Fox 1990 Just Bought And Started Acting Up. Need Help.

J

johnny85

Member

Aug 14, 2016

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Aug 21, 2016

#1

• Aug 21, 2016

• #1

I just bought a 1990 Cobra Clone last week. It has edelbrock performer heads and intake, Moroso CAI, 24lb injectors, BBK long tubes and flowmasters. Car was running great until this past friday. I would get on it and at about 3500rpm it acts like you are feathering the gas. It pulls then its like it lets off then pulls and it keeps doing this. Just riding around the car runs great its not until you go to call for power when it acts up. Saturday I changed the fuel filter to rule that out. I have check all the wires and cleaned the MAS as well. Fuel pressure at idle is about 37lb. What am I missing here? Any help would be great.

 

F

frank_mancuso

Member

Aug 29, 2015

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Aug 21, 2016

#2

• Aug 21, 2016

• #2

Is it tuned? Check the timing, pull the plugs and inspect the ignition wires

 

J

johnny85

Member

Aug 14, 2016

13

6

13

Aug 21, 2016

#3

• Aug 21, 2016

• #3

from what I was told yes it is tuned. I did not check the plugs but I did check the wires which seemed ok.

 

Mustang5L5

That is…until I whipped out my Bissell

Mod Dude

Feb 18, 2001

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Aug 21, 2016

#4

• Aug 21, 2016

• #4

Have you pulled the codes?

If it's tuned, you should see some sort of piggy back chip on the computer in the passenger side kick panel


Sent from my big ass iPhone 6 using Tapatalk

 

J

johnny85

Member

Aug 14, 2016

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6

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Aug 21, 2016

#5

• Aug 21, 2016

• #5

Just checked I dont see any Piggy back chip. I have a code reader I will check that in a minute.

Never mind cant read codes my reader is for 2000 and up

 

RaggedGT

Been here over a DECADE and still no CT

Mod Dude

Jul 20, 2014

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Aug 21, 2016

#6

• Aug 21, 2016

• #6

Use the search feature on this site.
Type in @jrichker 's name . He had at least a million posts/threads on how to dump the codes for a fox on here-and has great trouble shooting lists to work through once you have the codes

 

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J

johnny85

Member

Aug 14, 2016

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Aug 22, 2016

#7

• Aug 22, 2016

• #7

Well here is something new. I have never had more than 4 gallons in the tank since I had it (1 week now). This morning I filled her up with 93 octane and she ran like a raped ape. Im thinking fuel pump. I will be running the codes at work today as well. Just thought I would share that. What do you all think?

 

Mustang5L5

That is…until I whipped out my Bissell

Mod Dude

Feb 18, 2001

43,231

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Aug 22, 2016

#8

• Aug 22, 2016

• #8

If it was a fuel pump, you might get some lean codes spit back at you.

But honestly, it's really not worth speculating until you have codes in hand. Really does make troubleshooting a lot easier when you can narrow it down

 

jrichker

StangNet's favorite TOOL

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Aug 22, 2016

#9

• Aug 22, 2016

• #9

As suggested...

Dump codes sticky

Look at the top of the 5.0 Tech forum where the sticky threads are posted. One of them is how to dump the computer codes. Codes may be present even if the CEL (Check Engine Light) isn’t on. You don’t need a code reader or scanner – all you need is a paper clip, or if your lady friend has a hair pin, that will do the job.
I highly suggest that you read it and follow the instructions to dump the codes. http://www.stangnet.com/mustang-forums/threads/how-to-pull-codes-from-eec4.889006/

 

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FoxMustangLvr

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Aug 22, 2016

#10

• Aug 22, 2016

• #10

johnny85 said:

Well here is something new. I have never had more than 4 gallons in the tank since I had it (1 week now). This morning I filled her up with 93 octane and she ran like a raped ape. Im thinking fuel pump. I will be running the codes at work today as well. Just thought I would share that. What do you all think?

Click to expand...

Often times when the fuel pump is going out the car won't have any power during WOT but will cruise around just fine. However, a full tank of gas wouldn't "fix" a bad fuel pump. Maybe your gas tank isn't venting properly? I'm curious to see what codes come up.

 

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J

johnny85

Member

Aug 14, 2016

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Aug 22, 2016

#11

• Aug 22, 2016

• #11

Alright the only code I have is 11. We the fuel tank is out right now checking everything.

 

FoxMustangLvr

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#12

• Aug 22, 2016

• #12

11 is good!! Fuel pumps are inexpensive to replace but make sure you get new seals while the tank is out. Once back together double check your fuel pressure, should be about 39 psi with vacuum off.

 

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J

johnny85

Member

Aug 14, 2016

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Aug 22, 2016

#13

• Aug 22, 2016

• #13

Under there now and there is a vortech in line fuel pump mounted as well. Didnt know about that until just now.

 

89oem

Mustang Master

Dec 18, 2013

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#14

• Aug 22, 2016

• #14

Hows your vent line run?

 

J

johnny85

Member

Aug 14, 2016

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Aug 22, 2016

#15

• Aug 22, 2016

• #15

Vent line and everything else under there looked great. The strainer on the original fuel pump had black stuff in it and was very dirty. The end of the pump also had debris in it as well. Changed it out and all seems to be great now.

 

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FoxMustangLvr

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Aug 22, 2016

#16

• Aug 22, 2016

• #16

johnny85 said:

Vent line and everything else under there looked great. The strainer on the original fuel pump had black stuff in it and was very dirty. The end of the pump also had debris in it as well. Changed it out and all seems to be great now.

Click to expand...

All seems to be great now? What does that mean? Car is fixed and runs good again?

 

FoxMustangLvr

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Aug 22, 2016

#17

• Aug 22, 2016

• #17

johnny85 said:

Under there now and there is a vortech in line fuel pump mounted as well. Didnt know about that until just now.

Click to expand...

This is a sign from the car Gods, buy a Vortech!

 

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Mustang5L5

That is…until I whipped out my Bissell

Mod Dude

Feb 18, 2001

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Aug 22, 2016

#18

• Aug 22, 2016

• #18

Did you check engine running codes too? Technically, you should get three code 11s. Two with engine off, and one running


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J

johnny85

Member

Aug 14, 2016

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Aug 23, 2016

#19

• Aug 23, 2016

• #19

Mustang5L5 said:

Did you check engine running codes too? Technically, you should get three code 11s. Two with engine off, and one running


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Click to expand...

Yes sir you are correct. 3 code 11's. After changing the fuel pump the car is running great! I am taking it to the strip tomorrow to see what she will run.

 

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