My engine is hard starting?

Tiny
LEISURE40
  • MEMBER
  • 2013 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 4WD
  • 91,000 MILES
Check engine light is on. Starts hard in the morning after sitting all night. Starts fine after that.
Monday, December 17th, 2018 AT 4:54 PM

24 Replies

Tiny
DANNY L
  • MECHANIC
  • 5,648 POSTS
Hello,I'm Danny,

That means that the engine has a code stored in your vehicles computer.You need to have the codes checked to have us properly diagnose your vehicle.If you don't have access to a code reader/scanner your local auto parts stores have a tool loaner program and can rent you one. I've attached a tutorial showing what is involved on how to check codes.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

this guide can help as well

https://www.2carpros.com/articles/engine-cranks-excessively-before-starting

Once you have this done and get back to us with the information (codes) we can help diagnose your vehicle.Hope this helps and thanks for using 2CarPros.
Danny-
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Monday, December 17th, 2018 AT 6:32 PM
Tiny
MICHAEL_SHYMKUS
  • MEMBER
  • 11 POSTS
  • 2011 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 160,000 MILES
After my truck sits for about six or more hours it acts like it will not start, just keeps cranking. I put the pedal to the floor and it fires right up. It will idle up and down for a little bit until it warms up a bit. After that it fires right up. It will even start right up after sitting for two to three hours. I took it to the mechanic and he told me I needed my fuel injectors cleaned out. That did not work, just costed me money. I am getting a p0172, p0175, p0455, p0446, and a p0420. Any advice would help! Thanks in advance. I will post a video of what it does in the morning.
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Monday, January 25th, 2021 AT 11:44 AM (Merged)
Tiny
JONNYB1963
  • MECHANIC
  • 252 POSTS
Good morning,

Thanks for coming to see us today.
The P0172 and P0175 are both indicating the engine is running too rich on both banks. And are both a symptom and a cause of what else is going on here.
The next code P0445 indicates a "gross" vacuum leak in the Evaporation Emission Control system. And this one is accompanied by the P0446 which is a Evaporative Emission Control System Vent Control Circuit Malfunction.
The final code you gave is the P0420 which indicated the catalytic converter efficiency is below threshold (Bank 1)

So, the first two codes are the result of extra fuel being added to your intake system through the charcoal canister system that is used to store fuel vapors while the vehicle is sitting. The longer you sit, the more it stores which explains the reason why you have hit the accelerator pedal to start it.
See this links below:
Evaporative Emission Control System Vent Control Circuit Malfunction

Since the the code mentioned that it is a gross leak, I suspect that the solenoid that regulates how much fuel vapor gets added to the induction system us stuck open.

Here are some links to explain the system and some fixes:
https://www.2carpros.com/articles/how-emission-control-systems-work
https://www.2carpros.com/articles/evap-system-code-repair

The last code deals with the catalytic converter. P0420 means Catalyst System Efficiency Below Threshold (Bank 1).
This is probably because of the rich running that has been going on but can also be caused by:
Running on Leaded fuel (I doubt it)
A damaged or failed oxygen/O2 sensor downstream oxygen sensor (possible)
exhaust leaks.
A weak or degraded catalytic converter (probable).
Retarded spark timing (unlikely).
Leaking fuel injector or too high of fuel pressure .
Misfires.
Engine has been burning oil for a while.

Can you tell me how long (in terms of miles) has this been going on? The longer you run a catalytic converter under bad conditions the change of clogging and degrading their performance increases.

Let me know
Jon

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Monday, January 25th, 2021 AT 11:44 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning.

Good video.

The first thing I would do is check the fuel pressure when it is cold and the issue is present. The fuel pump may be draining down overnight and there is no pressure present and the system has to prime.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

I see the crank sensor is working as the tachometer is showing RPM when it does not start.

The 172,175 codes are for rich running. the 455,456 are evap codes which could be related to the first two codes.

The 420 is a catalytic converter code. You need a catalytic converter.

P0172-175

P0172
Descriptor
Probable Causes
Air Filter
Air Intake System
Crankcase Ventilation System Leak
Engine Oil Condition
Evaporative Emission (EVAP) Canister Cracked
Evaporative Emission (EVAP) Control System
Evaporative Emission (EVAP) Pipes, Lines and Hoses
Exhaust System
Fuel Injector
Fuel Level Low
Fuel Pressure Low
Fuel Quality
Injector O-Rings Vacuum Leak
Intake Manifold Vacuum Leak
Oil Dip Stick Unseated
Throttle Body Assembly
Vacuum Hose/Line
Vacuum Leak

The evap system is part of this possibility.

