Generic P303 engine misfire - Smart Car Forums
User Tag List

Reply
 
LinkBack Thread Tools Display Modes
#1 (permalink) Old 11-21-2012, 06:46 AM
SCOA Club
 
Join Date: Jun 2011
Location: North Mississippi
Posts: 24
Thanks: 15
Thanked 8 Times in 4 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Generic P303 engine misfire

Have a 2011 with 30,000 miles, changed oil every 5000 miles, use Mobil1. Started getting P303 code setting at idle. Pulled plugs and looked, plug closest to drivers side had pretty good wear on electrode, others didn't have much. Replaced plugs and still get this code at idle. If you let it idle to long, engine light will flash. Still same code. It will reset and if I am careful and not idle more than a minute or so it will not come back. Hard to do in town. Anybody have any real good non-motor removing thoughts........................
msmurphree is offline  
The Following User Says Thank You to msmurphree For This Useful Post:
westwrench (03-14-2013)
Sponsored Links
Advertisement
 
#2 (permalink) Old 11-21-2012, 09:02 AM
SCOA Club
 
elmosisu's Avatar
 
Join Date: Nov 2009
Location: South Willamette Valley
Posts: 224
Thanks: 108
Thanked 80 Times in 53 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Injectors might be dirty. Have you run any cleaner through the fuel system ever? I would put a full can of Seafoam during your next fill and go for a long drive to see if that helps
elmosisu is offline  
The Following User Says Thank You to elmosisu For This Useful Post:
westwrench (03-14-2013)
#3 (permalink) Old 11-21-2012, 10:32 AM
 
Join Date: Feb 2012
Location: home
Posts: 300
Thanks: 86
Thanked 133 Times in 82 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
There's ample evidence on this forum to suggest that these engines are prone to excessive carbon buildup around the exhaust valves. Many have made a compelling arguement for periodic use of injector cleaner and regular if not exclusive fillups with top tier (with all the additives already in there) gas.

I plan to run 6 oz of Seafoam directly through the top end when we hit 30K. You might consider doing the same to give it a good cleansing.
dhirtle is offline  
The Following User Says Thank You to dhirtle For This Useful Post:
westwrench (03-14-2013)
#4 (permalink) Old 11-21-2012, 11:03 AM
 
jefferios's Avatar
 
Join Date: Mar 2008
Location: Chesapeake, VA
Posts: 4,022
Thanks: 871
Thanked 433 Times in 260 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 29 Post(s)
Garage
Seafoam might be your way to go. Is your car idling rough?
jefferios is offline  
The Following User Says Thank You to jefferios For This Useful Post:
westwrench (03-14-2013)
#5 (permalink) Old 11-24-2012, 01:13 PM
 
Smart_NCG's Avatar
 
Join Date: Nov 2012
Location: Toronto
Posts: 8
Thanks: 0
Thanked 12 Times in 5 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Garage
Im Having the same problem with mine. It keeps throwing a P0303 Code.
I Replaced the Spark plugs, Checked the filter, Swapped Coilpacks, Swapped Injectors and still getting the same code. The car idles rough but runs fine.

-Also add seafoam to a half tank

Last edited by Smart_NCG; 11-24-2012 at 01:17 PM. Reason: -
Smart_NCG is offline  
The Following User Says Thank You to Smart_NCG For This Useful Post:
westwrench (03-14-2013)
#6 (permalink) Old 11-24-2012, 01:49 PM
10 weeks to cabrio season
SCOA Club
 
NCC1701's Avatar
 
Join Date: Mar 2008
Location: Florida Panhandle
Posts: 8,484
Thanks: 2,344
Thanked 1,498 Times in 890 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 97 Post(s)
Garage
Quote:
Originally Posted by dhirtle View Post
There's ample evidence on this forum to suggest that these engines are prone to excessive carbon buildup around the exhaust valves. Many have made a compelling arguement for periodic use of injector cleaner and regular if not exclusive fillups with top tier (with all the additives already in there) gas.

I plan to run 6 oz of Seafoam directly through the top end when we hit 30K. You might consider doing the same to give it a good cleansing.
Spark plugs changed to Denso Iridium around 30K. I'm closing in on 54K at 52 months. Nearly all Chevron 93, a few Shells & Texacos* ... all top tier premium. So far, no sign of roughness or missing.

Is an injector cleaner needed at any time when using good premium grade gasoline? (With all the additives already in there).

* and a half dozen or so tanks of No Name Ethanol Free.

