No Power To Coil

An alchemy of sparks, copper wire and earth

Moderators: User administrators, Moderators

User avatar
Ciaraneng
Registered user
Posts: 303
Joined: 26 Aug 2018, 09:04
80-90 Mem No: 16696
Location: Clonakilty, Co. Cork, Ireland

Re: No Power To Coil

Post by Ciaraneng »

Thanks guys. I’m hoping to get back to it tomorrow evening so will report back.


Sent from my iPhone using Tapatalk
1983 High Top 1.9 Petrol Early DG Engine

User avatar
bigherb
Registered user
Posts: 2579
Joined: 27 Mar 2008, 13:50
80-90 Mem No: 5789
Location: West Kent

Re: No Power To Coil

Post by bigherb »

You can't miss it.
Attachments
Coil Connector.jpg
Coil Connector.jpg (60.47 KiB) Viewed 2284 times
1982 Camper 1970 1500 Beetle Various Skoda's, Ariel Arrow

User avatar
Ciaraneng
Registered user
Posts: 303
Joined: 26 Aug 2018, 09:04
80-90 Mem No: 16696
Location: Clonakilty, Co. Cork, Ireland

Re: No Power To Coil

Post by Ciaraneng »

Some photos of my trouble-shooting so far.
Image


The main thing I found is that for the D15 feed to coil, the voltage starts off at about 8V when the ignition is switched on and slowly drops to about 2-3V.

It looks as if someone has taken a feed from the black D15 feeder wire at the T1a connection in the Engine Bay junction box. This feed runs back to a two-wired unit on the gearbox shown in the next photo. I'm not sure what this unit does (E D I T: maybe the reversing light switch?) but one of the wires was broken at the spade so it's not doing anything currently. The wire back from the unit splits again in the Engine Bay junction box and the wires appear to go to the back LH and RH lights.

Image

At the ignition I have a small black wire that goes live when I turn the key but it seems to run to Pin 9 of the 14 Pin connector that connects to the dash console.

Image

Image
1983 High Top 1.9 Petrol Early DG Engine

User avatar
Ciaraneng
Registered user
Posts: 303
Joined: 26 Aug 2018, 09:04
80-90 Mem No: 16696
Location: Clonakilty, Co. Cork, Ireland

Re: No Power To Coil

Post by Ciaraneng »

Any thoughts or ideas would be appreciated. My next move is to try to remove the dash and try to trace the coil wire back from the ignition switch to the Engine Bay junction box.
1983 High Top 1.9 Petrol Early DG Engine

User avatar
937carrera
Registered user
Posts: 3599
Joined: 05 Apr 2015, 19:29
80-90 Mem No: 16333
Location: N Yorks.

Re: No Power To Coil

Post by 937carrera »

Which of the connectors are you testing for voltage ?

You should disconnect the connector block when testing voltage so there is no chance of a backfeed

The spade near the gearbox is the reversing light switch
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

User avatar
Ciaraneng
Registered user
Posts: 303
Joined: 26 Aug 2018, 09:04
80-90 Mem No: 16696
Location: Clonakilty, Co. Cork, Ireland

Re: No Power To Coil

Post by Ciaraneng »

Hi Carrera. I disconnected T1A connector in the Engine Bay junction box and measured the voltage coming from the front of the van that would normally feed the coil (and in my case the reversing lights).
Last edited by Ciaraneng on 17 Sep 2019, 20:25, edited 1 time in total.
1983 High Top 1.9 Petrol Early DG Engine

User avatar
937carrera
Registered user
Posts: 3599
Joined: 05 Apr 2015, 19:29
80-90 Mem No: 16333
Location: N Yorks.

Re: No Power To Coil

Post by 937carrera »

Which one are you identifying as the T1a connector ?
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

User avatar
Ciaraneng
Registered user
Posts: 303
Joined: 26 Aug 2018, 09:04
80-90 Mem No: 16696
Location: Clonakilty, Co. Cork, Ireland

Re: No Power To Coil

Post by Ciaraneng »

937carrera wrote:Which one are you identifying as the T1a connector ?
It’s the one shown here
Image


Sent from my iPhone using Tapatalk
1983 High Top 1.9 Petrol Early DG Engine

User avatar
937carrera
Registered user
Posts: 3599
Joined: 05 Apr 2015, 19:29
80-90 Mem No: 16333
Location: N Yorks.

