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Joined: Nov 2015
Posts: 7,895 Likes: 241
Just barreling along Talk Morgan Guru
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Just barreling along Talk Morgan Guru
Joined: Nov 2015
Posts: 7,895 Likes: 241 |
Mark, is there any evidence of it getting damp in that location in the past, as it could creep into the crimped connections grow a bit of corrosion unseen and cause hi resistance in the splices ?
Jon M
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Joined: May 2012
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Talk Morgan Enthusiast
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Talk Morgan Enthusiast
Joined: May 2012
Posts: 1,639 Likes: 20 |
Hi, Just back from a 16 day trip across Europe, but on about 5 occasions, the following all went to Zero.
Speedometer Rev counter Coolant Temp Fuel Gauge
On most occasions they returned to normal almost immediately, but on one occasion did not come back for a few minutes. The engine was fine. On 2 occasions the fault occurred while on the Motorway and it didn't occur while driving through a Downpour. Mark, back to your original post and just another thought perhaps to consider.... There is another reason why a CAN may temporarily drop out as yours did other than a suspected faulty connection. Another possible reason is from radiated electrical noise or spikes. Noise can disrupt the comms causing data loss and symptoms like you experienced. Those twisted pair network wires will only offers partial protection to interference, in an ideal world they would be fully screened. By any chance have you done any electrical mods to your car lately? Run any power cables near to the CAN wires? That pair of joined red and black wires in your last pic, are they original? I have a dim recollection from another post that at one point you were experimenting with drawing air out of the cabin through the heater matrix with a cheapy electric fan?
Roger 2011 Plus 4
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Joined: Mar 2020
Posts: 170 Likes: 5
L - Learner Plates On
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OP
L - Learner Plates On
Joined: Mar 2020
Posts: 170 Likes: 5 |
Mark, is there any evidence of it getting damp in that location in the past, as it could creep into the crimped connections grow a bit of corrosion unseen and cause hi resistance in the splices ? Hi Jon, no sign of damp at all, looks clean. At some point I may have to revisit the splices, but will probably pay for them to be redone professionally.
Mark 2015 +4 Ferrari Le Mans Blue
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Joined: Mar 2020
Posts: 170 Likes: 5
L - Learner Plates On
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OP
L - Learner Plates On
Joined: Mar 2020
Posts: 170 Likes: 5 |
Hi, Just back from a 16 day trip across Europe, but on about 5 occasions, the following all went to Zero.
Speedometer Rev counter Coolant Temp Fuel Gauge
On most occasions they returned to normal almost immediately, but on one occasion did not come back for a few minutes. The engine was fine. On 2 occasions the fault occurred while on the Motorway and it didn't occur while driving through a Downpour. Mark, back to your original post and just another thought perhaps to consider.... There is another reason why a CAN may temporarily drop out as yours did other than a suspected faulty connection. Another possible reason is from radiated electrical noise or spikes. Noise can disrupt the comms causing data loss and symptoms like you experienced. Those twisted pair network wires will only offers partial protection to interference, in an ideal world they would be fully screened. By any chance have you done any electrical mods to your car lately? Run any power cables near to the CAN wires? That pair of joined red and black wires in your last pic, are they original? I have a dim recollection from another post that at one point you were experimenting with drawing air out of the cabin through the heater matrix with a cheapy electric fan? I have fitted the extractor fans but that was well after this issue started. Have been back through my notes and apart from a new battery, just prior to the trip, the only electrical mod was Cruise control fitted in Feb 2022 a good 18 months prior to the 1st time we noticed it. There is chance we simply missed previous events, but I can confirm that the issue occurs with cruise control off or on. Staying with interference as a possible cause, one of my 1st mods was to replace the radio with a Bluetooth amplifier attached under the dash which is almost always on attached to my phone so I can hear GPS instructions. Is there any simple way to shield either the CAN wiring or Cruise Control unit from each other. Regards
Mark 2015 +4 Ferrari Le Mans Blue
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Joined: Feb 2016
Posts: 7,922 Likes: 217
Talk Morgan Guru
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Talk Morgan Guru
Joined: Feb 2016
Posts: 7,922 Likes: 217 |
Does the cruise control use CANBUS derived speed or its own GPS module Mark?
Richard
2018 Roadster 3.7 1966 Land Rover S2a 88 2024 Royal Enfield Guerrilla 450 1945 Guzzi Airone
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Joined: Nov 2015
Posts: 7,895 Likes: 241
Just barreling along Talk Morgan Guru
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Just barreling along Talk Morgan Guru
Joined: Nov 2015
Posts: 7,895 Likes: 241 |
Try pulling the fuse to the Cruise to kill it's supply & go for a test run watching the Gauges ?
IIRC Mark's had his CC for 3 or 4 years now, without previous problems
Jon M
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Joined: Mar 2020
Posts: 170 Likes: 5
L - Learner Plates On
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OP
L - Learner Plates On
Joined: Mar 2020
Posts: 170 Likes: 5 |
Does the cruise control use CANBUS derived speed or its own GPS module Mark? Hi Richard, the cruise control connects to the VSS on the front offside wheel.
Mark 2015 +4 Ferrari Le Mans Blue
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Joined: Mar 2020
Posts: 170 Likes: 5
L - Learner Plates On
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OP
L - Learner Plates On
Joined: Mar 2020
Posts: 170 Likes: 5 |
Try pulling the fuse to the Cruise to kill it's supply & go for a test run watching the Gauges ?
IIRC Mark's had his CC for 3 or 4 years now, without previous problems Hi Jon, will add this to the list of tests. The issue is that a "Run" has to be a day out with stops and occasionally the dials behave themselves. Most annoying!
Mark 2015 +4 Ferrari Le Mans Blue
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Joined: May 2012
Posts: 1,639 Likes: 20
Talk Morgan Enthusiast
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Talk Morgan Enthusiast
Joined: May 2012
Posts: 1,639 Likes: 20 |
Wow, I'm impressed that you keep notes Mark  Is there any simple way to shield either the CAN wiring or Cruise Control unit from each other. Not really, I don't think that it would be that easy or practical. However having said that, I have used adhesive copper tape for RF shielding before. Maybe one of the vulnerable area's of the loom might be the first few inches of wiring exiting the chassis/engine connector, including the splices. It looks to be a bit of a birds nest and would hazard a guess that the twisting of the CAN wires is not great there. You could possibly get access to wrap the bundle in copper tape. That might help to protect from noise outside of the loom and from those near power wires, that I think you may have introduced? It's something perhaps you could try for a while and rip it off again if not needed, with no harm done. Don't forget to ground the copper tape though!
Roger 2011 Plus 4
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Joined: Feb 2016
Posts: 7,922 Likes: 217
Talk Morgan Guru
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Talk Morgan Guru
Joined: Feb 2016
Posts: 7,922 Likes: 217 |
Yes the wiring schematic implies CANBUS lines (high and low) are twisted pairs for both high and medium speed, the latter to/from BCU. Ditto the immersed fuel pump supply cables from what MMC call the "electronic fuel pump relay" which suggests the latter may use PCM to control motor speed. On the Roadster a screened cable is used instead for this feed, with screen braid grounded independent of motor ground, suggesting this may have caused issues prior.
Richard
2018 Roadster 3.7 1966 Land Rover S2a 88 2024 Royal Enfield Guerrilla 450 1945 Guzzi Airone
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