How is the ammeter at the control panel wired. Does the charge current from the alternator go all the way from the alternator up to the ammeter on the instrument panel and then back to the batteries? I always felt that glow plug button was kind of special and I noticed that my ammeter showed 30 or more when I depressed it and for as long as it was depressed.
On Wed, Oct 26, 2022 at 1:35 PM David Knecht via CnC-List < cnc-list@cnc-list.com> wrote: > Here are a few answers to the comments: > > All of this started with replacement of old switches for new ones. Same > wires but each terminal cleaned before attachment. I find it hard to > believe that cleaned terminals and new switches caused a ground fault > problem at some remote site that was not there before. Things were > generally working before I did anything. Now nothing works. > > To Dwights suggestion: After reading that Marine How to article years ago, > I replaced all the trailer connectors with heat shrink direct butt splice > connectors for each wire. I also installed a Blue Seas ACR/battery switch, > so the batteries are supposed to be isolated. > > I really can’t understand how this problem is affecting both batteries > when the two circuits are isolated by the ACR. When I try to start the > engine, everything goes crazy- including both battery volt meter readings. > The meter goes completely blank as if both batteries are dead and then > voltage slowly recovers over time. > > I am also mystified by how I can be measuring over 12V on the plus side of > the key switch and 10V on the other side when it is on. That is measured > relative to a ground terminal on the tachometer. There is nothing there > except the switch itself, right? I am guessing that means something in > terms of the problem, but I don’t know what. > Thanks- Dave > > S/V Aries > 1990 C&C 34+ > New London, CT > > > On Oct 26, 2022, at 11:48 AM, dwight veinot via CnC-List < > cnc-list@cnc-list.com> wrote: > > If you have a Universal M4-30 engine with associated engine control panel > with ammeter this article contains some very important information for you > to know. > Universal Diesel Engine - Wiring Harness Upgrade - Marine How To > <https://marinehowto.com/universal-diesel-engine-wiring-harness-upgrade/> > Dwight Veinot > C&C 35 MKII, *Alianna* > Head of St. Margaret's Bay, NS > d.ve...@bellaliant.net > > > > On Tue, Oct 25, 2022 at 11:10 PM David Knecht via CnC-List < > cnc-list@cnc-list.com> wrote: > >> More diagnosis- I found that when I checked the voltage at the engine >> panel ammeter (where power comes to the panel), it was 12V. When I checked >> at the input side of the key switch it was 12 V. When I turned the key >> switch on, I got 10V on the other pole of the key switch and everywhere >> downstream. I am presuming it should be 12V on both sides. I do not >> understand what that means and hoping someone else does. The other weird >> thing is that as I have worked on this, there are times when the battery >> meter in the cabin bounces all over the place from 9V to 12V and back and >> then finally settles at 12.9V. At the same time, the batteries are >> measuring 12.5V. Something very strange is happening. Dave >> >> S/V Aries >> 1990 C&C 34+ >> New London, CT >> >> <pastedGraphic.tiff> >> > >> On Oct 25, 2022, at 2:56 PM, David Knecht via CnC-List < >> cnc-list@cnc-list.com> wrote: >> >> HELP! I am stumped and hoping someone can point me in the right >> direction. Long descrition as best i can recall. Two weeks ago i thought i >> would get a head start on a project. My start button has been flakey this >> summer with now and then nothing happening when pressed. Decided to replace >> key switch, glow plug and start buttons. I installed key and glow but could >> not get start out so gave up. Engine started fine after rewiring. Come back >> next week and no response to start button. Battery fine. Lots of messing >> around but no luck. Come back today and wire in new start button in case >> old bad. Recheck wiring and realize key switch is wired backwards (does it >> matter? I guess you are supplying power to downstream stuff when off?). Did >> not check and misremembered which wire supplied power. Swapped wires on key >> switch and checked meter and 12v on proper side (bat).All looks good. Turn >> on key switch and fuel pump starts as normal. Push start button and >> nothing. Now i measure 4v at engine panel instead of 12. Battery meters >> dead display and measuring 4v at its inputs. But 12v at battery and main >> power switch. Other devices fine. Over an hour now and panel and battery >> meter up to 6v so seems to be slowly recovering. What is going on? Did i >> screw something up when key switch was backwards? Dave >> >> Sent from my iPhone >> >> >> > -- Sent from Gmail Mobile
