Go Back  CorvetteForum - Chevrolet Corvette Forum Discussion > Off Topic > Off Topic
Reload this Page >

SBC Chevy (396ci) cylders 1-4 not firing correct?

Off Topic Off Topic | Non-Corvette

SBC Chevy (396ci) cylders 1-4 not firing correct?

 
Old 03-15-2019, 12:04 PM
  #21  
TorchRedRocket
CF Senior Member
 
TorchRedRocket's Avatar
 
Member Since: May 2010
Location: Winfield IN
Posts: 8,283
Thanks: 0
Thanked 3 Times in 3 Posts
Default

Originally Posted by GEODON View Post
sounds like a shitbox. Something you would see at a parking lot at walmart at 11 at night
TorchRedRocket is online now  
Old 03-15-2019, 12:06 PM
  #22  
Nowhere Man
CF Senior Member
 
Nowhere Man's Avatar
 
Member Since: Feb 2003
Location: Sitting in his Nowhere land Hanover Pa
Posts: 34,107
Thanked 1,509 Times in 1,368 Posts
2015 C2 of Year Finalist
Default

Cracked distributor cap
Nowhere Man is online now  
Old 03-15-2019, 12:40 PM
  #23  
wcsinx
CF Senior Member
 
wcsinx's Avatar
 
Member Since: Mar 2002
Posts: 23,137
Thanked 35 Times in 34 Posts
Default

Originally Posted by mrscott25 View Post
For real...Check for sticky/leaking floats on the front carb. The dual carbs coupled with the tunnel ram and only problems with cyl. 1-4 points toward an issue in the carb.
This is the most likely possibility. You said the 1-4 plugs were wet ... prob. a stuck float flooding out one of half of your motor.
wcsinx is online now  
Old 03-15-2019, 02:09 PM
  #24  
flange
CF Senior Member
 
flange's Avatar
 
Member Since: Aug 2012
Location: resting comfortably in my mind
Posts: 15,081
Thanked 36 Times in 13 Posts
St. Jude Donor '14
Default

Originally Posted by 96 Vette CE View Post
flange is offline  
Old 03-15-2019, 02:10 PM
  #25  
snide
CF Senior Member
 
snide's Avatar
 
Member Since: Dec 2000
Location: You can lead a person to knowledge, but you can't make him think. - snide The problem with the gene
Posts: 84,117
Thanked 149 Times in 60 Posts
CI 4-5-7-8-9-10 Veteran
St. Jude Donor '07-'08-'09-'10-'11
Default

Where's that guy who had "396" in his username? Surely Shirley he'd have some great advice knowledge bullshit.
snide is online now  
Old 03-15-2019, 02:12 PM
  #26  
Der Flieger
CF Senior Member
 
Der Flieger's Avatar
 
Member Since: Oct 2004
Posts: 9,878
Thanked 18 Times in 6 Posts
Default

Typical DJ project. ***** it up and then runs to CFOT, (of all places), for advice. Just call a mechanic, DJ, there are some left around.
Der Flieger is offline  
Old 03-15-2019, 02:13 PM
  #27  
ptindall
CF Senior Member
 
ptindall's Avatar
 
Member Since: Aug 2006
Location: Picking on the weakest kid in the yard.
Posts: 26,221
Thanked 35 Times in 18 Posts
Default

Originally Posted by Sunset-C6 View Post
Swap carbs front to back, does problem follow carbs?
Beat me to it.

Last edited by ptindall; 03-15-2019 at 02:13 PM.
ptindall is offline  
Old 03-15-2019, 02:16 PM
  #28  
flange
CF Senior Member
 
flange's Avatar
 
Member Since: Aug 2012
Location: resting comfortably in my mind
Posts: 15,081
Thanked 36 Times in 13 Posts
St. Jude Donor '14
Default

I checked my old chilton for hot rods repair manual. it says the first thing to check for is a light at the end of a tunnel ram.
flange is offline  
Old 03-15-2019, 02:25 PM
  #29  
K-Spaz
CF Senior Member
 
K-Spaz's Avatar
 
Member Since: Jul 2012
Location: Central PA. My AR-15 identifies as a muzzleloader
Posts: 27,339
Thanked 204 Times in 167 Posts
I believe in the Beer Fairy
Default

TBI Ftw!
K-Spaz is offline  
Old 03-15-2019, 02:26 PM
  #30  
SilverC1
CF Senior Member
 
SilverC1's Avatar
 
Member Since: Feb 2005
Location: SF Bay Area California
Posts: 10,951
Thanks: 0
Thanked 11 Times in 9 Posts
Default

Originally Posted by motor city dave View Post
Wait until dark... or pull the car inside garage cover windows and shut door and turn off any lights.
Have someone turn car over.....watch the sparks jump.
If you have an inductive-coupling timing light (with the probe that clamps around the plug wire), you can use it on each of the plug wires in turn, to see if they are all triggering the timing light. The timing readings won't make any sense (other than on cyl. 1), but getting the flashes will at least give an indication that that particular plug and wire is firing.

(It also works if the timing light has to be connected between the plug wire and the spark plug, but just takes a bit longer to go through all of the cylinders.)

