Diagnostic Results

junkstang95

New Member

Nov 2, 2002

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Tampa

Feb 27, 2007

#1

• Feb 27, 2007

• #1

My 95 Cobra has been surging while at low rpm's and as I start to accelerate. I can watch the rpm needle bounce up and down (+/-) 500-1000 rpm's at idle or while I'm accelerating or driving at a consistent speed.


I had a diag done at a local Ford shop and they said that my right side upstream O2 sensor was bad and my purge canister needed replaced.

Of course I'm not going to pay the $600 they quoted to have them fix anything I just needed a starting point to fix things myself.

Now, I replaced the right side pre-cat O2 sensor and I still have the surge.

Should I have replaced both upstream sensors while I was under there?

What is the purge canister and could it be related to the surging?

Any other suggestions?

Thanks in advance.

 

gcomfx.com

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Oct 22, 2002

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Republic, MO

Feb 27, 2007

#2

• Feb 27, 2007

• #2

http://forums.stangnet.com/showthread.php?t=687869

Unplug it... see how the car runs.

 

junkstang95

New Member

Nov 2, 2002

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Tampa

Feb 27, 2007

#3

• Feb 27, 2007

• #3

I'll give it a shot.

 

T

tjh566

New Member

May 22, 2004

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Northern Va

Feb 27, 2007

#4

• Feb 27, 2007

• #4

dont tell me even the ford comps think we have 4 O2's

 

junkstang95

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Nov 2, 2002

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Tampa

Feb 27, 2007

#5

• Feb 27, 2007

• #5

tjh566 said:

dont tell me even the ford comps think we have 4 O2's

Click to expand...

Not sure, all I know is that the diag results stated pre-cat O2 sensor which is where they're located. I didn't assume anything else.

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

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Feb 27, 2007

#6

• Feb 27, 2007

• #6

I don't see either of those creating a surge. The tach jumping suggests an ignition issue.

The purge cannister isnt even needed and it should not affect or create a surge.

Good luck.

 

junkstang95

New Member

Nov 2, 2002

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Tampa

Feb 27, 2007

#7

• Feb 27, 2007

• #7

HISSIN50 said:

The tach jumping suggests an ignition issue.

Click to expand...

Thanks. Any suggestions?

 

T

tjh566

New Member

May 22, 2004

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Northern Va

Feb 27, 2007

#8

• Feb 27, 2007

• #8

coil, wires, could be a few things.

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

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Feb 27, 2007

#9

• Feb 27, 2007

• #9

The PIP can also cause a tach studder - you'd likely feel a slight chug or shudder if the PIP is the cause.

 

junkstang95

New Member

Nov 2, 2002

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Tampa

Feb 27, 2007

#10

• Feb 27, 2007

• #10

PIP?

 

mo_dingo

20+ Year Stangneter

Aug 26, 2003

3,031

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Tucson, AZ

Feb 27, 2007

#11

• Feb 27, 2007

• #11

pip=profile ignition pickup, a.k.a. halls effect sensor or ignition module. The sensor on the bottom of the distributor.
Scott

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

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Feb 27, 2007

#12

• Feb 27, 2007

• #12

Don't ask for an ignition module if you need to replace a PIP - they will give you a TFI module.

Stator is pretty conventional nomenclature for a PIP - only if you find that you need one.

When a PIP totally craps its pants, you can use a DMM and check the wave coming from it - but with a slight burp there's no way a DMM can help. And anything short of an oscilliscope probably won't help.

 

HGFireHazard

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Apr 10, 2005

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Michigan

Feb 28, 2007

#13

• Feb 28, 2007

• #13

tjh566 said:

dont tell me even the ford comps think we have 4 O2's

Click to expand...

They do, or at least my local one does. I went there last Summer to get O2s before getting my S/C tuned and they asked me which ones I needed...

Come on now.