Re: No Power To Coil

Post by 937carrera »

Well, that looks like the correct one, the loop off should go to the thermoswitch F35 - this is called T1c in the later wiring diagram in the DG wiring diagrams from syncrosport

It sounds to me like there is a broken wire, which passes some voltage, then as it heats up it goes higher resistance and the voltage drops.

Trace back to the fusebox and test the voltage there and also continuity from the fusebox to the connector
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

User avatar
Ciaraneng
Registered user
Posts: 303
Joined: 26 Aug 2018, 09:04
80-90 Mem No: 16696
Location: Clonakilty, Co. Cork, Ireland

Re: No Power To Coil

Post by Ciaraneng »

Will try that. Thanks Carrera.
1983 High Top 1.9 Petrol Early DG Engine

User avatar
bigherb
Registered user
Posts: 2579
Joined: 27 Mar 2008, 13:50
80-90 Mem No: 5789
Location: West Kent

Re: No Power To Coil

Post by bigherb »

Yours is correct for early vans, the reverse lights come off the connector and through that inline fuse to the reverse light switch on the gearbox.
Just to confirm you have the early type fusebox with bullet fuses?
Did you check the voltage with T1 disconnected? If the voltage from the fuse box was still low, then the problem is between the connector and the fuse box.
And DON'T leave the ignition switched on for any length of time while you are checking it could burn the loom out.
1982 Camper 1970 1500 Beetle Various Skoda's, Ariel Arrow

User avatar
Ciaraneng
Registered user
Posts: 303
Joined: 26 Aug 2018, 09:04
80-90 Mem No: 16696
Location: Clonakilty, Co. Cork, Ireland

Re: No Power To Coil

Post by Ciaraneng »

Thanks bigherb, since I have not seen any wiring diagrams with this reversing lights arrangement I assumed it was a fix that was added some time since the van was built. It's good to know this is the design. It would be great to have a wiring diagram for an early van but I have not been able to find one. It would be good also to understand how the coil is fed from the ignition. As I shown in the above photos, the only black wire from the ignition currently runs into the 14-pin connector into the dash console.

Yes, I checked the voltage with T1a disconnected so the fault appears to be somewhere between the ignition and the Engine Bay J-box. When I saw the voltage dropping gradually and consistently, I assumed that I was discharging a capacitor connected to the circuit. I had not considered that it might be a broken wire passing voltage with the voltage dropping as it heated up as Carrera described.

Good point on having the ignition off whilst tracing wires. I had not considered the loom fire risk. :shock:
1983 High Top 1.9 Petrol Early DG Engine

User avatar
bigherb
Registered user
Posts: 2579
Joined: 27 Mar 2008, 13:50
80-90 Mem No: 5789
Location: West Kent

Re: No Power To Coil

Post by bigherb »

What fusebox have you got bullet or blade fuses?
1982 Camper 1970 1500 Beetle Various Skoda's, Ariel Arrow

User avatar
Ciaraneng
Registered user
Posts: 303
Joined: 26 Aug 2018, 09:04
80-90 Mem No: 16696
Location: Clonakilty, Co. Cork, Ireland

Re: No Power To Coil

Post by Ciaraneng »

bigherb wrote:What fusebox have you got bullet or blade fuses?
Early-style bullet fuses.

Here's a photo of the back of the relay and fuse board. I didn't take a photo of the fuses but I checked them and they seem to all be intact.
Image
1983 High Top 1.9 Petrol Early DG Engine

User avatar
937carrera
Registered user
Posts: 3599
Joined: 05 Apr 2015, 19:29
80-90 Mem No: 16333
Location: N Yorks.

Re: No Power To Coil

Post by 937carrera »

The coil supply is not fused

There is a connection from the ignition switch direct to the fusebox, described as terminal 15. The feed then goes to the rear of the van where there is the spur for the reversing lights, which is then fused.

I don't know which fusebox connections are used - no wiring diagram to read, pretty sure you need to be looking for black wires

Hope that helps
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

Post Reply