Last edited by SilverC1; 03-15-2019 at 02:27 PM.
SilverC1 is online now  
Old 03-15-2019, 02:30 PM
  #31  
Klondike
CF Senior Member
 
Klondike's Avatar
 
Member Since: Feb 2006
Location: San Antonio Texas
Posts: 10,434
Thanked 94 Times in 77 Posts
Default

Sounds like a Front carb problem. Float too high or leaking float, or power valve got popped from a backfire and is leaking causing over rich on the primary jets. (old Holley problem)
Klondike is offline  
Old 03-15-2019, 04:30 PM
  #32  
ratflinger
NCM Grand Opening Veteran
Support Corvetteforum!
 
ratflinger's Avatar
 
Member Since: Sep 2005
Location: Obscurification is a practicable art!
Posts: 14,582
Thanked 38 Times in 31 Posts
St. Jude Donor '11, '17
Default

Originally Posted by snide View Post
Where's that guy who had "396" in his username? Surely Shirley he'd have some great advice knowledge bullshit.
Didn't he write the code that ran the Holley's? Seems like he was selling an app to auto-tune them also
ratflinger is offline  
Old 03-15-2019, 05:44 PM
  #33  
DJ_Critterus
CF Senior Member
Thread Starter
 
DJ_Critterus's Avatar
 
Member Since: Jan 2006
Location: FL.... America's Wang! No shrinkage. Winter's not coming!
Posts: 50,060
Thanked 75 Times in 46 Posts
St. Jude Donor '09
Default

It's following the carbs and I found the rear bowl leaking on the front carb. Got new gaskets coming.

Oh, should have mentioned I'm running an MSD ignition limited at 6.5K rpm. Never liked these double pumper carbs so I'll probably look for two carters or edelbrocks like I used to have on there.
DJ_Critterus is offline  
Old 03-15-2019, 09:37 PM
  #34  
JackDidley
CF Senior Member
 
JackDidley's Avatar
 
Member Since: Sep 2003
Location: Database Error Indiana
Posts: 16,087
Thanked 21 Times in 20 Posts
Default

Take off a valve cover and see if the intake valves are opening. A bad cam can do strange stuff and cams today seem to wear out just for the fun of it.
Drive by post for 2019.
JackDidley is offline  
Old 03-15-2019, 10:42 PM
  #35  
rgregory
CF Senior Member
 
rgregory's Avatar
 
Member Since: Oct 1999
Location: Arlington TX
Posts: 7,670
Thanked 65 Times in 44 Posts
Default

My Vette has an edelbrock carburetor and I had the same issue one time The right side of the engine was not firing though it had spark. I have a single plane manifold so I was not suspecting a carb issue since the left side was firing. What it turned out to be was the right side float was stuck so no gas on the right side of the carb. So even though the car has a single plane manifold it still wasn't getting any gas on the right side which surprised me.
rgregory is offline  
Old 03-15-2019, 11:01 PM
  #36  
Mikeceli
CF Senior Member
 
Member Since: Sep 2002
Location: Petaluma CA
Posts: 11,465
Thanks: 0
Thanked 6 Times in 6 Posts
Default

Originally Posted by Sunset-C6 View Post
Swap carbs front to back, does problem follow carbs?


Check for vacuum leaks also. W/ carb spray (be careful) or modified propane torch, etc.
Mikeceli is offline  
Old 03-18-2019, 10:52 AM
  #37  
DJ_Critterus
CF Senior Member
Thread Starter
 
DJ_Critterus's Avatar
 
Member Since: Jan 2006
Location: FL.... America's Wang! No shrinkage. Winter's not coming!
Posts: 50,060
Thanked 75 Times in 46 Posts
St. Jude Donor '09
Default

Originally Posted by JackDidley View Post
Take off a valve cover and see if the intake valves are opening. A bad cam can do strange stuff and cams today seem to wear out just for the fun of it.
Drive by post for 2019.
They're opening. It's a full roller motor and I have my valves set correctly using the EOIC method. I have two full rebuild kits for both carbs on the way and will rebuild them this weekend.
DJ_Critterus is offline  
Old 03-18-2019, 06:13 PM
  #38  
leadfoot4
CF Senior Member
 
leadfoot4's Avatar
 
Member Since: May 2001
Location: Western NY
Posts: 57,885
Thanked 401 Times in 370 Posts
Default

Originally Posted by Sunset-C6 View Post
Swap carbs front to back, does problem follow carbs?
Good idea. Or, give the float bowl of the front carb a tap or two, with a plastic hammer. Could be a stuck float or some debris stuck in the needle/seat assembly.
leadfoot4 is offline  
Old 03-18-2019, 11:28 PM
  #39  
centuryoldracer
CF Senior Member
 
Member Since: Apr 2015
Posts: 6,108
Thanked 61 Times in 54 Posts
Default

Originally Posted by DJ_Critterus View Post
Can't figure out why they aren't firing correct. I have 180psi on all cylinders, new plugs, and wires, Weiand tunnel ram w/ dual carbs. Timing is correct and hasn't changed. I have zoomie headers on the car and the first four pipes aren't as hot as the last four.

I am getting spark to all cylinders. old plugs looked a little wet, but this is the first time I've seen them like this in the 6 years I've had this motor in it and less than 1K miles on it.
Plug wires are on wrong
centuryoldracer is offline  
Old 03-18-2019, 11:31 PM
  #40  
centuryoldracer
CF Senior Member
 
Member Since: Apr 2015
Posts: 6,108
Thanked 61 Times in 54 Posts
Default

Originally Posted by DJ_Critterus View Post
It's following the carbs and I found the rear bowl leaking on the front carb. Got new gaskets coming.

Oh, should have mentioned I'm running an MSD ignition limited at 6.5K rpm. Never liked these double pumper carbs so I'll probably look for two carters or edelbrocks like I used to have on there.
Take the cap off and make sure all 8 of the little wings that trigger the spark are on there. I have a MSD distributor that 2 of them had broken off.
centuryoldracer is offline  

Thread Tools
Search this Thread
Quick Reply: SBC Chevy (396ci) cylders 1-4 not firing correct?


Sponsored Ads
Vendor Directory

Contact Us - About Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: