any help is appreciated, I'm not a mechanic and there aren't many specialist in the UK near me.

 

[Burla]

Did you record all of the codes of so post them

how many specific cylinders codes did you get?

 

[Mrbutt]

I will rescan it and take a picture of the fault codes, its the best way to be sure.

Will post back in a couple of days.

 

[Mrbutt]

Right, we re-scanned it and its just code P0308 Cylinder 8 Misfire

Does this help?

Any advice?

 

[Ken226]

Why were the valve springs, push rods and retainers replaced? Were only the cylinder 8 springs, push rods and retainers replaced? Or all of them?

If the cylinder 8 springs, push rods and retainers were replaced due to a broken valve spring, was a compression test and a leak down test and done to verify that it didn't bend a valve in #8? Because a broken valve spring very commonly let's the valve impact the piston.

It sounds like a compression test and leak down test on #8 should be done.


On the other hand, if the above mentioned parts were replaced in an attempt to solve the same misfire symptom you are currently asking about, then it's time to pull and check the VVT oil control solenoid for metal, and check the rockers for full range of motion, and read through Ed's cam replacement thread.

 

[Mrbutt]

Why were the valve springs, push rods and retainers replaced? Were only the cylinder 8 springs, push rods and retainers replaced? Or all of them?

If the cylinder 8 springs, push rods and retainers were replaced due to a broken valve spring, was a compression test and a leak down test and done to verify that it didn't bend a valve in #8? Because a broken valve spring very commonly let's the valve impact the piston.

It sounds like a compression test and leak down test on #8 should be done.


On the other hand, if the above mentioned parts were replaced in an attempt to solve the same misfire symptom you are currently asking about, then it's time to pull and check the VVT oil control solenoid for metal, and check the rockers for full range of motion, and read through Ed's cam replacement thread.

The valve springs, push rods and retainers etc were replaced simply in an attempt to resolve this same issue.

We have done a pressure test and its come back fine.

We have also replaced the Cylinder Deactivation Solenoid.

(Im not a mechanic and not sure if we have done this above) Do we still have to check the VVT oil control solenoid for metal?

Thanks for the help

 

[Ken226]

The valve springs, push rods and retainers etc were replaced simply in an attempt to resolve this same issue.

We have done a pressure test and its come back fine.

We have also replaced the Cylinder Deactivation Solenoid.

(Im not a mechanic and not sure if we have done this above) Do we still have to check the VVT oil control solenoid for metal?

Thanks for the help

When a lifter fails and wipes the cam, one of the first places for metal debris from the wiped cam to accumulate is the screen on VVT oil control valve. It's definitive.

@EdGs has a little, but not bad.

Post in thread 'Do I have a lifter going out? YES, I DO!!!!!!' https://www.ramforum.com/threads/do-i-have-a-lifter-going-out-yes-i-do.218028/post-3014533

The cylinder deactivation solenoid is a different part.

VVT oil control is bottom center, with the tan/white connector

 

[EdGs]

If your misfire was #8 also before the repairs were done, then replacing an MDS solenoid would have no effect as the MDS solenids are for cylinders 1, 4, 6, and 7.

While I had very little metal on my VVT oil control valve, I had a good bit of wear on one camshaft lobe. I just got lucky that those metal shavings didn't get circulated heavy through my engine.

 

[Mrbutt]

It’s always been cylinder 8, before and after the attempts to repair.

I will speak to the mechanic doing the work (name is Ed too) and see if he recalls any metal on the camshaft or anywhere and if we can check the VVT Valve.

Do you think it maybe the Cams?

To rule things out, is it definitely not an ECU issue?

 

[EdGs]

@Mrbutt, What codes did you have prior to and after the repair?

Have you examined the spark plugs for #8 cylinder?

You could swap coil pack from #8 with another cylinder, and if the problem follows the swap, bad coil pack.

Same for fuel injector on number 8 cylinder.

Have you verified movement of #8 valves compared to other cylinders?

Do you have any tick?

 

[Mrbutt]

@Mrbutt, What codes did you have prior to and after the repair?

Have you examined the spark plugs for #8 cylinder?

You could swap coil pack from #8 with another cylinder, and if the problem follows the swap, bad coil pack.

Same for fuel injector on number 8 cylinder.

Have you verified movement of #8 valves compared to other cylinders?

Do you have any tick?

It’s same code before and after.
It clears when we reset it, the misfire goes and then about 10mins later it all comes back.

There’s no tick noise. Movement on valves is fine too.

We’ve done the spark plugs and coil packs.

