Engine light

[Nathan Pitman]

Well the light had gone again come Monday morning and has remained off for a road trip to the Isle of Wight which included many hours of driving. I think in all likelihood it’s the “not driving it hard enough or for long enough” nudge. Will get it checked when the car is back in to have the steering wheel replaced. 

[Danelaw]

I had the check engine light come light up on Sunday morning around 2 or 3 miles after filling up with Aral 102 octane ultimate fuel (https://www.aral.de/de/retail/kraftstoffe-und-preise/unsere-kraftstoffe/aral-ultimate/aral-ultimate-102.html) in Germany. I bought an OBD dongle when I first got the car but have never used it and didn't bring it on this trip .

Given the light came on shortly after a fuel stop where I filled up (around 10 gallons) with a fuel at least 3 octane higher than any I've ever used before and lileky 4 or 5 higher than is normal for my car, I strongly suspect the cel is linked to the fuel. Later that same day I filled with Shell V-power 99, but the cel hasn't cleared yet. The car is running beautifully so I'm not going to worry about this until I've flushed more fuel through the system. If the cel persists I'll buy another obd dongle to help diagnose.

I do wonder whether I should have dropped to a 95 fuel for one fill, and might top up with 95 ron shortly just to drop the octane a little.

My car is an Evora S, but the 1zr Elise with us also filled with the Aral ultimate 102 and has not had a cel light. The "ultimate" is more expensive, but it was only that foreign monopoly Euro stuff so no problem there 😉.

Interested to know if others have had similar experiences with high octane fuels or any brands of fuel? I wonder if it is linked to the possible use of alcohol to increase the octane rating?

This seemed relevant to this topic, but could be split off if anyone feels I'm thread jacking or whatever it's called.

[Danelaw]

Update: couple of trips yesterday but cel still on. Ordered an OBD2 scanner this morning, then went to a car show this afternoon/evening. cel light still on but started the car to head home and the cel light had disappeared. 

Sods law it would happen after ordering a code scan, but I've decided my Evora is a show off that likes car shows. I'll take it to more if it keeps fixing itself.

[electro_boy]

I think if the fault is not persistent ie was just a short glitch rather than constant fault. The fault will reset after ~5 turns of the key?

Glad car is fixed and working fine. 

[Danelaw]

I've done many more than 5 starts (more like 10 or 12), but it seems to have taken a quarter of a tank of fuel to convince it that things are back to normal. I don't think I'll bother with anything higher than 99 octane in the future.

The frustrating thing is that I really felt sure there was nothing wrong but the little yellow light started to sew the seeds of doubt.

[Glasgow]

If there was a "significant" fault code that was cleared by the dealer then the car is sold to another customer without repairing the fault. Is there a way  the new customer can discover about the code before it re-appears again???

When buying a car, no one actually asks for a printout of the ECU report.  Even if we do, not many people would understand how to read it and the code would have been already cleared from the ECU history

I am asking this as last month I bought a few years old  Mercedes SL500 from a reputable dealership. 4 days later Engine Management Light on. Long story but faulty car rejected. I take it I was lucky the fault appeared a couple of days before I leave the car for a few weeks holiday, otherwise I could have missed the 30 days window for car rejection under Consumer Right Act.

 

A

 

Edited August 19, 2018 by Glasgow

[Bibs]

I think you get 6 months nowadays. 

[Techyd]

On 03/08/2018 at 10:34, Nathan Pitman said:

Well the light had gone again come Monday morning and has remained off for a road trip to the Isle of Wight which included many hours of driving. I think in all likelihood it’s the “not driving it hard enough or for long enough” nudge. Will get it checked when the car is back in to have the steering wheel replaced. 

How many miles is your car on?  is it worth cleaning the fuel injectors and/or changing the spark plugs?

I'm no mechanic but broadly I'd always understood supercharged engines to be geared up to run slightly rich because the forced induction from the supercharger so maybe there's a fault developing with one of the sensors?

Also - how black is your exhaust, that can be a sign of running too rich

[Nathan Pitman]

1 minute ago, Techyd said:

How many miles is your car on?  is it worth cleaning the fuel injectors and/or changing the spark plugs?

About 17k now. I don't do any of the servicing myself but I will ask B&C when it's next in to take a look.

1 minute ago, Techyd said:

Also - how black is your exhaust, that can be a sign of running too rich

Yea,  good call... the exhaust gets black pretty quick at the bottom and I clean the car once a week so perhaps that's the issue.

The car is going back in for a new steering wheel (once it arrives from Lotus) and some other cosmetic issues so when it's there I will ask them to check if it's running too rich. Not sure if connected but I get a fair number of pops (in addition to the cracks) from the exhaust when down shifting in sport.

[Techyd]

I think pops are okay on downshifts, they are caused by a change in fuel mixture ratio as the engine load changes (reduces) you momentarily can burn lean - don't think that's risky for the engine though.

Your mileage is pretty low so would expect your spark plugs are fine and you fuel injectors shouldn't be too bad at that mileage...

I've got my S booked in for an inspection at the beginning of the month (somewhere else) and I'm planning on talking to them around this anyway so I'll let you know what they tell me!

[Colin P]

400 Exhausts are always black within no time after a wash and generally just the bottom half. You’ll get pops on downshift, especially in the auto. I don’t think there’s much there to worry about.

Mechanically our cars are the same spec and similar mileage so a good comparison. 

[series_one]

Tech center keeps a history of mil lights so any Lotus garage can tell you what it was.