Got The Cold Start Shake Rattle And Roll This Morning YEIKS!

[Gunkk]

Tech at the local dealer said that three key turns will clear a code after the engine light goes off.

Found this interesting article about possible stuck Oil Control Valve as a contributing factor to the cold start shake-rattle-roll:

http://www.autoserviceprofessional.com/article/91744/Hyundai-CVVT-oil-control-valve

 

[bluegen10]

Hello all,

First of all I would like to appologize for reviving a dead post.

Second, I will be picking up my 2010 4.6 on Monday (20 May) and after reading this thread I am a little worried. Does anyone have any further information about this problem? Seeing as how the vehicle is used I am unsure if this car has ever had this problem and if so what was done about it. I do have the CARFAX and it states that the ECU has been replaced as of January 2013 so it should have all the latest updates and TSBs, should this fix the problem or is it just the band-aid. Laslty, would it be cosher to take it to the local dealer and ask them to check to see if all the latest TSBs have been applied and in the process ask them to run a compression test to make sure there is no problems that might have been caused?

Thank You

 

[StangKiller]

Hello all,

First of all I would like to appologize for reviving a dead post.

Second, I will be picking up my 2010 4.6 on Monday (20 May) and after reading this thread I am a little worried. Does anyone have any further information about this problem? Seeing as how the vehicle is used I am unsure if this car has ever had this problem and if so what was done about it. I do have the CARFAX and it states that the ECU has been replaced as of January 2013 so it should have all the latest updates and TSBs, should this fix the problem or is it just the band-aid. Laslty, would it be cosher to take it to the local dealer and ask them to check to see if all the latest TSBs have been applied and in the process ask them to run a compression test to make sure there is no problems that might have been caused?

Thank You

Call Hyundai and give them your VIN. In return, they can give you a complete service history which would include anything from oil changes to major repairs.

 

[frankv64]

Just happened to my 2012 5.0 with 20k miles. I started it in the garage as usual it started shaking the check engine light started flashing then it smoothed out 30 seconds later and check engine light went out

 

[kcgr]

I have had this on occasion. Usually after pulling the car out into the driveway, washing then pulling back in. The next morning I get the shudders. The way I've fixed this is to drive around the block after the wash, or let the car run idle for a min or two. After sitting, it doesn't like to have a 30 second run, then sit overnight then start again.

 

[CapoCriminali]

This recently happened to my 2010 4.6 w/110k miles. I didn't catch this thread in time and drove it out of my terribad garage (4" of horizontal clearance, a total height of just over 6', and a 90 degree turn on a 30 degree incline, ) and the knock persisted through 2 starts (<5m) and a tow.

When I picked it up from the mechanic who confirmed it was "rod knock" - it had stopped making the noise. Mechanic called it a "grenade" but curious if people here think differently based on everything indicating it was the problem from this post. Is the car still alright? Should I pay someone (not my mechanic, a Hyundai expert?) to rip the engine apart and validate before putting my trust in it again?

I'd welcome anyone's input here. Thanks in advance.

(Edit: hope necroing the thread was alright)

 

[MrBrady]

My 2014 5.0 did this about a week ago and has done it a few times in the past as well. It happened after a very cold, short move of the car - moving it from the driveway to the street, then the next day starting the car to drive somewhere. It shuttered and bucked, CEL flashed, then stayed on. Ran a scan tool and it said it was a misfire. AutoZone's diagnostic tool said it's likely either spark plugs or coil packs, but from what it sounds like in this thread, it's cold, very short on-off engine use?

Anyway, the misfiring went away after letting the car run for a few minutes and a gentle drive around the block. Then reset the CEL with the scan tool. No problems since.

 

[Gunkk]

My working theory is that the ECU goes temporarily insane and shuts off or changes the timing on one or more coils, causing the misfire. Had this a few times in both my cars over the years. Sometimes an immediate restart fixes it. Sometimes I have to let the car sit 20mins to go back to sleep and try and wake up on the right side of the bed next time. And sometimes I just have to let the car rough-idle for a couple minutes to get some heat into it, shut it off, then restart and it works just fine once its warm. No rhyme or reason. Just temporary insanity like a hot girlfriend. All this happens WITHOUT a flashing CEL. Hence the insanity, as a sane ECU would flash the money light.

 

[MrBrady]

My working theory is that the ECU goes temporarily insane and shuts off or changes the timing on one or more coils, causing the misfire. Had this a few times in both my cars over the years. Sometimes an immediate restart fixes it. Sometimes I have to let the car sit 20mins to go back to sleep and try and wake up on the right side of the bed next time. And sometimes I just have to let the car rough-idle for a couple minutes to get some heat into it, shut it off, then restart and it works just fine once its warm. No rhyme or reason. Just temporary insanity like a hot girlfriend. All this happens WITHOUT a flashing CEL. Hence the insanity, as a sane ECU would flash the money light.

OMG that video . At this point, I think my Genesis is probably marriage material or a dude, not quite sure yet.

