Lotus Exige 350 Sport – Faulty cam shaft positioner causing rev limiter to kick in at ~4k revs

[Oliver Williams]

Hi All,

This is my first post on TLF since becoming a Lotus owner and forum member ~5 months ago.

As a first-time owner I've already got a huge amount of value from the forums so I thought I'd pay it forward by posting a topic that I haven't seen covered elsewhere.

Important stuff upfront: the car in question is an Exige 350 Sport. It's a 2020 model, so presumably one of the later 350s to make it out the factory, and it's covered just over 2,600 miles. Picture at the bottom!

Last week, during a relatively spirited drive, the rev limiter started kicking in at ~4k revs, initially while overtaking which wasn't ideal. No warning lights, and other than not being able to make it past 4k revs, the car seemed to be running just fine. 

After exhausting all of my mechanical skills (by turning it off and then back on again) the engine warning light came on so I thought a trip to my local dealer was probably the best course of action.

The dealer initially thought it may be due to a faulty brake light (apparently a relatively common fault) but it turned out to be a faulty cam shaft positioner. Parts have been ordered for next day delivery and the work is being carried out under warranty by Endeavour Lotus, Colchester – who, incidentally, have loaned me a rather lovely yellow 410 Sport, which I have to say, has blown me away and got me seriously questioning if I should've held off and gone for a 390 Final Edition or 410 Sport. I have absolutely no regrets buying the 350, it's a truly phenomenal car, but the 410 is noticeably quicker, louder, firmer and grippier through the corners. But that's for another post!

Anyway, I hope the post is useful to someone in the future. Catch you around.

Ol

 

[KIMUTAKU]

Strange that such fault didn’t trigger any check engine light.

Thanks for sharing your experience!  Beautiful colour on your 350!

 

[fjc27]

Hi

I don't know if your problem has been fixed. Just to say a supposed failure can hide something else. Here is my story :

exige 380 2017, bought at 2500 km in a trustfull Lotus dealer in 2018. No problem mentionned, and no problem for a few hundreds of kilometers.

And then, random rev limiter at 3.8/4 k rpm started to make me crazy... The car ran well at full pace on track, but sometimes random rev lights appeared (and rev limiter intervened !) on road during one acceleration, and not the next one...  - like you

Sometimes the MIL light was on, sometimes not... One time, I captured the log fault : P0366 Camshaft Position Sensor B Circuit Range/Performance Bank 1 - sounds similar to your case

Restarting the engine solved the problem eacht time, until next ghost rev limiter...

I made the brake switch changed by a local dealer, but no improvement. I brought back the car to my original dealer. It was a nightmare to diagnose (he said to me 12 hr of work had been necessary, under warranty but Lotus did not pay all of them) and he found the root cause : a bent pin in a connector of the harness... 🙄

Edited May 3, 2022 by fjc27

[fjc27]

If I remember correctly, before the brake switch, they changed the camshaft position sensor because of the fault code, and it was highly unlikely that there was a real problem with the camshaft...