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

[BorregoV8]

Started the Borrego this morning and while starting it made a strange sound then the fun began sounded like it was running on 4 of its 8 cylinders and was shaking and bucking all the while the check engine lamp was flashing away like a beacon of distress then all of a sudden it just leveled out and everything was fine again. Looks like a trip to the dealer in order. Funny thing the day before when I started it it started just fine but let out a HUGE cloud of smoke!

 

[BorregoV8]

So They blamed it on me

Dealer said that it happened because the night before when I started the truck just to move to the other side of the driveway I didn't warm it up enough before shutting it off, hence some valve in there somewhere didn't close all the way and allowed raw fuel to leak into the cylinders all night hence flooding out the motor. They said never shut the motor off cold if it didn't run for at least 5 minutes prior. Said there were traces of fuel in the oil also and they changed that too to the tune of $38

 

[Mark_888]

Exactly what kind and viscosity of oil are you using?

 

[mikec]

"...hence some valve in there somewhere didn't close all the way and allowed raw fuel to leak into the cylinders all night hence flooding out the motor."

Ummm... what valve is "open" that allows fuel to flow with the engine off? Modern engines use fuel injectors that require electrical current to allow fuel flow; they are spring-loaded closed. With the engine OFF, there should be no fuel "leaking" into the cylinders. If there is such a mechanism on these engines, that sounds like a design screw-up to me. If raw gas is allowed to accumulate in the cylinders, while the engine is OFF, that means:
* raw gas is going to get blasted out the tailpipe next time you start. Horrible smog/emissions. And no way would that be legal.

* that raw gas is going to destroy the catalytic converters rapidly. Since they are an "emissions critical component" they have a long warranty... no way any car manufacturer will design something that risks the converters.

* if enough gas accumulates in the cylinder, the next time the engine is started it's possible it can "hydro-lock." I.e. the volume of liquid gas could be larger than the remaining volume in the cylinder when the piston is all the way up. Remember the recent pictures of the Genesis block blown apart from ingesting water? That's exactly what can happen with gas trapped in the cylinders too. Any incompressible liquid... oil, water, gas, etc.

Most modern engines have one fuel injector per cylinder, either aimed right at the intake valve ("multi-port port fuel injection") or in the cyl head injecting directly into the cylinder ("direct injection" like a diesel engine) and perhaps an additional "cold start" injector in the intake manifold. I wonder if the cold-start injector is the "valve" your dealer meant? It shouldn't "stick open" with the engine OFF. If it does, the injector is bad and needs to be replaced. Water in the gas can lead to rust buildup inside injectors, grit/dirt or other crud in the gas also leads to sticking injectors. Such injectors need to be properly cleaned or replaced.

I'd go back to the dealer and get details on this "valve" that didn't have time to close fully, and ask them to explain how gas can be "leaking" into a shut-off engine. I'll have to browse the online service manuals to see if I can see such a potential design flaw. I routinely start my car for just a few seconds to move it in/out of the garage if I want to do woodworking in the garage. My other cars I can just put the tranny in neutral and release the parking brake; they'll roll down the slight garage floor/driveway slope on their own. I can't do that with the Genesis though since the tranny won't shift out of Park unless the "ignition key" is ON so I just start it and drive it out. A few hours later I start it and back it into the garage again.

Finding gas in the oil typically means one (or more) fuel injectors have jammed open or otherwise leak. Very bad. You'll get lousy emissions, lousy MPG, wear out the catalytic converters more rapidly, etc. What's happening is all that excess gas, in one cylinder, floods that cylinder. It doesn't burn properly (too rich - too much gas, not enough oxygen) and the gas washes the cylinder walls clean of oil... and then that gas gets past the piston rings and ends up dripping into the oil pan. So the piston rings and cylinder wall can wear more rapidly. Plus gas in the oil is also dangerous for the rest of the engine: gas is almost as bad as water in the oil. The engine bearings will get clobbered by the gas. After one or two highway jaunts, I'd change the oil and filter again on this engine. A normal oil change often won't get all traces of gas out of the oil galleries, oil cooler, etc. A few oil changes (with cheap oil) is the usual recommended procedure; after a few changes use a quality oil for the final oil change.

mike c.

 

[bnajack]

This has happened to me a three times on cold start-up after sitting for 24 hours. The first time the "check engine" light was flashing and seemed like a bank of cylinders were not firing. I had it towed to the dealer. It threw an engine code that said a random mis-fire.

The second time the "check engine" light came on, but did not flash. The dealer called the tech line who said to check the fuel and it came back as bad gas.

The third time was this past weekend, but no "check engine" light came.

In every case, the engine clears up in a minute or two.

 

[BorregoV8]

This has happened to me a three times on cold start-up after sitting for 24 hours. The first time the "check engine" light was flashing and seemed like a bank of cylinders were not firing. I had it towed to the dealer. It threw an engine code that said a random mis-fire.

The second time the "check engine" light came on, but did not flash. The dealer called the tech line who said to check the fuel and it came back as bad gas.

The third time was this past weekend, but no "check engine" light came.

In every case, the engine clears up in a minute or two.

Yep EXACTLY what happened to me. Looks like Hyundai has no clue on whats causing it yet.

 

[mcginnpm]

They said never shut the motor off cold if it didn't run for at least 5 minutes prior.

That's the biggest crock I've ever heard from a dealer! If this were the case there'd be a huge safety warning in the owner's manual about it. The dealer is either incompetent or scamming you or both. Either way, your Genny is doing something it is NOT supposed to do and it needs a competent technician to look at it. Without OBDII codes, the causes of your problems could be myriad (MAF sensor, O2 sensors, vacuum leaks, EGR valve, fuel pump, injectors, pressure regulator, etc.)

