Really could do with some advice on electrics

[scrunch]

 

Really hoping someone can give me a bit of advice, my narrowboat wont start with the ignition, If I take a wire direct from the ignition on the back to the connector on the starter relay it will start with the key and run normaly.

I have tried to trace the wire from the ignition to the relay but cannot find if it, it doesnt appear to run straight to the relay as there are 2 wires joined together at the relay, totaly baffled why there would be 2 as I expected one wire from the back of the ignition staright to the relay, does anyone know why 2 wires is there something else I am missing, been trying now for hours and just cannot get my head round it. so any advice would be gratefully received.

I have put question marks as I have said not sure now that the wire goes direct.

 

 

 

 

[pearley]

I would say that the brown and black wires are the relay coil 'pull in' but there are no wires that colour on the switch. Where dies that thin white wire that seems to run in a circle behind the other wires on the relay go to?

[scrunch]

They are the two wires that if take them off and connect a live feed to it the engine turns on the starter.

[Alan de Enfield]

Not that I can help - but - is this a recent occurance, or has it always done it ?

 

Have you moved or re-wired anything ?

Have you been working 'around' the starter / solenoid area and knocked something

[Tony Brooks]

I suspect that you may have misidentified the connection on the starter solenoid. That light green box thing looks very much like a split charge relay to me and if so the wire you point to (Brown I think) goes to the main solenoid positive (battery) connection, not the thin solenoid operating cable.

 

Without more info on engine make and model, charging system etc. It is hard to help but my first step would be to look for any multi-plugs on the main wiring harness and then make sure they are clean and tight.

[scrunch]

Its a 1997 lister engine, to be truthful I also thought it was a split charge relay until I dropped a live wire on the small white wire spade and the starter turned, the photos not as good as i wanted, the two wires I am on about are behind the black wire in the photo you can just make them out behind the black wire.

[smileypete]

Do you have a 12V test lamp?

 

If not, a motor parts factor or Halfords should do something along these lines:

 

http://www.ebay.co.uk/itm/Silverline-Automotive-Circuit-Tester-for-6V-and-12V-systems-/

 

Nice thing about the one above is the sharp tip which can be poked through the wire insulation, handy if a terminal has gone high resistance.

 

If all else fails and the wire cannot be traced through the loom, a new wire could be run between switch and relay. However, without tracing the wiring to find the fault, it's likely to be a bit of a 'bodge'...

 

cheers, Pete.

~smpt~

[scrunch]

Appreciate all the advice.

I have digital test meter and a continuity tester its really the fact that there are two wires connected together that feed the relay on the small current side, I could just rewire a single wire from the ignition to the small side, but I am reluctant to until I can find out why there would be 2 wires, its almost like there are 2 ways to sart the engine, when it first went I thought there may be a safety switch connected to the throttle gear linkage to prevent starting in gear but nothing appears to be connected wire wise that side.

[Tony Brooks]

It all looks very well done so It is probably factory fitted so hopefully a Lister expert will be along soon to give chapter and verse.

[scrunch]

Cheers Tony for that I could strip the engine and rebuild it but electrics totally baffle my brain

[Tony Brooks]

If I understand the original post. The key will not energise the starter. The "start terminal" on the switch goes live at the appropriate time. A wire from the switch terminal to the starter does energise the starter.

 

If that is correct go and look for a multi-plug on the main wiring loom between the instrument panel and the engine. Check for loose or dirty connectors.

[scrunch]

Checked connections seem ok your exactly right on your post as to the problem .normally I would repair it by dropping a new wire on. But I need to know why there are two wires to the relay . It cannot be a take off to run 12v to anywhere as there is only 12v when the ignition is energised by the key .

[Tony Brooks]

Checked connections seem ok your exactly right on your post as to the problem .normally I would repair it by dropping a new wire on. But I need to know why there are two wires to the relay . It cannot be a take off to run 12v to anywhere as there is only 12v when the ignition is energised by the key .

 

Have you pulled the boots back so you can identify the cables and then very gently squeezed up the one in question? Sometimes the other connections make the thing seem tight but one or two are actually loose.

 

In the last resort you will have to open the loom but do NOT re-tape with insulation tape. Use non-adhesive looming tape otherwise it will go stiff.

[smileypete]

I'd disconnect it from the relay and check is there's any continuity to 12V or 0V, also check if it carries a voltage before or after starting the engine.

 

cheers, Pete.

~smpt~

[Eeyore]

Hello Scrunch.

 

Really hoping someone can give me a bit of advice, my narrowboat wont start with the ignition, If I take a wire direct from the ignition on the back to the connector on the starter relay it will start with the key and run normaly.

1/ Do you mean from the switch to the terminal marked as "this wire goes to starter solenoid"? If yes, you have bypassed the relay, your result is not entirely unexpected, but does not prove whether the relay is working or not. Try changing the green relay.

2/ Do you mean from the switch to the terminal marked as "this wire comes from the ignition switch?"? (the terminal with 2 white wires on). If yes, It could point to a fault in the wiring between the switch and relay. If the multi plugs are ok you will need to gently flex the entire loom an inch or so at a time whilst the key switch is held in the start position. Pay special attention to where the loom passes though any clips. With luck the flexing action will cause momentary contact between any broken wire.

 

I have tried to trace the wire from the ignition to the relay but cannot find if it, it doesnt appear to run straight to the relay as there are 2 wires joined together at the relay, totaly baffled why there would be 2 as I expected one wire from the back of the ignition staright to the relay, does anyone know why 2 wires is there something else I am missing, been trying now for hours and just cannot get my head round it. so any advice would be gratefully received.

