Running Lean

[cgmaster]

I changed my plugs and wires today. All of my cylinders looked like they were running lean and my #10 looked like it was running very lean and possibly detonating. My engine is mostly stock with the exception of the Mopar race computer, Mopar roller rockers and 3" exhaust with no cats. Is this normal?

Next week I was planning to put on 70 mm throttle bodies but if it is running lean now I am worried it will get worse. I also have an AEM setup that I have not installed yet because there is no one near me to tune it.

I am getting anxious to get my new engine in the car with all these little problems I have been having with the stock one.

 

[Schulmann]

What makes you think that you was running lean.
Can you post a pic with your plugs ?
What plugs do you use ?

On the Mopar computer I can't comment but I know that they are very special ...

AEM sounds great. Learn how to tune it ! Then supercharge your Viper.

 

[Jack B]

CQmaster:

I will second that, why do you think you are lean. You really cannot read plugs after driving on the street, The exception is a plug with a burnt tip, splatter on the insulator or physical damage. You will have to take a wot run and kill the engine, you then look for the heat line on the strap and the color band at the base of the insulator (on our plug that requires cutting the end off).

Forget all that, take the car to a dyno. Contrary to what you read ot hear, a dyno is more important for establishing or correcting a/f than it is to find peak hp.

 

[cgmaster]

I will try to post pics tommorow. What leads me to believe it was running lean is that the plugs were bright white and that on #10 the electrode was eroded very bad. The rest of the plugs had a small amount of erosion on them.

The plugs have about 3000 miles on them. And all I have run is Shell 93 octane fuel.

 

[Jack B]

Dangerous lean shows up as pepper looking matter on the insulator. If the strap is rough or has splatter on it, that is also a sign of runing on the dangerous side.

 

[cgmaster]

Here are links to the pics I took of the plugs. I can not get a good closeup pic though. I will keep trying to get better pics.

http://gallery.viperclub.org/showphoto.php/photo/23605/sort/1/cat/500/page/1

http://gallery.viperclub.org/showphoto.php/photo/23604/sort/1/size/medium/cat/500/page/1

 

[Jack B]

One thing i can tell you is that you need more timing, the temperature line on the strap is too far down towards the threads (if that is what we are seeing)

 

[Schulmann]

Before you drive your viper have this mopar PCM reprogrammed. Next stage in this trouble is the insulator breaking off the spark plug and killing the engin.

 

[cgmaster]

I have decided to go ahead and install the AEM. Now I need to find someone who can tune it around here. Depending on the cost I may go ahead and install my Caldwell engine and get it out the way. Going to a colder plug helped a little but it needs a real fix. Well I guess once you start doing mods it never ends.