random misfires

2001 greenGT

New Member

Mar 30, 2009

19

0

1

Jul 30, 2011

#1

• Jul 30, 2011

• #1

hi guys i just put comp cams xe268h cams in my car and changed the plugs to bosch i havent gotten the car tuned yet but it still runs fine with the stock tune but when i try to start it i have to pump the gas just to keep it from stalling when i put the sct to it im getting a code for random engine misfires dose anyone know what the problem would be ive heard that i should only use motorcaft plugs but these parts have about 60 miles on them

 

trinity_gt

10 Year Member

Jan 31, 2003

3,125

81

99

Canada

Jul 30, 2011

#2

• Jul 30, 2011

• #2

Did you remove the front cover when you installed the cams and if so, verify the torque on the crankshaft damper bolt.

 

joshjwc9

Active Member

Jun 12, 2006

1,095

17

39

Palm Harbor, FL

Jul 30, 2011

#3

• Jul 30, 2011

• #3

What is the actual code the SCT is giving you? Are you sure your COP boots are on your COP's all the way? You may have hurt the camshaft or crank position sensor too. Or the Crankshaft position sensor was not reinstalled correctly.

 

2001 greenGT

New Member

Mar 30, 2009

19

0

1

Jul 30, 2011

#4

• Jul 30, 2011

• #4

No everything is torqued and im sure I installed every thing correctly but when I started the car this morning no codes came up like I said it doesn't have a t

 

2001 greenGT

New Member

Mar 30, 2009

19

0

1

Jul 30, 2011

#5

• Jul 30, 2011

• #5

No everything is torqued and im sure I installed every thing correctly but when I started the car this morning no codes came up like I said it doesn't have a tune yet would that be the problem

 

Dark04GT

10 Year Member

Apr 27, 2008

758

62

59

NC

Jul 31, 2011

#6

• Jul 31, 2011

• #6

2001 greenGT said:

... like I said it doesn't have a tune yet would that be the problem

Click to expand...

Yes.

 

wmburns

SN Certified Technician

Aug 14, 2009

5,892

514

204

Houston Texas

Jul 31, 2011

#7

• Jul 31, 2011

• #7

A couple of things to check.

Check the cam sensor's electrical connector.

After this much work, check for vacuum leaks.

Note, excessive slack in the the timing chains can casue random misfires. As well as a mistimed bank.

Confirm that the CKP sensor has been correctly installed in the timing cover (not loose). As Trinty has said, problems with the crank damper can cause this.

Cheap UD pulleys can also cause random misfires by messing with the quality of the CKP sensor signal.

Check the alternator for excessive AC ripple. Yes I know it's a long shot. But it's smart to rule it out.

Excessive EGR flow can cause random misfires. However, this seems unlikely in this case.

 

2001 greenGT

New Member

Mar 30, 2009

19

0

1

Aug 6, 2011

#8

• Aug 6, 2011

• #8

ok i changed the plugs and it stopped all most every now and then it hikups a little but i think its cause of no tune and i havent put the ud pullys on yet but they r from steeda soo they r good im gonna get the car tuned at mustang magic so well c also ill let every one know what happens as these cams i put in are the comp cams xe268h but i chose NOT to do valve springs

 

Maxpowers

Member

Sep 9, 2009

859

2

19

Pittsburgh, Pa

Aug 6, 2011

#9

• Aug 6, 2011

• #9

Good luck and report back with some numbers.