free hit
counters
Unusual K series temperature problems - Engine & Ancillaries/Gearbox - The Lotus Forums Jump to content
Kevin Wheeler

Unusual K series temperature problems

Recommended Posts

Hi there

I wonder if any of you people can help me, please?

I have an 03 plate 111s with the K series VVC engine.

A little while ago I noticed that the display was not showing much of a temperature after a decent trip. Usually the display comes on at 71 then goes up to around 86 on the move, rises slightly into the nineties, when stationary, then the fans cut in. However, now, I am lucky if it reaches 80 degrees on the move.

Recently the car started to cough and splutter when stopped at the lights and I had to keep revving it to stop it stalling. I have also noticed that my fuel economy has decreased from 32 - 35 mpg to 25 mpg.

It has been into the local garage (not a Lotus specialist) and they have replaced the pre and post cat lambda sensors and the temperature sensor. They also changed the spark plugs because they were rather black with carbon. They have checked the coil and the leads and the fuel regulator. All seem to be normal. they tried a new MAP sensor and this changed nothing.

I have just taken it for a run (about 15 miles) and the temperature again only displayed up to 75 degrees on the run. Back on my drive it reached the early 80s whereas it normally reaches 95/96. Again, the engine was running very lumpy on tickover and needed a bit of encouragement to stay alive. Basically, it feels as if the choke is permanently out and the engine is over fuelling because it thinks it is cold!

I also noticed that on tickover both exhausts pipes were exhausting, when I am sure that the drivers side should only come on once the engine reaches 4,500 rpm. Both exhaust pipes are black with carbon. Again, this is unusual.

Does anybody have any ideas what might be wrong please? And what else to try? (It will go to the Lotus specialist next!)

Thanks

Kevin

Share this post


Link to post
Share on other sites
Upgrade today to remove Google ads and support TLF.

There are two coolant temperature sensors - one to ECU, one to dash.  Which one did they replace?

A specialist would have the correct diagnostic tool to plug in and identify if they were working correctly or not in no time at all...  :)

Dave

Share this post


Link to post
Share on other sites

It looks like they fitted the ECU coolant temp sensor - which presumably should tell the ECU the right number even if the dashboard is showing the wrong number. Thanks Dave.

I think it is a trip to the specialist needed!

Thanks Dave

Share this post


Link to post
Share on other sites

Since it's an S2 it will only use the brown sensor for both the dash and engine. Not surprising when these Rover type sensor fails, they will read up to a certain temperature and stop there. So basically, your ECU thinks that your engine hasn't warmed up forever and a day.

Share this post


Link to post
Share on other sites

Thanks Eric. That does seem to be what the car "thinks".

Oh, for a carburettor!

Share this post


Link to post
Share on other sites

You should verify if the temperature reading is correct or not. Some readings with an IR temperature probe will give you a good idea of the actual engine temperature. If it really is that low, I'd start by replacing the thermostat. Doesn't fully explain the rich running, but it's a first step.

Filip


I have made many mistakes in my life. Buying a multiple Lotus is not one of them.

 

Share this post


Link to post
Share on other sites

Thanks for your advice, people!

I have taken it to Sportomotive in Bournemouth who had the correct piece of kit. He looked at the machine and found that the MAP sensor was giving incorrect readings at idle.

Cos had had a similar fault with another Elise recently and the problem with that was an issue with the wiring loom. 

He has just phoned me and let me know that it was the same intermittent fault with mine that meant that my VVC valves were in the wrong position for idle, so when I was giving it some "beans" it was acting fine, but when I slowed down it was running really rich and lumpy. Apparently: fix the loom problem - fix the running problem!  Brilliant!

Hopefully, I can pick it up tomorrow and see if that has fixed it all!

On the bright side I should not need any sensors changing for a long time now!

  • Like 2

Share this post


Link to post
Share on other sites

Great news Kevin. The real story here is: don't mess around with a local garage, go straight to a specialist.

Justin

Share this post


Link to post
Share on other sites

Good to hear Cos is still being awesome. :thumbup:

Share this post


Link to post
Share on other sites

I agree @jep. Trying to save two two hour round trips just gave me grief!

And I will confirm Cos' awesomeness once I have driven the car tomorrow!

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...