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  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech

Spark plug change gone bad

  • Thread starter Thread starter AquamanCHS
  • Start date Start date Apr 11, 2004
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A

AquamanCHS

New Member
Sep 17, 2003
122
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N. VA
Apr 11, 2004
#1
  • Apr 11, 2004
  • #1
Okay, so I figure my plugs are do for a changing so I bought some new ones and started popping the wires out. To get to the plugs on the left hand side I had to remove the big ugly pipe going from the filter to the throttle body. I undo all the wires from the plugs and remove and replace the spark plugs on the right hand side. I ran out of daylight and figured I'd finish up tomorrow.

So I put everything back like I had it (or so I think) and fire it up. The car sounded different, like it had a deeper rumble or something. So I back out of my driveway and put it in first and as I begin to accelerate the car nearly stalls. So I put the clutch in real fast to get back to idle then I slowly rev the engine up and let out the clutch.. feels fine. I go down the road to a stop light and I do it again, only this time while accelerating I hear a pop from the engine (detonation?) and as I shift into second the car shutters at low RPMs until I let in the clutch and rev the engine up and let it out again.

I make it to my girlfriend's house and rev the engine a few times in the driveway to find that when I punch it, the car will hesitate and burble, then rev up, but when I rev slowly it'll go up fine. I inspected everything and it looks like everything is where it should be. So I drive to the movies and idle is rough and I'm having to keep it in higher RPMs or else the car will start shuddering again. Five minutes from home the Check Engine light pops on, but it had not been there before.

What's wrong with my baby? Did I get by a vacuum hose or something?
 

KJ Hoppus

New Member
Mar 18, 2003
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Elk Grove CA
Apr 11, 2004
#2
  • Apr 11, 2004
  • #2
1....are the wires on the right plugs?

2....are the hoses that run from the intake pipe to the upper plenum connected?

3....i beleive there is a sensor that plugs into the intake pipe right after the MAF on the passenger side of the pipe, make sure that is pluged in

4...make sure the MAF is pluged in all the way

5...if none of that works, get the code pulled and that will tell you what is wrong.
 
0

03gtdrkpny

New Member
Apr 4, 2004
79
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IL
Apr 11, 2004
#3
  • Apr 11, 2004
  • #3
Sounds like you need to re-check the gap on the plugs.

According to web sources the gap should be: Gap is 1.32-1.42 mm (.052 - .056 inch)
 

Aaron 4.6

Founding Member
Apr 10, 2001
2,695
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0
Georgia
Apr 11, 2004
#4
  • Apr 11, 2004
  • #4
Sounds like you have a mis-fire. I bet thats what the CEL is. Pull the boots, re-check the gaps and make sure you have good connections when you re-install.
 

pony_vert02

New Member
Mar 16, 2004
285
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AUSTIN,TX
Apr 11, 2004
#5
  • Apr 11, 2004
  • #5
all of the above are excellent suggestions.... especially from KJ Hoppus.... unless the plugs you are using are pre-gapped, then absolutely checkem again..
 
A

AquamanCHS

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Sep 17, 2003
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Apr 11, 2004
#6
  • Apr 11, 2004
  • #6
They're pre-gapped... should I not have used pre-gapped ones?
 

ASilver2001GT

Founding Member
Jun 2, 2002
636
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0
Huntsville/Birmingham, AL
Apr 11, 2004
#7
  • Apr 11, 2004
  • #7
AquamanCHS said:
They're pre-gapped... should I not have used pre-gapped ones?
Click to expand...

pull them and check to see if they're gapped properly
 
4

46gtsblown

Founding Member
Jan 9, 2002
278
0
0
Apr 11, 2004
#8
  • Apr 11, 2004
  • #8
I will almost bet that you have put your plug wires on wrong.


Dwayne
 

krly79

Member
May 6, 2003
464
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16
VA Beach & So Illinois
Apr 11, 2004
#9
  • Apr 11, 2004
  • #9
if none of that works you could check your MAF. It if is rotated to much in one direction then it will run really lean and have a rough idle and throw a code. That's what happened to me.
 
T

tacswa3

New Member
Apr 3, 2004
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0
Apr 11, 2004
#10
  • Apr 11, 2004
  • #10
Sounds like your wires are mixed on the wrong cylinders.
 
A

AquamanCHS

New Member
Sep 17, 2003
122
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Apr 11, 2004
#11
  • Apr 11, 2004
  • #11
Can someone show me a correct wiring diagram, then? I'm fairly sure they're in the right cylinders because the lengths of the wires wouldn't match up if they were put in the wrong cylinders.
 
S

SPKMustang

New Member
Feb 10, 2004
87
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0
Amherst, NY
Apr 11, 2004
#12
  • Apr 11, 2004
  • #12
you realllllyyyy need to check your wires...
make sure the right wires are going to the right cylinder.
It sounds like you are causing some major mis-fire conditions and are definitly risking damaging your engine!
 
A

AquamanCHS

New Member
Sep 17, 2003
122
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Apr 11, 2004
#13
  • Apr 11, 2004
  • #13
SPKMustang said:
you realllllyyyy need to check your wires...
make sure the right wires are going to the right cylinder.
It sounds like you are causing some major mis-fire conditions and are definitly risking damaging your engine!
Click to expand...

Then could someone please direct me to a diagram that will show me which wires lead to which cylinders?
 
S

SPKMustang

New Member
Feb 10, 2004
87
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Amherst, NY
Apr 11, 2004
#14
  • Apr 11, 2004
  • #14
hrrmmmm ill try and find something for you, if you have or can get the haynes manual thatd be a good first start, if not try and find some good pics of a stock 4.6 around
 

RysRed96GT

I like it FURRY!!!
Founding Member
Apr 9, 2001
3,207
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56
Pasadena, MD
Apr 11, 2004
#15
  • Apr 11, 2004
  • #15
also check the torque specs on the plugs. mine ran like ass because i didnt torque them down enough because i was afraid i'd strip them. make sure the torque is around 14 ftlb's. as stated, check all connections. im pretty sure the plugs are labeled

4 8
3 7
2 6
1 5
(front)
 
A

AquamanCHS

New Member
Sep 17, 2003
122
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Apr 11, 2004
#16
  • Apr 11, 2004
  • #16
So those are the cylinders, but which wires go where?
 

cold96snake

20+ Year Stangneter
Jan 26, 2004
817
1
39
Truly, out to sea
Apr 11, 2004
#17
  • Apr 11, 2004
  • #17
You need to use dielectirc on them too.
 
G

GinoGT

Founding Member
Aug 11, 2002
1,862
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36
Apr 11, 2004
#18
  • Apr 11, 2004
  • #18
Here I come to save the day!

I'm taking a pic of the page in my Haynes manual. Just a couple minutes.



Lighting provided by my computer's cold cathode lights.
 
A

AquamanCHS

New Member
Sep 17, 2003
122
0
0
N. VA
Apr 11, 2004
#19
  • Apr 11, 2004
  • #19
Thanks.. that's how I thought it was arranged, and the wires were in fact in the right positions. I brought the car in to a mechanic tonight to get looked at tomorrow. Thanks for your help all, I'll tell you what it was when I get the car back.

(p.s. - if I had mixed up a few cylinders in the wiring, wouldn't it mess with the firing order, thus giving me constant detonation? I only heard the pops when I got on it really hard from idle.. does anyone else have any ideas as to what it could possibly be?)
 
0

03gtdrkpny

New Member
Apr 4, 2004
79
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0
IL
Apr 11, 2004
#20
  • Apr 11, 2004
  • #20
I'd still put my money on plug gap or a bad plug wire.
 
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