Lucas Epic Timing Module

[kenhall1202]

After having a closer look at the pictures shown in the first post I'm pretty sure that what is shown is the rotor position sensor and not the timing sensor (going by the shape of the alloy housings).

[CitroJim]

It is Ken. The timing sensor housing is much smaller and mounts on the side of the pump...

[bddeazeley]

Thanks for the info Ken. I now have made a few continuity checks on the wiring from the ECU to the pump. The first thing I learned was that there is more than one version of the wiring circuit for the Lucas Epic pump and the first circuit diagram I was using was an LDV van version which is nothing like the Citroen/Peugeot (PSA) version so I would advise anyone to ensure they have the correct circuit version before embarking on any pump investigation. I have also come across Mercedes and Renault versions which are also different from the PSA version. The second thing I learned was that the faults identified by the Lexia session carried out by Dave Hallworth was spot on as a continuity check confirmed the Lexia diagnosis that the cam sensor/pump thermistor circuit was indeed open circuit. The interesting thing was that the actual sensors themselves appear to be ok according to further continuity checks I made. Confused?? I have attached a circuit diagram which may help in explaining my following findings:

Between pins 4 and 6 reads open circuit
Between pins 4 and 5 reads open circuit
Between pins 4 and 3 reads 45 ohms
Between pins 5 and 6 reads 3.4k ohms (this reading is the interesting one)

To sum up the open circuit appears to be between the top end of the Cam position sensor coil and the splice connection to the left of the Cam position sensor. I say 'splice connection' but that's my interpretation of the circuit and input from the more learned members would be appreciated.

[kenhall1202]

Your tests suggest that both the advance sensor coil and thermistor are both o/c which seems an unlikely coincidence. Continuity between connectors 5 and 6 would suggest they are both intact.
I don't think there is a splice connection between the two wires from each sensor to connector 4 - both the advance and rotor sensors have separate 4 core leads running to the pump terminal block.
I would agree with your diagnosis that the wire from the advance sensor to terminal 4 may be the problem. Difficult to check with the pump in situ - probably best done with the sensor off the pump. You could then strip a little of the outer cable sheath off as close as possible to the sensor to expose the 4 wires and then do a pin probe resistance check back to no 4 connector.

PS I would also suggest a full continuity test on the multicore cable between the Kostal connector and the pump.

[bddeazeley]

Thanks for the advice Ken and well spotted about the photographs being of a Rotor sensor. I have located on the web the attached descriptions on removing and refitting the cam sensor module from the pump and it appears to be relatively straight forward. Never having removed the injection pump before I will need to go Googling yet again lol. The reference in the description to MB refers to the Mercedes Benz version of the Lucas Epic pump.

[bddeazeley]

I have had another look at the wiring from the ecu to the pump and as Ken suggested I checked all the connections which were all good apart from the previously mentioned open circuit readings between pins 4 to 5 and pins 4 to 6. The splice on the lead from pin 4 that I mentioned in a previous post takes place on the printed wiring board (pwb) mounted under the plastic cover on the pump ie. the lead from pin 4 is soldered to a pad and the leads to the cam sensor and the other lead to the rotor sensor (both red) are soldered to another connected pad on the pwb. The pump will have to be removed to progress and any advice, descriptions or tips on removing the pump would be greatly appreciated. I do have the Haynes description on the pump removal . Can anyone tell me if the Haynes version is any good as I would prefer a layman's version. Any tips or pitfalls to avoid would be appreciated. Thanks.

[kenhall1202]

I would first try to remove the advance sensor with the pump in place. With the diesel feed/return pipework gubbins out of the way and the inlet manifold removed there should be enough space between pump and engine to get a ratchet spanner + Torx bit on the two screws which hold the advance sensor to the pump body. Stuff a rag between the pump and engine to catch anything dropped! To remove the sensor completely for bench testing the four leads will have to be unsoldered or snipped at the pump wiring board.

I don't know if it is possible to remove the pump without disturbing the cam belt / timing - mine has never left the engine. Repairs such as solenoid O ring and stop plunger renewal have been done with the pump in situ.

[bddeazeley]

Been some time but here is an update. I eventually managed to get a pump from a Peugeot 406 2.1td with a good cam sensor and as Ken recommended I changed the sensor with the pump in situ. I had to extend the leads to the sensor and re-route them as the original leads are encapsulated in a rubbery substance. Not a difficult job at all and the good news is the intermittant diesel knocking noise has disappeared. I now have to tackle the ABS problem which looks like badly corroded reluctor rings on the CV joint but I will start another post on that subject. The other interesting thing is originally I thought the cause of the diesel knocking noise was air in the fuel as I could see bubbles entering the pump from the filter particularly when the engine was hot. I changed the filter bowl and 'o' rings etc however I still have the bubbles, some quite large, and it now does not appear to effect the running of the engine. I have come to the conclusion that the bubbles are not air but diesel vapour which the pump doesn't mind. Any thoughts anybody?

[CitroJim]

That's excellent news on the sensor replacement

Well done, good work

[Vinyl]

@bddeazeley

Hopefully you'll receive email notification
My question to you is : what were the symptoms you were getting prior to the fix and also why you went straightforward to the hypothesis of cam actuator sensor

Did you use any equipment like laser 2000 and also what is lexia you mentioned in few posts earlier?

Thx