Lights disabled by starter

Lights disabled by starter

Author
Discussion

adcossey

Original Poster:

13 posts

58 months

Sunday 5th January 2020
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I got myself a 1976 RA29 Celica GT shipped to the UK from California, interior and paints completely shot but the body is good and the drivetrains known to be bulletproof. Gradually have been restoring it and have got to the engine, trying to start it this happened.



So I first took the cam cover off and adjusted all the valve gaps, gapped the spark plugs and then tried turning it over. Instantly came to life and started idling, and the cam chain sprayed a whole load of oil into the engine bay. I was so surprised it started up so perfectly after years of sitting around I did it again, the same result so I shut it off to put the cover on. I put the cam cover on and tried again, instead of starting it made a kinda click noise and wouldn't start, I tried again and this time it didn't make the click noise at all, was completely dead. The lights weren't working anymore so I figured the battery must have been on its last legs and starting it had drained it. While the battery was charging I checked in the cover, I thought maybe I'd left a socket in the head and it was jamming the engine but there was nothing there. I put the cover back on and the now fully charged battery back in, the lights came on. I went to start it, the click noise again and the lights went dead, tried to start again no noise and lights continued to not work.



It seems the lights only work if the battery has been disconnected from the car for a while, starting it then triggers something that cuts power to the lights needing the battery to be removed to reset. I don't really know where to go from this, obviously it's not a fault that is listed anywhere in troubleshooting section of manuals, but I cant even find examples of it online. Due to how repeatable it is it must be a specific failure (like a relay that's malfunctioning as apposed to a faulty earth or damaged wiring) so standard stuff like replacing the battery clamps seems a waste of time to me, am I wrong? If it has happened to anyone else I'd love to know what was causing it and how you fixed it, but if you've got an idea of what the issue could be I'd like to hear that too. Its because that it resets itself thats stopping me from just replacing the battery cables and working my way through the system

finlo

3,731 posts

202 months

Sunday 5th January 2020
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Have you tried to turn the engine over by hand?

adcossey

Original Poster:

13 posts

58 months

Sunday 5th January 2020
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Yeah, It turns easily just by twisting the fan belt

finlo

3,731 posts

202 months

Sunday 5th January 2020
quotequote all
At least that rules out some sort of catastrophic failure.

Auntieroll

543 posts

183 months

Sunday 5th January 2020
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Poor engine earthing ?

adcossey

Original Poster:

13 posts

58 months

Sunday 5th January 2020
quotequote all
Yeah someone mentioned looking at that when it first started. I took the earth wire from the battery off, thoroughly cleaned the mounting point and tested the wire for a broken connection. I've started looking into the other earthing points but I can't see how it would allow the lights etc to work (and even engage the starter solenoid) until the ignition is turned, then completely stop working till the battery was disconnected

GreenV8S

30,152 posts

283 months

Sunday 5th January 2020
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Measure the voltage across the battery and across the starter motor when you are trying to start it. They should be similar, and around 12V.

If they're much lower, you have a dead battery. If it does not recover after charging, it may need to be replaced. If the two voltages are not similar, you have a wiring problem. If you're seeing a healthy 12V across the starter and the engine is not cranking, either the starter has failed or there is a mechanical problem.

E-bmw

9,106 posts

151 months

Monday 6th January 2020
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GreenV8S said:
Measure the voltage across the battery and across the starter motor when you are trying to start it. They should be similar, and around 12V.

If they're much lower, you have a dead battery. If it does not recover after charging, it may need to be replaced. If the two voltages are not similar, you have a wiring problem. If you're seeing a healthy 12V across the starter and the engine is not cranking, either the starter has failed or there is a mechanical problem.
^^^^ Wot 'e said.

But with additional caveats.

The lights aren't being "disabled" by the engine, just that there is only so much current that the battery is giving out & it is all trying to go to the starter.

The battery should read 12.6 volts when/if fully charged, I suspect it doesn't & that would explain your issues.

