Plugs fouling, engine running rich?

[Funkmasta]

My neighbor has an 84 318iA, and it keeps fouling the plugs after about 4 days of driving, to the point of not starting. (I know this is the M20 forum, but my thread in the M10 forum has only gotten 6 views, and it is more of a "general" question)

The car recently (within last 4 months) passed emissions, so I don't believe it to be burning a ridiculous amount of oil.

I changed the O2 sensor, the cap and rotor are new, the AFM has been replaced.

Timing?
Other ideas?
The car seems to be running very rich, but I have not truly tested that.

[Jordan]

Did you check to see if the cold start valve is working? I've seen them get stuck open.. which creates issues.

[KenC]

Leaky injectors?

[Funkmasta]

I will try unplugging the cold start injector, swap the ECU, and will re-time it.

any other ideas?

How would I test for leaky injectors?

[Funkmasta]

Cold start unplugged, BLACK smoke @ WOT.

[RealizE]

Check the temperature sensor. If that's not working, it will be driving with the "choke" on all the time. If it's busted, you'll see black smoke, horrible smelling exhaust and really bad fuel economy.

Whilst it's idling, if you disconnect it and nothing happens it's a fair sign that it is stuffed.

[PУCCKAЯ_e30ka]

Check the temperature sensor. If that's not working, it will be driving with the "choke" on all the time. If it's busted, you'll see black smoke, horrible smelling exhaust and really bad fuel economy.

Whilst it's idling, if you disconnect it and nothing happens it's a fair sign that it is stuffed.

do you have a part# for that one? on m20?

[Funkmasta]

+1

[Belteshazzar]

Check the temperature sensor. If that's not working, it will be driving with the "choke" on all the time. If it's busted, you'll see black smoke, horrible smelling exhaust and really bad fuel economy.

Whilst it's idling, if you disconnect it and nothing happens it's a fair sign that it is stuffed.

otherwise, if it's good what happens?