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| Vx Corsa, N plate x14 Ecotec.
the customer has had the engine managemnt lamp on for over a year, and so far no one has been able, (Including a dealer) to get it to go out.
The car came in just before Easter with non starting, but as the recovery man was dropping it off, it started, and has been starting fist time over the last few days.
Code in memory for cam sensor, (Looks new, and code returns when cleared) Coil resistance, (also looks new, code has not yet returned) and immobliser. (Also has not yet returned.)
The HT spark does look very week on both circuits.
At one stage during the day the car did stop and was very difficult to start. No new codes recorded, and injector time was normal with a good RPM signal.
remember Andy-1 posting re-problem ECU’s on Vectra’s, are these poor also?
Regards Tony
Regards Tony"One advantage of a bad memory, is that you are always meeting "new" people....." |
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| Tony
Sorry but no known history of ecu faults on these. Fuel pump relays were a bit weak though.
So are you saying the cam sensor code is present, even without the engine running ? |
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| Hi Tony,
Just a quick question:
If you had a stronger spark, what do you think it will solve?
Tim
Ps-I wouldn’t be worrying about the spark yet. Unless your answer to the above is a good one.
Another great day solving some of life's little management troubles |
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| Andy,
The cam sensor code will only return once the engine is started. I have not been able to check the fuel pressure, as my adaptor keeps fouling the altenator bracket. All I can tell is that there is fuel there.
The week spark is worrying me most at the moment, I will see how strong it is with the engine running, and compare it when, (IF) it stops.
Regards Tony
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| Ok. A few things spring to mind here.
You say the cam sensor looks new, but as you didnt replace that do you trust it ?
Please check the belt timing is 100 percent spot on.
If the code is not getting set until cranking/running, its passing self test at ignition on, so this should rule out short or open circuits. Its the data stream from the sensor that the ecu doesnt like. If its not the ecu its self it must be getting interference in the loom. Does it look ok. Are things like the leads original ? It would be painful, but you could try separating the cam sensor wires from the loom and shielding them. (remembering to earth the shield). Years ago now we had to do a lot of loom changes on Cavaliers for cam and crank codes, due to interference problems.
All that said, the cam sensor is responsible for timing the sequential injection only, so this in its own right shouldnt cause a breakdown. I would be keen to know some more when its in a failed state. The cam sensor code may be responsible for the light coming on, but I dont think its causing your cut out/starting concern. ???
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| Andy,
I spoke to the customer on Saturday, and she said that the engine management lamp had been on for the last 5yrs!
I see on another thread that you refer to the phasing of the cam/crank sensors, are they both suposed to be "in time" with each other? Or just give the same waveform output?
Like you, I am sure that this is not the cause of the fault now, but it would be nice to see how the two are linked.
I still dont like the look of the spark, so will check it better tomorrow, whilst it is running, and compare it with when it stops.
Regards Tony
Regards Tony"One advantage of a bad memory, is that you are always meeting "new" people....." |
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| Andy,
Well the dam thing would not start this morning. But I did have in an 8 valve 1600 Astra on an "N" with the same design of coil. As soon as it was fitted it started, but after the fitting of a new coil it would not.
I had a closer look at the coil trigger traces, and found some "noise" Whist firing, and also between fires. (Which I took to be from the second section of the coil firing.) So I faxed a hard copy to BBA (Mike) who forwarded it on, and came back with it COULD be the ECU, but only by having it off the car could "noise from another sorce be ruled out.
I then had a look at the other traces, and found the same noise on nearly every wire you check. (Plese note that I am new to the Pico scope) What I cant make out is why the noise is at regular 25ms intervals.
The signal from the cam sensor looks good to me. (Except for the small amount of noise) I am getting four traces of 5 vlots, of varying durations.
I will have to try to get them transfered onto the home PC so I can post them.
One last thing to note, the vehicle had a new coil fitted by us in June that cured a mis-fire, so a spiked ecu is a possibility.
Regards Tony
Regards Tony"One advantage of a bad memory, is that you are always meeting "new" people....." |
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| Tony
Could this 40Hz "noise" be generated by faulty diodes in the alternator? Or, if your scope is sensitive enough; is it picking-up the mains-frequency [50Hz] EMF in the air that is always there - in varying strength.
Try scoping the wires with the engine off to see if it’s still there. If it is: try turning your fluorescent lights off.
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| Tony
Had a run of this a few years back. Splice another earth wire from the brown wire at the coil and take it straight to the battery. Let me know what happens ?
Will post tommorow night when I have a bit more time.  |
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| Andy,
I have checked for voltage down the power and earth lines of the coil, but this was with the engine running. I will try again when it stops. Most of the time when it wont start it will be firing, but just wont go the extra little bit to actually start.
When I get time I will try it with the altenator drive belt off.
Regards Tony
Regards Tony"One advantage of a bad memory, is that you are always meeting "new" people....." |
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