My Fix For Alternator Lt On After Start-up Until High Revs

My Fix For Alternator Lt On After Start-up Until High Revs

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Discussion

Penelope Stopit

Original Poster:

11,209 posts

115 months

Tuesday 17th January 2017
quotequote all
Disconnect the indicator warning light and run 2 leads from that light to 2 x 5 terminal relays as shown, connecting them to terminal 30 of each relay
Extend the leads that have been disconnected from the indicator warning light and connect them to terminal 87a of each relay (Marked on the diagram "To LH Indicator Lts" and "To RH Indicator Lts")
Leaving the Alternator Light original wiring as is, connect a lead to each side of the alternator light and run those leads to the relays, connect them to terminal 87 of each relay as shown
Run a fused ignition supply to terminal 85 of each relay coil
With a short lead, link together terminal 86 of each relay coil and extend that same lead to a 3rd 5 terminal relay connecting it to terminal 87a
Connect terminal 30 of this same 3rd relay to earth (Return/Ground or whatever else you call it)
At this same 3rd relay, connect coil terminal 85 to earth (Return/Ground or whatever else you call it)
At this same 3rd relay, connect coil terminal 86 with a lead to the fuel pump wire that goes directly to the pump (After the pump control relay)

Someone somewhere has got something wrong with this vehicles alternator warning light circuit, the wattage of the bulb should be 3 Watts or more, higher than 3 watts is not a problem apart from heat from that bulb, lower than 3 watts highers the alternators cut-in speed, I don't think a 3watt bulb is made for the type of warning light that is used but I could be wrong

Carrying out the above modification will solve the high cut-in speed problem.
What the circuit does is connect the indicator warning light directly across the alternator warning light to up the wattage to something in the region of 4.4 Watts when in the ignition on position, once the engine starts and the fuel pump has a permanent supply the earth will be broken from the relays and the LH/RH indicator warning light circuit will be back to standard. Remember to allow a second or 2 for the fuel pump to prime before the relays kick in and the crank the engine, the alternator will now have a low cut-in speed





Edited by Penelope Stopit on Friday 12th May 08:08

phillpot

17,264 posts

189 months

Tuesday 17th January 2017
quotequote all


You havin' a larf?

Think I'll stick to blipping the throttle! .. wink

Alan Whitaker

2,054 posts

188 months

Wednesday 18th January 2017
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A bit over the top. Just box it up and send it to Brice they can set it to come in at low rpm.

http://www.brise.co.uk/

Alan

RayTVR

1,072 posts

149 months

Wednesday 18th January 2017
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I find that driving the car usually makes it go off. Then I stop worrying.



tvrgit

8,473 posts

258 months

Wednesday 18th January 2017
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Oh thank God for this!

The last 14 years and 50,000 miles have been sheer mental torture, while I have worried endlessly about that warning lamp staying on for 2 seconds more than it would in any normal car. I've even "pushed the envelope" on many occasions, and driven the car 100 yards out of my street early in the morning with the WARNING LIGHT STILL ON (oh yes, I know how to live it on the edge), to avoid blipping the throttle and annoying the non-cogniscenti neighbours...

It has been little comfort, of course, to learn that every other car of the same model does exactly the same thing with no apparent ill-effects. No, what if mine is different and is truly fked?

The stress, the sleepless nights, the "anxiety" crease in the seat, all totally unnecessary.

Thank you, thank you, thank you.

phillpot

17,264 posts

189 months

Wednesday 18th January 2017
quotequote all

Been up all night trying to find a solution for this, my ulcers are giving me grief, but think I've cracked it.............







tvrgit

8,473 posts

258 months

Wednesday 18th January 2017
quotequote all
phillpot said:
Been up all night trying to find a solution for this, my ulcers are giving me grief, but think I've cracked it.............
That's pish. Consultants do not do "oversimplification". Drawing it on the back of a "feminine hygiene" packet is a nice touch though.

lewdon

316 posts

171 months

Wednesday 18th January 2017
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Hi Phillpot

Sorry to be pedantic but I think the extra bulb needs to be in parallel not series. I am happy to be corrected.

phillpot

17,264 posts

189 months

Wednesday 18th January 2017
quotequote all
lewdon said:
Hi Phillpot

Sorry to be pedantic but I think the extra bulb needs to be in parallel not series. I am happy to be corrected.
Dammit!



