PicoScope 7 Automotive
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Hi technicianTechnician wrote:
AP sensor has a 5V reference voltage, the ground is 0V, AD advises that the terminal 3 (output) is 4.3V at idle,
then if I am getting about 2.5V at idle and the voltage drops to about 1.7V when I rev the engine, then I think I should be looking to see if the 5V reference is dropping off when I rev the engine, if not, and I have not to date found a fault in the wiring, I am leaning towards the ECM, but if that were the case I can't understand why it revs and runs OK with the low fuel pressure disconnected?
I'm sorry to advise STC that today I have not managed to do all the checks you advised, I have lost about 4 hours working time today trying to sort out my mothers sky broadband between two companies, what a nightmare, and yes that ain't even sorted, so I'm not having a good day today, but thanks for all the help and advice todate.
1. See attachmentbut I am somewhat confused with two areas now on this fuel system, which are;
1 / What and where controls the low system fuel pressure regulation, the pump pressure is now 4.40 bar,
2 / If a MAP sensor has a 5V reference voltage, the ground is 0V, AD advises that the terminal 3 (output) is 4.3V at idle,
EAAD wrote:Hi technicianTechnician wrote:
AP sensor has a 5V reference voltage, the ground is 0V, AD advises that the terminal 3 (output) is 4.3V at idle,
then if I am getting about 2.5V at idle and the voltage drops to about 1.7V when I rev the engine, then I think I should be looking to see if the 5V reference is dropping off when I rev the engine, if not, and I have not to date found a fault in the wiring, I am leaning towards the ECM, but if that were the case I can't understand why it revs and runs OK with the low fuel pressure disconnected?
I'm sorry to advise STC that today I have not managed to do all the checks you advised, I have lost about 4 hours working time today trying to sort out my mothers sky broadband between two companies, what a nightmare, and yes that ain't even sorted, so I'm not having a good day today, but thanks for all the help and advice todate.
I recall looking at your description of the fault and my immediate response was check the 5v ref and associated values (I amended my post because, a) I thought I'd misread your post and b) I thought I didn't have enough knowledge to try to help, basically doubting my own ability.
It still doesn't sit right with me? I would try to get information other than autodata on this circuit and look again at this?
Both the 5v ref and the signal input to the ecu
Basically alter the input signal to the ecu manually and monitor the pid ..... again as been mentioned before, I don't want to teach egg sucking to my mums mum.
Kindest regards and best of luck mate.
Thanks STC, the diagram is very informative. Please read my last reply before this one, I refer to the MAP sensor and also talk about the air flow meter.STC wrote:Just out of interest, what is the pressure sensor voltage with 4.4 bar in the pipes?1. See attachmentbut I am somewhat confused with two areas now on this fuel system, which are;
1 / What and where controls the low system fuel pressure regulation, the pump pressure is now 4.40 bar,
2 / If a MAP sensor has a 5V reference voltage, the ground is 0V, AD advises that the terminal 3 (output) is 4.3V at idle,
2. I would concentrate on maintaining the required 2.6 bar physically in the system, confirmed by your gauge. I suspect that the Voltage reading in AD may well be wrong. Once again, 4.3v is too close to DTC territory for my liking. Of course that could be by design, we shall see.