Generation III External Engine LS1 | LS6 | Bolt-Ons | Intakes | Exhaust | Ignition | Accessories
Sponsored by:
Sponsored by:

Please help with a problem I am having

Thread Tools
 
Search this Thread
 
Old Jun 30, 2010 | 05:05 PM
  #1  
Thealien's Avatar
Thread Starter
Launching!
iTrader: (2)
 
Joined: Oct 2009
Posts: 219
Likes: 3
Default Please help with a problem I am having

I installed a very low mileage 2005 5.3 into my 1972 GMC Jimmy. I have been getting a lean bank 1 code since I started it. Thinking it was an intake leak we used a smoke machine and found no leaks. Thought it might be a bad O2 so I replaced it. I brought it to a local tuner and he says cylinders 1 & 3 are not firing (manifold stays cold on those cylinders). He said compression is around 200 on both cylinders. There is an injector pulse and spark.

Could an injector be bad and not throw a code? Any suggestions? I spent 4 months doing this swap myself. Have a couple of good mechanics who have been unable to fix the problem. I am really getting frustrated, please help!

Mark
Reply
Old Jun 30, 2010 | 06:18 PM
  #2  
Darkman's Avatar
TECH Addict
iTrader: (2)
 
Joined: Apr 2009
Posts: 2,167
Likes: 6
From: Spring, Texas
Default

If you pull the plugs for #1 and #3 after running, are they wet or dry?

Have you tried swapping the #1 and #3 injectors with some of the others?
Reply
Old Jun 30, 2010 | 07:59 PM
  #3  
Thealien's Avatar
Thread Starter
Launching!
iTrader: (2)
 
Joined: Oct 2009
Posts: 219
Likes: 3
Default

Not yet. Just trying to get some ideas.
Reply
Old Jun 30, 2010 | 08:15 PM
  #4  
JUICED1's Avatar
FormerVendor
iTrader: (3)
 
Joined: Mar 2010
Posts: 245
Likes: 0
From: ILLINOIS
Default

Make sure the injectore are pluged in all the way. Could be a loose conection.
Reply
Old Jun 30, 2010 | 08:17 PM
  #5  
mark_H14's Avatar
Registered User
 
Joined: Jan 2010
Posts: 11
Likes: 0
Default

i would say that it is also a loose connection..

Reply
Old Jul 1, 2010 | 04:48 AM
  #6  
Thealien's Avatar
Thread Starter
Launching!
iTrader: (2)
 
Joined: Oct 2009
Posts: 219
Likes: 3
Default

Wouldn't a loose connection throw a code?

We are getting an injector pulse signal. We are getting spark.

Thanks
Reply
Old Jul 1, 2010 | 08:51 PM
  #7  
JUICED1's Avatar
FormerVendor
iTrader: (3)
 
Joined: Mar 2010
Posts: 245
Likes: 0
From: ILLINOIS
Default

Unplug it and check, that way you know for sure. I can't say I"ve ever left any unplugged before.
Reply
Old Jul 1, 2010 | 11:22 PM
  #8  
OMGWTFBODY's Avatar
TECH Enthusiast
iTrader: (5)
 
Joined: Mar 2007
Posts: 614
Likes: 1
From: Huntsville, AL
Default

With an injector unplugged, the motor will run like ****. It will not throw a code until it reaches closed loop. With 2 misfiring, it will take a while.

After closed loop is reached, it will flash SES and go into limp mode.

I don't wanna know how I know this.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
Old Jul 2, 2010 | 04:52 AM
  #9  
Thealien's Avatar
Thread Starter
Launching!
iTrader: (2)
 
Joined: Oct 2009
Posts: 219
Likes: 3
Default

That is the strange thing, no misfire codes. The engine has been run quite a bit (50 miles) and is not in limp mode?

The only code I have gotten is lean bank 1?
Reply
Old Jul 3, 2010 | 11:26 AM
  #10  
Thealien's Avatar
Thread Starter
Launching!
iTrader: (2)
 
Joined: Oct 2009
Posts: 219
Likes: 3
Default

Well I bought some used injectors with only about 100 miles on them. The number 1 injector was very clogged. I replaced 1 & 3 and it is running much better now. I am thinking of sending them off for cleaning and flow matching. Any suggestions on where to send them?
Reply
Old Jul 3, 2010 | 02:22 PM
  #11  
Thealien's Avatar
Thread Starter
Launching!
iTrader: (2)
 
Joined: Oct 2009
Posts: 219
Likes: 3
Default

Here is the injectors for cylinders 1 & 3

Reply
Old Jul 6, 2010 | 09:09 PM
  #12  
JUICED1's Avatar
FormerVendor
iTrader: (3)
 
Joined: Mar 2010
Posts: 245
Likes: 0
From: ILLINOIS
Default

Good catch on the dirty injector. How many miles did your old ones have where they got that clogged. No clue where to get them cleaned. Sorry.
Reply




All times are GMT -5. The time now is 02:01 AM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE