Forced idle

[Arregueti]

My Evora is now showing some erratic behavior... I would appreciate your help in finding out/guessing why I randomly have a forced idle and slight delayed throttle response. I have had now the car throwing twice a CEL and traction control light. When cleared, it normally runs smoothly, but today the forced idle came back once and then disappeared. I attach a picture of the codes I got this last time (this morning when I had to cancel joining  a nice run out with some Lotuses and Porsches... brrr)

Any clues? TIA

 

 

[Reindeer]

I've had those codes.....I wish I could give you a straight answer to fix it though!

Easy things to try first .... .

Fully charge battery.

Clean and manually push throttle butterfly.

Unplug and contact clean throttle body connection......

Change/clean MAF.

Harder things to try....

Brake and clutch pedal sensors.........

I could go on

[Arregueti]

Thanks!

I will start with properly charging  the battery. It has been off the CTEK charger lately, so that may be an easy explanation. 
 

it is due its annual maintenance in three weeks, so I will start from there and have Komotec check the possible root cause.
 

It does not seem too serious but I would not want to damage something by using the car. 

 

[Cdm2018]

I had these codes and when I went to my lotus garage last week my guy there mentioned about a detected drop in voltage which could had caused the engine light to appear ? 
However he also said there wasn’t a reason that he could pinpoint but the items suggested earlier are useful to deduct others causes ?

I am convinced that in the wet or damp weather conditions the issues appear ? My traction light made reappearance in the last couple of days and hey presto weather has changed to wetter damp than last few weeks of hot dry weather ?  

[Arregueti]

Thanks for your thoughts.

Will start with charging the battery as suggested... it is also the one originally supplied with the car. At least I don’t think it has been changed in my ownership, so maybe it is on its way out. 
 

All the other suspects will be checked thereafter.

Thanks again

[Arregueti]

Just to update this thread. The car has kept having this issue. Running well, just a forced idle and, in the worse instances, an override to my throttle input.

Took it to its annual maintenance on Monday. Had to clear the codes to be able to climb the garage ramp...

it seems that my OBD reader deleted the engine’s history, so Komotec could not get to the root cause. After some driving around the area (and the good hour at brisk pace on the empty autobahn at 7:00 AM to get there) there were no signs of the codes coming back, but I decided to change the battery nonetheless. Played safe and went for the standard Varta. No wish to add lithium batteries charms to the equation...
 

it seems to go fine now. I hope I will not have to update this further. Fingers crossed. 

[Cdm2018]

My car did same as soon as I arrived at lotus garage no codes found and nothing in the history but as soon as I left the garage codes appeared ! Jinxed ☹️

[Arregueti]

@Cdm2018 A new battery is a good starting point, I would say. How old is yours?

[Cdm2018]

I don’t know had car for nearly 4 years and I bet it was in car at least couple so I guess 4-6 years old maybe it due for a change ? 

[RedS4]

I have had these lights - so I kept the battery on trickle charge and the problem seemed to disappear. 

I recently upgraded from NA to S (had a 1320 supercharger fitted along with the associated ancilliaries like injectors, plugs etc) and initially all good - then a few weeks later the issue returned regularly, despite the inclusion of a new battery and continued trickle charge...

Current theory is that is that it is a manifestation of a known issue with early Evora engine wiring looms not earthing properly.  There is a replacement loom now supplied by Lotus that earths directly back to the battery, rather than the chassis (like cutting out the Middle-Man...)...

I am now patiently waiting for a loom to come from Blighty to Sydney Australia as there aren't any here apparently.....

[Rambo]

What makes you think there are any here? It's Lotus 🤣🤣

[Bibs]

I've just checked and Lotus have a good supply of the main harness in stock if that's what you're after. 

[RedS4]

Apparently not, according to our local dealer.  There was a "known issue" with early engine harnesses not earthing properly to the subframe which confuses the EMS and throttle control systems.  This causes symptoms like the engine "hunting" at idle and activating Limp Mode, with all the associated OBD codes (P2104, P2135, P2173, P2119, P2105, P0507 and my favourite - P2106 the Limp Mode or "Forced Limited Power"...).  This get progressively worse each time it occurs.  The fix, am assured, is fitting a redesigned loom that earths directly to the battery rather than to the steel subframe, but mid October these didn't exist.

Six weeks later and I am advised that one is on the water, if not in fact already in Sydney, to be fitted next week.  Just in time for the registration to expire....

[Arregueti]

Hi, @RedS4

I keep struggling to spot the root cause for this problem with my car. Since summer last year I seem to have a "too rich" engine mix and all these symptoms (codes P 2119 and P2104 quite regularly and P0507 only once so far), getting worse as time goes by, too. Now, when I start the car I don't get any reaction to the throttle. I have to disconnect the battery each time.

Would you mind updating this thread on whether you found a permanent fix?

Thanks in advance.

[Rambo]

So, fid you ever clean your throttle body/butterfly valve, clean and/or change the MAF sensor?

[Arregueti]

It is a good question.

In all honesty I cannot tell for sure. The car has been with Komotec three times now and they have not managed to find the solution, but I am not sure what they have checked lately and what not. We changed the battery in 2021, as stated above, and the MAF sensor was zipped/fixed to place a few years ago and it solved the issue of weird codes for some time (before the latest resurrection of codes). The brake sensor was also a source of issues a few years back. But I am not sure what they have checked recently and what not. In any case, I don’t think they replaced any sensor since 2021.
 

The last time I left the car with them to try to address what looked to me as excessively rich mix and/or a potential leak, with fuel all over the diffuser, but they came back with no issue. Komotec has now mentioned the harness as a possible cause, but they cannot take my car until June for further checks and, anyway, they seem very busy to spend time looking at my car properly, so I am keen (desperate) to explore alternatives as I cannot use the car now.

It just seems to be getting worse, as I now have codes popping up every time I start the car, so I am not keen on driving it.

[Phaeton91]

My experience has been that the brake sensor is an issue for the traction control light and cruise control but not engine codes.

The MAF sensor should be cleaned - do it a few times, ie, spray it let it dry and repeat a few times.  It’s something you can do yourself with a can of CRC MAF cleaner spray.  Make sure you get in all the nooks and crannies.  
 

Then maybe look at where you are getting your fuel from - have you changed at all.  I found that it’s sensitive to fuel choice and I now only use shell v power.

Hope that helps - it’s a relatively low cost exercise to check this route out.   

[Arregueti]

Thanks @Phaeton91

It does help.

I don’t think it is the brake sensor either, but what do I know… My cruise control continues to work generally, but lately the traction control light does appear sometimes, resulting in no power whatsoever. It does not get to 2,000 rpm when the traction control light pops up…

I was wondering how to clean the MAF sensor myself, but also assumed it would be one of the first things to be done by a dealer. Please excuse my stupid question. Do you clean the MAF sensor in place or do you have to unfix it to clean (I ask because for me it would mean unzipping and zipping back in place)?

Regarding fuel, and to further feed my paranoia, my bigger problems with the car running rich and too hot started in July last year while in Austria and Italy, when I was doing the Stelvio and the Dolomites. Hopefully it was related to heat and has nothing to do with poor fuel. In any case things have not improved once back to my usual fuel suppliers…

Anyway, I feared I could burn the cats or do some serious damage, so the car is now with my local dealer. Will have to wait and see.

[electro_boy]

Cleaning the MAF sensor is easy:

• Remove the zip tie if you have one
• Remove the two screws holding it to the air intake tube
• Unplug the MAF sensor.  
• Use proper MAF cleaner (I believe general purpose electrical cleaner is not suitable), spray generously to clean it and let it air dry should only take a few seconds.

Refitting is the same as above but backwards.

[Arregueti]

Thanks @electro_boy.

I realised my question was a dumb one, but preferred being safe rather than sorry. 😁

I will give it a try when I get the car back.

[Phaeton91]

Don’t worry it’s not a dumb question - who would want to risk damaging their car or making something far worse for the sake of asking a question?

Have a watch of this video.  It’s not a Lotus engine but the layout and location of the MAF sensor is very similar.  As electro-boy says, there are screws to undo - just be extra careful not to drop them as almost impossible to find them again.

On the Lotus MAF sensor, you spray from underneath.  Look carefully for the little wires and you’ll see 2 separate sets.  Only use specific MAF sensor spray - nothing else, and do not touch them with fingers or anything else.

Oh and I’d suggest you take a photo or close up video of the way the zip wires are tied so you can redo them the same way.

The traction light is very strange in that it cuts power. Possibly for the best that it’s in the service centre for that.

 

[Arregueti]

Thanks @Phaeton91

That is very helpful indeed. Youtube also suggested another useful video, with the work carried out on a Camry, so I see what you mean with the two set of wires and spraying from underneath.

I will give it a try once things "settle" but for now I am happy with the car being at the dealer, as I prefer a technician to have a proper look before things get seriously bad. Fingers crossed for now.

[Rambo]

You might find this useful Arregueti. A very detailed write up with good, close photos.
https://www.thelotusforums.com/forums/topic/85552-quick-throttle-body-and-maf-sensor-clean/#comment-680519

 

[Arregueti]

Thanks @Rambo

I had completely missed that thread. Will definitely read through.

 

[RedS4]

On 28/03/2023 at 01:55, Arregueti said:

Would you mind updating this thread on whether you found a permanent fix?

Sorry for the slow reply.

YES!  My car is fixed and running perfectly.  The fix was replacing the complete engine wiring loom after Lotus in Hethel made a new batch.  i had to wait about six weeks for the loom to travel from England and then be fitted but has been worth it.

The old loom doesn't earth reliably which causes voltage fluctuations which upsets the EMS, sending it into "limp mode" with all the associated error codes. Disconnecting the battery for a while (longer the better) is a temporary fix that progressively gets less and less effective.

I understand ten new looms were made with two coming to Australia (one of which is now in my car).  I would suggest you get one of the remaining eight if any are still available (some should be as this problem manifested itself in most cars early in their life - my car was an exception as it was never used by the previous owner).