Griffinr

1,017 posts

180 months

Wednesday 18th January 2017
quotequote all
lewdon said:
Hi Phillpot

Sorry to be pedantic but I think the extra bulb needs to be in parallel not series. I am happy to be corrected.
You are correct, added a bulb to mine, and if you position the extra bulb under the dash you get the added bonus of a footwell light.
Altered mine as I leave home early and didn't want to disturb the neighbour. Then got my first complaint, he overslept!
Rob.

tvrgit

8,473 posts

258 months

Wednesday 18th January 2017
quotequote all
phillpot said:
lewdon said:
Hi Phillpot

Sorry to be pedantic but I think the extra bulb needs to be in parallel not series. I am happy to be corrected.
Dammit!


Should've done it on an etch-a-sketch - "shake-alt-delete".

RayTVR

1,072 posts

149 months

Wednesday 18th January 2017
quotequote all
I used to have a Delorean which suffered from exactly the same problem.

I found that by adding some additional components I could also make the alternator lamp disappear slightly more quickly.





glenrobbo

36,420 posts

156 months

Wednesday 18th January 2017
quotequote all
RayTVR said:
I used to have a Delorean which suffered from exactly the same problem.

I found that by adding some additional components I could also make the alternator lamp disappear slightly more quickly.

scratchchin I always thought that on the DeLorean, the alternator warning light went out when you got to 88 mph?

Great Scot Marty Andrew! wink


Edited by glenrobbo on Wednesday 18th January 11:36

tvrgit

8,473 posts

258 months

Wednesday 18th January 2017
quotequote all
RayTVR said:
I used to have a Delorean which suffered from exactly the same problem.

I found that by adding some additional components I could also make the alternator lamp disappear slightly more quickly.

Do you have a wiring diagram?

glenrobbo

36,420 posts

156 months

Wednesday 18th January 2017
quotequote all
I don't think the wiring diagram would be of much use Andrew. Unless Car Builder Solutions have started selling 15 gigawatt Flux Capacitors....
They are rarer than original S Series front indicators.

Barkychoc

7,848 posts

210 months

Wednesday 18th January 2017
quotequote all
I think you lot are being a bit mean to a new member thinking about fixes to various issues around the cars.

Don't be frightened off - it's all in jest.

glenrobbo

36,420 posts

156 months

Wednesday 18th January 2017
quotequote all
Barkychoc said:
I think you lot are being a bit mean to a new member thinking about fixes to various issues around the cars.

Don't be frightened off - it's all in jest.
Yes Chris, that's quite true. We're only jealous. We won't bite ( we can't, we've got no teeth left. Except for Phillpot, who's made some out of stainless steel. biggrin You need to watch him wink ).

DamianS3

1,803 posts

188 months

Wednesday 18th January 2017
quotequote all
Considering on Saturday you said...

Considering the cut-in speed of an alternator is approximately 1000 RPM give or take a bit, think now about the ratio crank pulley size to alternator pulley size, the alternator is going at some good revs even at engine tick-over
I doubt very much that the problem is a standard factory build problem

Good work on coming up with such a comprehansive fix since then. Have you had time to test it yet? Does seem OTT and not checked it for sanity either. I simply put a Jaguar v6 24v in and problem (? Feature) went away.. smile

All the best

Damian S3

tvrgit

8,473 posts

258 months

Wednesday 18th January 2017
quotequote all
DamianS3 said:
I simply put a Jaguar v6 24v in and problem (? Feature) went away.. smile
Do you have a wiring diagram?

Penelope Stopit

Original Poster:

11,209 posts

115 months

Wednesday 18th January 2017
quotequote all
A simplified method of my fix would be to use the handbrake warning light switch to trigger the relay's instead of the fuel pump supply
The problem with this method is that the circuit will only work when starting the car with the handbrake on and the indicator warning light wont work when the handbrake is on






Edited by Penelope Stopit on Friday 12th May 08:09