EEC and TFI

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Aug 22, 2011 | 11:00 AM

mm_ford

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EEC and TFI

I have an '84 or '85 Ranger 2.3l, single barrel carb engine that came installed in an '85 Austin London Taxi. The engine was installed new in '85, when the car was imported, along with the automatic transmission and all associated engine wiring. The rest of the car has the original Lucas wiring. The original carb was replaced by a non-computer controlled carb from an earlier Ranger engine which, I think, made most of the sensors and wiring to and from the EEC computer obsolete. My problem is that I am having a lot of problems with the Lucas wiring and, as part of my effort to track down shorts and bad connections, I've been removing as much of the old, obsolete wiring as possible. By the time I finished, I'd removed a ton of old wiring, including the EEC computer module, and the motor still seems to be running fine. My question - were the wires (three of them) running between the EEC and the TFI module on the distributor simply feeding info to the EEC, or was the EEC using these wires to impact the advance of the distributor? Do I need to replace the distributor with an older centrifugal or vacuum advance, or does the TFI module and distributor take care of the advance without the help of the EEC?

Thanks for any input, mm

Aug 22, 2011 | 04:24 PM

Franklin2

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From: Virginia

You do need to swap distributors to the older mechanical style. You are correct, the EEC takes the signal from the TFI, modifies it for timing purposes, and then sends it back to the TFI to advance and retard the timing based on other inputs.

They way you have it now is the TFI has reverted to a "limp mode" where it has set the timing so the engine will run, and that's it. It's locked at one value that is a compromise just to keep the engine running. The mechanical distributor will have a vacuum advance to modify the timing according to engine load, and it will have weights with springs down inside to modify the timing in relation to engine rpm.

When you switch distributors, make sure you get the proper coil to go with it, and the proper ignition box. If you use a Ford system, it will probably be a duraspark II system. Make sure if you run a new hot wire to the coil and you are using the Ford system, that it has a resistor inline with the coil + to drop the voltage to the coil. This is the way the system was designed to work, the original Ford vehicles had a special resistance wire built into the harness.