Scantool shows different readings than DMM - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

Reply
 
 
 
Thread Tools Search this Thread
Old 06-23-2006, 06:20 PM   #1
Member
Posts like a V-Tak
Thread Starter
 
Join Date: Jan 2005
Location: Columbus, OH
Posts: 66
Thanks: 0
Thanked 1 Time in 1 Post
jaye22 is on a distinguished road
Default Scantool shows different readings than DMM

Hello...
I am going to blow this car up. I still have a miss that is driving me crazy. I pulled the #2 injector pigtail while running and no difference... plug was NOT fouled nor burnt from lack of fuel. after checking things and replacing the plug that I dropped (oops) it changes the idle when pulled now (as do the other 5.) While having my Scantool on there (Actron CP9110) my voltage only shows 12.8 while my DMM shows 13.8... what is the deal with this? Could this be the problem with my weird miss?
jaye22 is offline   Reply With Quote
Old 06-23-2006, 10:43 PM   #2
Senior Member
True Car Nut
 
Join Date: Feb 2006
Location: Somewhere different on the globe every month....
Posts: 2,896
Thanks: 0
Thanked 0 Times in 0 Posts
Cheetah is on a distinguished road
Default

I am assuming the DMM is the Digital Multi Meter?

Before you blow the thing up, see if you have voltage at the pulg for the injector, I am curious to know if each injector has its own fuse. I do not know
Cheetah is offline   Reply With Quote
Old 06-24-2006, 01:43 AM   #3
Member
Posts like a V-Tak
Thread Starter
 
Join Date: Jan 2005
Location: Columbus, OH
Posts: 66
Thanks: 0
Thanked 1 Time in 1 Post
jaye22 is on a distinguished road
Default

i have 12~13 Volts at the injectors...
jaye22 is offline   Reply With Quote
Old 06-24-2006, 02:40 AM   #4
Senior Member
Certified GM nut
 
Join Date: May 2005
Location: Wickliffe, Ohio
Posts: 2,155
Thanks: 0
Thanked 0 Times in 0 Posts
McGrath is on a distinguished road
Default

Maybe check the gap on the plugs ( .060" )and check the ignition coils resistance per directions in "Tech Info" and report back.

Ed
McGrath is offline   Reply With Quote
Old 06-24-2006, 07:17 AM   #5
Senior Member
True Car Nut
 
Join Date: Aug 2004
Location: In your garage, swipin' da lug nutz
Posts: 3,067
Thanks: 0
Thanked 0 Times in 0 Posts
sandrock is on a distinguished road
Default

Just for craps n' grins, have you tried reseating ALL the main connectors in the engine bay? There are 2 big ones (one I am pretty sure has the injector wires on it) right near the alternator (which btw if you have leaky valve cover gaskets these will be rather nasty looking), and then there is the main connector at the firewall (I would not suspect this but one never knows).
sandrock is offline   Reply With Quote
Old 06-24-2006, 07:26 AM   #6
Senior Member
True Car Nut
 
Join Date: Feb 2006
Location: Somewhere different on the globe every month....
Posts: 2,896
Thanks: 0
Thanked 0 Times in 0 Posts
Cheetah is on a distinguished road
Default

Have you checked the resistance of the injector to make sure its good?
Cheetah is offline   Reply With Quote
Old 06-25-2006, 12:29 AM   #7
Member
Posts like a V-Tak
 
Join Date: Feb 2003
Location: st. louis
Posts: 96
Thanks: 0
Thanked 0 Times in 0 Posts
techy is on a distinguished road
Default

Try noid light to see if injector pulse is steady?
techy is offline   Reply With Quote
Old 06-25-2006, 08:50 AM   #8
Senior Member
Certified Car Nut
 
Join Date: Oct 2003
Posts: 19,756
Thanks: 0
Thanked 0 Times in 0 Posts
1993 SLE is on a distinguished road
Default

are you sure that its the injector??

there are a lot of things that can cuase a miss...

have you checked the coils?
have you done a compression test?
1993 SLE is offline   Reply With Quote
Old 06-25-2006, 09:07 PM   #9
PopaDopaDo
True Car Nut
 
popatim's Avatar
 
Join Date: Jan 2005
Location: NY
Posts: 4,957
Thanks: 0
Thanked 0 Times in 0 Posts
popatim is on a distinguished road
Default

Injectors are typically supplied 12v as long as they key is on and the computer fires them by grounding its other wire. The transistor for that wire inside the computer* could be fried or a problem in the wire.


* depends on the injection type, sequential injection typically fires them individually.
popatim is offline   Reply With Quote
Old 06-26-2006, 09:15 AM   #10
Member
Posts like a V-Tak
Thread Starter
 
Join Date: Jan 2005
Location: Columbus, OH
Posts: 66
Thanks: 0
Thanked 1 Time in 1 Post
jaye22 is on a distinguished road
Default

I switched the computer with a known good and problem still persists. Any more suggestions? Could the BCS be bad? anyone know the symptoms for this piece?
jaye22 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
How to measure ohms with a DMM? raptor660 Audio (and aftermarket electronics) 13 10-07-2010 08:24 PM
02 Sensor Readings (2 Scantool Vids) Lowrider0308 1992-1999 6 08-29-2007 06:16 PM
DMM and remote turn on FiReDeViL Audio (and aftermarket electronics) 5 04-21-2007 12:21 AM
Scantool Ownership Update--Reply only if you have a Scantool 95BonnevilleSESC Lounge 14 01-29-2004 09:18 AM
MAF Scantool Readings mremer 2000-2005 4 01-13-2004 10:19 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not 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 Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 12:25 PM.


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.