No Spark
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No Spark
95 F250 7.5l
Left for 2 weeks, came back to no spark.
Tested for 12v at TFI module get 12v at run and coil terminals. No 12v on start terminal get 0.9v ON and 0.7v START. Traced the wire to pin 4 of the ECU. Have continuity to there. The schematics all say the wire goes to the ecu. The written descriptions and trouble shooting guides say the start terminal on the TFI feeds directly off of the ignition switch. Fuel pump runs. Tach moves when cranking. So the ECM seems to be working.
Any ideas?
Thanks
Left for 2 weeks, came back to no spark.
Tested for 12v at TFI module get 12v at run and coil terminals. No 12v on start terminal get 0.9v ON and 0.7v START. Traced the wire to pin 4 of the ECU. Have continuity to there. The schematics all say the wire goes to the ecu. The written descriptions and trouble shooting guides say the start terminal on the TFI feeds directly off of the ignition switch. Fuel pump runs. Tach moves when cranking. So the ECM seems to be working.
Any ideas?
Thanks
Fleet Owner
Joined: Aug 2005
Posts: 23,666
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From: Easton,Ks
Originally Posted by rholston
95 F250 7.5l
Left for 2 weeks, came back to no spark.
Tested for 12v at TFI module get 12v at run and coil terminals. No 12v on start terminal get 0.9v ON and 0.7v START. Traced the wire to pin 4 of the ECU. Have continuity to there. The schematics all say the wire goes to the ecu. The written descriptions and trouble shooting guides say the start terminal on the TFI feeds directly off of the ignition switch. Fuel pump runs. Tach moves when cranking. So the ECM seems to be working.
Any ideas?
Thanks
Left for 2 weeks, came back to no spark.
Tested for 12v at TFI module get 12v at run and coil terminals. No 12v on start terminal get 0.9v ON and 0.7v START. Traced the wire to pin 4 of the ECU. Have continuity to there. The schematics all say the wire goes to the ecu. The written descriptions and trouble shooting guides say the start terminal on the TFI feeds directly off of the ignition switch. Fuel pump runs. Tach moves when cranking. So the ECM seems to be working.
Any ideas?
Thanks
Pin 4 has always been an input pin on the PCM for the IDM that checked to see if the coil fired.
This goes along with E series but not the F series for 1995.
The START pin of the ICM has always been an input and received its power from the Ignition switch in the start position.
Somehow I cannot believe the 1995 Ford F series wiring diagram (and all of the manuals both Ford and after market are based on this one print).
I am going to have to take my 95 F series apart to see who is right.
Try pulling out your SPOUT jumper and see if it will start.
I think the way it should be is shown in the diagram below from the 1995
POWERTRAIN CONTROL/EMISSIONS
DIAGNOSIS manual.
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If pin 4 goes to the ICM then the pinouts in the TFI plug are different. I tested all the wires to verify they were what the diagrams said. The diagram you posted is correct but the "start" wire which is Yellow/BLK goes to pin 4 of the ECM verified with ohm meter.
So either I over looked one of the wires or ? Either way none of the pins show 12v when cranking except for the two coil wires which also have 12v when ON. So I'm missing the start signal to the TFI.
More information it is a California truck with auto trans.
I will try to start without the SPOUT jumper tonight.
So either I over looked one of the wires or ? Either way none of the pins show 12v when cranking except for the two coil wires which also have 12v when ON. So I'm missing the start signal to the TFI.
More information it is a California truck with auto trans.
I will try to start without the SPOUT jumper tonight.
Fleet Owner
Joined: Aug 2005
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From: Easton,Ks
After a little more looking there seems to be a System H and it does not use a Start pin on the ICM.
The IDM comes from the ICM pin 4 and goes to the PCM pin 4.
I do not know what years the System “H” was used but it seems to be used in All 1994-1996 F-series but not in the E-series with the 7.5. It was not used in 1993 F series.
Let me know if you get spark when you remove the SPOUT with this system.
The IDM comes from the ICM pin 4 and goes to the PCM pin 4.
I do not know what years the System “H” was used but it seems to be used in All 1994-1996 F-series but not in the E-series with the 7.5. It was not used in 1993 F series.
Let me know if you get spark when you remove the SPOUT with this system.
Last edited by subford; Jul 12, 2007 at 05:52 PM.
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Still no spark with SPOUT jumper out.
The tach moving PIP is registering in the ECM, so PIP is good.
Power to coil.
Ground has continuity to other grounds.
This is looking more like the TFI module is bad. Auto Zone tested it and it registered good bought a new one any ways still nothing put the old one back in. But the diagram you show the TFI module may be different so the tester may not work properly?
The tach moving PIP is registering in the ECM, so PIP is good.
Power to coil.
Ground has continuity to other grounds.
This is looking more like the TFI module is bad. Auto Zone tested it and it registered good bought a new one any ways still nothing put the old one back in. But the diagram you show the TFI module may be different so the tester may not work properly?
Fleet Owner
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From: Easton,Ks
The TFI module should only be bought from a FORD dealer.
Some have taken 4 or 5 back to Auto Zone before buying one from FORD.
But it sounds more like you have a bad pick-up (PIP sensor) unit in the distributor.
Just replace the Distributor and it should come with a TFI module and Pick-up unit already.
EDIT:
You can take a test light, ground the clip and probe the tach side of the coil and it should flash while cranking.
If it does then the coil is bad.
Some have taken 4 or 5 back to Auto Zone before buying one from FORD.
But it sounds more like you have a bad pick-up (PIP sensor) unit in the distributor.
Just replace the Distributor and it should come with a TFI module and Pick-up unit already.
EDIT:
You can take a test light, ground the clip and probe the tach side of the coil and it should flash while cranking.
If it does then the coil is bad.
Last edited by subford; Jul 13, 2007 at 02:35 PM.
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Thread Starter
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Got it running!
Bad ground. Cleaned up the grounds by the battery, running now.
Thanks for the help.
Bad ground. Cleaned up the grounds by the battery, running now.
Thanks for the help.
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Fleet Owner
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From: Easton,Ks
Originally Posted by rholston
Got it running!
Bad ground. Cleaned up the grounds by the battery, running now.
Thanks for the help.
Bad ground. Cleaned up the grounds by the battery, running now.
Thanks for the help.
The Ignition ground comes from the Distributor and the engine block ground.
Glad you got it running anyway.