The Triumph Dolomite Club - Discussion Forum

Yes, this is guaranteed to be an L.T. electrics problem.
Just to expand on this a bit......

( This all assumes you have points and capacitor ignition with a ballast resistor. If not see the bit at the end. )
1. Did the red IGN light come on at the same time as the rev; counter dropped to zero and the engine cut-out ?
If so it will be a dodgy connection on the thick brown wire to the connector block on the battery + lead, a faulty Ignition switch, or a dodgy thick white wire from the Ignition switch as far as the splice connector. ( This is equivalent to turning the ignition off.

2. If the red IGN light doesn't come on when the fault occurs, then go back to the fuse box. If you have an early 1850 <1500 then the Ignition circuit doesn't actually connect to the fuse box; neither does it on LHD > 15,000 so ignore this bit. So if you have an RHD 1850 >1500 you will find 2 white wires on the fuse box. This is your first check. They may be 2 wires on separate tags or 1 connector with 2 wires on it. Check these connections.

3. Then check the white wire connection to the in-loom ballast resistor ( white / pink wire ) With an early 1850 on Strombergs you may have a ceramic block by the coil. Check these connections next.
4. Then check the white / yellow wire on the coil + terminal.
5. Now check the white black wire on the coil - terminal.This should go straight to the distributor. Follow it through to the points connection inside the distributor. ( This is where my 1850 had a broken wire at one time. ) Finally check the braided earth wire is still on the base plate. I've never been convinced on the necessity of this, but A.C. Delco must have fitted it for a reason.
6. From 5 above if you find the wire goes back through the bulkhead and then re-appears then you have a very early current sensing rev; counter. A fault in this will stop the L.T. electrics, but is quite an unusual fitment.
7. And do check the points gap is O.K. Points sticking open will give the same problem. A short circuit capacitor ( or the wiring to it ) will also give this problem.
8. If a wiring / connector check reveals nothing then it can be an ignition coil going open circuit intermittently. Running with a 12V 2.2W test bulb on the coil + will tell a lot when the fault occurs

9. Now if you are running electronic ignition then depending which make you have fitted.....
Check the +12V supply to the module. This is normally on the unfused side of the IGN ON supply.
Check the module earthing. Can be via a screw on the module or on the distributor base plate.
Then its down to a faulty bit of electronics probably.
If its a Lumenition opto; unit drop me a P.M. and I can give you a few more pointers.
Let us know how you get on.
HTH,
Tony.

Hi Guys

thanks for all the info and replys, im going to check all the things you have suggested over the weekend hopefully, just to confirm its a 73 1850 auto running all standard ignition, points condenser etc, i havnt had any dash lights come on when this happens,
also to put another slant on this fault, when driving it today around 30mph it happened again, however if I move my foot on the throttle a little more to accelerate or less to coast along it goes back to normal so it seems the position of the throttle peddle has something to do with it, possibly something on the kick down circuit ??

mike

Hi Tony

I followed all your advice and I think I've cured it ! The fuse box and all the coil connections are fine, however when it came to the wire inside the distributor I found the problem, the wire in the base coming from the coil had risen up from where it should be seated and the two small screws that hold the rotor on were hitting it when its running and broken the wire connection, i took it out re soldered it and hey presto, here's some pics...

fuse box all cleaned up the problem wire thanks for all your help !

Nice pics there.
Looks like someone has already been at the wiring as the OE loom would have had clear boots over the lucar connectors at the fuse box.

Trouble brewing on that heater jubillee clip too...

Jonners

_________________
Note from Admin: sadly Jon passed away in February 2018 but his humour and wealth of knowledge will be fondly remembered by all. RIP Jonners.

And with the perished pipe below/behind it.

Jer

Yea il keep an eye on them guys, up until this year the car was off the road since 2010 and now its my daily driver so i recken i might get a few things croping up

Hi Jon, I took your advice from previously and swapped the standard 1850 fuse box for the MGB 4-fuse unit.
And guess what. My 1850 doesn't have the clear plastic boots on the standard push-on connectors either; and its a 1977 car.
Only on the after-market accessories I've fitted.
So I've got to fit a plastic insulator by the side of the new fuse box as the fused connectors are a bit close to the bulkhead. ( Ther are aligned up/down rather than left/ right on the Triumph box).
BTW Thanks to Julian for the hint on cleaning the brass connectors with Silver dip ! Tip of the decade that one.
Cheers Both,
Tony.

I must say the wiring on my car doesnt look like its ever been tampered with, its all very original looking wires and connectors ??

Fair enough...

ERO is an early one with the old grey squshy rubber loom joiners and has clear yellowy boots over its fuse box lucars.

Later ones have the harder plastic loom joiners and harder plastic square section sleeves over the fuse box lucars IME.

Long as they are clean and pass current...

Jonners

_________________
Note from Admin: sadly Jon passed away in February 2018 but his humour and wealth of knowledge will be fondly remembered by all. RIP Jonners.

What a gorgeous looking 1850, love the colour. How are you getting on with the car? Hope you and Dolly are well.

Kind Regards

Russell.

Russell, he sold the car.

_________________
Toledo Man

West Yorkshire Area Organiser & forum moderator
Meetings take place on the first Wednesday of the month at 8.00pm at The Old Brickworks, Wakefield Road, Drighlington, Bradford, BD11 1EA

1972 Dolomite 1850 auto (NYE 751L - Now for sale)
2003 Volvo XC90 D5 SE (PX53 OVZ - The daily driver)
2009 Mercedes-Benz W204 C200 CDI Sport (BJ58 NCV - The 2nd car)
1991 Toyota Celica GT (J481 ONB - another project car)
Former stable of SAY 414M (1974 Toledo), GRH 244D (1966 1300fwd), CDB 324L (1973 1500fwd), GGN 573J (1971 1500fwd), DCP 625S (1977 Dolomite 1300) & LCG 367N (1975 Dolomite Sprint) plus 5 Acclaims and that's just the Triumphs!

Check my blog at http://triumphtoledo.blogspot.com
My YouTube Channel with a bit of Dolomite content.

"There is only one way to avoid criticsm: Do nothing, say nothing and BE nothing." Aristotle

Ahh. Hopefully it stayed within the club, it was a lovely looking example, the colour really suited it.

Kind Regards

Russell.