CPGCharlie Posted January 10 Share Posted January 10 Hi All, I've posted a few times and my electrical gremlins and issues remain. I have just had back both my rev and speedometer, refurbished after what we believe is a power surge fried them both. I now am just looking for an auto electrician to try work out what the underlying problem is and fix it. The Toad immobilizer has been immobilised itself and now the cars misfiring. Help. Does anyone have a referral to an electric specialist. I'm based in West Berkshire Many thanks, Charlie Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted January 10 Member Share Posted January 10 There's Ivor Terrill in Oxford, but the car has to go to them. Jonathan Link to comment Share on other sites More sharing options...
jackb_ms Posted January 10 Share Posted January 10 I called Ivor Terril for the issue I have with my car. And they told me they won't touch a Caterham. I'm still looking for one. Jack Link to comment Share on other sites More sharing options...
rj Posted January 17 Share Posted January 17 Almost sounds like a faulty alternator Link to comment Share on other sites More sharing options...
Gridgway Posted January 17 Share Posted January 17 4 hours ago, rj said: Almost sounds like a faulty alternator Voltage regulator? Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted January 17 Member Share Posted January 17 Unfortunately no-one has come up with an electrical specialist. Other options include a Caterham service provider and.... The Power of BlatChat. I think that we could make some progress using the latter if that's what you'd like. Jonathan Link to comment Share on other sites More sharing options...
John Vine Posted January 17 Share Posted January 17 I've just re-read your earlier posts: Aug 2022 Apr 2023 Sep 2023 This does read like a tale of utter woe. Have you spoken to some of the specialists mentioned -- such as PGM, Sevens & Classics or Millwood? Maybe it would be worth trailering your car to one of these? You say you have a DTAFast ECU. I imagine that could cause difficulty with the regular specialists that deal with MBE units. Have you asked DTAFast for advice? Also, I'm intrigued by the apparent "frying" of your tacho and speedo. If that's what happened, it does point the finger at a possible voltage surge at the alternator/regulator. Another thing to have investigated at the same time, perhaps? JV Link to comment Share on other sites More sharing options...
CycleSi Posted January 17 Share Posted January 17 Charles Dunn Motor Engineers in Wooburn Green are definitely worth contacting about this (01628 528338). I dropped my R500K off there only this morning. Link to comment Share on other sites More sharing options...
rj Posted January 18 Share Posted January 18 19 hours ago, Gridgway said: Voltage regulator? Yes, but it's internal Link to comment Share on other sites More sharing options...
rj Posted January 18 Share Posted January 18 18 hours ago, John Vine said: Also, I'm intrigued by the apparent "frying" of your tacho and speedo. If that's what happened, it does point the finger at a possible voltage surge at the alternator/regulator. Another thing to have investigated at the same time, perhaps? Two possible reasons for frying the gauges: Either overvoltage (caused by a faulty voltage regulator inside the alternator) or a failing earth that causes some of the installation to draw current through the gauges. - I'd be happy to look at the car if it was brought to me - and I am not scared by the DTA Ecu. Only unfortunate issue is my location... Link to comment Share on other sites More sharing options...
rj Posted January 18 Share Posted January 18 PS: Have you checked the earth strap between engine and chassis? Link to comment Share on other sites More sharing options...
Gridgway Posted January 18 Share Posted January 18 (edited) 3 hours ago, rj said: Two possible reasons for frying the gauges: Either overvoltage (caused by a faulty voltage regulator inside the alternator) or a failing earth that causes some of the installation to draw current through the gauges. - I'd be happy to look at the car if it was brought to me - and I am not scared by the DTA Ecu. Only unfortunate issue is my location... I'd be curious as to how a bad earth elsewhere would force more current through the gauge than Mr Ohm would normally allow? Edited January 18 by Gridgway spelling Link to comment Share on other sites More sharing options...
Area Representative Richard Price Posted January 18 Area Representative Share Posted January 18 1 hour ago, Gridgway said: I'd be curious as to how a bad earth elsewhere would force more current through the gauge than Mr Ohm would normally allow? Generally, a wiring loom is tied to ground (the chassis) at various points of the loom. Typically, the largest current is drawn by the starter motor, with a large cable from the battery to the starter motor, and grounding through the engine, then with another large cable from the engine back to the battery. However, an engine/car loom is also likely to have several smaller earth cables also connected to the engine and other exposed metal. If that main earth strap from the engine to battery is faulty in any way, then the starter motor current would try to use any alternative path back to the battery. Those smaller cables, in the worst case, may then act like a fuse, and simply burn up! To burn up tracks in something like a Tacho, may only take a comparatively small but greater than the design current to flow to cause damage. The car in question may have wiring that has been "adapted" at some point as a 2005 Duratec with a DTA ECU predates any factory Duratec cars. 1 Link to comment Share on other sites More sharing options...
Gridgway Posted January 18 Share Posted January 18 My schoolboy physics says that can't happen. There is still only 12v (or a bit more) driving current down a wire (track). To drive more current, you need more volts or less ohms. Link to comment Share on other sites More sharing options...
OldAndrewE Posted January 18 Share Posted January 18 Think of it as a fuse Graham (as Richard suggests). The circuit will try to pass more current than the fuse will take and the fuse will blow. It is the load that determines the current, not the wiring connecting it. If the wiring is inadequate it will blow. Link to comment Share on other sites More sharing options...
Gridgway Posted January 18 Share Posted January 18 Then it will always blow Andrew. For the gauge to blow in this way there must be an earth through the gauge at 0 ohms (well obviously slightly above 0). This must be in parallel with the other earth so that when the other earth doesn't work, this one takes its place. If they are in parallel then a proportion of the current will flow through the gauge even when the other earth is working properly. The resistance of the main earth and the earth through the gauge will be similar, certainly not orders of magnitude different. If we look at the main earth while the starter is cranking. Let's say it's 100A and 0.01 Ohms. That's a PD of 1V. That 1V split across the two earths in parallel will fry the earth through the gauge anyway. I'm happy that my argument could well be false, but am interested in working out exactly why! The thing that is driving my thinking is that poor earths are the bane of Caterhams. If that resulted in the gauge taking the strain as it were and frying, it would be a very common occurrence and it's not! Link to comment Share on other sites More sharing options...
Area Representative Richard Price Posted January 18 Area Representative Share Posted January 18 Graham, your thinking is close to correct. Yes, it is quite likely that a proportion of the high current would flow if the resistance was low enough. However, the resistance of most car looms, in practice is noticeably higher than you may assume. As this thread is really about a car with a non engine standard installation, its also likely to have a loom that has been modified. Sadly, I've worked on a few cars that have had looms modified to suit different engines, ECU's, or instrument layouts, some of which I'm surprised they ever worked at all! However, We're going off topic here. Sadly, unless the OP can find a "friend" (who really knows what he's looking at), I suspect it my take hours of investigation to identify what the root cause of these issues is before being able to sort it out. 1 Link to comment Share on other sites More sharing options...
rj Posted January 18 Share Posted January 18 Reading this I am getting more and more convinced it's a faulty earth somewhere. As Richard suggests it only takes very little to fry the gauges, and even less if it's reverse polarised. Link to comment Share on other sites More sharing options...
rj Posted January 18 Share Posted January 18 Charlie Are you on WhatsApp? I'd like to see some things, which maybe could be done on a video call. It's not so easy for me just to pop in as I'm some 650 miles away from you. Link to comment Share on other sites More sharing options...
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