Ignition issue.

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Jul 14, 2015 | 12:58 PM

clwi

Thread Starter

Racer

Joined: Jun 2015

Posts: 315

Likes: 20

From: Vasteras, Sweden

Ignition issue.

72, 454 HEI and MSD box.
Car was unstable at idle but ran fine otherwise.
Red that pluggap should be 0,045 with HEI, had 0,035 previously.
Adjusted to 0,045 and the car ran like crap when it got hot, stumbles and misfires.
Went back to 0,035 and it still runs like crap...
Could it be that plugs or coil has been damaged.
Strange thing is, when it is Cold it runs perfect.
Please someone, give me a solution!

Jul 14, 2015 | 03:07 PM

bashcraft

Le Mans Master

Joined: Jan 2006

Posts: 6,499

Likes: 137

From: Butler Pa

You have a vacuum leak. When it's cold the choke is closed and masking the problem.

Jul 14, 2015 | 03:11 PM

dochorsepower

Drifting

Joined: Sep 2010

Posts: 1,412

Likes: 50

From: Laguna Niguel California

What is the quality of your spark plug wires? Big blocks have always been sensitive to spark plug wire quality.

Jul 14, 2015 | 04:10 PM

clwi

Thread Starter

Racer

Joined: Jun 2015

Posts: 315

Likes: 20

From: Vasteras, Sweden

Quote:

Originally Posted by dochorsepower

What is the quality of your spark plug wires? Big blocks have always been sensitive to spark plug wire quality.

It ran just fine Before i started to fiddle with sparkplug gap...

Jul 14, 2015 | 04:13 PM

clwi

Thread Starter

Racer

Joined: Jun 2015

Posts: 315

Likes: 20

From: Vasteras, Sweden

Quote:

Originally Posted by dochorsepower

What is the quality of your spark plug wires? Big blocks have always been sensitive to spark plug wire quality.

MSD street fire wire, ran god Before plug adjustment.
But i have been thinking of that and the coil.

Jul 14, 2015 | 04:40 PM

MelWff

Race Director

Joined: May 2006

Posts: 18,606

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could you have broken the connection in the spark plug boot by pulling on them when changing the plugs? Do you have an ohm meter to test them?

Jul 14, 2015 | 04:48 PM

clwi

Thread Starter

Racer

Joined: Jun 2015

Posts: 315

Likes: 20

From: Vasteras, Sweden

Quote:

Originally Posted by MelWff

could you have broken the connection in the spark plug boot by pulling on them when changing the plugs? Do you have an ohm meter to test them?

Checked all plugs before reinstalled them, did not ohm them.
Did ohm all Cables, could not detect any issus.
Thing is, why does it run god when cold??