I have put question marks as I have said not sure now that the wire goes direct.

The wiring could to be a version of insulated return. The alternator probably has separate positive and negative connections, with the negative isolated from the frame. The starter will also has separate positive and negative connections, but the negative will not be isolated from the frame. Instead the (heavy/thick) negative pass through a separate solenoid that only connects it to the starter when the key switch is operated.

This second solenoid ( sometimes called an earthing or grounding solenoid ) is the reason for the second wire continuing on from the green main start relay. This second wire appears to operate the small white relay, which then operates the grounding relay in much the same way as the green one operates positive solenoid, which is usually part of the starter motor assembly.

 

It is not uncommon for the grounding solenoid to have been bypassed at some point in the past, something that is likely if the answer to question 1/ above is yes.

 

A picture of the engine bay showing the main battery lead connections to the engine could be useful.

 

​I suspect that the black relay is a timed unit controlling the glow plugs.

 

 

 

Hope this is of some use.

Steve (Eeyore)

Edited January 17, 2015 by Eeyore

[scrunch]

Thanks Steve that does make sense I think a bit more playing around tomorrow , the small relay had a plastic tie around the wires pulling them to the black relay, I am wondering if there had been a problem and this was a bodge to solve it, I cut the cable tie to be able to photograph it so perhaps I should put a tester on it just to see.

Really appreciate you taking the time to give such a good explanation.

Kev

[Sir Nibble]

I am a little surprised to see all these white wires. Normal code is Brown=battery + White=ignition + White/red=start

[scrunch]

Each white wire has a colour stripe . bit more messing earlier but still no luck a few more things to try Saturday . Keep having to go to work how selfish of them I got a boat to fix

[scrunch]

Right before I explain how much of an idiot I am I thought for any else with problems I should say .

The bleck relay is for the glow plugs, the white well its actualy silver but flash makes it look white is for the engine stop and the green as I knew is for the starter motor.

 

I have spent days testing circuits with no luck whatsoever disconnecting the main engine electrical multi wire connector and making sure each wire had continuity up to the ignition, I even had an electrical bloke have a look nothing really at the end of my patience. This morning I decided to unwrap the wire tidy stuff so I could get the multi plug higher up to have a proper look and lo and behold when I reconnected it, the engine fired up, what it basicaly was when I disconnected the plug and bent it up it the wire must have connected where its broke showing a circuit but when I plugged it back in the broke wire disconnected itself.could really kick my self the amount of time I have wasted.

 

Still not technicaly fixed as I have no idea, if or how the multi plug comes to bits, I have removed 2 small screws that hold a small clamp on but really dont want to risk damaging any more wires , I have took a couple of photos any help again would be really appreciated.

 

 

[Eeyore]

Right before I explain how much of an idiot I am I thought for any else with problems I should say .

The bleck relay is for the glow plugs, the white well its actualy silver but flash makes it look white is for the engine stop and the green as I knew is for the starter motor.

 

I have spent days testing circuits with no luck whatsoever disconnecting the main engine electrical multi wire connector and making sure each wire had continuity up to the ignition, I even had an electrical bloke have a look nothing really at the end of my patience. This morning I decided to unwrap the wire tidy stuff so I could get the multi plug higher up to have a proper look and lo and behold when I reconnected it, the engine fired up, what it basicaly was when I disconnected the plug and bent it up it the wire must have connected where its broke showing a circuit but when I plugged it back in the broke wire disconnected itself.could really kick my self the amount of time I have wasted.

 

Still not technicaly fixed as I have no idea, if or how the multi plug comes to bits, I have removed 2 small screws that hold a small clamp on but really dont want to risk damaging any more wires , I have took a couple of photos any help again would be really appreciated.

 

 

Good afternoon Kev,

Pretty sure you're not an idiot! A broken wire in the multiplug would have a good few scratching their heads.

Couple of quick checks for you.

Are all the pins in the male half of the connector secure, making sure that they don't move when you press on the ends with your finger.

Are the sleeves/tubes in the female half secure, a wooden tooth pick is about the right size for checking if they move in or out when they shouldn't.

You can also check both halves by gently pulling and pushing on the white wire (with stripe) where it enters the connector.

A permanent fix using the original style of connector will require the remainining wires to be cut back in length to match any broken one before refitting the connector. There is usually enough slack in the extension harness to allow this.

A quick fix can be achieved by bypassing the connector with the white (with stripe) wire. Cut the wire close to the connector and insert a suitable length wire to reach around the connector, use insulated bullet or spade terminals as required.

Hope this helps.

Steve (Eeyore)

Edited January 24, 2015 by Eeyore

[scrunch]

Cheers Steve for that much appreciated Sunday morning job then at least it will make me not do my usual Sunday slob day

[smileypete]

From the look of things the backshell of the multiway definitely unscrews, it has grip bumps moulded on.

 

Not 100% sure of what you said earlier, but the 'two wires' you mention earlier sound like two in the photo taped together which may be the starter solenoid relay feed, and not the brown/black wires which go to the relay coil?

 

ISTR on some engines there may be some interplay between glo plug and starter solenoid relays, so the glo plugs do/don't run when the starter is turning.

 

ETA: Maybe the pins on the multiway just need some proper contact cleaner.

 

cheers, Pete.

~smpt~

Edited January 24, 2015 by smileypete

[jonathanA]

They are an 'amp' multipole connector from memory the lister wiring loo uses a 17 or 19 way version. You can get new bits from RS or Farnell

 

If you google amphenol connectors you should be able to find a tech spec and some assembly pictures. There's usually two connectors one at the engine end and one at the panel so if the broken wire is the removable bit you could possibly remove it from the boat to repair.