Last edited by NCC1701; 11-24-2012 at 03:03 PM.
NCC1701 is offline  
#7 (permalink) Old 11-25-2012, 01:57 PM
 
Join Date: Feb 2012
Location: home
Posts: 300
Thanks: 86
Thanked 133 Times in 82 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
many previous posts from people who replaced plugs with Iridiums and threw phantom misfire codes too - apparently the system is very sensitive to the gap - did you gap them before installation or just put them in out of the box?

as for the seafoam - I don't see a downside to using it every 10K miles as cheap insurance, like I said this engine seems to accumulate carbon on the exhaust valves, which may or may not have anything to do with a bunch of engines with worn out valve guides and compression issues at only 50K miles. any extra measures you take to keep the top end from gunking up with deposits seems like a safe bet.
dhirtle is offline  
The Following User Says Thank You to dhirtle For This Useful Post:
westwrench (03-14-2013)
#8 (permalink) Old 11-30-2012, 10:46 PM
 
Smart_NCG's Avatar
 
Join Date: Nov 2012
Location: Toronto
Posts: 8
Thanks: 0
Thanked 12 Times in 5 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Garage
I Diagnosed the problem with my P0303 Code. My Smart would idle rough and after it would warm up, the car would Run on 2 Cylinders if i idled for more the 30 seconds. I Used a Light Noid on the 3rd Injector while it was misfiring and found it had no signal. Every time i reset the car it would start working again.

So after I traced the 3rd injector signal wire to the ECU and checked the Resistance with Injector 1 and 2 and found no signal problem.

This tells me that the ECU in malfunctioning some how. I'm hoping on Having a Star Diagnostic System hooked up to it by this weekend to see whats going on.
Smart_NCG is offline  
The Following 3 Users Say Thank You to Smart_NCG For This Useful Post:
chieftmc (12-03-2012), jwight (12-01-2012), PureSmarts (07-22-2013)
#9 (permalink) Old 12-01-2012, 01:38 PM
SCOA Club
 
Join Date: Jan 2012
Location: Northern Virginia
Posts: 949
Thanks: 15
Thanked 1,012 Times in 461 Posts
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 42 Post(s)
Quote:
Originally Posted by Smart_NCG View Post
I Diagnosed the problem with my P0303 Code. My Smart would idle rough and after it would warm up, the car would Run on 2 Cylinders if i idled for more the 30 seconds. I Used a Light Noid on the 3rd Injector while it was misfiring and found it had no signal. Every time i reset the car it would start working again.

So after I traced the 3rd injector signal wire to the ECU and checked the Resistance with Injector 1 and 2 and found no signal problem.

This tells me that the ECU in malfunctioning some how. I'm hoping on Having a Star Diagnostic System hooked up to it by this weekend to see whats going on.
Some late-model engine control modules will turn off the injector driver to a cylinder on which a misfire is detected. This is done for emissions control reasons. I do not know whether the smart system does this. I mention it only to point out that what you are seeing may be the result of some other fault being detected, rather than the cause.
Rustedwrench is offline  
#10 (permalink) Old 12-03-2012, 07:26 AM
SCOA Club
 
chieftmc's Avatar
 
Join Date: Jan 2008
Location: Terre Haute, IN
Posts: 10,534
Thanks: 4,375
Thanked 2,248 Times in 1,400 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 30 Post(s)
Garage
Quote:
Originally Posted by Smart_NCG View Post
I Diagnosed the problem with my P0303 Code. My Smart would idle rough and after it would warm up, the car would Run on 2 Cylinders if i idled for more the 30 seconds. I Used a Light Noid on the 3rd Injector while it was misfiring and found it had no signal. Every time i reset the car it would start working again.

So after I traced the 3rd injector signal wire to the ECU and checked the Resistance with Injector 1 and 2 and found no signal problem.

This tells me that the ECU in malfunctioning some how. I'm hoping on Having a Star Diagnostic System hooked up to it by this weekend to see whats going on.
Please let us know what you find out
chieftmc is offline  
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Smart Car Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


331

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



  Similar Threads
Thread Thread Starter Forum Replies Last Post
Mitsubishi engine code #2 misfire greenek1 smart Operation and Maintenance 51 11-17-2013 05:09 AM
Code P0301 #1 misfire pack smart smart Operation and Maintenance 31 07-22-2012 11:21 PM
Need a good 451 engine...anybody got a wreck with a good engine? shop hermit smart General Discussion 0 08-18-2011 01:41 PM
Generic car maintenance tips jwight The Car Lounge 0 07-26-2011 08:59 AM
OPOC Engine, could be the next smart engine? BB Benz Tech & Gadgets 31 03-02-2011 02:24 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On