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In working on a 2005 Dodge Charger with the 2.7L with 105,000 miles on the clock. Car came in with a check engine light for misfire on cyl #1. Found cyl 1 spark plug and coil had oil contamination. Started repairs by replacing all 6 plugs per maintenance schedule, cyl 1 ignition coil, and valve cover gasket w/spark plug tube seals. Noticed timing chain tensioner was almost all the way out while I had the valve cover off. Also noticed a strong vacuum leak at the front of the intake manifold. Plenum was warped enough to leak around cyl 1. Replaced intake plenum seals and applied rtv to save from having to replace. After starting the vehicle again, same result with engine running great until it got up to operating temp. Misfire returned on cyl #1. Swapped fuel injector to cyl #2 and again, cyl 1 misfire came back at operating temp. Observed pulse width and noticed all values were about the same until operating temp then cyl 1,3,5 stayed around 2400 and cyl 2,4,6 dropped down to around 1800. Checked compression with engine cold and found all cyls at 175-190 with cyl 1 at 185. Any guidance for what I should check next would be great!
 

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In working on a 2005 Dodge Charger with the 2.7L with 105,000 miles on the clock. . . . .
I was attempting to find some specs on this particular vehicle - engine combination but found nothing for a 2005 Dodge Charger. Is it possibly a later model with 2.7L V6 engine? What is the VIN for the vehicle?

. . . Observed pulse width and noticed all values were about the same until operating temp then cyl 1,3,5 stayed around 2400 and cyl 2,4,6 dropped down to around 1800. . . . .
What data PID on your scan tool were you observing that gave you this difference?
 

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Welcome to Allpar. Diagnose for P0301. It could be ignition, fuel system or engine mechanical. Rule out the possible causes one-by-one so you can zoom in on the culprit.
Some RTV won't withstand gasoline or gasoline fumes and will dissolve. There are hydrocarbon-proof RTVs. If the intake manifold warp is too severe, replace it.
The bank with the misfire will show 'lean' as the raw unburned oxygen from cyl #1 will go past the O2 sensor. The PCM will try to drive that side 'rich' in order to compensate. The misfire must be solved first.
A compression test may be too quick to test for leaky valve seats while cranking or at an idle. A cylinder 'leakdown' test would be more accurate for this. A hiss out the throttle body would be intake valves and a hiss out the tailpipe would be exhaust valves.
If the lean condition from the intake manifold vacuum leak has been going on for awhile, then it is possible that the valve seats have burned.
By 2005, the 2.7L engine was a fairly good engine. If the timing chain and guides are worn, replace the water pump as well. Determine engine health as best you can. If it is too worn, especially bottom end wear, consider a reman or replacement long block.
 

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Welcome to Allpar. Diagnose for P0301. It could be ignition, fuel system or engine mechanical. Rule out the possible causes one-by-one so you can zoom in on the culprit.
Some RTV won't withstand gasoline or gasoline fumes and will dissolve. There are hydrocarbon-proof RTVs. If the intake manifold warp is too severe, replace it.
The bank with the misfire will show 'lean' as the raw unburned oxygen from cyl #1 will go past the O2 sensor. The PCM will try to drive that side 'rich' in order to compensate. The misfire must be solved first.
A compression test may be too quick to test for leaky valve seats while cranking or at an idle. A cylinder 'leakdown' test would be more accurate for this. A hiss out the throttle body would be intake valves and a hiss out the tailpipe would be exhaust valves.
If the lean condition from the intake manifold vacuum leak has been going on for awhile, then it is possible that the valve seats have burned.
By 2005, the 2.7L engine was a fairly good engine. If the timing chain and guides are worn, replace the water pump as well. Determine engine health as best you can. If it is too worn, especially bottom end wear, consider a reman or replacement long block.
I'll roll with a leak down test. The customer has approved the intake manifold replacement and by now with the plugs, coil, valve cover gaskets, and now intake, we are up to about $2000. I really would hate to get $2000 into it and find out we have a burned up valve. I'm starting to catch on to the nuances with Chrysler. I'm much more familiar with BMWs. I didn't know they would be so different with regards to your basic operation such as the difference in how the DME (BMW's PCM) controls injector flow by adjusting pulse width. I'm used to it being individually controlled vs. controls on a common fuel rail per bank. Definitely makes sense now that you have explained that. I suppose I'll put the intake manifold and plenum on. What method of leak down test do you recommend?
 

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Discussion Starter #6
I was attempting to find some specs on this particular vehicle - engine combination but found nothing for a 2005 Dodge Charger. Is it possibly a later model with 2.7L V6 engine? What is the VIN for the vehicle?



