2001 GT running rich - Page 2 - MustangForums.com


4.6L General Discussion This section is for non-tech specific information pertaining to 4.6L (Modular) Mustangs built from 1996 to 2004.

Reply
 
 
 
Thread Tools Search this Thread
Old 09-17-2012, 07:08 AM   #11
camhar25
Thread Starter
 
Join Date: Aug 2009
Location: North carolina
Posts: 11
Default Rich

Took the car to the stealer last week for diagnosis.They said the airflow meter numbers were way out of wack.Changed the airflow meter and the car is still running rich and the idle is up and down or stalling out.Blowing black smoke when idling and still no check engine light.Any ideas?I also instlled a new idle air control valve,and a temp sensor thinking these could be bad.In all my experience the check engine light should be on.
camhar25 is offline   Reply With Quote
Old 09-17-2012, 08:33 AM   #12
cliffyk
TECH SAVANT
 
cliffyk's Avatar
 
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,924
Default

Quote:
Originally Posted by schmallz View Post
Hey cliffy,

I'm throwing p1152, and only p1152(and p1000) i've swapped the o2 sensor from side to side, changed nothing. So i then decided to take the car down to JBA in San Diego.

They have tested the wiring harness and even managed to hook up the o2 sensor directly to the ECU. Still acted funny. The heater core in the o2 sensor isn't heating up for what ever reason. After a full day of testing and diagnosis, they still are at a complete loss for what is going on.

It idles fine when I start it up, but when I start crusing in 3rd gear or higher it will sputter as the short term FT slowly climps to 1.250(I can watch this on my tuner)

Any ideas?
Sorry I missed this--the OČ sensor heaters are all connected to the same +12V source, the same source that powers the EVAP stuff, and switched to ground via MOSFET transistors in the PCM.

If the heater is not being powered as it should then there is a wiring problem with the +12 V source or the switched ground wire running back to the PCM--or, sit down for this, the MOSFET in the PCM is blown.

Here is a kludgy sort of test/solution. Get an older 4-wire OČ sensor with a 6.0 Ω heater; on our stock sensors the heater is 3.3 Ω, more about this in a bit. The Bosch 13275 is a good pick as it was used on a bunch of mid-90s cars and is usually cheap--$25 to $30.

The 3.3 Ω heaters cannot be continuously powered without burning up, however the older 6.0 Ω units can be--so installed the older sensor with the sensor output wires connected normally, but with the heater wires connected to ground and a switched (HOT in run) +12 V source that can supply at least 3 A.

This will result in a functioning, continuously heated OČ sensor that will make the PCM happy...
cliffyk is offline   Reply With Quote
Old 09-17-2012, 08:46 AM   #13
cliffyk
TECH SAVANT
 
cliffyk's Avatar
 
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,924
Default

Quote:
Originally Posted by camhar25 View Post
Took the car to the stealer last week for diagnosis.They said the airflow meter numbers were way out of wack.Changed the airflow meter and the car is still running rich and the idle is up and down or stalling out.Blowing black smoke when idling and still no check engine light.Any ideas?I also instlled a new idle air control valve,and a temp sensor thinking these could be bad.In all my experience the check engine light should be on.
They didn't charge you for the new MAF did they? If so then at least get the old one back from them.

As I said in an earlier post failing front OČ sensors would cause this, and could do it for a while without throwing a DTC; monitoring the short term fuel trims will also reveal this situation. The OČ sensors cannot be properly tested in situ without an oscilloscope, however armed with a scope their output at idle should look like this:



The signal will oscillate ("switch") 3 to 4 times per second between 0.2 V and 0.85 V. However the voltage range can be as low as 0.0 V to 0.6 V and still not throw a DTC, thing is this will be telling the PCM the mix is lean and it will compensate by adding fuel--up to +25% before throwing a code.
cliffyk is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
How to get good HP out of a 4.6 without spending big bucks. Luke9222 4.6L General Discussion 19 10-23-2015 12:55 AM
Code troubleshooting Jb145700 4.6L V8 Technical Discussions 8 09-24-2015 05:08 PM
01 Mustang Overheating :( MusicCity615 General Tech 7 09-12-2015 08:05 AM
New member and just bought my first mustang Luke9222 New Member Area 7 09-04-2015 07:46 AM
Speedometer issue after tuning articman General Tech 0 09-04-2015 05:42 AM


Tags
1996, 2001, 302, 46, 97, bad, burning, car, coil, ford, gt, mustang, oil, rich, running, runs

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

Forum Jump


All times are GMT -5. The time now is 04:31 PM.