You need a scan tool that can read live data to monitor the long term trims of the O2 sensors. That will help diagnose the correct failure for this issue.

Roy
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Monday, January 25th, 2021 AT 11:44 AM (Merged)
Tiny
MICHAEL_SHYMKUS
  • MEMBER
  • 11 POSTS
I forgot to mention that when I took it to the mechanic he told me that my fuel pressure was great and I even checked it myself and the fuel pressure was good.
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Monday, January 25th, 2021 AT 11:44 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Did you check it first thing in the morning when this issue is present?

What was the exact fuel pressure?

Roy
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Monday, January 25th, 2021 AT 11:45 AM (Merged)
Tiny
MICHAEL_SHYMKUS
  • MEMBER
  • 11 POSTS
The mechanic did and he told me it was reading what it was supposed to. I will do it again tomorrow morning just to be sure for myself.
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Monday, January 25th, 2021 AT 11:45 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
You said you even checked it yourself? Do not understand.

Roy
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Monday, January 25th, 2021 AT 11:45 AM (Merged)
Tiny
MICHAEL_SHYMKUS
  • MEMBER
  • 11 POSTS
I have checked it myself, but not first thing in the morning. When I checked it the PSI was normal, but I cannot remember the exact numbers.
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Monday, January 25th, 2021 AT 11:45 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Okay, I need the exact numbers as fuel pressure is critical in trying to help you.

Roy
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Monday, January 25th, 2021 AT 11:45 AM (Merged)
Tiny
JONNYB1963
  • MECHANIC
  • 252 POSTS
If you can without too much trouble go ahead and get the FRP for Roy. But based on what you have going on lets focus on the Evap system.

Regards
Jon
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Monday, January 25th, 2021 AT 11:45 AM (Merged)
Tiny
MICHAEL_SHYMKUS
  • MEMBER
  • 11 POSTS
I have no idea where to start with a EVAP system.
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Monday, January 25th, 2021 AT 11:45 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
That is the system that does not allow the vapors into the air.

https://www.2carpros.com/articles/evap-system-code-repair

If you have no idea, I would take it to a shop and have them do a smoke test to look for any leaks. That would be the easy way to find the issue. Once you have an answer, get back to us so we can further help.

Roy
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Monday, January 25th, 2021 AT 11:45 AM (Merged)
Tiny
MICHAEL_SHYMKUS
  • MEMBER
  • 11 POSTS
Okay, sounds good. I will keep in touch. Thank you!
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Monday, January 25th, 2021 AT 11:45 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
You are welcome.

We re always glad to help.

Roy
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Monday, January 25th, 2021 AT 11:45 AM (Merged)
Tiny
MICHAEL_SHYMKUS
  • MEMBER
  • 11 POSTS
Well I got my truck into a very reputable mechanic the other day. It ended up being the alcohol/fuel mixture was messed up. They reset the fuel system computer and it starts up perfectly now!
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Monday, January 25th, 2021 AT 11:45 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Glad to hear is running good.

I am concerned. Resetting does not fix anything, it just makes the pcm forget the codes and issues. I hope it does not come back but I would prepare yourself for the fact the codes will return.

Roy
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Monday, January 25th, 2021 AT 11:45 AM (Merged)
Tiny
MICHAEL_SHYMKUS
  • MEMBER
  • 11 POSTS
The computer thought the alcohol content was at 72% so he set it to what it’s supposed to be at. The actual fuel was good, the computer just thought it was way higher than it should have been, so it was flooding it with way too much fuel.
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Monday, January 25th, 2021 AT 11:45 AM (Merged)
Tiny
MICHAEL_SHYMKUS
  • MEMBER
  • 11 POSTS
Also I fixed my evap leak today, I replaced the purge valve behind the intake manifold and it fixed that. For my p0420 the mechanic did test and he said all my 02 sensors are functioning properly, but my left catalytic converter needs to be replaced.
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Monday, January 25th, 2021 AT 11:45 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Okay, got it. So repairs have been made and will be made to get rid of the 420. 420 has nothing to do with O2 sensors. It is a worn out catalytic converter.

As far as the alcohol, why did it change? Something had to make it change. I disagree with the fact it was flooding. Something change to get to that percentage.

Roy
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Monday, January 25th, 2021 AT 11:45 AM (Merged)

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