What data PID on your scan tool were you observing that gave you this difference?
I'm using Chrysler's WiTech2 and watching PCM Data injector pulse width live.
 

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I would monitor the oxygen sensors for bank 1, right or passenger side for cylinders 1 - 3 - 5 and for bank 2, left or driver side for cylinders 2 - 4 - 6. You indicate that the bank 1 injector pulse remains higher at 2400 while bank 2 injector pulse drops to a lower value of 1800. Bank 2 is moving towards a leaner air - fuel mixture while bank 2 is not moving towards a leaner air - fuel mixture and remaining rich.

Watch the signal from the bank 1 and bank 2 oxygen sensors and the short term and long term fuel trims for bank 1. I suspect that bank 2 is oscillating between rich and lean (> 0.45 volts and < 0.45 volts) and behaving as expected. Bank 1 is reporting a lean condition (< 0.45 volts) to the PCM all the time and is not oscillating. The PCM is trying to drive the bank 2 sensor to a rich condition and you will see positive long term fuel trims and possibly positive short term fuel trims instead of oscillating between rich and lean. Also check to ensure that bank 1 is going into CLOSED LOOP operation. It may be staying in OPEN LOOP. It appears bank 2 is going into CLOSED LOOP operation and reducing injector pulse width and moving towards a leaner air - fuel mixture.

So either the bank 1 oxygen sensor has failed or has a wiring problem and is tending towards sticking with a lean reporting state. Also it is possible that there is a vacuum leak in the intake manifold or an exhaust leak at the bank 1 exhaust header pipe between the engine head and bank 1 oxygen sensor.

Slowly increase the engine rpm from idle to about 2500 rpm while monitoring bank 1 oxygen sensor signal and bank 1 long term and short term fuel trims. If you have an intake manifold vacuum leak near bank 1, as you increase engine rpm the long term fuel trim and short term fuel trim will tend to move towards a more normal state (less variance from a zero value). If the oxygen sensor signal and fuel trims remain constant high positive value at higher engine rpm, then you do not have an intake vacuum leak but could have a bank 1 exhaust manifold leak.

Also check the vacuum hose from the intake manifold to the power brake booster. Remove the hose from the booster and plug it to remove a possibility of a leak in the vacuum booster causing a lean condition while you are doing your testing.
 

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As for a leak down test, I do it the poorman's way. Hold the engine at #1 TDC on the compression stroke or loosen the bank 1 rocker shafts to ensure that all the valves are fully closed.
Use an air hose adapter that screws into the spark plug hole for #1 and apply air pressure. Shop air pressure can be reduced with a regulator. Listen for a 'hiss' at the t/body (intake), tailpipe (exhaust) or crankcase (piston rings) to determine if there is a compression leak at that cylinder and what is actually leaking.
Cranking compression tests with a compression gauge are not as helpful and won't tell you what is leaking, although a wet compression test will test for piston ring sealing. The pumping action of a cranking compression test may be happening too fast to catch a possible burned valve seat.
An intake manifold vacuum leak on these engines will usually give a fast idle. A more severe vacuum leak may exceed the IACs ability to reach minimum idle and set a 'target idle not reached' fault code. The IAC may be fully closed and still have too high an idle due to air getting in elsewhere. A single manifold runner vacuum leak can make a cylinder lean and burn valves.
 

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In working on a 2005 Dodge Charger with the 2.7L with 105,000 miles on the clock. Car came in with a check engine light for misfire on cyl #1. Found cyl 1 spark plug and coil had oil contamination. Started repairs by replacing all 6 plugs per maintenance schedule, cyl 1 ignition coil, and valve cover gasket w/spark plug tube seals. Noticed timing chain tensioner was almost all the way out while I had the valve cover off. Also noticed a strong vacuum leak at the front of the intake manifold. Plenum was warped enough to leak around cyl 1. Replaced intake plenum seals and applied rtv to save from having to replace. After starting the vehicle again, same result with engine running great until it got up to operating temp. Misfire returned on cyl #1. Swapped fuel injector to cyl #2 and again, cyl 1 misfire came back at operating temp. Observed pulse width and noticed all values were about the same until operating temp then cyl 1,3,5 stayed around 2400 and cyl 2,4,6 dropped down to around 1800. Checked compression with engine cold and found all cyls at 175-190 with cyl 1 at 185. Any guidance for what I should check next would be great!
My 07 Charger has pretty much same symptoms. I've thrown everything at this thing and either the #1 misfire returns or both banks run rich.

Did you by chance replace the tensioner that you noticed was bad?

What ended up being your fix?

Thanks
 
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