rebuild almost complete but.................................
Discussion
I've got no earth at the coil - as a result no voltage in the primary = no spark - I can induce a spark by tapping an earth on so any help with where that earth comes from would be more than welcome. I will keep an open mind so will not post what Ive tried so far.
Edited by pringli on Saturday 7th June 13:03
The timing and duration of the earth (basically the dwell angle) are controlled by the ECU. I think that the signal comes directly from the ECU after it has processed information from various sources including the hall sensor and ignition amplifier in the distributor.
So it could be a fault in the wiring itself, or in the hall sensor that picks up the timing signal, or in the ignition amplifier module in the distributor.
Don't know how to test them without substitution.
So it could be a fault in the wiring itself, or in the hall sensor that picks up the timing signal, or in the ignition amplifier module in the distributor.
Don't know how to test them without substitution.
ok youve confirmed the method for me so now I need to know how it gets from A to B etc.. ie what conditions should exist on which terminations. 
Also I know this sounds stupid but what termination on the coil has the 12v on when ign is on? (please check before posting as mine is on the -ve terminal but the wiring is as it was before body off [different size connectors]) more
Also I know this sounds stupid but what termination on the coil has the 12v on when ign is on? (please check before posting as mine is on the -ve terminal but the wiring is as it was before body off [different size connectors]) more
pringli said:
ok youve confirmed the method for me so now I need to know how it gets from A to B etc.. ie what conditions should exist on which terminations.
Also I know this sounds stupid but what termination on the coil has the 12v on when ign is on? (please check before posting as mine is on the -ve terminal but the wiring is as it was before body off [different size connectors]) more
That sounds wrong to me (coil +ve terminal should be connected to the +ve supply) but I can't see it making any difference. The spark works just as well either way round, as anyone running wasted spark will tell you.Also I know this sounds stupid but what termination on the coil has the 12v on when ign is on? (please check before posting as mine is on the -ve terminal but the wiring is as it was before body off [different size connectors]) more
cheers Peter, as the coil is has no diodes etc I figured it wouldnt make any difference to its operation but it serves to confuse the wiring diagram issue even more. I am sure I am missing something simple(other than the earth), which is why I dont want to say what I've already tried and discourage someones suggestions.
What happens if you crank the engine with a bulb or preferably a LED tester between - on the coil and earth? The LED should flash on and off as the TFI opens and closes the circuit.
However, when the SPOUT signal is missing, the TFI uses the PIP signal for ignition timing. This means that in degraded mode the ignition will work, just the timing won't be optimal.
Translation:
TFI: The small electronic box mounted to the side of the distributor
PIP:'raw' ignition timing signal from distributor
SPOUT: fine tuned ignition timing signal from EEC-IV
EEC-IV: engine management computer.
Conclusion: The ignition should even work when not connected to the ECU. If the distributor doesn't generate a pulse, try changing the distibutor with TFI and Hall sensor.
tvrgit said:
The timing and duration of the earth (basically the dwell angle) are controlled by the ECU. I think that the signal comes directly from the ECU after it has processed information from various sources including the hall sensor and ignition amplifier in the distributor.
So it could be a fault in the wiring itself, or in the hall sensor that picks up the timing signal, or in the ignition amplifier module in the distributor.
Don't know how to test them without substitution.
If we're talking about the V6, the Hall sensor / TFI generates a PIP signal that is sent to the EEC-IV. The EEC-IV then calculates the SPOUT signal and sends it to the TFI. The TFI then uses the SPOUT signal for the exact ignition timing and dwell angle.So it could be a fault in the wiring itself, or in the hall sensor that picks up the timing signal, or in the ignition amplifier module in the distributor.
Don't know how to test them without substitution.
However, when the SPOUT signal is missing, the TFI uses the PIP signal for ignition timing. This means that in degraded mode the ignition will work, just the timing won't be optimal.
Translation:
TFI: The small electronic box mounted to the side of the distributor
PIP:'raw' ignition timing signal from distributor
SPOUT: fine tuned ignition timing signal from EEC-IV
EEC-IV: engine management computer.
Conclusion: The ignition should even work when not connected to the ECU. If the distributor doesn't generate a pulse, try changing the distibutor with TFI and Hall sensor.
Ronald, do you mean between the 12v to the coil and earth? If so the answer is nothing - lamp permanently lit as there is no interruption - if not and you mean between the feed TO the -ve and eth, there is nothing at all as the feed would appear to be dis - which then leads me to the question of the exact path of the cct feeding the -ve.
Edited to add: this looks increasingly like TFI/Hall sensor
Edited to add: this looks increasingly like TFI/Hall sensor
Edited by pringli on Saturday 7th June 15:54
Ian, I forgot to tell you that my story is valid for the 2.9. The 2.8 could be a bit different.
the TFI could be regarded as an electronic switch that alternatively switches on and off the current from - on the coil to earth on the engine block. As long as the 'switch' is closed, the coil will charge itself. As soon as the 'switch' opens, the coil will spark, exactly like when you're tapping a lead from - on the coil to earth.
