Fox T-Bird/Cougar Forums

Technical => Engine Tech => Topic started by: tbirdera on June 07, 2007, 07:01:18 PM

Title: tbird is doing 10MPG HELP!!!!!
Post by: tbirdera on June 07, 2007, 07:01:18 PM
Guys my 5.0 t bird is using way too much gas. The 5.0 is hardly modded. Its had a tune up. My mods are bbk headers , h pipe, magnaflow exhast, bbk intake. Shouldnt my 5.0 be doing 28 mpg high way and 17 mpg city???Can someone let me kno what it could be??? injecters maybe?
Title: tbird is doing 10MPG HELP!!!!!
Post by: Tbird232ci on June 07, 2007, 07:33:37 PM
All that madd racin.
Title: tbird is doing 10MPG HELP!!!!!
Post by: tbirdera on June 07, 2007, 08:25:28 PM
Oh man. Nah i dont do "madd" racing . Im serious what could it be cause its causing me alot of money on gas.
Title: tbird is doing 10MPG HELP!!!!!
Post by: grutinator on June 07, 2007, 08:56:24 PM
check your o2 sensors, usually when they go back they stick giving either a way rich or way lean reading... way lean in your case
Title: tbird is doing 10MPG HELP!!!!!
Post by: Prototype Services on June 08, 2007, 02:56:47 AM
Sounds like you have the engine modified beyond what the speed density can handle, and it has gone into closed-loop default and running rich. Could also easily be the O2 sensors causing it to go full rich.
Title: tbird is doing 10MPG HELP!!!!!
Post by: tbirdera on June 08, 2007, 03:02:51 AM
the 02 sensors are brand new motor craft
Title: tbird is doing 10MPG HELP!!!!!
Post by: Carpimp1987 on June 08, 2007, 04:23:26 AM
i got lots more mods and i still get like 22 city and close to 29 highway.

i don't know what to tell you
Title: tbird is doing 10MPG HELP!!!!!
Post by: Dogcharmer on June 08, 2007, 07:25:22 AM
You might have a leaking fuel injector. Here's how to test them:

"Remove the injectors, get a 9volt battery and two test leads with alligator clips (unless you saved an injector connector at some point). Get a can of gum out, the tube fits right into the injector input port. Push the tube down into the little hole and squirt. If it comes out the other end, it's sticking open. If it doesn't come out the other end unless you power up the injector with the battery, then it's ok. You can get an idea of spray pattern with this test also." That was from the Corral.

I haven't tried it myself yet but I need to because my mileage sucks too. I just got 11.9 on my last tank.
Title: tbird is doing 10MPG HELP!!!!!
Post by: Sick88Tbird on June 08, 2007, 08:32:21 AM
I had the same problem 3 years ago when I first did the HO swap in my old T-bird(it sat for a year)...it was the most frustrating thing in the world...an $8 fuel filter later and good fuel mileage was restored, it's a cheap fix and if it doesn't cure your ailment, it's still money well spent.

Good luck,
Don
Title: tbird is doing 10MPG HELP!!!!!
Post by: V8Demon on June 08, 2007, 09:40:09 AM
Quote from: Prototype Services
Sounds like you have the engine modified beyond what the speed density can handle, and it has gone into closed-loop default and running rich.


You're kidding, right?  Go to http://www.50tech.com and read around a little.  You'll see what kind of combos can be run on the Fordd EEC-IV SD computer.  All his mods are exhaust and intake related, absolutely stock internals.  THe SO SD computer can handle that and quite a bit more even before he'll NEED an adjustable fuel pressure regulator.  That being said IMHO it should be one of the first mods accomplished on an EEC-IV or EEC-V equipped car with a return style fuel system. 

Run codes and tell us what you get.
Title: tbird is doing 10MPG HELP!!!!!
Post by: thunderjet302 on June 08, 2007, 06:14:08 PM
:iagree:

I'm running a .533 lift cam and GT-40P heads with a Mark VII SD computer with virtually no problems. Once in a great while it has a bit of idle surge but that's usually when I get on it and stop right away:hick: .
Title: tbird is doing 10MPG HELP!!!!!
Post by: tbirdera on June 08, 2007, 07:59:33 PM
i think its the injectors cuase i changed teh fuel filter and teh car has a tune up. When i change dteh iifters i changed all gaskets on top and hoses as well. And yes teh engine is really stock so it shouldnt be drinking so much gas. . If i get new injectors I need 14lbs injectors correct??
Title: tbird is doing 10MPG HELP!!!!!
Post by: jcassity on June 08, 2007, 09:55:25 PM
also do an injector balance test,,, see my diy link above my sig.  You dont have to pull injectors for this test,, just unhook them one at a time.

Im surprised no one has ask that you pull the codes,,, do so before you tear into anything.
Title: tbird is doing 10MPG HELP!!!!!
Post by: V8Demon on June 08, 2007, 11:53:15 PM
Quote
Im surprised no one has ask that you pull the codes,,,


See post #10:D
Title: tbird is doing 10MPG HELP!!!!!
Post by: 84 Fila on June 09, 2007, 12:01:10 AM
I got a set of explorer injecters if ya need
Title: tbird is doing 10MPG HELP!!!!!
Post by: 32VFoxBird on June 09, 2007, 12:39:28 AM
Quote from: 84 Fila;152818
I got a set of explorer injecters if ya need


those are blue top (24lbs), right?
Title: tbird is doing 10MPG HELP!!!!!
Post by: tbirdera on June 09, 2007, 06:35:56 PM
i dunno how to pull codes guys.
Title: tbird is doing 10MPG HELP!!!!!
Post by: 5.0willgo on June 09, 2007, 07:15:53 PM
3 ways for you
1.There is a way to self test in the link that jcassity posted. It's section 5 on his index.

2.You can purchase a scan tool at parts stores for around $30 that all you do is follow the instructions in the book and count the blinks.

3.Also AutoZone does a free code scan that you can just go up to the counter and ask them to scan your car for you.
Title: tbird is doing 10MPG HELP!!!!!
Post by: tbirdera on June 09, 2007, 11:12:52 PM
o0o nice thanks for the input
Title: tbird is doing 10MPG HELP!!!!!
Post by: 460 turbo truck on June 15, 2007, 04:27:52 PM
You can also just turn the key on.

Take a long screwdriver, or pipe, and place it on each injector, ( to the best of your ability ) and listen for the fuel,

Or get a fuel pressure gauge, and turn the key on and see if your fuel pressure drops drasticly within the first 30 Seconds of turn off the key
Title: tbird is doing 10MPG HELP!!!!!
Post by: Old_Paint on August 11, 2007, 01:49:07 PM
Something I haven't seen mentioned yet.  It could very well be a leaking Fuel Pressure Regulator.  Easy enough to check.  On the fuel rail for the injectors, you'll find a piece with a vacuum line attached.  Turn the key on and off several times to get it up to max fuel pressure, then go pull the vacuum line off and check to see if raw fuel is at that connection.  There should be nothing but AIR there.  If there is fuel coming out the nipple on the regulator, or a strong smell of fuel, chances are the diaphram in the regulator is punctured, and it's dumping fuel straight into the intake.  Notice any black smoke or stutter at low RPM?  Your favorite Autozone or Advance store will have the regulator.
Title: tbird is doing 10MPG HELP!!!!!
Post by: Sick88Tbird on August 11, 2007, 03:32:00 PM
Having a trans with direct drive and over drive might help also. :hick: