Black spark plug

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Apr 14, 2013 | 07:41 AM

#16

Aljay

Senior Member

Joined: Nov 2012

Posts: 999

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From: Tx

Year: 2001

Model: Cherokee

Engine: I-6

Quote:

Originally Posted by Outlaw Star

Those would be carbon deposits. Symptoms leading to either a rich fuel mixture or weak ignition system. If only in one cylinder, check plug wires for resistance, could be a faulty/defective spark plug or check the terminal inside the distributer cap. If those check out good then check your injector for malfunctions.
Plug reading has become a lost art nowadays but you may learn a lot about the condition of the motor by looking at them.

Today's gasolines make plug reading even harder , damn ethanol fuels suck all the way around .

Apr 14, 2013 | 07:42 AM

#17

cruiser54

::CF Moderator::

Joined: Aug 2011

Posts: 43,971

Likes: 1,579

From: Prescott, Az

Year: 1990

Model: Cherokee (XJ)

Engine: 4.0

Quote:

Originally Posted by Aljay

Today's gasolines make plug reading even harder , damn ethanol fuels suck all the way around .

Doesn't even smell like gasoline anymore.

Apr 14, 2013 | 07:45 AM

#18

Aljay

Senior Member

Joined: Nov 2012

Posts: 999

Likes: 0

From: Tx

Year: 2001

Model: Cherokee

Engine: I-6

Quote:

Originally Posted by cruiser54

Doesn't even smell like gasoline anymore.

I still remember dad bringing home av-gas in the late 70s on into the 80s !
But then again how many people still have a tach/dwell meter in there tool box ? ,yeah a business card will get you home but . Lol

Last edited by Aljay; Apr 14, 2013 at 07:48 AM.

Apr 14, 2013 | 07:47 AM

#19

cruiser54

::CF Moderator::

Joined: Aug 2011

Posts: 43,971

Likes: 1,579

From: Prescott, Az

Year: 1990

Model: Cherokee (XJ)

Engine: 4.0

Quote:

Originally Posted by Aljay

I still remember dad bringing home av-gas in the late 70s on into the 80s !

That was me, too. Needed it for the 10.5:1 compression motor in my Datsun 2000 running at sealevel.

Apr 14, 2013 | 07:53 AM

#20

Aljay

Senior Member

Joined: Nov 2012

Posts: 999

Likes: 0

From: Tx

Year: 2001

Model: Cherokee

Engine: I-6

Quote:

Originally Posted by cruiser54

That was me, too. Needed it for the 10.5:1 compression motor in my Datsun 2000 running at sealevel.

57 Chevy with a 283 punched 60 over I think when we finally bolted the heads on it the compression was up there pretty good .

I learned about points and such the old fashioned way .