Go Back   Ford Truck Enthusiasts Forums > Diesel > 1999 - 2003 7.3L Power Stroke Diesel
Sign in using an external account
Register Forgot Password?


1999 - 2003 7.3L Power Stroke Diesel SPONSORED BY:

Reply
 
 
 
 
LinkBack Thread Tools Search this Thread
  #1  
Old 02-01-2007, 02:45 AM
davhut davhut is offline
Senior User
 
Join Date: Mar 2005
Posts: 112
davhut is starting off with a positive reputation.
Question 2000 7.3L Map Sensor Operation???

Hello all. Looking for a Factory Ford Tech or other knowledgable person to explain the operation of the Map sensor on the 2000 7.3L engine. Some background is in order; I've had the truck for a few years and had noted some electrical issues related to crappy connections. I had previously cleaned the in-cab connections as well as those located at the rear but had not done the engine compartment. This cleared up a number of problems. The fun started after doing same under hood. My fuel mileage dropped from a reliable 18 city to 12Mpg or so. I have examined the input to the ECM using both a Snapon MT2500 scantool & the Ford NGS tool & see some strange behavior. I notice that the ECM when first powered has a default value of 57Hz for the variable freq MAP input as well as the Variable DC Voltage (0-5v). The 57Hz value is present until the engine is shutdown & restarted, at which I see a value of 0Hz (I suspect it's the computer locking the input out as out of range). I have been all through the factory service documentation & have searched other places. I have seen 2 different answers to the question as to what signal the MAP sensor passes to the ECM. One lists a DC voltage between 0 & 5v while the other lists a variable frequency signal of between ~50Hz & 150Hz or so.Now for the reason for the interest; my fuel milage sudenly dropped from ~18mpg in town to ~12mpg. That's when I ran the scan tests above. What I am trying to remember is what I saw for the MAP variable freq input when I looked a year ago - I keep thinking I saw readings in the ~80-160Hz region. So, I am trying to determine just what I should have for the input; variable freq or DCV signal (or both?). I keep thinking this may be it as my mileage is very good when I first fire it up (after reseting the ECM) while my performance is every bit as good as it is with the signal suppressed by the ECM (0Hz) but my mileage goes to pot. I have tried both a new MAP sensor & a new ECM with the same results as above. The wiring also checks out, hence my question to the Ford Tech Community above. Thanks in advance for any input.
Reply With Quote
Old 02-01-2007, 02:45 AM
 
 
 
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Some great sensor information fordpride 1999 - 2003 7.3L Power Stroke Diesel 14 09-07-2014 03:00 PM
Temperature, Pressure vs Voltage - Troubleshooting whitetmw 1999 - 2003 7.3L Power Stroke Diesel 1 07-11-2014 06:56 PM
Severe Driveability: Possible dead ECM? rchalmers3 1987 - 1996 F150 & Larger F-Series Trucks 20 10-21-2010 03:45 PM
MAP sensor value dlburch 1999 - 2003 7.3L Power Stroke Diesel 4 01-12-2008 11:47 PM
Flex-Fuel Gurus MazdaRangerGuy Ranger & B-Series 18 05-02-2007 10:42 PM


Go Back   Ford Truck Enthusiasts Forums > Diesel > 1999 - 2003 7.3L Power Stroke Diesel

Tags
2000, 2003, 73, 73l, 73map, diesel, ecm, f350, ford, fuel, location, map, mileage, problems, probs, sensor

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 On
Trackbacks are On
Pingbacks are On
Refbacks are On

Forum Jump


Participate In The Forums

Create new posts and participate in discussions. It's free!

Sign Up »





All times are GMT -5. The time now is 08:42 PM.


Powered by vBulletin® Version 3.8.7 AC1
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Advertising - Terms of Use - Privacy Statement - Jobs
This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. Ford® is a registered trademark of the Ford Motor Company.

vbulletin Admin Backup