Injector has not been done yet though.

What do you think are the best steps to move forward? Doing the injector?
The auto electrician seems to think ecu replacement may be the next step?

 

[GeauxinUp]

Like Ed said, it's hard to know what to recommend without knowing what diagnostic steps were taken before the parts cannon got thrown at it.

Tried swapping spark plugs, coil pack, injector to another cylinder to see if trouble follows??

 

[Ken226]

Injector has not been done yet though.

What do you think are the best steps to move forward? Doing the injector?

Yes. Get the low hanging fruit before you drag out the ladder.

 

[EdGs]

It’s same code before and after.
It clears when we reset it, the misfire goes and then about 10mins later it all comes back.

There’s no tick noise. Movement on valves is fine too.

We’ve done the spark plugs and coil packs.

Injector has not been done yet though.

What do you think are the best steps to move forward? Doing the injector?
The auto electrician seems to think ecu replacement may be the next step?

Injector would certainly be the easiest.

 

[Mrbutt]

Thanks everyone.

Once we try the injector, if that doesn't resolve the issue, what comes next?

I was thinking it may be an MDS delete, however its the wrong cylinder for that.

Is it ever the ECU? If so, can someone advise how we sort this from UK?
There isn't anyone I know of here that can supply or rectify it.

 

[Ken226]

Is it ever the ECU?

Yes, but not common and very easy to test.

Use a 4 channel oscilloscope. Put 1 on #8 injector, and 2 on one of the others. 3 on #8 coil and 4 on another coil.

Compare the waveform of #8 injector driver with a good injector driver. Compare #8 coil driver with a known good coil driver.

If the mosfet that drives #8 injector is bad, or the mosfet that drives #8 coil is bad, it'll be obvious.



But,

First swap #8 injector with another one and see if the misfire follows the injector to the new cylinder, orr if it stays home. If it stays, then the problem is either the wiring or the PCM.

Load test the wire circuit integrity with a test light that draws several amps, and wiggle the harness around while the light is illuminated to reveal bad connections. If the wires are good, check the PCM connectors for loose pins on the #8 coil and injector driver wires.

After those tests are done, then you can worry about the oscilloscope.

 

[Mrbutt]

That's an excellent post. We will try this and see how we get on. Very helpful.

So if the injectors are fine, we test the circuit, then ECU/PCM

Thanks again

 

[Ken226]

So if the injectors are fine, we test the circuit, then ECU/PCM

Thanks again

If the injector is fine, test the circuit.

A noid light is cheap and handy, and will show if the signal from the PCM is making it to the injector.

How To Test Fuel Injectors with a Noid Light TUTORIAL

In this how to tutorial I show you how to use a noid light to troubleshoot and test your fuel injectors.

youtu.be

If the noid light doesn't flash, check the circuit with a multimeter.

If the circuit is fine, check the connectors. Get the right size pin and drag test the female terminals inside the connectors.

Is Your Mercedes Connector Wired Correctly? Check This Now

Mike here, with an electrical diagnostic tip focusing on a Mercedes-Benz connector that had a broken wire from a previous car repair. This do it yourself gui...

youtu.be

If the noid light doesn't flash, that means injector 8 isn't firing and 1-7 is, and if the connectors/circuit test good, then yea, probly has a dead driver mosfet and need a new PCM.

 

[Adamcr68]

Yes. Get the low hanging fruit before you drag out the ladder.

First time the I heard the”before you drag out the ladder” part.
I like it, I have heard “get the low hanging fruit first” plenty of times but dragging out a ladder adds a better mental picture to it.

 

[Mrbutt]

If the injector is fine, test the circuit.

A noid light is cheap and handy, and will show if the signal from the PCM is making it to the injector.

How To Test Fuel Injectors with a Noid Light TUTORIAL

In this how to tutorial I show you how to use a noid light to troubleshoot and test your fuel injectors.

youtu.be

If the noid light doesn't flash, check the circuit with a multimeter.

If the circuit is fine, check the connectors. Get the right size pin and drag test the female terminals inside the connectors.

Is Your Mercedes Connector Wired Correctly? Check This Now

Mike here, with an electrical diagnostic tip focusing on a Mercedes-Benz connector that had a broken wire from a previous car repair. This do it yourself gui...

youtu.be

If the noid light doesn't flash, that means injector 8 isn't firing and 1-7 is, and if the connectors/circuit test good, then yea, probly has a dead driver mosfet and need a new PCM.

Good explanation, we will work through these and let ou know how we get on