mysterious electric - less voltage?

For all those wiring gremlins we love, this is the place to discuss them.

Moderator: Board Moderators

Post Reply
User avatar
don.hasi
Senior Poster
Posts: 1294
Joined: Sun Jul 11, 2010 08:03
Model: Eclat S2.2 Riviera
Colour: Black
Year: 1982
Location: Germany RLP/Elsass

mysterious electric - less voltage?

Post by don.hasi »

here are the symptoms:

From the start a have various voltages, when I turn the indicator, turn on the lights, the fans kick in etc. you could see it at the water temp, which is the quickest item which "notices" the change of electric power use. This goes so far, that the water temp adds 10 degrees more than it normally have. The otter switch does operate right and measures his own values (so it kicks in at 100° or 110° with the lights on). Oh... and the oilpressure notices it too and varies about 1bar

Today something changed: my heart stood still when I have had 120° suddenly on the water gauge :shock: but a short check delivered the voltage was not at the normal level with 13,8V, it was only a little bit over 12... I would say 12,3 or 12,5.This all with the exception of lefthand drive turns... than for a short time, it goes back 10° and the voltage gauge meter gets shortly higher.

Seems to be a loose or poor connection. But where? I have checked the alternator wiring. Seems to be correct. Of coure the belt is strong too.

Any suggestions for me to look at?

Thanks in advance
ImageImageImageImageImage

User avatar
MrCoolA
Senior Poster
Posts: 2728
Joined: Sat Sep 26, 2009 15:33
Model: Lotus Excel SE
Colour: Pacific Blue
Year: 1989
Location: gateshead

Re: mysterious electric - less voltage?

Post by MrCoolA »

don.hasi wrote:here are the symptoms:

From the start a have various voltages, when I turn the indicator, turn on the lights, the fans kick in etc. you could see it at the water temp, which is the quickest item which "notices" the change of electric power use. This goes so far, that the water temp adds 10 degrees more than it normally have. The otter switch does operate right and measures his own values (so it kicks in at 100° or 110° with the lights on). Oh... and the oilpressure notices it too and varies about 1bar

Today something changed: my heart stood still when I have had 120° suddenly on the water gauge :shock: but a short check delivered the voltage was not at the normal level with 13,8V, it was only a little bit over 12... I would say 12,3 or 12,5.This all with the exception of lefthand drive turns... than for a short time, it goes back 10° and the voltage gauge meter gets shortly higher.

Seems to be a loose or poor connection. But where? I have checked the alternator wiring. Seems to be correct. Of coure the belt is strong too.

Any suggestions for me to look at?





Thanks in advance

Possibly a bad/poor earth have you tried removing the straps and cleaning then replacing??
Previously Jerry (Taylor)
Now "Black Flag"


Lotus Excel SEI1989 253.6hp 190lbft
Lotus Elise S3 1.6. Motorsport Green 2011.

ttedj
Senior Poster
Posts: 440
Joined: Tue Feb 23, 2010 20:43
Model: excel se
Colour: vulcan grey
Year: 1989
Location: lincolnshire

Re: mysterious electric - less voltage?

Post by ttedj »

I second the poor earth. On the midget I had a poor earth from the lights. It was earthing through any route possible and lots of incorrect lights were turning on.

ted
1989 Lotus Excel
1974 MG Midget
2006 AUDI A4 3.0 Tdi quattro
2008 VW TIGUAN (wife's)
2 Black cats

User avatar
don.hasi
Senior Poster
Posts: 1294
Joined: Sun Jul 11, 2010 08:03
Model: Eclat S2.2 Riviera
Colour: Black
Year: 1982
Location: Germany RLP/Elsass

Re: mysterious electric - less voltage?

Post by don.hasi »

sounds possible.

But I couldn´t find the straps :oops: could anyone give me an advise where to search for?
ImageImageImageImageImage

ttedj
Senior Poster
Posts: 440
Joined: Tue Feb 23, 2010 20:43
Model: excel se
Colour: vulcan grey
Year: 1989
Location: lincolnshire

Re: mysterious electric - less voltage?

Post by ttedj »

Between Engine and chassis on the drivers side low down. And from the battery to the chassis - under the rear drivers side wheel arch.

Ted
1989 Lotus Excel
1974 MG Midget
2006 AUDI A4 3.0 Tdi quattro
2008 VW TIGUAN (wife's)
2 Black cats

pompey ice
Senior Poster
Posts: 251
Joined: Fri Feb 23, 2007 16:20
Model: eclat excel [skinny]
Colour: ice blue
Year: 1983
Location: portsmouth

Re: mysterious electric - less voltage?

Post by pompey ice »

Hi , There's also an earthing point located on the brake pedal box [ all the guages and engine electrics go to there ]

cheers Ian

steven popay
Senior Poster
Posts: 326
Joined: Fri Nov 04, 2005 00:30
Model: H.C WIDE BODY
Colour: BLACK
Year: 1988
Location: bury

Re: mysterious electric - less voltage?

Post by steven popay »

there is also the live connection at the chassis but you would normally expect starting problems if it was that.

User avatar
don.hasi
Senior Poster
Posts: 1294
Joined: Sun Jul 11, 2010 08:03
Model: Eclat S2.2 Riviera
Colour: Black
Year: 1982
Location: Germany RLP/Elsass

Re: mysterious electric - less voltage?

Post by don.hasi »

Thank you all for your inputs so far… I will lay down under her clothes this weekend to investigate her straps :mrgreen: In the meantime she has offered her Jedi-self-repairing-meditation-modus and shows stronger voltages like never before Image

But no positive surprises without some negatives… the alternator seems to deliver some craspy noises and it should be a good idea to get a spare one. :(

Further I have found the strap of the bonnet loose under the PAS-pipes. Where is the counterpart of the other end, where do I have to mount it in the engine bay?
ImageImageImageImageImage

User avatar
don.hasi
Senior Poster
Posts: 1294
Joined: Sun Jul 11, 2010 08:03
Model: Eclat S2.2 Riviera
Colour: Black
Year: 1982
Location: Germany RLP/Elsass

Re: mysterious electric - less voltage?

Post by don.hasi »

Dear gentlemen,

I need your help with the earth stripes. There were several hints from you each time I report from my wobbly temperatures and volt gauges.


First: I have located a cable coming from the bonnet, but don´t know where the counter part is? I couldn´t also find a picture or drawing where the second point is located.

Second: I have an ignition amplifier from Lucas. Here is the earth stripe completely rotten. Where is here the counter part?

Third: I have seen the earth bonds from the carbs. They seem to be ok. How does they appear, when they are near to their lifetime end? How do they effect the engine running?

Fourth: I still haven´t found the earth stripe from the pedal box to the engine. I would suppose that someone of you have the car already lifted for servicing etc. Could you please give me a picture, where I have to search?

Fifth: the MY >89 have several more points under the section “Earth, bonds & capacitors” in the parts list, which are also not showed up. Beside some setscrews, where I don´t know where to search, there is also a defined earth cable engine to chassi with no hint where it is located. Could you please help?

Thanks in advance
Don
ImageImageImageImageImage

User avatar
Steve C
Senior Poster
Posts: 801
Joined: Tue Nov 01, 2005 11:31
Year: 0
Location: Hampshire

Re: mysterious electric - less voltage?

Post by Steve C »

There's a thick earth strap that goes to the block underneath the carbs. Mine corroded up after I degreased the engine.

I just unbolted it, cleaned it up and covered it in grease again :-)

Post Reply