free hit
counters
Mechanical help Esprit S4 - Engine/Ancilliaries - The Lotus Forums Jump to content
Scott94s4

Mechanical help Esprit S4

Recommended Posts

I have a 94S4 Esprit. The engine runs fine when it is cold, until it warms up to temperature, then it performs like it has one dead cylinder. I was told that it was acting like it had a bad coil pack so I replaced it. It is still doing the same thing and I am not sure where to go from here. Do you have any idea what this could be?
 
Thank you for your help
Scott Williamson

Share this post


Link to post
Share on other sites

Upgrade today to remove Google ads and support TLF.

Spark plug breaking down as temperature increases?


All we know is that when they stop making this, we will be properly, properly sad.Jeremy Clarkson on the Esprit.

Opinions are like armpits. Everyone has them, some just stink more than others.

Share this post


Link to post
Share on other sites
11 hours ago, Scott94s4 said:
Do you have any idea what this could be?

Have you tried running Frrescan or Espritmon? They may show something to give you some ideas. :thumbup:


Cheers,

John W

http://jonwatkins.co.uk

Share this post


Link to post
Share on other sites

No I have not tried either. Don't have those programs, where can I get them?

Share this post


Link to post
Share on other sites

Have you searched the forums?  Seems like I have seen this mentioned before?

Share this post


Link to post
Share on other sites

Thank you guys for the help!  I will check it out and see what I can come up with.

Share this post


Link to post
Share on other sites
On 04/09/2019 at 21:51, Scott94s4 said:
I have a 94S4 Esprit. The engine runs fine when it is cold, until it warms up to temperature, then it performs like it has one dead cylinder.

It's possible that a tappet has closed causing the valve not to seal when hot.

A hot compression test would prove or disprove this theory. :thumbup:


Cheers,

John W

http://jonwatkins.co.uk

Share this post


Link to post
Share on other sites

John,

If it has just started doing this, wouldn't you expect to see a tappet get looser? The adjustments use shims so I would expect they will get looser and not tighter?


All we know is that when they stop making this, we will be properly, properly sad.Jeremy Clarkson on the Esprit.

Opinions are like armpits. Everyone has them, some just stink more than others.

Share this post


Link to post
Share on other sites

You'd think so wouldn't you but as I understand the tappets close as the valve head hammers itself into the seat & the valve stem stretches.

Happy to be corrected by someone with more detailed knowledge of metallurgy. :thumbup:


Cheers,

John W

http://jonwatkins.co.uk

Share this post


Link to post
Share on other sites

Either closing or opening can occur. Closing is normally if the valve shim wears when siting on the top of the valve stem (a little dimple forms), but you can get some closure of the valve gap due to excess wear on the valve or valve seat (such as caused by a defect in the material). It's not as common but not impossible either.

 

The answer to Michael's question will be key, things like valve wear (and ring wear etc) are gradual changes that would increase over the course of several thousands of miles. Things like a plug / plug lead failure would be pretty quick to manifest. Knowing how the onset was will narrow things down, but the outcome of the ECU scan may make things a lot simpler.

Share this post


Link to post
Share on other sites
3 minutes ago, andydclements said:

 Closing is normally if the valve shim wears when siting on the top of the valve stem (a little dimple forms),

Shim wear or a dimple forming on the bottom of the shim would increase the gap between shim & cam lobe (tappet) surely. :ermm:


Cheers,

John W

http://jonwatkins.co.uk

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.

Guest
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...