Very much confused! Why is my 1980 FI Spider running so rich

[lugbutz]

Hi...

So... I have a 1980 FI Spider and am really looking forward to getting it on the road this next week cause spring is in the air and Winter has finally passed.
Problem:
Issue is the engine is always running rich and seems to flood repeatedly.

Symptoms:
Plugs are black and greasy looking, Exhaust smells gassy, Starts, runs, but a over short time, exhaust is oily and flooding occurs.

What Ive tested and replaced: Ive used Bosch FI Diagnostics and Artigue's excellent FI diagnostics as guidelines.
1. Fuel injectors tested and functioning according to spec
2. Cold start valve - Tested and passedf
3. Engine Compression across the board is excellent
4. Fuel line pressure is correct (35 psi)
5. Fuel Pump is new and functioning as expected, Fuel Filter as well
6. New fuel lines, tested, no leaks
7. Tested AFM Functioning in spec
8. Throttle Sensor - new and tested working as expected
9. New OS Sensor But has been exposed to flooding, rich environment for several months. (Wondering if it needs to be replaced)
10. New Coolant Sensor
11. New Temperature Sensor
12. Timing has been confirmed
13. Pressure Regulator Tested and Passed
14. Charcoal Filter Tested and passed Is properly sealed.
15. AFM Tested and passed

I am wondering if the key problem is the Fuel Mixture Adjustment Screw OR Idle Speed Adjustment is causing the problem. Mechanic is suggesting the problem maybe the ECU. I am struggling with this given the car was running well in the fall

[RRoller123]

Injectors probably need service, likely leaking. Certainly due anyway after 39 years. Good place to start, can't be a bad move, and could easily be a cause of your symptom.

Send them out to one of the service centers, the turnaround is very fast. I used OK Injectors in Oklahoma, Tim A used a local source here in MA that he really liked, and there are many others.

[lugbutz]

Have been serviced... no leaks...

[RRoller123]

Including the CSI?

[ga.spyder]

I have chased a rich condition/flooding condition for a couple years.I was at the point of giving up on the car.My main issue was after running for a little while,it wouldnt restart . Out of frustration I unplugged my cold start injector,and the car immediately started.Long story short...the thermo time switch was triggering the CSI to dump fuel into the manifold when it shouldnt. Hence,flooding and a no start condition when warm.I hope my 'accidental fix' may help you find your issue.

[RRoller123]

+1, worth a try, very simple test.

[royn]

Hi,
I had the same symptoms on my car and it was a faulty termo time switch as gy.spider suggested in his post. Hope you have sorted the problem. It`s easy to fix /change, but the termo time switch is expensive !

[Daddio]

Easy to eliminate the cold start injector; unplug the wires and pinch off the fuel line.
You have repeatedly unplugged and replugged all the electrical connectors, including the computer connector, to 'clean' them off, right?

[wizard124]

Disconnect the plug at the AFM sensor. Inspect carefully; look for recessed contacts. Repair as necessary.

My rubber cover at the plug was cracked. I wrapped electrical tape to repair/seal it. In doing this, I pulled one of those contacts deeper into the plug. My car then ran extremely rich. Black sooty exhaust and rough running. Not drivable at all.