HELP. Muliple Misfires.

Bwill

New member
6
0
1
Genesis Model Type
1G Genesis Sedan (2009-2014)
2011 Genesis 4.6. My car has 123xxx miles on it and has always been maintained well. Thursday, car was running fine. Drove 35 miles from work to the gas station. Ran inside and when I came back out and started my vehicle, the engine was shaking, rough idle and CEL was flashing. Had my buddy come over for a tow and he hooked up obdII scanner. Trouble codes p0302 p0304 p0306 and p0308 p0300. Multiple misfires and random misfire. Dealer called Friday and said I needed a new motor and they suspected bent valves. They said they "monitored some data" to come to conclusion. I requested a compression and leakdown test to make sure and waiting on results. Anyone have a similar issue and what was the outcome?
 
Last edited:

jazzie366

New member
14
1
3
Genesis Model Type
1G Genesis Sedan (2009-2014)
2011 Genesis 4.6. My car has 123xxx miles on it and has always been maintained well. Thursday, car was running fine. Drove 35 miles from work to the gas station. Ran inside and when I came back out and started my vehicle, the engine was shaking, rough idle and CEL was flashing. Had my buddy come over for a tow and he hooked up obdII scanner. Trouble codes p0302 p0304 p0306 and p0308 p0300. Multiple misfires and random misfire. Dealer called Friday and said I needed a new motor and they suspected bent valves. They said they "monitored some data" to come to conclusion. I requested a compression and leakdown test to make sure and waiting on results. Anyone have a similar issue and what was the outcome?

I just bought this exact car, never seen this issue in any of the research I did. Definitely get those results and see if it's actually a timing issue. I've never seen it with these cars though, however my experience is limited.
 

Bwill

New member
6
0
1
Genesis Model Type
1G Genesis Sedan (2009-2014)
Compression test results
Drivers side:
110
115
115
110
Pass side:
90 on all cylinders
 

jazzie366

New member
14
1
3
Genesis Model Type
1G Genesis Sedan (2009-2014)
Compression test results
Drivers side:
110
115
115
110
Pass side:
90 on all cylinders
That’s extremely low on the passenger side, specification is 128PSI minimum, typical being 150PSI. However, this gives me a bit of hope that the engine isn't ruined, but more likely that the timing chain has jumped time and a timing set should be installed. Normally, when you lose timing, it's catastrophic, valves hit the piston, you lose all compression and the engine is ruined. However, you still have decent compression on some of the cylinders. This gives me hope that you had tensioner failure, which just let the timing move out of adjustment, the chain may not even be bad. Don't run it anymore. I would have a shop remove the timing cover on the engine, it doesn't cost a lot to have them do this. The entire timing job pays 6.8 hours of labor. A typical repair shop costs $75-100 for labor, so maximum of $700 for a chain to be replaced. Also, it's VERY unlikely only one side skipped timing without there being some sort of other issue at play, the reason I say this is because this engine has 3 timing chains, one for the right side, one for the left, and the other for the oil pump, for both cylinder banks to skip that means what has likely happened is the crankshaft sprocket has slipped. This would cause both to go out at once. If I'm not mistaken they probably use a woodruff key to hold this sprocket in place, these tend to snap if they're manufactured incorrectly, or just bad luck.

Now, here's what I would do if I were you:

Take it to a mechanic and have them check the timing. General rule of thumb: Not over 5 teeth out of time and you're safe to attempt a timing job with decent certainty that it will fix it, even on an interference engine. Now, do me a favor if you can, go out to the car and check the ENG SNSR-2 fuse. This controls the variable valve timing. With no VVT actuation, the car will run like shit and be very near totally out of time, this would usually set a code, but you never know. On a Mazda CX-7, the ENG BAR 2 fuse will blow and won't throw any related codes, and it will take the PCM with it, fun times.

Anyways, I digress, have the timing checked, if it's off, but not by much, put a timing set in it. If it's off by a lot, used engine time. Check the fuse before anything though!
______________________________
 

Bwill

New member
6
0
1
Genesis Model Type
1G Genesis Sedan (2009-2014)
That’s extremely low on the passenger side, specification is 128PSI minimum, typical being 150PSI. However, this gives me a bit of hope that the engine isn't ruined, but more likely that the timing chain has jumped time and a timing set should be installed. Normally, when you lose timing, it's catastrophic, valves hit the piston, you lose all compression and the engine is ruined. However, you still have decent compression on some of the cylinders. This gives me hope that you had tensioner failure, which just let the timing move out of adjustment, the chain may not even be bad. Don't run it anymore. I would have a shop remove the timing cover on the engine, it doesn't cost a lot to have them do this. The entire timing job pays 6.8 hours of labor. A typical repair shop costs $75-100 for labor, so maximum of $700 for a chain to be replaced. Also, it's VERY unlikely only one side skipped timing without there being some sort of other issue at play, the reason I say this is because this engine has 3 timing chains, one for the right side, one for the left, and the other for the oil pump, for both cylinder banks to skip that means what has likely happened is the crankshaft sprocket has slipped. This would cause both to go out at once. If I'm not mistaken they probably use a woodruff key to hold this sprocket in place, these tend to snap if they're manufactured incorrectly, or just bad luck.

