Spark Plugs
 

Evening all...

After a complete rebuild and new P/C with rings...I was doing my 500 mile break-in service and I was looking at my plugs and noticed that 6, 5, & 4 had a fair amount of carbon build up versus 1, 2, 3 which were fine.

My car ran a bit rich until I could tune the Air fuel which it did take multiple times with varying weather temps and finding out I had a bad fuel relay.

I cleaned them up and I should have taken a photo.

I am using Bosch W4CS and set at .07m


Why one side

Ignition comes to mind if the spark is weak. Turbo car, right? Could the other bank's intake rubbers be bad? They could be running lean.

Cam timing - easy enough to check when you readjust the valves at 1K or so.

Carbon fouled plugs are due to a rich (too much air) not lean mixture. I'm not familiar with the engine but by adjusting the mixture you probably fixed the issue. If not it sounds like it may be uneven air/fuel distribution or an intake manifold leak. What is the cylinder layout on the engine? All even on one side and odd on the other?

I replaced the manifolds and gaskets..and torqued them to speck and rechecked..

Could my spark plug wire set for that side be going bad..

Uh....rich = too much air? On what planet?

ed

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Opps, meant to say fuel not air. Brain moving faster than my fingers. A better description would be a higher fuel to air ratio than optimal. Good catch.

My guess was also a fuel/air ratio issue on that bank. Are you running the CIS, or have you put an EFI setup on it?

very strange as you are stock CIS -- from the manual --

'The CIS air flow sensor plate measures the amount of air that is being drawn into the system. This sensor plate is attached to a fuel distributor that evenly meters the amount of pressurized fuel sent to each injector. The system doesn't differentiate among the six injectors: it sends the same amount of fuel to them at all times. Unlike pulsed-injection systems like the Motronic system or even the earlier Mechanical Fuel Injection system, the CIS injectors distribute fuel to the cylinders at all times. The opening and closing of the intake valves controls the intake of fuel into and out of the combustion chamber.

Through 1979, CIS was a semi-open-looped system, which means that it didn't monitor the output gases from the engine to see if the air/fuel mixture was set at the appropriate levels. In 1980, emissions requirements forced the introduction of an oxygen sensor into the system, which helped the engine to better run at the appropriate mixture level through the regulation of fuel pressure inside the fuel distributor.

Hmmm...Weird. Maybe something in the lines? Past that, I've got nothing. Good luck, and let me know if you do find out what it is. I'd like to avoid (or at least more quickly figure out) any issues with my car.