The current path is then: ignition switched +ve -> +terminal on coil -> -terminal on coil -> TFI -> earth on engine block -> chassis earth.
I meant to test the 'switch' by putting a bulb parallel to it(so between -ve on coil and earth): when open, the current should flow through the bulb, which is in series with the coil. when closed, the bulb will be bypassed by the 'switch', so it won't light up.
If the light doesn't come on, the earth lead between the block and the chassis could be faulty. I don't think this is the case as you say you can create sparks by tapping the engine block.
If the light doesn't flash, it will be either the wire, the TFI or the Hall sensor. Easy to check continuity of the wire, the other parts are easiest checked by substitution.
the TFI could be regarded as an electronic switch that alternatively switches on and off the current from - on the coil to earth on the engine block. As long as the 'switch' is closed, the coil will charge itself. As soon as the 'switch' opens, the coil will spark, exactly like when you're tapping a lead from - on the coil to earth.
The current path is then: ignition switched +ve -> +terminal on coil -> -terminal on coil -> TFI -> earth on engine block -> chassis earth.
I meant to test the 'switch' by putting a bulb parallel to it(so between -ve on coil and earth): when open, the current should flow through the bulb, which is in series with the coil. when closed, the bulb will be bypassed by the 'switch', so it won't light up.
If the light doesn't come on, the earth lead between the block and the chassis could be faulty. I don't think this is the case as you say you can create sparks by tapping the engine block.
If the light doesn't flash, it will be either the wire, the TFI or the Hall sensor. Easy to check continuity of the wire, the other parts are easiest checked by substitution.
Ronald when I put the test lamp (in parallel) between coil -ve and earth it lights - fair enough - but there is no 'switched' earth coming to the coil. Do you know which wire on the TFI connector should go to the coil (and which one should be earth)? I can then test for continuity.
Many thanks for help so far.
ps Mine is also 2.9
Many thanks for help so far.
ps Mine is also 2.9
Edited by pringli on Saturday 7th June 16:42
I'm sorry, my workshop manual only shows the connections between ECU and TFI, not between TFI and coil. Unfortunately ford put the diagrams in another manual, that I don't have.
As far as I know, the current flows through the TFI body into the distributor body and into the engine block. There is an earth wire on the TFI plug, but I believe it's just an electronic or 'clean' earth. I don't have the diagrams to check this though.
I would check continuity with an ohmmeter: unplug the TFI plug, unscrew the negative lead from the coil and mesure resistance from the coil's negative lead to each of the terminals on the TFI plug. One of them should give zero ohm, the others should give infinite. Also check between the coil's negative lead and engine block: This should give infinite.
Hope this helps!
PS: Also check for oxidation on the terminals.
As far as I know, the current flows through the TFI body into the distributor body and into the engine block. There is an earth wire on the TFI plug, but I believe it's just an electronic or 'clean' earth. I don't have the diagrams to check this though.
I would check continuity with an ohmmeter: unplug the TFI plug, unscrew the negative lead from the coil and mesure resistance from the coil's negative lead to each of the terminals on the TFI plug. One of them should give zero ohm, the others should give infinite. Also check between the coil's negative lead and engine block: This should give infinite.
Hope this helps!
PS: Also check for oxidation on the terminals.
Edited by Sweet Thunder on Saturday 7th June 17:23
Not at work yesterday so had another attempt at finding the problem. I had already tried substituting the dissy etc. so back to the wiring. The diagram in the book shows the green from the dissy going to the coil but I had already connected a lead between those two connections and had no success. Then it came to me, what if the earth that was present on the green at the dissy (but not getting to the coil via the immobiliser) was not the 'switched' earth? So I removed the connector and took out the locking wedge and fished out the green, substituting a lead to the coil via my test lamp. Cranked engine .............................SUCCESS
. So the green is obviously in contact with an earth leaving the dissy(hence no pulsed earth) but is disconnected going back from the coil on the black wire that is via the META immobiliser. I had already attempted to trace the black back into the loom to break the cct down but without cutting back a long way found it impossible. So I have reused the original connector from the green at the dissy and run a new wire to the coil bypassing the immobiliser and keeping it neat and tidy. So now it remains to bolt up the body, bleed brakes, refit bonnet (and I know how long that takes to line up).
Thanks for the input everyone especially Kevin (Ketvrin)for stopping by with a complete dissy and Ronald (sweet thunder) for his technical input which allowed me to picture the cct..
. So the green is obviously in contact with an earth leaving the dissy(hence no pulsed earth) but is disconnected going back from the coil on the black wire that is via the META immobiliser. I had already attempted to trace the black back into the loom to break the cct down but without cutting back a long way found it impossible. So I have reused the original connector from the green at the dissy and run a new wire to the coil bypassing the immobiliser and keeping it neat and tidy. So now it remains to bolt up the body, bleed brakes, refit bonnet (and I know how long that takes to line up). Thanks for the input everyone especially Kevin (Ketvrin)for stopping by with a complete dissy and Ronald (sweet thunder) for his technical input which allowed me to picture the cct..
soon!
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