Earthing or Voltage regulator or....?

[lotusfan]

Dear forumfriends,

After the oil leakage problem was solved, the following problem has occurred. When I drove the car home the first time I noticed that in the night the Volt meter read around 10 Volt (which is too low and in the red)
Mart van der kooij has measured the voltage and it was OK although the meter showed a too low reading. He thought that the meter might need recalibrating.

Now the fuel gauge swings its needle regularly. More alarmingly, the voltmeter has discovered the Limbo dance as well and swings like a pendulum though sometimes with a very high frequency. Finally, yesterday evening I discovered that the headlamps flirted with the other road users by means of flickering up and down in light intensity.

I suspect a faulty earthing (am I correct in presuming that that is located in the rear wheel arch on the side of the battery? Are there any other earthing points to check?

Van der kooij informed me that the alternator was renewed so I ruled out a faulty Voltage regulator. Does anyone know how it can be checked?

Finally the car sometimes is a bit stuttering on pick-up. I thought that that was because of the long time the car has been standing still (I am pampering the car with high grade fuel and carburetter cleaner etc). Once the throttle remains pushed after the first stuttering the car accelerates smoothly enough.

Has anyone any other ideas?

[RRHANS]

If you have a handheld voltmeter I would measure on the battery terminals.
engine running, all electrics on (heater, headlights...)
You should have more than 13V
I would also check the connections on the back of the alternator, especialy the one secured with a nut under the rubber cover.
Also the connection on the startermotor.
When working on these, it is best to disconnect battery negative lead.
If your spanner touches other metal parts, you will have fireworks

Veel succes.

[robertverhey]

I think you are experiencing some of the model's inherent traits or "bugs". My gauges have always been jumpy and my in-dash voltmeter also reads low, around 10 volts, despite an external voltmeter showing voltage in the correct 12-14 volt range. I've learned to live with it, but if recalibration is possible I'd be interested to know how it's done. The fuel gauges are badly damped (if at all), so prone to a lot of variation especially on corners. There is no voltage regulator on the later models' instruments, as far as I've been able to ascertain, so they run at the full 12 volts: more reason for fluctuation as various relays click in and out. And this car has relays in abundance! As for the headlights yes I'd start by checking the the earths (and the positive feed of course), there's quite a few earths but tracing the earth leads back from the headlights to wherever they connect to the chassis would be a good start (or maybe bridging another earth lead to see if that solves the problem and indicates a poor connection within the earth wire itself). Yes the two main earths are as you say the battery lead to chassis, accessed via the rear right wheel arch, and a lead between the chassis and engine block, near the right hand engine mount. I understand there's another one up under the dash near the pedal box, but I've not found it, others may be able to direct you (and me) to it and any others.

The stutterring on pickup is another trait, Lotus did try to alleviate it with three-stage jetting on the later models, but it's something I've learnt to live with and get around by applying more throttle than for most cars on take-off. That said, a good tune up can get rid of most of this, but still, occasionally, one can get "bogged down" on take-off unless the revs are kept up.


Hope this assists

Robert

[amarshall]

There should be an earth strap from the engine block to the chassis at the front.

Individual sensors on the engine also have their own earths and a fault on one of these can cause gauges to jump - I had a peculiar link between oil pressure and temperature on mine due to a fault of this type. It was easily solved by replacing the earth lead which had been disturbed.

I would suggest that you check all wiring behind the instrument panel carefully.

Hesitation - there have, historically, been some misfire problems caused by the rev. limiter, but I think these tend to happen higher up the range. It sounds more like a fuelling problem to me.

[MrCoolA]

I'm with Angus re the rev limiter, when mine failed it was in the higer rev ranges...
You can disconnect the rev limiter and see if that makes any difference, but and that is a big but.. ...make sure you dont leave her off especially if you have car mats as once trapped behind the mat she will reach destruction revs very quickly....

Alot of the Excels suffer from a stutter at about 2.5K if you are not flooring her, you can try variouse things to reduce it like higher octane, a rolling road tune, better plugs.
There should be loads of stuff on here if you search

but it may well be worth the usual cheap try out first i.e

New Dizzy cap/Rotor arm
New Plugs (i like the iridium ones)
New plug leads
New coil...........

