C5 01 p0300 cold start
Thread Starter
2nd Gear
Joined: Sep 2016
Posts: 2
Likes: 0
C5 01 p0300 cold start
Hi all im new here.
I've been reading, searching, taking notes/tips and learning in this forum for long time now always when i needed help about fixing and learning about vettes i find it here so i want to say thanks for such a nice forum and i finally had to register because i couldnt find a solution for this problem.
I searched every where for this problem googled it, checked other forums like ls1 but didnt find anything so before you guys eat me alive about not searching i actually did search for days
the problem is i've been getting the multiple cylinder misfire p0300 on cold starts only stays for almost a minute as current/history (p0300 H C) and then after a minute from a cold start the code goes to H (history) and the check engine "light/icon" stays on.
Also at cold starts when i start the car and let it warm up i hear chain noise (could be loose or slightly broken timing chain) for a second.
New red GM performance spark plug wires from gene
New plugs (ngk tr55 v-power)
New battery (exide) 700+ CCA (i think 780 or 720 not sure i have to check again once im back home)
NOTE: Ive had this problem even before i changed the wires, plugs (and battery wich i believe isnt the problem and probably has nothing to do with it but i thought id mention it)
I searched and asked some of my friends and some gaurages that i work with here in my country if i could find anybody with a fancy scanning tool to check the oxygen sensors and a couple more things
Could be bad coil that is acting wierd when cold and causing the misfire
Could be oxygen sensor
Ive also read it could be crankshaft and/or camshaft position sensor?
Maybe bad chain?
I just dont want to throw a bunch of parts at it by guessing the problem hoping to hear if someone had similar problem and how did you deal with it
Car is a stock c5 corvette 2001 ls1 around 86.000 miles with dual cone air intake and tigershark corsa exhaust
SPEEDWAY WHITE
I've been reading, searching, taking notes/tips and learning in this forum for long time now always when i needed help about fixing and learning about vettes i find it here so i want to say thanks for such a nice forum and i finally had to register because i couldnt find a solution for this problem.
I searched every where for this problem googled it, checked other forums like ls1 but didnt find anything so before you guys eat me alive about not searching i actually did search for days
the problem is i've been getting the multiple cylinder misfire p0300 on cold starts only stays for almost a minute as current/history (p0300 H C) and then after a minute from a cold start the code goes to H (history) and the check engine "light/icon" stays on.
Also at cold starts when i start the car and let it warm up i hear chain noise (could be loose or slightly broken timing chain) for a second.
New red GM performance spark plug wires from gene
New plugs (ngk tr55 v-power)
New battery (exide) 700+ CCA (i think 780 or 720 not sure i have to check again once im back home)
NOTE: Ive had this problem even before i changed the wires, plugs (and battery wich i believe isnt the problem and probably has nothing to do with it but i thought id mention it)
I searched and asked some of my friends and some gaurages that i work with here in my country if i could find anybody with a fancy scanning tool to check the oxygen sensors and a couple more things
Could be bad coil that is acting wierd when cold and causing the misfire
Could be oxygen sensor
Ive also read it could be crankshaft and/or camshaft position sensor?
Maybe bad chain?
I just dont want to throw a bunch of parts at it by guessing the problem hoping to hear if someone had similar problem and how did you deal with it
Car is a stock c5 corvette 2001 ls1 around 86.000 miles with dual cone air intake and tigershark corsa exhaust
SPEEDWAY WHITE
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
Other things can cause a misfire code besides simply ignition
Most common thing would be a broken valve spring or rocker arm
I doubt that it would be the timing chain--as a timing chain failure would show instant catastrophic damage
Most common thing would be a broken valve spring or rocker arm
I doubt that it would be the timing chain--as a timing chain failure would show instant catastrophic damage
Melting Slicks
Joined: Jun 2002
Posts: 2,246
Likes: 66
From: Middletown CT
The P0300 can be many things. Because it happens on cold starts I'm wondering if you have a bad fuel injector leaking down. Are you getting any gas in the oil? You can do a fuel pressure test which should tell you if you have proper pressure at the fuel rails and if it is bleeding off as the car sits. It could also be a fuel filter restriction.
Not sure what the chain noise is but a while back someone posted a picture of a timing chain that had a link that was on the verge of a catastrophic failure but he caught it in time. I don't recall what the symptom was that made him look at the chain.
Broken valve spring can also cause that code, but I would not expect that to clear as the engine warms up.
Not sure what the chain noise is but a while back someone posted a picture of a timing chain that had a link that was on the verge of a catastrophic failure but he caught it in time. I don't recall what the symptom was that made him look at the chain.
Broken valve spring can also cause that code, but I would not expect that to clear as the engine warms up.
Last edited by Greg_E; Oct 23, 2016 at 07:35 AM.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Just to be clear on a few things.
