pekwah1
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| posted on 17/10/20 at 10:22 AM |
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Blacktop zetec coil switched earth
Hi guys,
Having a bit of a problem with the car not starting.
Thought it might be the coil, tested resistance which gives me 0.10 on the primary measured on 200M
On the secondary getting 10.55 on both measured on 20K.
Doing some more testing I’ve got a good 12v permanent, but think I’m not getting a switched earth.
I basically hooked up a 12v lamp to permanently live and the other terminal to the switched earth socket (tried both) at the connector and get
nothing.
Anyone have any ideas why the switched earth has disappeared and where I’m likely to find the problem?
I’ve been tracing the two brown wires but can’t see any issue there.
Thanks
Andy
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rusty nuts
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| posted on 17/10/20 at 10:35 AM |
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The coil is normally switched by the ECU , might be a good idea to check for live feed , earth and CPS signal?
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pekwah1
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| posted on 17/10/20 at 02:18 PM |
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Thanks for the reply, what’s the CPS and how do I check that?
Again love feed to the coil is fine, earths at ECU appear fine, but don’t have switched earth at the coil 3 pin connector
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obfripper
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| posted on 17/10/20 at 05:27 PM |
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What engine managment system are you running?
Without a crank signal, you won't get any switched earth at the coil pack.
The cps is the crank position sensor, to check the signal use the ac setting on a multimeter expecting approx 1-2v while cranking, or an oscilliscope
which will show a sine wave with a gap every 36 peaks.
If this is ok, the fault may be wiring, or a management fault.
If you have oem injection, you'll need an obd type scan tool capable of data to check there is an incoming crank signal, and for any stored
fault codes that may be related.
If you have aftermarket injection, you'll need the specific software and cable to connect to a pc, and check all inputs for correct signal while
cranking.
Dave
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pekwah1
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| posted on 17/10/20 at 06:10 PM |
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Ah thanks, I was clearly being a bit dumb there!!! I was messing around with the coolant and may have inadvertently spilt a load all over the crank
sensor so maybe that’s a good place to start.
It’s running on OEM ECU, did scan for fault codes but nothing there, but yeh sounds like maybe the crank sensor.
Thanks for the help!
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big_wasa
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| posted on 18/10/20 at 01:18 PM |
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Crank sensor would stop most things.
Should see if your getting an rpm signal while cranking.
[Edited on 18/10/20 by big_wasa]
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pekwah1
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| posted on 18/10/20 at 03:03 PM |
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Thanks for the help all, turns out it was a stupid error, I’d managed to trap the CPS wire in between the engine block and gearbox when refitting the
engine and cut through the wire, all now sorted!
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