In chilly wet weather engine turns over but doesn't start.

[chip williams]

2010 Genesis, V8 4.6L, 80K miles, new battery, good gas. Original plugs, ignition wires, fuel filter and brake sensor. When I try to start the car in the rain on cold days (45 F) with button starter she keeps turning over but doesn't start. After three or four tries she usually starts. Sometimes runs a little rough. Never a problem on dry or warm days. Dealer hasn't a clue but I have not paid for a diagnostic. Anyone have this problem or an idea why the difficult starting? Will a diagnostic find the problem?

 

[Chad86tsi]

One possibility: Fuel pressure leaking back in to tank.

Fuel systems have check valves that let the fuel travel one way, to the engine, and prevent it from flowing back into the tank when the engine is shut off. If the valve fails, there is no longer any pressure in the line, and it takes 2-6 seconds for pressure to build to the minimum for the injector to function properly. Long enough for most to give up and stop cranking.

This can be confirmed with a fuel pressure tester on the fuel line after the pump. Run the car, verify pressure, then shut off. It will settle a little, but should not move at all for at least 24 hours. A car should hold nearly full pressure several days minimum, some will hold for weeks. If it drops off even 1/2 way, it will lead to hard starts. Most cars that I've seen this in leaked down over about 6 hours, so a trip to the store, it still had enough pressure to start in the parking lot, but overnight it was all leaked down.

You can confirm this by getting it to start and run successfully and then shutting down immediately after you confirm its running right, leaving everything still still stone cold. If it then starts back up perfectly on first crank, you know it was fuel pressure leak down.

On older cars with keyed ignitions, the simple work around was to put the key to "on" but not start the car. This would cause the pump to "prime" in anticipation of a start. If you waited 2-6 seconds and then tried to start, it was up to pressure by then and started fine. Others required you to also step on the brake, or to turn past "on" but just before "start" to initiate the prime. You could hear the pump in older cars with little sound deadening so you know what to do. I have No idea how to prime the system in these cars, and it may not even be possible, requiring repairs of the faulty valve.

 

[EdP]

2010 Genesis, V8 4.6L, 80K miles, new battery, good gas. Original plugs, ignition wires, fuel filter and brake sensor. When I try to start the car in the rain on cold days (45 F) with button starter she keeps turning over but doesn't start. After three or four tries she usually starts. Sometimes runs a little rough. Never a problem on dry or warm days. Dealer hasn't a clue but I have not paid for a diagnostic. Anyone have this problem or an idea why the difficult starting? Will a diagnostic find the problem?

In theory, most plugs are good for 100k or more so they should not be a problem. Back in the old days with distributor caps and plug wires you could stick your head under a dark hood at night and see the sparks jumping from wire to ground, especially on a rainy night. The setup today is more sophisticated, but you can still have electrical leakage. I don't know if a diagnostic will find it but chances are, it would when cold and raining. You'd have to leave it at the dealer on a cold rainy night for that.

 

[Gunkk]

Check the coils.

 

[chip williams]

One possibility: Fuel pressure leaking back in to tank.

Fuel systems have check valves that let the fuel travel one way, to the engine, and prevent it from flowing back into the tank when the engine is shut off. If the valve fails, there is no longer any pressure in the line, and it takes 2-6 seconds for pressure to build to the minimum for the injector to function properly. Long enough for most to give up and stop cranking.

This can be confirmed with a fuel pressure tester on the fuel line after the pump. Run the car, verify pressure, then shut off. It will settle a little, but should not move at all for at least 24 hours. A car should hold nearly full pressure several days minimum, some will hold for weeks. If it drops off even 1/2 way, it will lead to hard starts. Most cars that I've seen this in leaked down over about 6 hours, so a trip to the store, it still had enough pressure to start in the parking lot, but overnight it was all leaked down.

You can confirm this by getting it to start and run successfully and then shutting down immediately after you confirm its running right, leaving everything still still stone cold. If it then starts back up perfectly on first crank, you know it was fuel pressure leak down.

