Mustang Bullitt Forum banner

1 - 2 of 2 Posts

·
Registered
Joined
·
75 Posts
Discussion Starter #1
I just finished changing my spark plugs, they seamed fine but #5 was definately leaner than the rest and #2 and #4 were a little lean. Is this common? They were not lean enough to cause concern on a N/A motor, but could cause concern later if I decide to use a power adder.
 

·
Banned
Joined
·
7,235 Posts
Really hard to read the plugs with todays fuels. These things run around 14.6- 15.1 on the A/F ratio.
If you read a plug after normal running around,this will tell you nothing about the WOT.
Unless you have a bad injector,all cylinders should be close to the same A/F. I have heard that cyl. 5-7 can run a bit leaner than the others,but only a Exhaust Gas Temp reading would prove that.
I use the Innovate A/F unit,hooked to the exhaust for real time A/F check,which is an average of either 4 or 8 cylinders,depending how it is hooked up. Always shoot for a bit richer to correct for a lean cyl.
 
1 - 2 of 2 Posts
Top