Are you saying the motor misses for about a minute and then it clears up?
Does it run OK once it clears, even through the RPM range?
Does it idle OK?
Where are you located, sounds like you are out of the US? Fuel type available?
Do you know the history of the car, i.e., did it sit a long time?
I agree with Greg, think I would start with a fuel injector leak test and pulse test then move on from there. I certainly wouldn't start throwing parts at it. There is a tester for the injectors, not sure where you are located, but I bought one several years ago for help with another car and it has been a good tool to have. Fuel pressure gauge is also required. Not sure if you have access to these tools or can rent them.
Are you saying the motor misses for about a minute and then it clears up?
Does it run OK once it clears, even through the RPM range?
Does it idle OK?
Where are you located, sounds like you are out of the US? Fuel type available?
Do you know the history of the car, i.e., did it sit a long time?
I agree with Greg, think I would start with a fuel injector leak test and pulse test then move on from there. I certainly wouldn't start throwing parts at it. There is a tester for the injectors, not sure where you are located, but I bought one several years ago for help with another car and it has been a good tool to have. Fuel pressure gauge is also required. Not sure if you have access to these tools or can rent them.
Thread Starter
2nd Gear
Joined: Sep 2016
Posts: 2
Likes: 0
Are you saying the motor misses for about a minute and then it clears up? I was saying that the code is there for a minute and then it clears up but since u mention it there is a tiny miss sound that isn't really noticeable unless the hood is open it disappears "quickly"
Does it run OK once it clears, even through the RPM range? runs perfect sir
Does it idle OK? idles ok
Where are you located, sounds like you are out of the US? Fuel type available? I'm located in Bahrain, fuel available here is Regular 91 octane and Premium 95 octane (hope this is what u meant with "fuel type" sry if my English isn't great)
Do you know the history of the car, i.e., did it sit a long time? it was some sort of a "garage queen" (maintained) before I bought it and when I bought it became my daily driver
Last edited by Ali666; Oct 23, 2016 at 10:31 AM.
Melting Slicks
Joined: Jun 2002
Posts: 2,246
Likes: 66
From: Middletown CT
There are some good troubleshooting tips in this thread. The symptom sounds like it was similar to yours. the problem in this case was resolved by doing a crank position sensor relearn. The sensor was not replaced, just reprogrammed. I'm not saying that is your problem but it is probably easier to do than some of the other tests. To do the relearn you would need a Tech 2 or or Scan and tune software such as EFILive. Don't know if you have access to either. FYI you can buy Tech 2 knockoffs from China for Under $300.
https://www.corvetteforum.com/forums...from-hell.html
That chain noise you said you hear troubles me. If it was something with the timing chain that could cause variations in the pulses received by the CKP sensor. Can you tell if that noise is coming from the front of the motor?
As Vettenuts mentioned below, you need to do some testing. I don't know if there is a cheaper way to test the fuel pressure, but the Kent Moore tool is crazy expensive.
https://www.corvetteforum.com/forums...from-hell.html
That chain noise you said you hear troubles me. If it was something with the timing chain that could cause variations in the pulses received by the CKP sensor. Can you tell if that noise is coming from the front of the motor?
As Vettenuts mentioned below, you need to do some testing. I don't know if there is a cheaper way to test the fuel pressure, but the Kent Moore tool is crazy expensive.
Last edited by Greg_E; Oct 25, 2016 at 08:36 AM. Reason: Added info.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
I think I would do some diagnostics and not throw in any parts yet. The reason I asked about the fuel and the amount of time it sat (prior to you buying) was that the 10% ethanol fuel here in the US can make a mess of things. I have had to rebuild several carburetors due to this fuel sitting too long.
This is similar to the injector tester I use. A fuel pressure gauge is required to use as you must monitor the pressure drop during each test. Not sure if there is anyone that rents tools where you are.
http://www.ebay.com/itm/Injector-Tester-Digital-Display-12V-Vehicle-Battery-Car-Truck-Automotive-Tool/272414429530?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20150313114020%26meid%3D72dbfa351bc34f8cbb9986ef9d7bb09b%26pid%3D100338%26rk%3D2%26rkt%3D17%26sd%3D322031471384
This is similar to the injector tester I use. A fuel pressure gauge is required to use as you must monitor the pressure drop during each test. Not sure if there is anyone that rents tools where you are.
http://www.ebay.com/itm/Injector-Tester-Digital-Display-12V-Vehicle-Battery-Car-Truck-Automotive-Tool/272414429530?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20150313114020%26meid%3D72dbfa351bc34f8cbb9986ef9d7bb09b%26pid%3D100338%26rk%3D2%26rkt%3D17%26sd%3D322031471384
Last edited by vettenuts; Oct 25, 2016 at 07:18 AM.
