Anyone with Northstar V8 Experience? Random Misfire - German Shepherd Dog Forums

Increase font size: 0, 10, 25, 50%

GermanShepherds.com is the premier German Shepherd Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools
Old 04-04-2014, 11:32 PM   #1 (permalink)
Crowned Member
 
shepherdmom's Avatar
 
Join Date: Dec 2011
Location: Rural Nevada
Posts: 4,425
Question Anyone with Northstar V8 Experience? Random Misfire

Have been dealing with a very frustrating random misfire in our Northstar V8. Has anyone else had a problem with this and if so how did you fix it? We have replaced all 4 coils on the front bank where the misfire is happening.
shepherdmom is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 04-05-2014, 01:06 AM   #2 (permalink)
Crowned Member
 
Nigel's Avatar
 
Join Date: Jul 2012
Posts: 4,049
Default

Leaky injectors, vacuum leaks, washed or whitish colored plugs (head gasket) check fuel pressure/regulator just throwing out some ideas that could potentially cause a misfire.

Last edited by Nigel; 04-05-2014 at 01:13 AM.
Nigel is offline   Reply With Quote Quick reply to this message
Old 04-05-2014, 01:39 AM   #3 (permalink)
Crowned Member
 
shepherdmom's Avatar
 
Join Date: Dec 2011
Location: Rural Nevada
Posts: 4,425
Default

Quote:
Originally Posted by Nigel View Post
Leaky injectors, vacuum leaks, washed or whitish colored plugs (head gasket) check fuel pressure/regulator just throwing out some ideas that could potentially cause a misfire.
The misfire is moving around from 8 to 6 to 4 etc staying on that one side. Since we replaced the coils its not throwing a code anymore but is still misfiring. Husband is going to change plugs this weekend but he doesn't really think that is the problem.
shepherdmom is offline   Reply With Quote Quick reply to this message
Old 04-05-2014, 02:16 AM   #4 (permalink)
Crowned Member
 
Lucy Dog's Avatar
 
Join Date: Aug 2008
Location: Connecticut
Posts: 6,896
Default

What check engine codes is the car throwing? Just a misfire or other codes too?

If the car misfires, it will immediately throw a code for a misfire.
Lucy Dog is offline   Reply With Quote Quick reply to this message
Old 04-05-2014, 02:25 AM   #5 (permalink)
Crowned Member
 
shepherdmom's Avatar
 
Join Date: Dec 2011
Location: Rural Nevada
Posts: 4,425
Default

Quote:
Originally Posted by Lucy Dog View Post
What check engine codes is the car throwing? Just a misfire or other codes too?

If the car misfires, it will immediately throw a code for a misfire.
Just misfire... But it is misfiring a lot more often than it is throwing codes.
shepherdmom is offline   Reply With Quote Quick reply to this message
Old 04-05-2014, 02:33 AM   #6 (permalink)
Crowned Member
 
Lucy Dog's Avatar
 
Join Date: Aug 2008
Location: Connecticut
Posts: 6,896
Default

You actually feel the car misfire? Are all three cylinders misfiring at once or is it one at a time? Is it a quick misfire then back to normal or is it continuous while the cars running?

The only way to really diagnose the problem is with exact codes. You can go to any autoparts store and they'll scan the codes for free.
Lucy Dog is offline   Reply With Quote Quick reply to this message
Old 04-05-2014, 02:41 AM   #7 (permalink)
Crowned Member
 
Lucy Dog's Avatar
 
Join Date: Aug 2008
Location: Connecticut
Posts: 6,896
Default

Quote:
Originally Posted by shepherdmom View Post
Just misfire... But it is misfiring a lot more often than it is throwing codes.
That's impossible. If there's an actual misfire, there's an immediate code. A car won't misfire without throwing a code - it happens simultaneously. Your check engine light might not come on immediately, but if you hook up a scanner, there will be a pending misfire code at the very least.
Lucy Dog is offline   Reply With Quote Quick reply to this message
Old 04-05-2014, 03:34 AM   #8 (permalink)
Crowned Member
 
