#30 injectors vs. Stock #24 - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 05-19-2010, 01:39 PM
Registered User
 

Last journal entry: More information
Last photo:
Join Date: Mar 2010
Location: santa monica, CA
Posts: 204
Wiki Edits: 0

Thanks: 5
Thanked 0 Times in 0 Posts
#30 injectors vs. Stock #24

Hi guys,

I had put some #30 accel fuel injectors into my 1996 impala LT1. It ran a bit rich, but it seemed OK. However, today i was sputtering all over the place, actually stalling out. The car started right back up, but as i stepped on the gas, i'd eventually start chugging and stall out again.

Is this due to the #30 injectors? I put them in because the #24 stock injectors i had were fouled. I never tuned to PCM to work with the #30's, i just assumed the PCM would adjust.

What do you think?
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 05-19-2010, 04:59 PM
Registered User
 
Last photo:
Join Date: Apr 2007
Location: Seattle, Wa
Posts: 6,437
Wiki Edits: 0

Thanks: 3
Thanked 331 Times in 288 Posts
Quote:
Originally Posted by tylerwerrin
Hi guys,

I had put some #30 accel fuel injectors into my 1996 impala LT1. It ran a bit rich, but it seemed OK. However, today i was sputtering all over the place, actually stalling out. The car started right back up, but as i stepped on the gas, i'd eventually start chugging and stall out again.

Is this due to the #30 injectors? I put them in because the #24 stock injectors i had were fouled. I never tuned to PCM to work with the #30's, i just assumed the PCM would adjust.

What do you think?
Bad assumption! That's a 25 percent increase in fuel flow with no other changes and it's everywhere from idle to WOT, either the engine cold or hot. The computer when new has about a 10% adjustment range. A 1996 uses Manifold Absolute Pressure (MAP) instead of directly measuring air flow as in Mass Air Flow (MAF) systems. The MAP system is a lot less capable of making adjustments to fuel quantity as it computes air flow rather than measures it. Since air flow hasn't changed, and the sensors that read it haven't changed their outputs, it has no real good way of knowing about the 25 percent more fuel till it gets into closed loop operation with the O2 sensors switched on. At that point they just see rich and try to dial the switched on time sequence back for the injectors. But with 25 percent excess flow and 10% authority to change that flow on their best day, that leaves the engine 15% too rich.

There's two solutions, back to 24 pound injectors or a pre-processor put onto the ODB II computer. Lots of web sites, just Google the question.

Bogie
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 05-20-2010, 01:11 PM
Registered User
 

Last journal entry: More information
Last photo:
Join Date: Mar 2010
Location: santa monica, CA
Posts: 204
Wiki Edits: 0

Thanks: 5
Thanked 0 Times in 0 Posts
:-( I hope i didn't cause any major problems! I ran it less than 5 miles like this... do you think its OK? I'm gonna swap the old injectors back in as soon as they are clean...
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 05-20-2010, 02:39 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 595 Times in 545 Posts
Quote:
Originally Posted by tylerwerrin
:-( I hope i didn't cause any major problems! I ran it less than 5 miles like this... do you think its OK? I'm gonna swap the old injectors back in as soon as they are clean...
In 5 miles most likely you didn't do any terminal damage.

The major concern would be if there were so much raw fuel introduced into the engine that the cylinders were "washed" of oil, this will lead to accelerated bore/ring wear.

My thought is that the engine will survive this indignity w/o any real problems. At worst, that 5 miles will be more like a couple thousand, wear-wise.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 05-20-2010, 03:05 PM
Registered User
 
Last photo:
Join Date: Apr 2007
Location: Seattle, Wa
Posts: 6,437
Wiki Edits: 0

Thanks: 3
Thanked 331 Times in 288 Posts
Quote:
Originally Posted by tylerwerrin
:-( I hope i didn't cause any major problems! I ran it less than 5 miles like this... do you think its OK? I'm gonna swap the old injectors back in as soon as they are clean...
Probably not.

Bogie
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
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.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Edelbrock Performer vs. Stock Intake crussell85 Engine 8 04-03-2010 08:34 AM
i want to make more power randy24devan Engine 16 01-02-2009 01:00 AM
Debating stock vs performance cam bearings CNC BLOCKS NE Engine 46 03-18-2008 11:03 AM
Stock TPI system on mild 383 Drewnashty Engine 38 03-12-2008 01:25 PM
stock vs. aftermarket intake darom Engine 13 11-03-2004 07:35 PM


All times are GMT -6. The time now is 09:24 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.