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I'm going to be removing a Motorcraft 2150 carburetor in a 2.8L V6 and swapping it for a Ford CFI (and ECU) from a 3.8L V6. I've just recently pulled everything (ECU, throttle body, sensors, harnesses, etc) from a Mercury Cougar.

When I was removing the CFI from the Cougar, I've noticed that the EEC-IV harness has two inputs for the heated O2 sensors (one in each manifold), but the 2.8L only has one O2 sensor (around the driver's side manifold).

  • Is there a way to connect both O2 sensor inputs to a single O2 sensor? Or do I need to take off the other manifold and tap a hole into it?

  • If I can connect both inputs to a single sensor, would it make any difference in the performance of it? Could the EEC-IV & CFI even make adjustments for each "side" of the engine? It does have separate injectors, but it seems like the air-fuel mixture would get combined in the intake after the CFI.

Kevin Evans
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1 Answers1

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Drill and tap the other manifold, or have a good welder braze or weld an O2 bung somewhere accessible. However, please see my comments above... maybe I can improve this answer.

This sounds like a cool project, and I don't want to discourage it, but there may be more than just mounting the throttle body and expecting correct Air/Fuel ratios without ECU (EEC-IV) remapping. Possibly you could fudge a little with coolant temp sensor resistors and possibly throttle position sensor... but I doubt a manifold pressure drop of say, 2psi on the 2.8 equates to the same CFM (and needed fuel injection) as the 3.8 mapping. I could be wrong, if the intake manifold configuration is very similar.

Just keep in mind that a 25% reduction in displacement translates to a 25% reduction in airflow CFM for any given RPM. The airflow is calculated from the signal of pressure drop of the MAP (manifold pressure sensor) and is only valid for that particular manifold. The information is scaled in the EEC-IV along with RPM and throttle position, to determine the proper fuel injector (in your case central, single-point) pulse width.

None of that was an answer to your original question... but I'd rather not send you down a path if there are other monsters to be slayed first.

SteveRacer
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