Questions I'd want answered by the dealer include: How did you determine there was fuel leaking into the cylinders? Did you physically see it and, if so, where and how much? How did you determine there was fuel in the oil? Was it on the dip stick when you pulled it out or did you, on a hunch, drain some (or all of the) oil and analyze it? How do you know fuel "leaked all night into the cylinders"? (Perhaps they think liquids are compressible? A cylinder filled with more fluid in it than the cylinder volume at TDC would likely cause the engine to seize up...or blow a gasket...or bend a rod.)

 

[Mark_888]

That's the biggest crock I've ever heard from a dealer! If this were the case there'd be a huge safety warning in the owner's manual about it. The dealer is either incompetent or scamming you or both. Either way, your Genny is doing something it is NOT supposed to do and it needs a competent technician to look at it. Without OBDII codes, the causes of your problems could be myriad (MAF sensor, O2 sensors, vacuum leaks, EGR valve, fuel pump, injectors, pressure regulator, etc.)

Questions I'd want answered by the dealer include: How did you determine there was fuel leaking into the cylinders? Did you physically see it and, if so, where and how much? How did you determine there was fuel in the oil? Was it on the dip stick when you pulled it out or did you, on a hunch, drain some (or all of the) oil and analyze it? How do you know fuel "leaked all night into the cylinders"? (Perhaps they think liquids are compressible? A cylinder filled with more fluid in it than the cylinder volume at TDC would likely cause the engine to seize up...or blow a gasket...or bend a rod.)

More than likely they have gotten information that other V8's have experienced this same problem and they have been told what the cause is from HMA. Just because they did not see the fuel leaking in the cylinders does not mean they are scamming him.

If Hyundai had known about the problem when they printed the owners manual, they would have redesigned the engine so it would not happen. The V8 Tau is a new design, and there could be some things that need improvement. As we have seen, Hyundai does not like air its dirty laundry in public, so they are not going to warn people about it unless it affects everyone.

 

[mike813]

Has anyone had this again lately? I had the same symptoms several times. It's at the dealer now and they're looking in to it. The check engine light was on and according to the dealer the computer indicated misfire. 2009 4.6 with about 20k miles. Thanks!

 

[BorregoV8]

Has anyone had this again lately? I had the same symptoms several times. It's at the dealer now and they're looking in to it. The check engine light was on and according to the dealer the computer indicated misfire. 2009 4.6 with about 20k miles. Thanks!

Yes every once in a while not as bad as that first time but I will get a rough cold start with a plume of smoke. This might happen once every 3 months or so. Please let us know what your outcome was. I do still worry about it.

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[gerryb]

Holy sh$t this happened to my Genesis this morning. 16K miles and it has run great every day. Started it this morning and it was clearly not firing on all cylinders, engine light started blinking and bad smell from exhaust. Shut it down and restarted - same thing! Call the assistance number to get it towed to the dealer tonight.

 

[DesertGen]

Had this happen after doing my last oil change a week ago. Started car twice for less than a minute, then let it sit till morning. Upon startup in the AM got all the valve train noise, etc. Disconnected the batt, reset the ecu, all is well.
Thanks to this site for providing info on this in a number of posts!

 

[ASHDUMP]

This just happened to me for the first time. I shut the car off for about 10 seconds and started back up fine. The engine was jumping and the engine light was flashing. I've got 25K on the Genesis.

 

[MHT]

You can add me to the list. I exsperienced the same problem just a few days ago. The car is running fine now. I took it to the dealer and you pretty much know what happened. The problem could not be duplicated and everything checked out ok , no fail codes in the data base.
I wonder if we will see a recall in the future for the bad engine start, tilt telescopic steering problem and map update? All cars have their share of problems so I am not overly concerned but Hyundai needs to get a handle on this if they want to be a contender in the market they are entering with the Genesis and Equus.

 

[abenc]

Holy sh$t this happened to my Genesis this morning. 16K miles and it has run great every day. Started it this morning and it was clearly not firing on all cylinders, engine light started blinking and bad smell from exhaust. Shut it down and restarted - same thing! Call the assistance number to get it towed to the dealer tonight.

Notice decreased performance/power and bit noiser engine couple of weeks ago (with onset of cold weather) but thought it was my imagination.

Yesterday rapid banging noise from engine and check engine light constantly on. No bad exhaust, no shaking of body. Turning on/off did not help. Got car towed to dealer, was told computer "registered misfires". Dealer upgrading "engine computer software".

 

[gerryb]

Notice decreased performance/power and bit noiser engine couple of weeks ago (with onset of cold weather) but thought it was my imagination.

Yesterday rapid banging noise from engine and check engine light constantly on. No bad exhaust, no shaking of body. Turning on/off did not help. Got car towed to dealer, was told computer "registered misfires". Dealer upgrading "engine computer software".

Got mine back yesterday. Dealer essentially said the same thing. "there's a campaign for this problem that Hyundai set-up - requires reflashing the ECM."

 

[homeofstone]

Just wandering if anyone with this cold start problem has ever jumped another car off or had their car jumped off (boosted with jumper cables)?
Some ecm's can be sensitive.

 

[DesertGen]

Never gave a jump here

 

[gerryb]

No jump here either. I have a portable battery pack/air compressor for that when needed. Great thing to have around the garage, esp with winter coming.

 

[Akin67]

Is this problem only occurring on the V8's or V6 as well?