[fitz]

mine seems to hesitate a bit earlier than that, around 1800 and seriously bogs down if for example i forget i'm in it and change into second too early. I find that its not too bad in 1st (you go past it quick enough) and then if you change so that you are keeping it at around 2800+ it picks up nice and smoothly. I too have the flickering fuel gauge, but its not too bad, just keep it topped up - the rest of the dials work fine on mine though..

glad its back on the road and you're enjoying it!

[hodders]

just to echo what Jerry said:

try variouse things to reduce it like higher octane, a rolling road tune, better plugs.
....
New Plugs (i like the iridium ones)

For me, the minor stutter completely disappeared after the last A service with the new plugs - I forget what type they are.
And I was sure it was fuel related (dirty carb jets), but no.
She now pulls like Cheryl Cole in a men's locker room.

[Lotus-e-Clan]

Definitely change the ignition "consumables" like plugs and leads before playing with carbs. If you have a high mileage car then the dizzy might need an overhaul and should be tested to check smooth operation of the centrifugal ]advance.

BTW. there have been cases of faulty spark plugs even from new so beware...and thin tipped platinum plugs do give a better, more complete, burn of the mixture...I have proved this using a on board wideband meter on my car.

You should also make sure all of the vacuum devices work and are not introducing air leaks on the induction side.

Only then should you focus on the carbs. If your hesitation problem really IS a fueling issue then the areas to check relate to progression: (The best way to tackle this is to fit a wideband air/fuel meter and record whats happening on the road because you need to confirm if hesitation is due to weakness or is it bogging due to richness - but not every one has a wideband)

1) progression hesitation from idle to mains on part throttle: Check float levels - including needle valve function, and float punctures, obviously clean idle jets too.

2) accelerator pump fuel delivery on other than part throttle: Check fuel volume and balance of fuel delivery to pump jets (need a graduated tube device to do this properly but a visual check with carbs on the bench is adequate if you know what you're looking for). If the fuel stream volume from the 4 pump jets is low or unbalanced then check pump diaphragms, pump lever mech, internal non return ball valves and galleries.

And finally, contrary to popular belief, hesitation /flat spots on twin 45 Dellorto'd engines is not the default behaviour ..it's really down to a set up and maintenance. My 89SE is hesitation free (when warm!)...Well it was up to and including October 2009!!! (on a sorn at the mo )

[lotusfan]

Thanks guys for the feed back! It is highly appreciated. The next few days will, hopefully, leave me some time to figure it all out and report back to you.

[lotusfan]

Dear Friends,

As promised, I have taken the opportunity of a four day holiday to sort out differnt things.
I started with the battery and, although the Varta 44AH (yes I know too weak) was from 2009,
the long time standing still of the car didn't do it any good. It had only 68% capacity and was declared bad.

After a long search I found an excellent replacement: an Optima battery which delivers great starting power (about 715 amps I believe). Strangely enough, this simple replacement quieted the "limbo dancing" Voltage gauge in no small way. Some flutter is still sometimes visible but it had decreased tremendously!

Now, all I need is a battery cover because it didn't come with the car. Tips will be appreciated and yes I already called Mike Taylor (line busy) and SJ sportscars ( although busy I could leave them a message). I fear though that the postage and packing will be almost as expensive as the part itself.

I then shifted my attention to the fuse box. The interior, door and boot lights didn't work and yes, the fault could easily be traced to a default fuse. When replaced, I was bathed in the lotus's welcoming lights.
The problem is that I don't have any owners manual with the car so that I don't know what circuitry is protected by what fuse. I found that on the lower right corner of the fusebox, where 2 fuses of 2 amps are situated (cornered in by 2 fuses of 20 smps), the upper 2 amps fuse, had blown. A replacement 3 amp blew, as did a 5 amps (just to try of course). What circuitry is protected by this fuse?
Does anyone have a wiring diagram?
Finally, is the horn supposed to be like this? It sounds like the last breath of a goat and should be more at home in a Suzuki Alto

[lotusfan]

Sorry, when searching the internet I read about numbers of fuses. I looked again and it is fuse number 17 as far as I can see. Any ideas?

[robertverhey]

These'll get you out of trouble

[lotusfan]

Dear Robert,

Thank you very much for these pictures. They are a great help indeed. I noticed already that the fan of the interior heating had stopped working. I now know that this is probably caused by fuse 17. I will have to investigate....

By the way, do you know if an excel se of 1987 (probably modelyear 1986) has central locking? I'm asking because the fuse seems OK but the system is not working.

Once again, thanks.

Kind regards,

Frederik van Kappen