5.0L (1979-1995) Mustang Technical discussions on 5.0 Liter Mustangs within. This does not include the 5.0 from the 2011 Mustang GT. That information is in the 2005-1011 section.

Bad Computer?

Thread Tools
 
Search this Thread
 
Old Jan 13, 2008 | 04:47 PM
  #1  
bbbngowc's Avatar
bbbngowc
Thread Starter
3rd Gear Member
 
Joined: Mar 2007
Posts: 787
From:
Default Bad Computer?

Just wondering what are some of the symptoms that I would see if my car's computer was bad? Prolly wouldn't start huh?
Old Jan 13, 2008 | 05:10 PM
  #2  
mjr46's Avatar
mjr46
D.R. THE PATHETIC DORK
 
Joined: Jun 2007
Posts: 30,871
From: West Virginia
Default RE: Bad Computer?

ORIGINAL: bbbngowc

Just wondering what are some of the symptoms that I would see if my car's computer was bad? Prolly wouldn't start huh?
uhhhh no not always...an ecm is the last thing you condem once you verify all power and grounds in the ecm are good and all inputs are good to the ecm....but it could cause it not to start....why is that your problem??/ cranks but won't start??? if so do you have spark?? fuel?? compression??
Old Jan 13, 2008 | 05:20 PM
  #3  
Kumdie's Avatar
Kumdie
 
Joined: Jan 2008
Posts: 6
Default RE: Bad Computer?

I have the same problem.. I replaced the distributor cap, spark plugs, mass air flow sensor, engine coolant sensor. I am getting a spark from the plugs and I check the fuel pressure and its good. According to this Haynes book the only other problem is something like "fuel management" so is that reffering to the ECU/ECM? I figure if the computer doesn't know how much gas to give it wont start or it is just automatically flooding itself (before I replaced the MAF I know for a fact the plugs were soaked in fuel which they might very well be again). I turn the key and it just sits cranking I used to get it started by giving it a little gas but now that seems to not even work. Anybody that can help either of us I can really use some input. Mabey even the timing is off? I just don't know any help is greatly appreciated.

Old Jan 13, 2008 | 05:55 PM
  #4  
mjr46's Avatar
mjr46
D.R. THE PATHETIC DORK
 
Joined: Jun 2007
Posts: 30,871
From: West Virginia
Default RE: Bad Computer?

ORIGINAL: Kumdie

I have the same problem.. I replaced the distributor cap, spark plugs, mass air flow sensor, engine coolant sensor. I am getting a spark from the plugs and I check the fuel pressure and its good. According to this Haynes book the only other problem is something like "fuel management" so is that reffering to the ECU/ECM? I figure if the computer doesn't know how much gas to give it wont start or it is just automatically flooding itself (before I replaced the MAF I know for a fact the plugs were soaked in fuel which they might very well be again). I turn the key and it just sits cranking I used to get it started by giving it a little gas but now that seems to not even work. Anybody that can help either of us I can really use some input. Mabey even the timing is off? I just don't know any help is greatly appreciated.

did you perform a koeo test and did you verify injector pulse and how did you know you had spark....did you use a spark checker at the plug and do you have fuel pressure?/ pump power up briefly in the koeo mode??
Old Jan 13, 2008 | 06:52 PM
  #5  
Joel5.0's Avatar
Joel5.0
5th Gear Member
 
Joined: Jan 2006
Posts: 3,926
From: Puerto Rico
Default RE: Bad Computer?

As Mjr46 said, you need to go through the testing procedures...... How to Solve an EFI NO START + DIY KOEO/KOER/Cylinder Balance Self-Test
Old Jan 13, 2008 | 07:03 PM
  #6  
Mustangkiler's Avatar
Mustangkiler
5th Gear Member
 
Joined: Dec 2005
Posts: 2,005
From:
Default RE: Bad Computer?

When you got lean and rich codes at the same time and its taking off by itself, thats what happened to me with my truck.
Old Jan 13, 2008 | 07:35 PM
  #7  
bbbngowc's Avatar
bbbngowc
Thread Starter
3rd Gear Member
 
Joined: Mar 2007
Posts: 787
From:
Default RE: Bad Computer?

The reason I asked, is because I got this new ODB Scanner that reads vehicles from 83-present. It's not reading my car. Keeps telling me "the vehicle is not responding".

The car starts. Timing is off. And some other stuff going on, wondered if changing the computer would prolly be the reason to the probs.
Old Jan 13, 2008 | 07:39 PM
  #8  
mjr46's Avatar
mjr46
D.R. THE PATHETIC DORK
 
Joined: Jun 2007
Posts: 30,871
From: West Virginia
Default RE: Bad Computer?

ORIGINAL: bbbngowc

The reason I asked, is because I got this new ODB Scanner that reads vehicles from 83-present. It's not reading my car. Keeps telling me "the vehicle is not responding".

The car starts. Timing is off. And some other stuff going on, wondered if changing the computer would prolly be the reason to the probs.
are you plugged into the connector under the hood????....you have to enter a mode that says koeo or koer on the scanner or memory codes
Old Jan 13, 2008 | 07:53 PM
  #9  
Kumdie's Avatar
Kumdie
 
Joined: Jan 2008
Posts: 6
Default RE: Bad Computer?

Yes I preformed the KOEO test two things that came up as a potential problem one caused by the MAF which has just been replaced, and "heated oxygen sensor indicated lean or rich right side". I pulled a plug and grounded it on the side of the motor and verified spark. I used a fuel pressure guage which said I had 32 psi.
Old Jan 14, 2008 | 07:08 AM
  #10  
bbbngowc's Avatar
bbbngowc
Thread Starter
3rd Gear Member
 
Joined: Mar 2007
Posts: 787
From:
Default RE: Bad Computer?

ORIGINAL: mjr46

ORIGINAL: bbbngowc

The reason I asked, is because I got this new ODB Scanner that reads vehicles from 83-present. It's not reading my car. Keeps telling me "the vehicle is not responding".

The car starts. Timing is off. And some other stuff going on, wondered if changing the computer would prolly be the reason to the probs.
are you plugged into the connector under the hood????....you have to enter a mode that says koeo or koer on the scanner or memory codes
Is there another connector than the 2 under the hood on the drivers side? This is what I'm connected to. When I run the KOEO mode I get "this vehicle is not responding" When I run the Timing Mode, it goes through the process, but then it just stays on "retrieving codes. Please wait...." It never finishes retrieving codes.




All times are GMT -5. The time now is 08:35 PM.