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  • Fox 5.0 Mustang Tech

Engine loses ALL power when in WOT.

  • Thread starter Thread starter BlackFox5.0
  • Start date Start date May 10, 2004
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blk9450

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your moms bed
May 11, 2004
#21
  • May 11, 2004
  • #21
im saying o2 sensors. it worked for me man, and you havent tried it yet...
 

BlackFox5.0

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Aug 7, 2000
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May 11, 2004
#22
  • May 11, 2004
  • #22
I don't have $100+ to spend on them things but I should change them since one is original, lol and the other is a little bit newer....I'll try pulling voltage from them and see how they react. I will do a search for a thread about this a few weeks ago.

Thanks for your input, at this point, ANY suggestions are good ones. I have never been more frustrated with a problem like this.

Did yours seem to misfire, and when you give it gas it stutters and bogs at the same time?

Will the computer give off a code for a faulty O2? I wish our computers were OBD2 because I know they do it
 
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blk9450

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May 11, 2004
#23
  • May 11, 2004
  • #23
yea it should throw a code. much to my surprise, the sensors were only $33 each at advanced auto parts, by me. my car would run fine till about half throttle or a little more and it would almost die as if the coil wire became unhooked, but it would come back a second afteri let off the throttle
 

BlackFox5.0

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May 11, 2004
#24
  • May 11, 2004
  • #24
Ok, tomorrow I will check for codes, and test the O2's voltage, today is day 3.
 
H

Hydrocarbon

New Member
Nov 18, 2003
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Medford Oregon
May 11, 2004
#25
  • May 11, 2004
  • #25
It doesn't make sense to me that it could be an o2 sensor problem. I thought that the ECM ignored signals from the o2s at WOT, because the car would need to have a richer mixture. So the computer looks up the fuel tables for WOT.

Don't just pull the codes, do a full fledge quick test, both KOEO and KOER. Then do a cylinder balance test, to see if you have a bad injector or something. You could also try the wiggle test and see if you can get the computer to throw a code.
 

blown93feature

New Member
Dec 9, 2003
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living on edge like the motor
May 12, 2004
#26
  • May 12, 2004
  • #26
your car is running lean at wot and thats why your loosing power.I would check your fuel pump it's probably failing under load.If it isn't that it could be your afpr if you have one and if it's not that check your factory fuel pressure reg if thats what your using.

Do you have a a/f gauge in the car? I f you do then you would know for sure if what I'm saying is right because if the gauge goes leaner than 13/1 then thats why power is lost because your running out of fuel.The higher the number the leaner it gets the worse it runs.I believe you have a n/a motor correct?

If you have a afpr than you have the ability to bump the pressure up a little if you don't than 1/1 ratio is all you have with the factory p/r and obviously no adjustment capabilities.

I would have the pump checked out first than go from there.If you respond back and say that the pump is brand new than check the rest of the fuel system,I just believe thats where your problem could be,I hope it all works out for you.

L8r joe.
 

BlackFox5.0

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May 12, 2004
#27
  • May 12, 2004
  • #27
It's not fuel, I have a new 255lphHP pump, and Kirban AFPR ate at 51psi with vacuum off.

I checked the voltage at the O2s, and the right bank O2 has a voltage, .20v lower then the left. I think it could be this sensor. I think I'll try changing it and see that helps. I forgot to put the spout back in after setting the timing and drove to my g/f's house last night with it like that , and drove ok, but on my way home this morning the car would barely go, it was CONSTANTLY misfiring....
 

BarnStang

Founding Member
Mar 2, 2001
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Hagerstown, MD
May 12, 2004
#28
  • May 12, 2004
  • #28
51psi seems high. Have you pulled the spark plugs to see what they look like? THat should give you some indication of whats going on. I hope the O2 sensors helps, but the severity of your problem should not be caused by the O2 sensors. You should also be able to dial in 12-13 degrees of advance easy. If not, then there may well be an ignition problem. THe TFI could still be at suspect even if it tested ok. Or the pickup coil inside the distributor. And even more unlikley, the harmonic balencer. You can check the harmonic balancer by brining the #1 piston to TDC and see if the timing marks line up at zero. If not, then the harmonic balancer ring could have slipped around a bit. Possible, but not likley. Something to check.

