75 still running rich, 75 still running rich Options

[brooks944]

My 75 is running rich and fouling plugs after just a few miles. One of the members spent several hours helping me check and figure out the FI a couple of years ago and that made a difference (both on the car and how much I value your experts here). I have 2 extra 'brains' is it time to change that and check? One is from a '75 and one from a 74, does that matter? Both are for a 1.8 which my car is. Fuel injectors are rebuilt as well as the cold start valve. Most vacuum hoses changed. Thanks for any input.

Rick

[malcolm2]

So who has more ideas about running rich? All 4 cylinders, right Rick?

Rick and I have been trying things.

* CHT ohms test was correct at room temp and 300*
* spare '75 ECU found no benefit.
* fuel pressure is normal
* Cold Start Valve is unplugged and replaced with a fuel pressure gauge.
* fresh plugs were fouled very quickly as pictured

At this point he is going by smell, but he is trying to borrow an A/F rig to pin-point how much rich.

I sent him the Itinerant posting about "asking the car what it wants", he may learn from that.

Mentioned that he might want to check (one cause they all should be checked, but also to eliminate some mechanical probs.)
*compression
*valve clearances
*and timing

But what makes the whole system rich?

[Bartlett 914]

So who has more ideas about running rich? All 4 cylinders, right Rick?

Rick and I have been trying things.

* CHT ohms test was correct at room temp and 300*
* spare '75 ECU found no benefit.
* fuel pressure is normal
* Cold Start Valve is unplugged and replaced with a fuel pressure gauge.
* fresh plugs were fouled very quickly as pictured

At this point he is going by smell, but he is trying to borrow an A/F rig to pin-point how much rich.

I sent him the Itinerant posting about "asking the car what it wants", he may learn from that.

Mentioned that he might want to check (one cause they all should be checked, but also to eliminate some mechanical probs.)
*compression
*valve clearances
*and timing

But what makes the whole system rich?

I would guess the AFM is messed up. Maybe the relationship between the flapper and the pot internally is out of position with each other telling the ECU the flapper is open more than it actually is.