Intermittent loss of power through rev range (UK Leicester)

[Paul C]

Hello.
I have just joined Lotus Elan Central.
I am hoping you can help me out with an issue I have with my Lotus Elan SE Turbo.
The car starts easily and runs well under normal running conditions.
The issue I have is when I accelerate with any vigour (I other words when I floor the accelerate pedal).
The feeling I get, ... is as if a spark plug in intermittently working cause the vehicle to lose power and judder.
This happens at random through out the rev range in any gear.
I have changed the plugs, replaced the cam sensor with the new type and change the HT leads about 4 years ago. That said I bought them off the internet an am thinking of changing them again.
Question 1) Can anyone recommend a good make of HT lead to use.
Question2) Has anyone experienced the same issue with their Elan SE Turbo.
Any help would be gratefully appreciated as I don't have a diagnostic tool to read fault codes.
Cheers
Paul C

[Fredjohn]

I bought Kingsborne HT leads from US. Been perfect for 8yrs. I'm UK based. Would also be worth checking your coil packs and that they are properly earthed.

If you have a paperclip, you have a diagnostic code reader!
See entry in wikilec above under Check Engine Light.

Presume you are UK based, but put your location in your heading through the control panel above. It'll help if someone lives near to you and could advise on your problem.

PS welcome to LEC. Full of useful info and helpful knowledgeable friendly folk.

[Saltire]

I second John’s comments - I run Kingsborne leads on my S2 and they have been excellent. Link here. I have the 7mm ones. They are very helpful on the phone or by email if you get in touch.

As John says, a paper clip is all you need to short out the diagnostic plug and read fault codes (although I and several others have fitted a switch in the glovebox which puts the car into the same diagnostic mode). There is also a piece of free software called ElanScan, which will give you a much more comprehensive run down on what’s happening. You’ll need a PC and an interface cable (cables available on this forum too).

Welcome to the team, and enjoy the car

[RonR]

Welcome to LEC!

I had a similar problem early in my ownership, after much head scratching it turned out to be the plug gaps - they were delivered preset but with a 1.1mm gap, the Turbo engine needs 0.8mm. So I assume under high pressure the spark was breaking down.

[MPx]

I too had a Kingsbourne set in yellow. Fitted in 2011 along with new coil packs to try to cure a high tacho reading and some odd retard events recorded in Elanscan. Made no difference! Nevertheless looked good and worked well until about 2019 when I started getting a sporadic misfire. A typical symptom run was 2021 Castle Combe. Did about 50 miles up to near Bristol and all was well, then misfire a few times, then CEL comes on, then OK for a bit and CEL goes off, OK for a while longer, then the cycle repeats. Was very concerned on arrival at the circuit as the last bit on the M4 was very bad. But it was absolutely fine for 3 sessions at full chat and all of the drive home. Got SWLC to investigate for the second time in Feb this year and they found the leads were falling apart and there was a 1cm gap in the electrode core on one with quite a bit of charring/etc. They fitted a new set of blue leads and I've not had the problem since (in my very limited milage). So I may well have just been unlucky on my set of Kingsbournes or they may just have a circa 8 year/8k mile life.

[Paul C]

Good afternoon.

Thank you all for your advise and help with this subject.
I have ordered a set of Kingsborne HT leads from the US and once fitted will feed back the results, I will also check the earth resistance ensuring the coil pack is grounded correctly.
Its really encouraging to hear from enthusiastic, experienced people such as yourselves who are willing to help.
I really appreciated it.
Thank you.

Cheers Paul C.
PS
I live in south west Leicester.

[Rambo]

Paul - see here http://wikilec.com/view/CEL for the paper clip test that John (Fredjohn) was on about in his reply. Very easy to do so let us know if it throws up any fault codes as between us we probably have experience of most things M100.

And, as Jonathan (Saltire) mentions, long term, Elanscan is the way to go. Having said that, I've managed without for 18 years, despite having Geoff's Elanscan cable

Welcome to fault finding and LEC

[Simon_P]

The symptoms that you describe are fairly common and usually HT related as you suggest. Most often I have found it to be the coil packs giving up.
I've used the ebay HT leads without issue, if you do buy new ones remember that they won't fit in the clips if they are bigger diameter than standard.

Most HT issues don't set a fault code so don't be surprised if there are none.

[Paul C]

Hello Everyone.

Finally got round to fixing the issue thanks to all your tips and advice.

Started with changing spark plugs and HT leads (Cambiare HT leads), still had the issue so I then changed the two coli packs (Cambiare coil packs). This fixed the issue and the car is now running very well reaching boost of 0.5 on the gauge as it originally did before experiencing the issue.

Plus thank you for the paper clip tip for the fault codes.
I tried this, but no fault codes came up.

That said, the car is running as it should and the fun is back especially today as the sun was out and the roof was down.

Thank you all for your help, very much appreciated.

Cheers Paul C

[peteoddcar]

Hi Paul,
Glad you solved the issue - I had similar on my car a couple of years back - new leads, plugs, (0.8 ) and eventually coils.
I am guessing that you are the Paul C who likes a bit of windsurfing on the Gower?

[Paul C]

Hi peteoddcar.

Yes, ... You are absolutely correct. lol, and you must be the peteoddcar that moved from Norfolk back to Essex.
Now, why do I think our paths crossed in not so dim and distance past.
Trips to Wuppertal ring any bells.

Hope you and your family are keeping well and all is good.
Must catch up some time now that we are both retired.

Cheers Paul C