In the dog house

[Dolomitejohn]

The sprint is now officially in the dog house. Engine has had a couple of hesitations over past few journeys, but nothing to signal a break down. Last couple of journeys have been over last year or so.
Then today it upon starting it for first time in 3 weeks there is nothing from the starter or solenoid. Lights OK and incators flashing OK so battery OK. It tap the solenoid with a bit of wood and try again. Nothing. Left for 5 mins and it cranks and fires. So off I go. Then it hesitates again and tacho drops to zero but then carries on. Then does it again and again. Each time the tacho drops to zero. In car park in town I check the ignition to harness connector. Seems OK. So off I set home. It hesitates and then cuts out completely. Won't restart. When cranking tacho occasionally jumps up to 3000 or so.

Car has ignition points and transistor assisted booster unit. No suppressor. Been like this for last 24 years. Booster module is a maplins unit.

My thinking is coil or the maplins unit.

Any ideas? Was hoping to go to the national day next week.....

Waiting for recovery now.

John

[Dolomitejohn]

Oh and the cool was very hot.

[Galileo]

Mine cut out the day randomly with a tacho straight to zero, popped the bonnet and headed straight for the wiring, the main ignition feed had come off the fuse box, no idea how, wasn't loose. Anyway, point is with your tacho heading straight to zero I'd concentrate on your wiring, and I'd head right to the beginning at the fuse box and work your way along to the solenoid and back up again looking for a loose/corroded connector or frayed shorting wire. It could be your electronic ignition but as you describe it reads like an instant loss of electrical power.

Wiring on a Dolomite is ridiculously simple, brown from the battery, White/Red to solenoid, White/yellow is the starter override to the coil when starting, white then Pink/Yellow (ballast wiring) to the coil. In the underwhelming fuse box green feeds an 'exciting' amount of kit, tacho along with just about everything else, hazards etc. Pink does lighting, horns and clock. White/slate is the tacho signal from the coil.

Coil does get hot if it is left on for even a relatively brief amount of time.

[Dolomitejohn]

Update....... Recovery truck arrived (45 mins) and the engine then started....... So is temperature a factor?

I will check the wiring. Its been a few years since I cleaned it all up.

Thank

John

[xvivalve]

Could it be a problem in the fuse box? I had a similar problem years ago where the fault was finally traced to one of the fuse retainers had lost its ability to spring; there was enough contact to make indicators work, but not the wipers, and cranking was intermittently beyond scope also

[Carledo]

Green wires don't feed the tach, the smaller of the 2 (unfused) white wires does that, along with the voltmeter.

But if the tach doesn't twitch on cranking, or suddenly zeroes when running, (and engine dies too) my first suspect is ALWAYS coil!

Steve

[Dolomitejohn]

Hi guys thanks for the comments. They line up with mine pretty much. Have just ordered new coil and fuse box. (I did have a fuse box issue a few years back when wipers etc stopped-was corroded fuse). Hopefully will be fixed for next Sunday, especially as I am only 25 mins from Hatton.....

Cheers.

John

[Galileo]

Green wires don't feed the tach, the smaller of the 2 (unfused) white wires does that, along with the voltmeter.

But if the tach doesn't twitch on cranking, or suddenly zeroes when running, (and engine dies too) my first suspect is ALWAYS coil!

Steve

Sorry to disagree but it does on my Sprint, I got a green going to the tacho, then a green going off to the brake light switch, mines an early '75 Sprint so maybe it was changed?

[Matt Cotton]

Sorry you have had a few problems John. I look forward to catching up next weekend.

Regards

MC

[Carledo]

Green wires don't feed the tach, the smaller of the 2 (unfused) white wires does that, along with the voltmeter.

But if the tach doesn't twitch on cranking, or suddenly zeroes when running, (and engine dies too) my first suspect is ALWAYS coil!

Steve

Sorry to disagree but it does on my Sprint, I got a green going to the tacho, then a green going off to the brake light switch, mines an early '75 Sprint so maybe it was changed?

It's possible they may have changed from the early cars like yours, (series 1) to the series 3 cars like mine! I stripped the loom completely on my car whilst rebuilding it to accept the 16 fuse box I bought. My car definitely had the tach and voltmeter fed by a white wire! One of the things I wanted to do was to get ALL the instrumentation (and NOTHING else) onto a single fuse. Which meant relocating the VS to behind the dash and using the second tag on the input side of it to feed all the non stabilised instruments, tach, voltmeter and the electronic speedo i'm still saving up for! Then using alternative green wires to separately feed stuff like washers/wipers, brake lights, reverse lights, HRW and indicators. I had to cannibalize 2 complete car looms (1x series 3 and 1x series 4) to do it, but I now have a total of 21 fuses and 11 relays and feel that the car's circuitry is "adequately" protected!



Steve

[MIG Wielder]

The sprint is now officially in the dog house. Engine has had a couple of hesitations over past few journeys, but nothing to signal a break down. Last couple of journeys have been over last year or so.
Then today it upon starting it for first time in 3 weeks there is nothing from the starter or solenoid.

Car has ignition points and transistor assisted booster unit. No suppressor. Been like this for last 24 years. Booster module is a maplins unit.

My thinking is coil or the maplins unit.

John

Hi John, From my experience, loss of the rev counter while the engine is running down to a stop is absolutely typical of an LT failure as has been noted.
For the failure of the engine to turn over this could be the actual ignition switch going open circuit, or the starter inhibitor link down on the lower RHS.
The car may have transistor assisted points but it still requires that the points are in good condition. It might be worth having them out, cleaning them and resetting the gap.
Tony.