FORD TFI TROUBLE-SHOOTING

STEP 1

Determine if the engine is getting fuel. If injector is fueling chances are the TFI electronics are ok. If the electronics fail the fuel system shuts down except for about 20 seconds of start of cranking. If no fueling or if it quits after 20 seconds of cranking go to step 2.

STEP 2

Check for spark at one of the spark plugs. If spark is found, you may have a fuel system problem. If spark is not found, check for spark at the coil wire. If you have spark, you may have a bad rotor, cap, or wires. If you still have no spark, unplug the harness at the TFI module. With key off, there should be no voltage present at any terminals of the harness. With key in the run position there should be voltage at the "TFI POWER RUN(H4)" and the "TACH IDM (H5)" terminals. Pull the small wire off the starter solenoid so engine will not crank. Have an assistant try to crank the engine. There should be voltage at "TFI POWER RUN(H4), TFI POWER CRANK (H3), and TACH IDM (H5)" terminals. If there is not voltages present, there is a posible wiring problem. If voltages are ok, go to step 3.

STEP 3

With coil wire removed to watch for spark, place ignition key in the run position. Momentarily touch a jumper wire from "TACH IDM (H5)" terminal of the harness to a good ground. Spark should jump every time the jumper is grounded. Do not ground the jumper for more that a couple of seconds. If no spark is found, make sure that with the key in the run position there is voltage at one of the coil terminals. If voltage is present, the coil may be bad, go to step 4. If spark is found, the problem may be the TFI module or the PIP (profile ignition pickup or reluctor in the distributor) so go to step 5.

STEP 4

We should now test the coil. Use an ohm meter and probe the resistance of the teo small terminals, and you should find 0.3 to 1.0 ohm. If the resistance is not ok, it may be a bad coil. If the resistance is ok, probe one small terminal and the coil wire terminal. Resistance should be 8000 to 11,500 ohms. If the resistance is not ok, replace coil. If the resistance is ok, go to step 5.

STEP 5

Testing the pickup coil (PIP) in the distributor is not an easy task, and best to test the TFI module first, then replact the pickup coil (PIP) if the TFI module tests ok. I have seen very few pickup coils on Ford TFI systems go bad. Test the TFI module according to the chart below. These values may be valid only on an OEM module, but may apply to aftermarket.

TFI RESISTANCE
Terminals to jumpResistance (OHMS)
D1 to H112.8K
D1 to H217.4K
D1 to H31000
D1 to H411.5K
D1 to H54.2K
D1 to H60.0K
D2 to H11.2K
D2 to H25.8K
D2 to H312.6K
D2 to H4100
D2 to H515.8K
D2 to H611.6K
D3 to H1100
D3 to H24.7K
D3 to H313.7K
D3 to H41200
D3 to H516.9K
D3 to H612.7K
D1 to D2 11.5K
D1 to D312.6K
D2 to D31100
D1 to BASE0.0K
D2 to BASE12K
D3 to BASE13.1K
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