Focus Fanatics Forum banner
1 - 7 of 7 Posts

·
Registered
Joined
·
362 Posts
Discussion Starter · #1 ·
Hey guys, heres the story. For about a year now I have had less than normal power output from the ol' SVT. About 3 months ago the CEL came on...02 sensor and running rich. After many trips to Ford, ive had the 02 sensor replaced, the MAF cleaned and the Fuel Pressure Regulator replaced. The last one finally made the light stay off. I was excited to get my car back because I though that must have been the thing causing the lack of power, but it is still happening. Heres the deal...


From about 3000 rpm and up, at anywhere from 25% to 50% throttle open the car accelerates like it should.

As I roll into the throttle more past 50% throttle I should be getting greater and greater acceleration, especially as my RPM's pick up. At that point where my throttle gets to about 90% open, the acceleration increase stops. The engine makes more noise, but doesn't accelerate any faster than when the throttle was 3/4 open.

To sum it up, whenever I push past 75% throttle my car makes a lot of noise but doesnt produce the power it should, it almost feels like it is running way to rich or way too lean. ANY IDEAS???


Anyway, i am going to take 3 runs on a dyno next weekend so I will post what I find...if I am right my numbers will be way low, due to my A/F ratios being way off.
 

·
The Librarian
Joined
·
13,116 Posts
1) Check/Replace Fuel filter.
2) Check Fuel Pump output.
3) Check for clogged CAT.

Any mods or aftermarket tune on your car?
When's the last time the air filter was replaced?
 

·
Registered
Joined
·
406 Posts
The SVTF throttle body is WAY big for the little engine it is feeding. At 75% open, it is feeding all the air the engine needs to make max power so opening it the other 25% doesn't really do a whole lot except open the TPS a bit more. That MAY change the timing and fuel map but I am not sure it is enough to feel.
 

·
Registered
Joined
·
1,067 Posts
it could be TPS related. maybe your TPS voltage gets to 5.0 volts too soon, or maybe it never gets there at all. If you have access to a scan tool, monitor TPS voltage to see when it reaches WOT. You can also do that using a DVOM, but it's a bit trickier to do while driving.

If you see 5.0 volts before 3/4 throttle, it is getting there too quick.

If it stays below 4.5 volts even with the throttle fully depressed, you aren't reaching WOT at all. (of the two options, I favor this one to be the problem)

If you see either condition, time to replace the TPS sensor.
 

·
Registered
Joined
·
459 Posts
I have a SRI, HIA tune, alumi Flywheel and I have the same issue.
If it's a problem i'd like to fix it, but I have no problem getting up to speed on half gas sometimes even lower.
It's fast as it is, but I do feel your pain as far as needing that extra something that would make you floor it , only to find out it's not there.
 

·
Registered
Joined
·
362 Posts
Discussion Starter · #7 ·
Nevermind....the CEL is back on!!! My bet is it is the same as they all have been..."Engine running Rich bank 1"

I'm going back into Ford tomorrow...I must be like family to them by now!

Anyway...I will suggest they check Fuel pump and throttle position sensor...Any other palusible guesses...just throw any halfway educated guesses at me and i'll pass the word to the mechanics. (it can't be my intake can it??)
 
1 - 7 of 7 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top