Go Back   Ford Truck Enthusiasts Forums > Older, Classic & Antique Trucks > 1973 - 1979 F-100 & Larger F-Series Trucks
Sign in using an external account
Register Forgot Password?


1973 - 1979 F-100 & Larger F-Series Trucks Discuss the Dentsides Ford Truck

Reply
 
 
 
 
LinkBack Thread Tools Search this Thread
  #1  
Old 01-24-2008, 08:15 PM
68-F250-4x4 68-F250-4x4 is offline
Senior User
 
Join Date: Dec 2007
Posts: 172
68-F250-4x4 is starting off with a positive reputation.
Exhaust Leak/Vaccum Leak/Gas Mileage

Would having a minor exhaust leak leak cause a decrease in gas mileage? When I bought my truck the exhaust manifold gaskets to the heads were shot and it was leaking alot of air through there. I bought new gaskets and installed them but the drivers side still has a leak. Probably because it was ran so long like that before I got it and the manifolds were all pitted up. Now the noise caused by this is one thing, and doesnt really bother me a whole lot, but if this is decreasing my gas mileage then I would like to do something about it and fix it.

Next will having a vacuum leak cause a decrease in gas mileage? I'm pretty sure it does but just want to make sure. I think I might have a vacuum leak because when I am driving speed limit on the highway you can hear a little bit of a whine sound coming from the engine. when you let the gas off it doesnt do it, and when you give it gas it either doesnt do it or you cant hear it over the exhaust? But definatly a little something there when just cruising. Is this a vacuum leak?


Thanks for the help guys!
Reply With Quote
  #2  
Old 01-24-2008, 11:36 PM
fmc400's Avatar
fmc400 fmc400 is offline
MSEE
 
Join Date: Apr 2004
Location: Austin, TX
Posts: 10,386
fmc400 has much to be proud offmc400 has much to be proud offmc400 has much to be proud offmc400 has much to be proud offmc400 has much to be proud offmc400 has much to be proud offmc400 has much to be proud offmc400 has much to be proud offmc400 has much to be proud offmc400 has much to be proud of
That doesn't sound like a vacuum leak to me - vacuum is lower as you get on the gas. Manifold vacuum is supposed to be highest at idle. If you have a good enough vacuum leak, you will have problems with really rough idle, poor cold-running, bogging on acceleration, and even dieseling, to name a few. If you have a whining noise with higher RPMs I'd be looking at your belts or alternator bushings. As for that exhaust leak, I'd doubt it affects your mileage too much if at all. The gas is already burnt by the time the exhaust can find the leak.
Reply With Quote
Old 01-24-2008, 11:36 PM
 
 
 
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
guttless madewell 1994.5 - 1997 7.3L Power Stroke Diesel 20 10-04-2010 12:05 AM
exhaust leak? stroken 1999 - 2003 7.3L Power Stroke Diesel 4 04-10-2008 07:17 AM
Intake Air/Exhaust Manifold Preheat Shroud Imdok Ford Inline Six, 200, 250, 4.9L / 300 3 10-11-2007 02:11 PM
86 Bronco, awake from ten year coma BaronVonAutomatc 1978 - 1996 Big Bronco 11 04-15-2007 09:04 AM
Help! 7.3 Fuel Milaege randy332 1999 - 2003 7.3L Power Stroke Diesel 7 03-08-2007 07:47 AM


Go Back   Ford Truck Enthusiasts Forums > Older, Classic & Antique Trucks > 1973 - 1979 F-100 & Larger F-Series Trucks

Tags
affect, air, boost, economy, fix, ford, fuel, gas, idle, intake, leak, mileage, poor, truck, vacuum

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 03:38 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