On older cars with keyed ignitions, the simple work around was to put the key to "on" but not start the car. This would cause the pump to "prime" in anticipation of a start. If you waited 2-6 seconds and then tried to start, it was up to pressure by then and started fine. Others required you to also step on the brake, or to turn past "on" but just before "start" to initiate the prime. You could hear the pump in older cars with little sound deadening so you know what to do. I have No idea how to prime the system in these cars, and it may not even be possible, requiring repairs of the faulty valve.

Chad Thank you. A faulty fuel check value is worth checking. I doesn't explain why this only happens in the cold and wet but worth a try. The car usually starts first thing in the morning but is hard starting after a short trip and the car has sat from 15 minutes or longer. If the car were older I would suspect ignition wires and plugs. And with the push button start I can't control the fuel pump or the starting other than by pressing the button. New automated cars are great when they work, a real challenge to diagnose when there is an intermittent problem like this. Thank you for your advice.

 

[OUsig]

1) your starter is going out
I had the same thing happen to me and mine went out in the middle of a busy Starbucks parking lot...during a huge rainstorm and was a major pain in the butt. I had to get a tow truck to the dealership. fun stuff!
Get your starter replaced ASAP
The coils or plugs have nothing to do with what you are stating - that issue would come up during driving

2 - you may have a bad EVAP purge solenoid that is located right on top of the engine (I have also had to replace this on my vehicle)
3 - possible your brake pedal sensor is going out. that is an easy and cheap fix you can DIY

 

[chip williams]

The starter seems to be working fine. When the engine turns over it does so vigorously. Also will a bad evap purge solenoid show up on an engine diagnostic? Thank you for your comments. You sound like you know more than the techs who work for my Genesis dealer.

 

[EdP]

1) your starter is going out
I had the same thing happen to me and mine went out in the middle of a busy Starbucks parking lot...during a huge rainstorm and was a major pain in the butt. I had to get a tow truck to the dealership. fun stuff!
Get your starter replaced ASAP
The coils or plugs have nothing to do with what you are stating - that issue would come up during driving

How does the starter affect it? It is cranking, that is the job or the starter, turn the engine over. Once started, he says it runs rough. How would that starter cause that? The function of the starter is complete once the engine is running, not matter how good or bad.

 

[Gunkk]

Fuel, air, compression, and spark ... need all 4 to run an engine.

1. Check Fuel pressure.
2. Make sure throttle plate is opening.
3. Test compression.
4. Verify all 8 plugs are firing.

 

[OUsig]

The starter seems to be working fine. When the engine turns over it does so vigorously. Also will a bad evap purge solenoid show up on an engine diagnostic? Thank you for your comments. You sound like you know more than the techs who work for my Genesis dealer.

Any update here?
Maybe Throttle body needs to be cleaned? If so pull off the air intake and with the engine running, spray Seafoam all over the throttle body plate (slowly to not let the engine die and put the spray tube very close to the throttle body plate). This will help with low RPM engine air and idle and maybe could be the issue if you have some carbon buildup on the plate.

You should see an engine code if you have a vacuum leak anywhere in the system. Sounds like that could be the issue somewhere in the emission system. Especially if it runs rough for a minute or less once started then smooths out? I also had to replace the fuel tank air filter on mine. If you pull out your trunk mat, toward the back seat there will be an access panel. Take that off to find most of the parts for the EVAP system. Easy to replace with basic hand tools. I have a few extra parts still if you end up needing (they are expensive from the dealership)
It also wouldnt hurt to run a can of Seafoam in the gas when you have say 1/4 tank left to really clean out that part of the system.
Let us know!

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[OUsig]

How does the starter affect it? It is cranking, that is the job or the starter, turn the engine over. Once started, he says it runs rough. How would that starter cause that? The function of the starter is complete once the engine is running, not matter how good or bad.