For every 0.1 volts under 12.6 your battery has lost around 25% charge.

Please also check ALL high current connections to battery/chassis/engine/starter/alternator as this would also explain the issue.

Penelope Stopit

11,209 posts

108 months

Monday 6th January 2020
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Lights working, lights not working...................................What lights?

Am I missing something here?

anonymous-user

53 months

Monday 6th January 2020
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That sounds very much like the battery is dead, or, your starter motor is jammed (that would be the clicking). Hit it with a hammer and try again.

A flat battery will also make the clicking happen as the starter solenoid flies out, but the motor doesn't turn.

The lights going off at the same time indicates a dead battery. If it wasn't, they'd come back on.

P.s turn the lights off!

hman

7,487 posts

193 months

Monday 6th January 2020
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Bump (push) start it

adcossey

Original Poster:

13 posts

58 months

Monday 6th January 2020
quotequote all
Penelope Stopit said:
Lights working, lights not working...................................What lights?

Am I missing something here?
Before I started the car I tested whether the headlights worked, after I tried starting it the headlights stopped working (till the battery was disconnected for a while then reconnected)

Matt_E_Mulsion

1,690 posts

64 months

Monday 6th January 2020
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It sounds like the battery is dead. Replace it.

paintman

7,669 posts

189 months

Monday 6th January 2020
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Leave the headlights switched off. Don't have anything else turned on whilst trying to start it.

It isn't 'resetting itself' after waiting for a short period/disconnecting the battery. All that's happening is a very slight recovery by the battery which won't amount to much.

How old is the battery? If it has been left discharged then it's very likely it's dead & charging it won't do much as it won't be able to hold a charge.

Try a known good fully charged battery & see what happens.

adcossey

Original Poster:

13 posts

58 months

Monday 6th January 2020
quotequote all
paintman said:
Leave the headlights switched off. Don't have anything else turned on whilst trying to start it.

It isn't 'resetting itself' after waiting for a short period/disconnecting the battery. All that's happening is a very slight recovery by the battery which won't amount to much.

How old is the battery? If it has been left discharged then it's very likely it's dead & charging it won't do much as it won't be able to hold a charge.

Try a known good fully charged battery & see what happens.
The battery's brand new, It's for a slightly bigger engine (3 litre as opposed to 2.2) and is a heavy-duty 3-year guarantee from Halfords.I have tried without the lights on to see if it was a load issue but the same thing happens

paintman

7,669 posts

189 months

Monday 6th January 2020
quotequote all
Try connecting jump lead from the battery earth terminal to a good clean metal point on the engine block.
See what happens.

Auntieroll

543 posts

183 months

Monday 6th January 2020
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Clamp a good quality jump lead from the engine block direct to the earth terminal of the battery and then try it.

Penelope Stopit

11,209 posts

108 months

Monday 6th January 2020
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adcossey said:
Penelope Stopit said:
Lights working, lights not working...................................What lights?

Am I missing something here?
Before I started the car I tested whether the headlights worked, after I tried starting it the headlights stopped working (till the battery was disconnected for a while then reconnected)
Ok then, thought you may have meant some other lights

You've got plenty of people on the case

adcossey

Original Poster:

13 posts

58 months

Friday 17th January 2020
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cheers for all the replys, I have done the following:

checked the battery, 13.9 volts between the terminals
checked the main battery earth, once again 13.9 volts between the engine block where it bolts to and the positive terminal

checked on the starter, the voltage to the positive (13.9)
checked the starters earthing (just touched the probe against the casing) 13.9 volts between battery and the casing

I removed the starter and cleaned a whole load of oil off it
took out the battery and wired it up with jump leads, all works fine both the solenoid and starter (and I guess battery)

have put it all back together, cleaned and re attached all the wires and once again checked the voltages, the same as before but it still isnt turning over

paintman

7,669 posts

189 months

Friday 17th January 2020
quotequote all
When you tested the starter motor off the car did it just spin nicely or try & fling itself across the floor?