Car starts poorly in morning but fine rest of the day


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Old 12-20-20, 10:49 PM
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Car starts poorly in morning but fine rest of the day

I've had this issue for quite some time now. It never seemed like a big deal but I think it's getting worse recently.

Basically it goes like this: car parked overnight or for a long time (8+ hours), when I go to start the car up, it seems to have a hiccup or an unclean combustion to ignite the engine parts and get it started. It's hard to explain but you know the difference when a car starts right up upon turning the ignition key and when a car sort of sounds like it started half-ass, not a full, powerful ignition feeling.

Well, I took a video if my description doesn't make sense. See it here:

https://youtu.be/NujpCyivqho

That particular morning was pretty bad. It doesn't usually struggle that bad to start, but that was one of the worst starts. Other days it's still a poor start but sounds more like a cough and half-ass effort start like it didn't fully combust and ignite.

After driving it some and then parking somewhere to go into a store and come back out, it starts right up instantly with full loud powerful ignite combustion feeling.

So my guess is it has something to do with either a bad check valve or maybe a fuel pump issue? Something is failing to keep the pressure so gas or oil (?) is leaking back or out somewhere. Is that also why I have a strong smell of gas whenever I start up the car in the morning and walk outside to the back of the car? I can always smell strong gas (I'm guessing something to do with unburnt fuel or fuel that leaked out and is being burnt off the moment you start the car.

2013 VW Scirocco R, 2.0L TFSI, gasoline, auto, APR Stage 2+ tuned, 72,000 km.
 

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12-21-20, 08:08 PM
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first quick test. next time you know it has sat long enough to cause the problem. turn the key on BUT dont start TWICE. then start. if it starts normal fuel pressure is leaking off. most likely back to the tank fia check valve in fuel pump. next best guess is a failed coolant temp sensor. not failed enough to set a code but bad enough to flood the engine. when cold(not ran 8 hours) compare coolant temp to intake air temp they should read the same.
 
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Old 12-21-20, 02:01 AM
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sounds like it is missing due to coolant or possibly excessive fuel in one or more cylinders usually if its coolant you will notice coolant loss and have to add some eventually but it can be a slow leak.
would probably let it set overnight and pull the plugs and look down the cylinders or put a bore scope down the cylinder to see if you see any liquid and maybe find out what it is but typically fuel would not take that long to leak down.
suppose another possibility is slightly weak ignition causing a misfire.
 
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Old 12-21-20, 04:30 AM
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thanks for the reply. Coolant levels exactly the same as always and this issue has been going on for probably over a year now, but I only drive the car twice a week, and about 8,000 km per year. So I think the coolant is fine.
If it was a weak ignition, wouldn't it be happening ALL the time and not just when car was left parked overnight? I noticed the specific pattern and it was always just happening when car was left parked for a long time like overnight. But after driving it and parking somewhere and going back into the car 1 or 2 hours later, it starts up fast and powerful like normal. It has something to do with the fact the car is left parked for a long time and something is happening in that long period of time.

The closest thing I have researched that it sounds like is a bad check valve. I don't know what these things are, just based on the symptoms, this description seemed to be really close to it. Anyone else concur? Other ideas?
 
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Old 12-21-20, 05:24 AM
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First thing I would check is the battery.
 
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Old 12-21-20, 06:26 AM
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I lean towards fouled spark plugs. Either fouled with fuel, leaking injectors or, with carbon deposits after shut down, that burn away during engine operation.
 
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Old 12-21-20, 07:18 AM
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Originally Posted by guy293482
APR Stage 2+ tuned
Let me guess; it gets parked outside overnight?

Sounds like it's running rich, probably because the gas in the tank & the engine get cold.
When cold fuel is sprayed, it expands and cools, when that cold fuel hits the cold cylinder block it is "quenching": instead of the easy to ignite gasoline vapor, you're getting hard to ignite droplets of gasoline.

My first suggestion would be to try a tank of higher octane fuel, second is check for vacuum leaks, third is check for faults on the O2 and airflow sensors, and disconnect and then reconnect them to make sure they are fully plugged in.
 
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Old 12-21-20, 07:24 AM
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usually a bad check valve will just cause it to crank over a little longer before starting but once the pump build enough pressure the engine starts like normal, and a bad check valve would not take long to lose all the pressure in the rail, same would be true for injectors they usually do not take 8 hours to leak down usually its minutes could still have a bad spray pattern though.
so would imagine it has more to do with the engine being cooled off completely would still let it set pull the plugs, look for liquid, inspect plugs and ignition system might even check codes for misfire some scanners will have misfire data and you may be able to narrow down what cylinder is missing.
 
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Old 12-21-20, 08:35 AM
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Picking up on what alan73 said in the last post:

I just went through a fuel-injector problem and I used one of those OBD 2 scanners to isolate the problem (I traced it to the exact cylinder). You can get a reader as cheap as $35:

(https://www.amazon.com/thinkcar-Scan...NsaWNrPXRydWU=)

and since your car is a 2013 it will have a connection port somewhere under the dash around the steering wheel to connect the reader.

I would take readings right before you start your car when you suspect you are going to have the problem. Then after the car starts and runs for a little bit, shut the car off and take another reading.

You would get information on any misfiring cylinders, banks running lean/rich/etc., and not just short term but long term also. And other good stuff. A good chance it might point you in the right direction.

Seems to me it could help.