If you have a FP gauge, what does the fuel pressure do as you open the throttle and the power falls off or starts to miss?
 

ninety15.0

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Mar 10, 2004
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May 12, 2004
#29
  • May 12, 2004
  • #29
Dont you have a blower on your car? If you do i thought that you had to retard timing a little pit with every added pound of boost? i may be wrong and that may only be for nitrous, but did you ever consider that the timing may be too far advanced? just a thought but it takes about 2 seconds to change. Also i doubt that a .2v change between the two O2 sensors would be your only problem. Plus if the O2 was bad you would def get a CE light.
 

BlackGT89

Member
Dec 16, 2002
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Huntsville, AL
May 12, 2004
#30
  • May 12, 2004
  • #30
Black Fox - Lots of good suggestions from everyone. Have you considered the timing chain ? How many miles on the present one ? If they stretch and get too much slack in them, they will produce similar results. The following link is a website that describes how to test for this. Good luck.
http://www.misterfixit.com/chanslop.htm
 
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blk9450

Founding Member
Jan 31, 2002
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your moms bed
May 12, 2004
#31
  • May 12, 2004
  • #31
BarnStang said:
And even more unlikley, the harmonic balencer. You can check the harmonic balancer by brining the #1 piston to TDC and see if the timing marks line up at zero. If not, then the harmonic balancer ring could have slipped around a bit. Possible, but not likley. Something to check.
happened to me once, check the rubber, thats how i knew
Click to expand...
Click to expand...
 

BlackFox5.0

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May 12, 2004
#32
  • May 12, 2004
  • #32
This engine has maybe 10k miles on it, it's still fairly new. I pulled codes and only got ones related to my missing EGR system, (I don't have vacuum lines to the air pump, and EGR soleniod, but the lines are plugged) And als got a code saying that the ECT was out of range, cause we did the test when the engine wasn't in operating temp.

Never got anything about O2's so they are fine....The problem seems to have gotten better though, it doesn't lose as much power as before, but i can't still feel the missing power as it's not throwing me back in the seat like it used to.

I don't need a Boost retard because I'm only running 6psi, and my timing is still very low. Still driving me crazy!
 
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blk9450

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May 12, 2004
#33
  • May 12, 2004
  • #33
did it throw the ect code with koer or koeo cause if it was the latter test, then the computer logged these out of range ect signals, and it means you need a new ect. this would definately affect timing
 
N

noslow5_0

New Member
Nov 7, 2003
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dallas tx.
May 12, 2004
#34
  • May 12, 2004
  • #34
well something nobody has mentioned either would be the WOT relay... i doubt its computer related though... i think more along the lines of mechanical.... good luck!!! dont give up man... an like the case was with my freakin dimmer switch it'll turn out to be something little causin a big problem....
 

BlackFox5.0

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May 12, 2004
#35
  • May 12, 2004
  • #35
blk9450 said:
did it throw the ect code with koer or koeo cause if it was the latter test, then the computer logged these out of range ect signals, and it means you need a new ect. this would definately affect timing
Click to expand...


It was koeo. The sensor should be fine, it's just cause i didn't let the engine warm up prior to the test
 

ninety15.0

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Mar 10, 2004
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May 12, 2004
#36
  • May 12, 2004
  • #36
I have two quick questions...because i am dealing with the same exact problem. What does the WOT relay do, and where is it located? Second, what does the dimmer switch do and where is that? i know i have heard some stuff about those two thigns but i havent checked them yet. thanks for the info
 

BlackFox5.0

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May 12, 2004
#37
  • May 12, 2004
  • #37
The dimmer switch thing was just an electrical problem noslo had and I helped him with it. It's nothing related to this problem, just a comparison....
 

BlackFox5.0

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May 12, 2004
#38
  • May 12, 2004
  • #38
Checked my FP, it was at 25psi tried adjusting it, nothing....won't budge...

It's a Kirban, and I heard it's rebuildable, where can I get a kit to rebuild it? i bet the diaphram inside is toast from the boost....
 

r6bullet

New Member
Jul 25, 2003
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May 12, 2004
#39
  • May 12, 2004
  • #39
If I remember correctly your computer sees 5volts at WOT which would put the computer in open loop, therfore no longer using the o2 sensor information. In open loop the pcm runs off a set configuration. Maybe you need a computer tune?
 
B

blk9450

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Jan 31, 2002
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May 12, 2004
#40
  • May 12, 2004
  • #40
thats it then... glad you found it
 
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