V6 Discussion and questions about the base carbureted or MPFI V6's and the rare SFI Turbo V6.

Can an ECM be bad and not know it?

Thread Tools
 
Search this Thread
 
Old Sep 30, 2009 | 04:24 PM
  #1  
ken3983's Avatar
Thread Starter
Senior Member
 
Joined: Oct 2001
Posts: 504
Likes: 1
From: reidsville,nc,usa
Car: 1989 Firebird Formula 350
Engine: 350 TPI
Transmission: 700R4
Axle/Gears: 9 Bolt Borg Warner 3.27 gears
Can an ECM be bad and not know it?

My car has been running like ****! I've got a new cap,rotor button, cleaned and re-gap the plugs, wires look good, checked timing, new fuel pump and FPR. Disconnected the battery to reset the ECM and drove it to reset the IAC. According to my scanner, the TPS is at .45v and it showing a rich condition. All the info looks like its in spec. The only thing I can think of is a bad ECM. The O2 sensor varies alot while driving. It can be at 700mv and drop to 40 and then back up again all over the place. It does change voltage rather rapidly which I think is normal. I have looked for vac leaks and can't find a thing. Maybe a bad eeec? This is driving me crazy!! Idle is bad with a 'skipping' and sputtering exhaust. Bad cat? HELP!

Ken
Reply
Old Sep 30, 2009 | 05:15 PM
  #2  
RBob's Avatar
Moderator
iTrader: (1)
 
Joined: Mar 2002
Posts: 18,432
Likes: 233
From: Chasing Electrons
Car: check
Engine: check
Transmission: check
Re: Can an ECM be bad and not know it?

Check the resistance of the injectors while they are hot. Any that are under 12 ohms are bad.

If they are the original Multec injectors just save yourself the trouble and put some nice Bosch ones in. See LinderTech and/or Southbay for replacements.

Note that to set the IAC and the ECM idle control, need to do an idle learn. Search with my name as the author along with 'idle' and 'learn' as key words.

RBob.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
skeltor
DFI and ECM
17
Feb 2, 2016 10:37 AM
88rscamar0
Transmissions and Drivetrain
5
Sep 23, 2015 09:08 PM
Billy Decker
Engine/Drivetrain/Suspension Wanted
0
Sep 4, 2015 03:46 PM
willyjoejr
Exhaust
2
Sep 3, 2015 09:26 AM
RyanJB
TPI
0
Sep 2, 2015 01:27 PM




All times are GMT -5. The time now is 05:26 PM.