Hi.
My 2.0 zetec mondeo died as I was driving it into drive and when I checked it out it seems there is no spark. I have replaced the coil pack but to no availe. I am now looking for a wiring schematic of the ecu to trace any faults in the wiring loom of ecu.
Has anybody had this problem before.
Thanks
col
Edited by Dynamic Dave on 20/06/2008 at 13:36
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"Seems to be no spark?" Confirm that first by sticking something conductive up a plug-lead and seeing if a spark jumps to earth when cranked.
If so; check your inertia switch.
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Thanks. I have removed the spark plug and put it in the the plug lead and earthed the plug, turned over the engine and still no spark. I have replace the coil pack which made no difference. I have checked all the fuses and all are fine. There is a 12v feed to the coil pack and a good earth from it as well. What and where is the inertia switch.
Thanks
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If there's no spark; then forget the inertia switch, that only cuts the fuel pump.
Does the rev counter move when cranking? Check the plug is tight on the crankshaft sensor.
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havn't checked the rev counter when cranking. I will remove the four plugs so engine turns faster on starter and see if the rev counter works. I will also check both the camshaft sensor and crankshaft sensor to see if they are signaling ok. Thanks
I don't know if the coil pack is ok because I replaced it with an old one but will see if I can get new one. I might also be forced to replace the ECU.
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Steady on; there's a long way to go before changing the ECU. What have you got in the way of testing equipment?
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I have an electronic multimeter which has a vast amount of settings on it so most things can be checked I also have a laptop pc with limited ford software but I think it is only a fault code diagnostic checker and seeing as there is no engine management light on I don't think there is much hope there. Do you have any suggestions.
Thanks
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That's a long way better than nothing; plug it in and read it - can't hurt.
If you have any form of live-data; look for engine rev info. [Should be around 300 revs cranking.]
Measure the resistance of the crank sensor disconnected. I know that there's no spark; but does the fuel pump run for a few seconds at key-on?
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yes the fuel pump works as soon as the ignition is turned on so it prims the fuel system and the fuel is getting into the cylinders as well. Can i test the crank sensor with the ohm part of test meter. Will it give different readings when engine turned over.
Again thanks
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Are you sure that it's injecting fuel?
The crank sensor should read about 400 Ohms disconnected.
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yes fuel getting to plugs as they are wet when i remove them and if i crank engine over with the plugs out the petrol vapour comes out plug holes. How hard is it to chack the crank sensor and would this stop the spark if it were faulty.
thanks
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That's surprised me. It's very rare to get total ignition failure with the fuelling side still functioning.
That would rule out the crank sensor and raise questions about the pulsing of the coilpack. When you mentioed that it had a good earth; what were you testing?
There should be a constant[?] key-on feed on the black wire to it's centre terminal and the two outer wires [usually green] should switch on-and-off when cranked - if your meter has a "Duty Cycle" function, that might be fast enough to read it.
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hi mate
I unplugged the plug onto the coil pack and tested the 3 wires there. The middle one is indeed a constant 12v supply. The other wire seeems to be a constant earth as I test it with a continuity meter that says its going to an earth point but never tried to see if it was pulsing. As for the other wire I am unsure of. I tried to create a "test fire" of the coil pack in my garage and tried to wire it as I would an old coil causing the primary coil to collapse and this creating a spark but could get nothing out of it and the coil pack is only a few years old.
I spoke to a local sparky who said that its definetly not the key or transponder as this would cut the starter and fuel pump as well. He said that I could swap the ECU for another one of the same family tree but if it was all ok it would only allow the car to start for a few seconds and then it would cut out. I would have to get the ecu to " learn" codes or something.
I am a bit unfamiliar with my multi meter with the "duty cycle" and how to test the pulse side of things. Could I do it with the continuity side of meter or voltage. My meter is at my garage and will pick it up later and see what settings it has.
Yet again thanks for your valuable help
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Some meters can also record the switching and can check for a signal on the coil wires.
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sorry to butt in on this one but when he tested the coilpack wireing centre wire constant 12v (ing on ) and a continuity check on earth is okay, that is not right the earth is triggered by the ecu to fire the coils so is it possible that the wireing has chaffed somewhere and is giving constant earth ie no switching, possibly burning the dis pack out or worse, i know on the later focus's escorts etc if the dis go's down it can spike the ecu and you end up changing both
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TB
Always feel free; there's something very wrong here. They sure do back-spike; but I've never seen two switching FETs go down together?? [Yet....]
ST
Can you confirm - at key-on, not cranking; black wire in the centre is 12volts and the two green[?] outer wires are really not[?] at 12 volts; with the plug CONNECTED? At that point; all 3 should be 12 v.
You need to back-probe the plug with dressmaking pins, or make 3 flyleads, to get the reading.
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Thanks guys
I will check all this in morning and get back to you. I had the coil pack from the car in my other car and managed to tap a wee shot of a work colleague's mondeo so I could try my coil pack on his motor and guess what his car started buy only ran on 3 cyclinders so there is a prob with coil pack as well but not enough to stop all the spark from all the plugs.
Thanks again all
st
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hi all, right i have done the following. The plug going into the coil pack shows a 12v supply with ignition on and none when off. The 2 brown wires on either side of the 12v supply, one is showing no continuity to earth but the other one is showing a constant earth even when cranking. When the plug is back in the coil pack the middle pin is 12v, one of the brown wires is 12v and the other brown wire shows 3v. I have unplugged the main plug to ecu and did all the tests again but got different results. With the coil plug removed the middle wire is showing 12v and both brown wires do not show a continuity to earth. With the coil plug back in the middle wire shows 12v and both the brown wires show 12v also. I thought that the coil wires might be shorting out in the loom but when the ecu plug is out i tested to see if any of the coil wires were shorting out and they were not.
I am now thinking of getting a replacement ecu but I have been told that the car will only start for a few seconds with another ecu until it has been coded correctly to the key and transponder.
Can you give me any tips before I splash the cash on a new coil pack and a replacement ecu from a scrap car?
Does anybody else think my tests have shown the ecu to be faulty?
Thanks again all
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OK; as far as I can read that, then it would appear that the ECU is holding-on an earth on one transistor and not switching the other. That would indeed fry the coilpack; if the potting compound on the base of the pack is white, is one coil browned?.
A secondhand ECU would need re-coding - find out the cost of that before you buy one.
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ok thanks for all your help. Am not sure wheather to repair car or scrap it now as I will need to replace coil pack and ecu and then have it recoded. The sparky said that the car would run for around 2 seconds with a replacement ecu until it was correctly coded. I don't know if it is possible to get the ecu, key, ignition barrel and transponder out of the same vehicle which would save me having to get everything recoded.
The sparky also said it had to be the exact family tree as well and the one on my car is "OUCH"
OUCH being the correct word
Thankyou all for your kind help
ST
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