2000 taurus cylinder 5 missfire - Ford Forums

ecortez677 · 07-29-2008, 12:06

I have a 2000 for taurus 3.0L that has a cylinder 5 missfire. Has fuel spark and good compression. Long term fuel trim bank 2 sensor 1 @ 18% average, Bank 1 sensor 1 at 12% average. O2 senors working ok. Any Ideas anyone?

**tbird100636** · 07-30-2008, 09:14

Quote:

Originally Posted by ecortez677

I have a 2000 for taurus 3.0L that has a cylinder 5 missfire. Has fuel spark and good compression. Long term fuel trim bank 2 sensor 1 @ 18% average, Bank 1 sensor 1 at 12% average. O2 senors working ok. Any Ideas anyone?

3.0L Vulcan or Duratec???

ecortez677 · 07-30-2008, 12:11

It is a vulcan

**tbird100636** · 07-30-2008, 21:34

Well if the spark plug is good (clean, correct gap, no black carbon tracking on the porcelin insulator) the plug wire is good, the coil pack isn't cracked, then the only things left are a fuel injector or cylinder leakage past a valve. This will not show up doing a compression check, you have to leakdown test the cylinder. Any more than 15% leakage with the cylinder TDC of the compression stroke indicates excessive leakage. Listen for leakage from the tailpipe, intake, through the oil filler opening. To check for an injector swap injectors between cylinders (you may be able to carefully lift the front half of the rail without removing the upper intake to swap injectors 5 and 6). then see if the misfire has moved to cylinder that the suspect injector has been moved to.

ecortez677 · 07-31-2008, 09:58

Well the first leakdown test I did a week ago, showed a leakdown of 25%, 2nd leakdown test I did yesterday showed, 85%. So I loosened the rocker arms and the leakdown test came down to 25%. So do you think we could have a bad lifter?

**tbird100636** · 07-31-2008, 20:41

Quote:

Originally Posted by ecortez677

Well the first leakdown test I did a week ago, showed a leakdown of 25%, 2nd leakdown test I did yesterday showed, 85%. So I loosened the rocker arms and the leakdown test came down to 25%. So do you think we could have a bad lifter?

Sounds to me you had the #5 cylinder on TDC of the exhaust stroke so the exhaust valve was open yesterday. 25% leakage is too much, you have a leak past the valves or the rings. Listen through the tailpipe, intake tract, and the oil filler opening. This will tell you which is leaking.

ecortez677 · 08-01-2008, 11:32

It is confirmed. Cylinder 5 was on compression stroke. Still have exhaust valve hanging up.

**tbird100636** · 08-02-2008, 14:38

Quote:

Originally Posted by ecortez677

It is confirmed. Cylinder 5 was on compression stroke. Still have exhaust valve hanging up.

Then that would be your 25% leakage, and you should hear it leaking in the tailpipe. I was refering to the cylinder being on the exhaust stroke when you had 85% leakage.

ecortez677 · 08-02-2008, 18:13

And the 85% leakage was on the compression stroke.