no earth pulse from ecu to injectors ?????
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T.
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So not an ECU fault when injectors not working - it's doing what it's supposed to do ! Regards Dave
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In your case, I don't think it is actually "electrical interference" the ECU is programmed to shut off injectors if there is a potentially catalyst damaging misfire ! How old is the fiat ? Regards Dave
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The ECU uses the crankshaft sensor to work out if the engine is misfiring, basically when a cylinder fires properly, the crankshaft is rotated at a "known" speed, when it misfires the crankshaft isn't rotated as quickly and the ECU can pick this up, when the signal from the 02 sensor then indicates that the mixture is capable of damaging the catalyst then injectors will not be opened on the "offending" cylinders. There is obviously a lot more to it than that, but that is the short version ! Regards Dave
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What can happen is that the ignition coils fail, the high energy generated by the coils can find it's way back into the ECU and burn out the "drivers" for other actuators IE injectors - once this has happened it's 99.9% a new ECU is required. Never heard of one "recovering" after swapping coils. Only 2 wires needed to run these coils, one live 12v feed and the other wire goes to ECU to be earthed "switched on and off" Fault codes are generated by the ECU, not sent to them by external components ! Ecu knows which cylinder is misfiring (if misfire monitoring is available on your ECU) by the speed of the crankshaft, as already mentioned. Sometimes by fitting non oe parts, the internal resistances of these parts may be different to what the ECU is expecting to see, and may cause running problems all of there own - for example, fitting non genuine 02 sensor's on Rover's, the heated element resistance is different and the ECU will ignore the new sensor and stay in open loop ! Regards Dave
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I don't think you ever did say what year this punto was ! However, I do think you are staring down the barrel of a new/recon ECU, if you have no earth pulse to one of the coil packs, then unless there is a wiring fault between ECU and coil pack you will need to replace the ECU. You can buy a recon one from Fiat, but would also strongly recommend you replace both coil packs with genuine parts too. It's not any particular sensor that causes the ECU to stop pulsing the injectors (doesn't stop coils intenionally !!) it's the misfire monitoring that makes the ECU stop pulsing injectors. Regards Dave
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So, what have you got now, do you have a spark at all four plugs or only two ? Dave
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But back to the problem if you have put coils on it then its the ecu and there is no need to change the coils again they will be ok. Certainly you should consider opening the ecu and going over the joints around the driver transistors at least. After that its change the ecu, cheapest is to get one from a scrappy and have it virginised, total cost about £80 total. Not sure whether a dealer ecu is virginised or pre-coded cos dealers always say they need a red key, but you dont need a red key if its virginised. T.
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I respectfully disagree !! the system should be a IAW 59F and the injectors are fired individually. Also the ECU's are plug and play, apart from having to carry out a phonic wheel reset after fitting. Regards Dave
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T. ps why dont posters give releavant info in the original post instead of having to drag it out of them, its like drawing teeth.
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Messages 1 to 20 of 29.
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