 

[joegr]

My working theory is that the ECU goes temporarily insane and shuts off or changes the timing on one or more coils, causing the misfire. Had this a few times in both my cars over the years. Sometimes an immediate restart fixes it. Sometimes I have to let the car sit 20mins to go back to sleep and try and wake up on the right side of the bed next time. And sometimes I just have to let the car rough-idle for a couple minutes to get some heat into it, shut it off, then restart and it works just fine once its warm. No rhyme or reason. Just temporary insanity like a hot girlfriend. All this happens WITHOUT a flashing CEL. Hence the insanity, as a sane ECU would flash the money light.

Here is what I have heard, with some evidence to support it.
On cold start (most any engine), the mixture is made richer than normal due to the fact that some fuel will condense on the cold surfaces of the cylinder, head, and piston. If you shut the engine down before it really warms up at all, some fuel will still be sitting in the cylinders. If later, after it is completely cold again, you go to restart it, it will be in enriched mixture mode again. The combination of this and of the fuel left in the cylinders from before causes it to flood on at least one cylinder, maybe more. The flood on the cylinder(s) causes a misfire which is detected. This causes the PCM to shut down fuel to that(those) cylinder(s). This condition is locked in until you shutdown and restart, or in some cases the PCM may try again in a few minutes on its own. AFAIK, this applies to most fuel injected cars.

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[CapoCriminali]

Here is what I have heard, with some evidence to support it.
On cold start (most any engine), the mixture is made richer than normal due to the fact that some fuel will condense on the cold surfaces of the cylinder, head, and piston. If you shut the engine down before it really warms up at all, some fuel will still be sitting in the cylinders. If later, after it is completely cold again, you go to restart it, it will be in enriched mixture mode again. The combination of this and of the fuel left in the cylinders from before causes it to flood on at least one cylinder, maybe more. The flood on the cylinder(s) causes a misfire which is detected. This causes the PCM to shut down fuel to that(those) cylinder(s). This condition is locked in until you shutdown and restart, or in some cases the PCM may try again in a few minutes on its own. AFAIK, this applies to most fuel injected cars.

I'd be curious to match the cylinders that misfired/shutdown - that'd help solidify your thoughts on the fact that it's flooding on some, maybe? I had codes:

P0300 - Random/Multiple Cyldiner Misfire Detected
P0308 - Cylinder 8 Misfire Detected
P0304 - Cylinder 4 Misfire Detected
P0307 - Cylinder 7 Misfire Detected
P0301 - Cylinder 1 Misfire Detected

What scares me is my local mechanic heard it while it was happening and called the engine "a grenade" b/c "that's rod knock, it could die now, it could die in some miles, who knows"... and then when I picked it up, it wasn't making the sound anymore and they didn't really know what to make of that.

I'm at the point that I already "replaced" the Genesis as our daily driver. Now I'm just trying to determine how bad this was for the motor so I can decide if we sell, keep, or gift to parents. Anyone think I'd be nuts for the last 2?

 

[joegr]

I'd be curious to match the cylinders that misfired/shutdown - that'd help solidify your thoughts on the fact that it's flooding on some, maybe? I had codes:
...

In the case of what I was describing, the misfiring cylinders would seem random. I was describing the more generic issue of occasional hard start/rough running when starting after a very short prior run. Unfortunately, I'm not convinced that this is the problem that you experienced.

 

[CapoCriminali]

In the case of what I was describing, the misfiring cylinders would seem random. I was describing the more generic issue of occasional hard start/rough running when starting after a very short prior run. Unfortunately, I'm not convinced that this is the problem that you experienced.

So - we started the car up, backed the car up ~6 feet then shut it off. We were moving something in front of it and adjusting the fit (small space in the garage). About 5m later, we started it back up and drove it the 6 feet forward and stopped it.

It sat for 2 days like that, then we tried to go out and got the check engine light flashing, the codes listed above, a puff of smoke (too dark in our basement garage to tell the color, but not thick) and the knocking sound. We shut it off right away, and stupidly, tried starting it twice more over the next 2 days. Finally 4 days later, we just drove it out (no tow truck could get us) and had it towed to the mechanic. Mechanic started it to pull it off the flatbed, and heard the sound and said it was probably rod knock based on the sound, but they'd take it and look at it. Without tearing down the engine, they said it was rod knock, but when we picked it up, it wasn't making the noise any longer. That trip home (~20m, local roads) it was fine. We haven't had a chance to start or drive it since, though I'm not sure how comfortable I am.

Hope that helps explain and maybe shed some light. I feel like a bit of an idiot if it was just this issue and the motor is fine. :\

 

[joegr]

I've never heard of cold-restart flooding going on like that, not for days. I think you have something else. In the best case, it could have been a stuck open injector or some electrical problem with the same result. It does seem unlikely that a mechanical problem inside the engine would manifest like that and then go away on its own.

 

[Gunkk]

Yeah flooded cylinder lockout makes a lot of sense!

The only "temporary mechanical thing" I can think of is something like VVT oil control going goofy, but I wouldn't expect that to trigger a misfire.