Fuel Distribution ?


Wrinkled Member
What cylinders usually tend to receive more fuel (run rich) than the others on a mostly stock '87 turbo V-6?

Thank you
Thank you for the reply.

I just changed my plugs & #5 was darker, more wet looking than the rest.
You can not compare plug conditions from normal drivivng to what really counts which is WOT 1/4 mile pulls and shut down and read the plugs at the race track conditions.

Trying to read plugs that have been in the engine for several hundered miles or more and determine what is going on will tell you nothing that is of value to WOT racing conditions.

To truly read a spark plug and understand what is going on at WOT you need to be able to cut-off the threaded portion of the plug body so that you can see way up on the electode what is happening.

The size and color of the fuel ring show A/F ratios and the heat mark on the ground strap shows where the timing is at. AS you can see in these pictures there is one set of plugs that look mostly good for A/F ratio and another set that looks a bit rich for A/F ratio.
The timing mark is hard to see as these plugs have rusted a bit over the last 10 months but the timing will leave a burn mark on the ground strap.....Ideally very close to the 90* bend....too close to the base and you will be putting head gaskets on it....too far towards the tip and you are leaving power on the table.....

again these are for WOT conditions, not cruising where the o2 sensor is controlling the fuel


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How do you cut the plugs? Special tool, or a band saw of some sort?

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How do you cut the plugs? Special tool, or a band saw of some sort?

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Hacksaw and chuck up the plug in the lathe if I am doing it at home.

At the track put the plug in a drill motor chuck and spin the plug towards you while stroking
the hack saw back and forth. Takes about 45 seconds per plug and you really need a helper using the hand drill method.

Is much eaasier than I had thought it would be after I did a few.