 
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Old 12-21-20, 10:48 AM
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Originally Posted by zoesdad
I would take readings right before you start your car when you suspect you are going to have the problem. Then after the car starts and runs for a little bit, shut the car off and take another reading.
I definitely agree about getting the OBDII reader- but get a bluetooth model, and then download any of several free apps, like Torque, DashCommand, or CarScanner, which ALSO give you live data-

You can setup screens to show real time data for each cylinder for spark timing, and IIRC fuel injection.
 
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Old 12-21-20, 04:21 PM
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Yes, first time it was the battery and I got that replaced just 2 weeks ago.
 
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Old 12-21-20, 04:25 PM
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I just had a full walnut blasting carbon cleaning on intake valves 1 month ago. Super clean now.
Thank you for input.
 
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Old 12-21-20, 04:36 PM
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Thanks Hal! Great stuff.
Yes parked outside overnight. But here's the thing. It's not just happening in winter cold season. It also has the poor start back in the heat of summer. Now APR Stage 2+ with RFD does have it's known issues for rough idling in cold starts but that is a separate issue I believe from actual ignition/starting the engine.

Yes, the testpipe file is mapped for 98 Octane. I'm not sure what that means because I think the highest octane in my country (South Korea) is called premium gas and I believe it is 93 or 95 Octane. Not 100% sure. I'll have to ask the gas station next time. All I know is that when I bought the car (2nd hand) I was told it needed PREMIUM GAS which is the top tier gas here so I get that all the time. I wonder if the octane isn't exactly the same match, if that could cause the issue or is that the reason why I'd be running RICH all the time. I've been running rich since I bought the car in 2017. Makes no difference if it's summer or winter, it's always running rich but not so much to the point I get a fault code. No fault codes ever came up for running too rich. I guess it's just under that threshold of setting off a fault code but it's still pretty rich.

Your next option about checking for vacuum leak sounds right. I have two small leaks in the intercooler piping both sides (turbo to intercooler and intercooler to exhaust). My mechanic guy ordered replacement hoses from APR and we are going to try and replace the hoses next month when it arrives. After that, we'll see how everything goes, but that may just be another issue and not related to this starting issue.

The last option of checking for o2 and airflow sensors, disconnecting and reconnecting them to make sure they are fully plugged in is a good idea too. I don't think that's been done. I'll have to ask my mechanic to do that for me.

You don't think it has anything to do with a bad check valve or maybe the fuel pump? Is it true that when you replace the fuel filter, it is recommended to also replace the fuel pump at the same time?
 
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Old 12-21-20, 04:41 PM
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Thank you Alan! Good points. I didn't know that about check valves. So if it was a bad check valve, then it should be happening all the time not just only mornings after car has been left sitting for a long time.

I have a software called VCDS by Rosstech. I don't know how to use it well but I am learning the basics. I do recall checking for misfires and saw some while at idle. I forgot which cylinders and if it was consistently the same cylinder or randomly all over the place between 1 and 4 equally. I'll have to check that again. If you or anyone knows how to use VCDS properly, maybe you could tell me how to check for stuff using it. I am also using the Rosstech forums for VCDS help.
 
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Old 12-21-20, 04:46 PM
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I've tried Torque before (the free version?) on my phone. I don't know what settings I should set it to and what to read? Could you direct me and tell me exactly what I should look for when using these apps?

I do have VCDS and plugged it into my obdII port . Maybe I can find everything I need with my VCDS? It cost like $200 so it ought to have almost everything I need right? What I don't know is what the normal readings are supposed to look like for each measuring block. For example when you said spark timing and IIRC fuel injection, what is a healthy reading supposed to look like? I don't know what I'm supposed to be looking for.
 
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Old 12-21-20, 08:08 PM
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first quick test. next time you know it has sat long enough to cause the problem. turn the key on BUT dont start TWICE. then start. if it starts normal fuel pressure is leaking off. most likely back to the tank fia check valve in fuel pump. next best guess is a failed coolant temp sensor. not failed enough to set a code but bad enough to flood the engine. when cold(not ran 8 hours) compare coolant temp to intake air temp they should read the same.
 
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Old 03-16-21, 05:59 AM
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"I definitely agree about getting the OBDII reader- but get a bluetooth model, and then download any of several free apps, like Torque, DashCommand, or CarScanner, which ALSO give you live data-

You can setup screens to show real time data for each cylinder for spark timing, and IIRC fuel injection."

hal: do you have an url for this device?
 
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Old 03-16-21, 06:21 AM
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Go to Torque website. It has extensive page of various OBDII dongles that will work with a cell phone. Torque Pro is few bucks, rather worth the expense.
 
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Old 03-18-21, 05:07 AM
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In response to Iceman681
"first quick test. next time you know it has sat long enough to cause the problem. turn the key on BUT dont start TWICE. then start. if it starts normal fuel pressure is leaking off. most likely back to the tank fia check valve in fuel pump. next best guess is a failed coolant temp sensor. not failed enough to set a code but bad enough to flood the engine. when cold(not ran 8 hours) compare coolant temp to intake air temp they should read the same."

This. Yes, I noticed that if I only powered the car up without turning on the engine and did it 2-3 times, the car would start up better/faster. Sometimes I would even pump the accelerator pedal 4-5 times before turning on the car all the way and even though my car doesn't use carburator(?) I swear doing that for some reason seems to make my car start up better than if I don't push the accelerator a few times before turning the key all the way to start the ignition.

Why can't any of my mechanics figure this out or fix it? I've had this issue for 1.5 years and nobody is fixing it despite me telling them the symptoms.

*frustrated*
 
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Old 06-08-21, 02:34 PM
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Have you cleaned the throttle body?
 
 

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