shepherdmom's Avatar
 
Join Date: Dec 2011
Location: Rural Nevada
Posts: 4,425
Default

Quote:
Originally Posted by Lucy Dog View Post
That's impossible. If there's an actual misfire, there's an immediate code. A car won't misfire without throwing a code - it happens simultaneously. Your check engine light might not come on immediately, but if you hook up a scanner, there will be a pending misfire code at the very least.
We have a code reader. It is not throwing codes. When it first started happening it was random misfire cylinder 8... Husband moved the coil to 6 and the next code it threw was 6 so he replaced that coil. The coil worked for about 2 weeks then went bad. You could really feel that. Code stayed on so he returned and replaced coil. Then it started moving around to 4 then back to 6 so he replaced the other 3 coils. It hasn't thrown a code since but you can still feel the intermittent misfire, especially when sitting at a stop sign and sometimes going uphill. This has been going on for a while now and it's making me crazy. Hubby says he will replace plugs this weekend and if that doesn't fix it, I'm going to have to take it to a dealer. Grrr.. Did I mention I HATE cars.
shepherdmom is offline   Reply With Quote Quick reply to this message
Old 04-05-2014, 09:23 AM   #9 (permalink)
Senior Member
 
Join Date: Feb 2014
Location: Hamburger
Posts: 359
Send a message via Yahoo to sehrgutcsg
Default

If you've already replaced the coils and it is no longer throwing codes and the misfire is intermittent I would be looking at spark plug wires I hope this information helps you out.
sehrgutcsg is offline   Reply With Quote Quick reply to this message
Old 04-05-2014, 11:35 AM   #10 (permalink)
Crowned Member
 
Lucy Dog's Avatar
 
Join Date: Aug 2008
Location: Connecticut
Posts: 6,896
Default

Quote:
Originally Posted by shepherdmom View Post
We have a code reader. It is not throwing codes. When it first started happening it was random misfire cylinder 8... Husband moved the coil to 6 and the next code it threw was 6 so he replaced that coil. The coil worked for about 2 weeks then went bad. You could really feel that. Code stayed on so he returned and replaced coil. Then it started moving around to 4 then back to 6 so he replaced the other 3 coils. It hasn't thrown a code since but you can still feel the intermittent misfire, especially when sitting at a stop sign and sometimes going uphill. This has been going on for a while now and it's making me crazy. Hubby says he will replace plugs this weekend and if that doesn't fix it, I'm going to have to take it to a dealer. Grrr.. Did I mention I HATE cars.
I don't think I've ever heard of a car actually misfire and not throw a code. Does your scanner show pending codes too? I've had cars that have misfired without the CEL coming on. I'll connect my scanner and there will be pending codes.

Typically, misfires are caused by a few things unless you're getting other codes: spark plugs, coils, injectors, electrical wiring, or ECU. That's pretty much it.

Smart moving the coil around from 8 to 6 to test it. That was going to be the first thing I recommend you doing, but he already did that. It's very obvious when a coil is completely bad because you lose a lot of power. It typically isn't a quick misfire and back to normal.

When was the last time he did the spark plugs? How many miles and years.

Fuel injectors are also a possibility, but it's pretty rare for them to fail. For all three to fail in a small time frame is a very low possibility.

If all of these things don't fix the problem, it's most likely something electrical. Wiring from the ECU to the coils can and do go bad. There could be a short somewhere in the wiring on cylinder 8 causing electrical issues to jump from 8 to 6 to 4. That's a real possibility. The ECU itself can also have a short somewhere and may need to be replaced. When you get into electrical stuff like this, you really need to know what you're doing and can get expensive.

Regardless what the problem is, be careful driving the car if it keeps misfiring. When a car misfires, unless the injectors aren't spraying fuel and that's causing the misfire, fuel is going to leak into your catalytic converters and eventually kill that too. Depending on the car, each cat installed usually runs about $400-$500 each at least. Enough misfires and it's going to kill your cat.
Lucy Dog is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the German Shepherd Dog 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:
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.


Thread Tools

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



All times are GMT -4. The time now is 10:27 AM.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.3.2
PetGuide.com
Basset Hound Forum Doberman Forum Golden Retriever Forum Beagle Forum
Boxer Forum Dog Forum Pit Bull Forum Poodle Forum
Bulldog Forum Fish Forum Havanese Forum Maltese Forum
Cat Forum German Shepherd Forum Labradoodle Forum Yorkie Forum Hedgehog Forum
Chihuahua Forum Retriever Breeds Cichlid Forum Dart Frog Forum Mice Breeder Forum