Engine & Transmission Post your Engine and Transmission related problems here.
Sponsored by:
Sponsored by:

1996 S10 Blazer 4.3L backfires on startup only

  #1  
Old 11-13-2010, 12:34 PM
New Member
Thread Starter
Join Date: Nov 2010
Posts: 4
Iesa is on a distinguished road
Default 1996 S10 Blazer 4.3L backfires on startup only

I can sure use some help with something that has been going on about 3 months. Whenever I start my 96 Blazer it pops 2-3 backfires, sounds like nearer the front rather than tailpipe; then after that it runs just fine, not rough at all. This problem is worse when it is cold; after the engine has warmed up, and even sits for 2-4 hours, it will always start, sometimes with the popping sounds, sometimes starting normally as it is supposed to do. A couple of times, it refused to start at all, so I decided to try something--I drilled a small hole for easier access into the plastic air intake just above the throttle body ( I use a small metal screw to seal it afterwards.). I then sprayed some starter fluid into the throttle area beneath the hole I drilled. The car started right up! So, this tells me, at least I think it tells me, that it may be a fuel delivery problem. I still have not fixed the problem, but I need some good help in what I should diagnose. I will appreciate any and all suggestions.
 
  #2  
Old 11-13-2010, 06:01 PM
Rottidog's Avatar
BF Veteran
Join Date: Sep 2008
Location: Winnipeg, Manitoba
Posts: 2,523
Rottidog has a spectacular aura aboutRottidog has a spectacular aura about
Default

Sounds like an issues I had with an '80 GM Sierra Grande years back. The coil was shot, it would start sometimes & other times not. Frusterating as all hell & it backfired once & sent the muffler into the great wide yonder (never found it or even parts of it lol) Also could be a timing issue & yeah, fuel delivery. Have you checked the fuel pump, hear it spin up when you turn the key to Run but don't start it?
 
  #3  
Old 11-13-2010, 07:04 PM
swartlkk's Avatar
Administrator
Join Date: May 2005
Location: Waterloo, NY
Posts: 40,802
swartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond repute
Default

I would start with a fuel pressure test. See what it goes up to as well as whether it bleeds down after the pump shuts off. The details are in the link found in my signature.
 
  #4  
Old 11-14-2010, 03:30 PM
New Member
Thread Starter
Join Date: Nov 2010
Posts: 4
Iesa is on a distinguished road
Default

When I replaced the fuel filter, I turned the ignition on in order to see if the fuel pump was pushing ample fule out; it squirted out about 4-5 inches, which I figured made the fuel pump good. I will resort to a pressure test soon. I had autozone put a code reader on it and no codes showed and it read as a "pass". Thank you both so much for responding by the way.
 

Last edited by Iesa; 11-14-2010 at 03:31 PM. Reason: Forgot to thank the responders.
  #5  
Old 11-14-2010, 03:43 PM
swartlkk's Avatar
Administrator
Join Date: May 2005
Location: Waterloo, NY
Posts: 40,802
swartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond reputeswartlkk has a reputation beyond repute
Default

The fuel pressure needs of your engine are very specific. A gauge is the only way to verify that the pump is functioning properly.
 
  #6  
Old 11-17-2010, 08:38 AM
New Member
Thread Starter
Join Date: Nov 2010
Posts: 4
Iesa is on a distinguished road
Default Thanks--redid the autozone scan

I went to a different autozone location and the scan showed there that it was o2 sensors or catalytic converter. Could these sensors malfunctioning make it backfire on startup only?

2nd question: is there a relay somewhere under the hood for these sensors? (the fuse box next to driver side fuses # 4,5,9 and 10 were all good.)
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
chris015
1st Gen S-series (1983-1994) Tech
12
10-16-2010 09:58 PM
Finalman
Engine & Transmission
8
08-08-2010 12:35 PM
pacoton
Engine & Transmission
0
11-08-2009 08:56 AM
Bybsurfr32
2nd Gen S-series (1995-2005) Tech
6
11-01-2009 06:50 PM
bblazer123
Engine & Transmission
2
01-05-2008 05:42 PM


Thread Tools
Search this Thread
Quick Reply: 1996 S10 Blazer 4.3L backfires on startup only


Contact 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.