Thanks for providing ZERO information or help to the OP. Sorry I didnt notice how he said it keeps turning over before starting before I replied.
My vehicle did a very similar thing and thus I provided at least a decent reply to try and help. Mine would randomly not start at all then after a try or 2 it would fire up like normal
It was the starter going out then it did go out in the parking lot

 

[edizzle89]

Thanks for providing ZERO information or help to the OP. Sorry I didnt notice how he said it keeps turning over before starting before I replied.
My vehicle did a very similar thing and thus I provided at least a decent reply to try and help. Mine would randomly not start at all then after a try or 2 it would fire up like normal
It was the starter going out then it did go out in the parking lot

He's just stating that the fact the engine turns over every time means it's probably not the starter so that the OP doesn't try to change his starter for no reason, which seems like useful information. I don't think he meant to make any kind of jab toward you.

 

[OUsig]

He's just stating that the fact the engine turns over every time means it's probably not the starter so that the OP doesn't try to change his starter for no reason, which seems like useful information. I don't think he meant to make any kind of jab toward you.

Quite possibly - if so he needs to learn to be more neutral and speak (type) with tact. Either way, I would rather someone take some time to bring information not just rebut another statement
I am over and I simply try to help so no worries

 

[EdP]

Quite possibly - if so he needs to learn to be more neutral and speak (type) with tact. Either way, I would rather someone take some time to bring information not just rebut another statement
I am over and I simply try to help so no worries

If you took the time to read the thread, earlier I offered suggestions and stand by them. I did not want to see him spend hundreds of dollars for a part not needed. I care less about tact than honesty and facts. My questions were valid. No matter your thoughts on reading this, I can assure you, I've been called worse. Thank you for reading though.

 

[chip williams]

I have taken the car to three different good independent shops with NO firm diagnosis. Best guess is failing fuel pump or low fuel pressure from a clogged fuel filter. The fuel pressure test requires a special tool so my next stop is the dealer. My car has not thrown a single code... no engine lights even though after a hard start the engine idles high (1000rpm) and has little power. New data point. This problem is NOT related to the cold or wet even though that is when the problem first presented. The problem occurs when the ENGINE IS WARMED UP and the car has sat for a short time after a short trip. The car will turn over vigorously and not start. On the third or 4th try the car starts but has sometimes has a high idle and low power. If I drive the car in this mode for a while then turn it off it starts back up fine and runs normally (idle, 700 rpm and good power.) ? NO engine lights. I will run a can of seafoam thru the tank and will spray the throttle body. Thanks for that recommendation

 

[memphiskane]

Just throwing this out there but possibly EVAP. Do you have a problem filling the gas tank, or starting after filling the gas tank?

 

[chip williams]

Wouldn't that throw a code? I removed the gas cap when the car wouldn't start yesterday after sitting for 15 minutes on a 70 degree day and there was no pressure differential between the tank and the atmosphere. No gas escaped or was drawn in. Is that normal? But to answer your question I have not had any problems filling the car with gas or starting after filling.

 

[chip williams]

Any update here?
Maybe Throttle body needs to be cleaned? If so pull off the air intake and with the engine running, spray Seafoam all over the throttle body plate (slowly to not let the engine die and put the spray tube very close to the throttle body plate). This will help with low RPM engine air and idle and maybe could be the issue if you have some carbon buildup on the plate.

You should see an engine code if you have a vacuum leak anywhere in the system. Sounds like that could be the issue somewhere in the emission system. Especially if it runs rough for a minute or less once started then smooths out? I also had to replace the fuel tank air filter on mine. If you pull out your trunk mat, toward the back seat there will be an access panel. Take that off to find most of the parts for the EVAP system. Easy to replace with basic hand tools. I have a few extra parts still if you end up needing (they are expensive from the dealership)
It also wouldnt hurt to run a can of Seafoam in the gas when you have say 1/4 tank left to really clean out that part of the system.
Let us know!

thanks will do.....

 

[memphiskane]

My EVAP canister close valve was intermittent with no code. I was just thinking if the purge valve wasn't operating correctly it could cause similar problems. It doesn't always throw a code, do you idle somewhat rough cold or hot?

It was just a thought.

 

[chip williams]

Yes the car often has a rough idle after a hard start. Is there a test for the purge value or evap canister or do I just replace them?