free hit
(supposed) voltage issue when idling - Engine/Ancilliaries - The Lotus Forums Jump to content

(supposed) voltage issue when idling

Recommended Posts

Electrical issue on my Italian Spec 2.0L '96 S4.  Just after engine start sometimes dashboard lights fade. It takes just a blast on the accelerator to bring them back to standard lighting and problem disappears.

When playing this trick, I hear a clicking sound when lighting becomes 'normal' again. Being a mechanical/automotive engineer I strongly suspect a voltage regulator issue.

My Esprit tends to drain battery and it's kept under mantainer. Once it drained the battery when idling due to an hi-power iPad charger plugged in the lighter socket. I jump started the car and after a drive it was fine again and the morning after it started regularly. So I suppose the Valeo stock alternator is working fine.

Any clues?


Share this post

Link to post
Share on other sites

Upgrade today to remove Google ads and support TLF.

Even when they are "working fine", the Valeo alternators provide famously insufficient current at low engine speeds. Your Esprit will be 'running off the battery' at RPMs less than ~1100 especially with electrical loads (headlights, A/C, interior or cooling fans).


The voltage regulators can overheat as a result, melting the potting compound around the components. The black goo actually drips down onto the A/C compressor providing a visual indicator of failure.


You can easily replace just the VR if you choose (they are available), but many owners have fitted a Bosch alternator that provides more current at low RPMs.

Atwell Haines

'88 Esprit

Succasunna, NJ USA

Share this post

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...