AndyB Posted September 19, 2012 Posted September 19, 2012 I'm installing a modern (ish) engine into a 1960's car, this engine has injection and a ECU. I'd like to place the ECU in the cabin, this means cutting the wiring loom to route it through the bulkhead. It also needs a lot of redundant wiring removed. Several of the sensors on the engine have shielded wiring, when I cut and then rejoin these wires, they may be a gap in the shielding. My question. Are these wires shielded because the static they produce will affect the good running of the engine, may scramble the ECU, or just stop me tuning into the Archers? The first two are a worry, I can live without the Archers. Thanks
Triumph-V8 Posted September 19, 2012 Posted September 19, 2012 It is more the noise that comes from outside on the wire that affects the signal the wire should transport to the ECU. These influences are quite seldom, but if you have them it is very hard to get rid of them. So better shielding and avoiding noise from ingnition and alternator and many other suspects is a good idea because it can be done before starting the system and tuning the software which should be a fun without the trouble nobody needs. That is the reason why many wires are shielded and sometimes but not always the car runs without the shielding pretty well. Shielding does no harm, just a little bit of work like an insurance. So if difficult one can try without but if easy installed it should be used. Wrap aluminum paper around the cut as the last layer before insulating tape or shrinking tube and make it contacting with the shielding. That will do the job pretty well!
CHRIS211083 Posted September 19, 2012 Posted September 19, 2012 Wires are shielded to stop interference from the other electrical signals being produced by the car. The Shielding should be earthed as to remove the interference so the car can run correctly. I recently EFI'd my Classic Mini and If you put the crank trigger cable near to no.1 HT lead the car would miss fire. However the only shielded wire on this system is the crank trigger sensor. So how many shielded wires do you have and what do they do??? Chris.
spitfire6 Posted September 19, 2012 Posted September 19, 2012 (edited) Greetings, If the manufacture shielded the wires/cables I would continue this method. I would note if the shield was connected at one end or both for future reference. Braiding is readily available to continue the shielding if you want. check Ebay for braiding. Do not buy the hair stuff; It don't work! I would guess that the system might work without new/replacement shielding, but as the cost is small, to continue the shielding. If your system has individual shielding; you will have to continue the same. I.E individual or overall screening/shielding. Many times I have used normal wires/cables when screened cables were not available without any problems, but, this was a ******/Jury Rig and was only done when property or people would not be effected by my action. You could still listen to radio, as it’s in a metal box, with filters on the incoming wire's. Cheers, Iain. Edited September 19, 2012 by spitfire6
AndyB Posted September 19, 2012 Author Posted September 19, 2012 Thanks, was unsure if the shielding was to protect the sensor or the rest of the cars electric system from the sensor.
Nick Jones Posted September 19, 2012 Posted September 19, 2012 It's to stop the wires carrying low level signals (crank position sensor, TPS, temp sensors etc) acting like radio aerials and picking up electric noise from HT leads/plugs/alternator etc which drowns out the real signal and causes the ECU to do odd things. I'd keep it as it is shielding wise - not so very hard to do. Trouble is with noise related problems - they are often random and intermittent and sods to track down, so design/build out where possible! Nick
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