LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

missing, backfiring...please help

Thread Tools
 
Search this Thread
 
Old 09-23-2006, 10:18 AM
  #1  
Registered User
Thread Starter
 
blk1994z's Avatar
 
Join Date: Sep 2003
Location: bowmanstown, pa
Posts: 274
missing, backfiring...please help

I have done numerous searches and tried a couple different things which i will list. I installed a new fuel pump, filter, pressure reg, wires, plugs. Fuel pressure is about 46psi. I also installed new o2 sensors. When i start my car it has a rought idle, it crackles though the exhaust, hesitates pretty bad once i start driving it. The opti is an OEM unit and has about 10k miles on it. I checked for spark at the coil, that is good also. I checked the wiring for the o2 sensors, and injectors and that also is good. Any ideas what could be wrong here? The left side runs lean, and the right side runs rich. Also this is kinda weird, it just started doing this. When i turn the key on aux the pump primes and i get 46psi, than for about 10 seconds after that i can hear fuel running but its not leaking or loosing pressure? Than once those 10 seconds are up i hear a click(relay)? and the pressure drops to 40 and holds there?
blk1994z is offline  
Old 09-23-2006, 10:21 AM
  #2  
Registered User
 
klrz28's Avatar
 
Join Date: Aug 2003
Posts: 328
Re: missing, backfiring...please help

check your plugs and wires, i bet money on thats your problem lt1's love to eat plug wires.
klrz28 is offline  
Old 09-23-2006, 04:01 PM
  #3  
Registered User
 
Redchevcam's Avatar
 
Join Date: Apr 2005
Location: Allen, Tx north of Dallas
Posts: 39
Re: missing, backfiring...please help

Possible that when you were replacing wires....that you got some of the wires mixed up. I did that...twice! im a friggin idiot. i did everything in my right mind to get it to stop backfiring. Then after much drama, i traced all the wires back and sure enought 6 and 2 were switched....i have no idea how...i had them numbered and everything. But as soon as i did that it was fixed. Also check the plugs....if u are running crappy champion or some low grade plug....then it will back fire and miss.
Redchevcam is offline  
Old 09-24-2006, 08:59 AM
  #4  
Registered User
Thread Starter
 
blk1994z's Avatar
 
Join Date: Sep 2003
Location: bowmanstown, pa
Posts: 274
Re: missing, backfiring...please help

i checked the wires 3 times, even took them all off and re installed them. also the plugs are new ngk's.
blk1994z is offline  
Old 09-24-2006, 10:16 AM
  #5  
Registered User
 
klrz28's Avatar
 
Join Date: Aug 2003
Posts: 328
Re: missing, backfiring...please help

check the plugs with a ohm meter they all should be really close to the same...what gap you have em at? if u dont have ltcc u should be around .035-.040. if that isnt it it could be your opti or ignition module...if your positive its not the plugs. its one or the other.. how many miles on the opti? do you have msd ? msd's wear them opti' out

Last edited by klrz28; 09-24-2006 at 10:24 AM.
klrz28 is offline  
Old 09-24-2006, 07:06 PM
  #6  
Registered User
Thread Starter
 
blk1994z's Avatar
 
Join Date: Sep 2003
Location: bowmanstown, pa
Posts: 274
Re: missing, backfiring...please help

Opti has about 10k new plugs,wires. Plugs gapped at .050, i have a msd coil. I guess ill have to try the igm, than opti.
blk1994z is offline  
Old 09-25-2006, 05:44 AM
  #7  
Guest
 
Guest47904's Avatar
 
Join Date: Sep 2004
Posts: 0
Re: missing, backfiring...please help

Don't know that much about MSD replacement coils but pull it off and look very closely at the body for tell tale white marks or any cracks no matter how small. These are indications of spark shorting to the laminations.
Guest47904 is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
93 RedBird
Fuel and Ignition
4
11-15-2015 08:24 AM
Z28ELECTRICIAN
New Member Introduction
2
10-19-2015 06:36 AM
Bigfatrat
Parts Wanted
2
10-04-2015 08:54 PM
Ks0209
LT1 Based Engine Tech
10
10-01-2015 07:32 AM
tommalcolm
Computer Diagnostics and Tuning
2
09-11-2015 03:39 PM



Quick Reply: missing, backfiring...please help



All times are GMT -5. The time now is 12:39 AM.