Now, here's what I would do if I were you:

Take it to a mechanic and have them check the timing. General rule of thumb: Not over 5 teeth out of time and you're safe to attempt a timing job with decent certainty that it will fix it, even on an interference engine. Now, do me a favor if you can, go out to the car and check the ENG SNSR-2 fuse. This controls the variable valve timing. With no VVT actuation, the car will run like shit and be very near totally out of time, this would usually set a code, but you never know. On a Mazda CX-7, the ENG BAR 2 fuse will blow and won't throw any related codes, and it will take the PCM with it, fun times.

Anyways, I digress, have the timing checked, if it's off, but not by much, put a timing set in it. If it's off by a lot, used engine time. Check the fuse before anything though!

Thanks Jazzie. Car is at the dealer now so I can't check the fuse but I will do that. I'll probably take it to a different shop for the timing check as the dealer is charging $165/hr labor. Dealer told me my only option was a used/new motor and quoted me a used motor with 95k miles @ $8,800.
 

Bwill

New member
6
0
1
Genesis Model Type
1G Genesis Sedan (2009-2014)
That’s extremely low on the passenger side, specification is 128PSI minimum, typical being 150PSI. However, this gives me a bit of hope that the engine isn't ruined, but more likely that the timing chain has jumped time and a timing set should be installed. Normally, when you lose timing, it's catastrophic, valves hit the piston, you lose all compression and the engine is ruined. However, you still have decent compression on some of the cylinders. This gives me hope that you had tensioner failure, which just let the timing move out of adjustment, the chain may not even be bad. Don't run it anymore. I would have a shop remove the timing cover on the engine, it doesn't cost a lot to have them do this. The entire timing job pays 6.8 hours of labor. A typical repair shop costs $75-100 for labor, so maximum of $700 for a chain to be replaced. Also, it's VERY unlikely only one side skipped timing without there being some sort of other issue at play, the reason I say this is because this engine has 3 timing chains, one for the right side, one for the left, and the other for the oil pump, for both cylinder banks to skip that means what has likely happened is the crankshaft sprocket has slipped. This would cause both to go out at once. If I'm not mistaken they probably use a woodruff key to hold this sprocket in place, these tend to snap if they're manufactured incorrectly, or just bad luck.

Now, here's what I would do if I were you:

Take it to a mechanic and have them check the timing. General rule of thumb: Not over 5 teeth out of time and you're safe to attempt a timing job with decent certainty that it will fix it, even on an interference engine. Now, do me a favor if you can, go out to the car and check the ENG SNSR-2 fuse. This controls the variable valve timing. With no VVT actuation, the car will run like shit and be very near totally out of time, this would usually set a code, but you never know. On a Mazda CX-7, the ENG BAR 2 fuse will blow and won't throw any related codes, and it will take the PCM with it, fun times.

Anyways, I digress, have the timing checked, if it's off, but not by much, put a timing set in it. If it's off by a lot, used engine time. Check the fuse before anything though!

Jazzie are you a mechanic somewhere? You seem to have a lot of knowledge.
 

jazzie366

New member
14
1
3
Genesis Model Type
1G Genesis Sedan (2009-2014)
Jazzie are you a mechanic somewhere? You seem to have a lot of knowledge.
Full time master mechanic. I can answer any questions you have. I may not know everything, but JDM/KDM cars are my SHIT. Can't stand American cars. Euros are too flashy and don't provide the quality that Asian cars do.

Edit: they're out of their minds with that engine quote: LKQOnline

$3000 shipped, 67k miles. Should be about 1200-1500 in labor and fluids to install at a reputable shop.
 

Bwill

New member
6
0
1
Genesis Model Type
1G Genesis Sedan (2009-2014)
Full time master mechanic. I can answer any questions you have. I may not know everything, but JDM/KDM cars are my SHIT. Can't stand American cars. Euros are too flashy and don't provide the quality that Asian cars do.

Edit: they're out of their minds with that engine quote: LKQOnline

$3000 shipped, 67k miles. Should be about 1200-1500 in labor and fluids to install at a reputable shop.
You rock. Appreciate all the help.
______________________________
 

air540g

Registered Member
48
23
8
Genesis Model Type
1G Genesis Sedan (2009-2014)
Try to add some fuel additive to your fuel tank.

sometimes the moisture in the fuel makes engine runs poor.
 

jazzie366

New member
14
1
3
Genesis Model Type
1G Genesis Sedan (2009-2014)
Try to add some fuel additive to your fuel tank.

sometimes the moisture in the fuel makes engine runs poor.
The 40PSI below compression spec is what's making it run poor, trust us, not the fuel.
______________________________
 

air540g

Registered Member
48
23
8
Genesis Model Type
1G Genesis Sedan (2009-2014)
It is very easy. If you have DIY ability, you can do it by yourself without any risk.

1) check engine inside surface.
remove intake manifold and spark. use endoscope to check engine inside surface. if you can find scratches on surface, then buy a sencond-hand engine is more cheaper than rebuild it. see pic1

If engine inside surface is ok, then check timing.
remove valve cover, you can see the timing chain. check the timing is ok or not. see pic2

if timing is wrong, just go to shop to change timing chain and chain tensioner.
 

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