Evora 400 mixture too rich

[Henrique Vilar Gomes]

Hello everyone

I've been having trouble with my new Evora 400,

the car is now 3000km, but already during break-in displayed once this problem:

the engine stalls during start;

is very sluggish in acceleration from about 2500 rpm (seams a snail compared with my Z4 M... although after break-in and above 5000 rpm the car becomes what it's supposed to be in the numbers that Lotus claims), but below that only noise ?;

in relaxed driving sometimes the electronic stability advisory comes up;

when I go to work, I do a lot of free way, sometimes fast, sometimes slow, but when I hit traffic and come out of steady speed the engine does not adapt to the changes requested in regime for traffic driving, it's rise in rpm isn't smooth and round, as if it's torque curve would be very bumpy (pardon my lack of English terms for discription as I am Portuguese);

as I'm used to the Z4 M, when I smash the accelerator in any gear and from any rpm, I'm used to an energetic kit, and this doesn't happen in the Lotus (so disappointed in the engine's lack of soul, because in all other aspects the car is fenomenal, I love the car but the engine makes me feel embarrassed ?), in the Lotus when I kit the accelerator just a lazy acceleration is felt...

They tell me in the Lotus dealer shop that it's a problem with the flow air measure gage, and thus the rich mixture, I'm going today to have the car checked again for the 3rd time in 3000km...

Can anyone help?

Thank you in advance

Kind regards

Henrique

 

 

[Colin G]

Probably the mass air flow sensor issue. I had the same and has now been fixed, no issues since.

[JayEmm]

My acceleration feels good but not sharp - I had a Z4 M and the throttle map in those is quite aggressive. Even in standard.

The power curve on the Evora should be totally linear, perhaps even to a fault - it masks the speed very well!

That being said my exhaust is as black as a coal miners hat so maybe mine is also running rich? It gets driven properly

[Bibs]

The Evora has always run slightly rich which is why you have a black exhaust. The extra fuel is used to keep the piston crowns cool under higher boost conditions.

 

[CocoPops]

33 minutes ago, JayEmm said:

The power curve on the Evora should be totally linear, perhaps even to a fault - it masks the speed very well!

I was trying to explain this to my 5yr old twins, who on saturday were saying "faster faster" when travelling at 70mph on the motorway.

I was explaining that it's only really the acceleration they notice, not the speed.

 

[Henrique Vilar Gomes]

Thank you guys for the answers, they were very helpful

[trcm]

Z4M is a turbo box too, so you have to expect quite different power delivery (torque certainly) across the rev range to a supercharged car.

[Henrique Vilar Gomes]

Nope, it's a naturally aspired (NA) engine (Z4 M Coupe 2007).

Yesterday came home in im and it's got quite a quick even in 6th from 2k rpm. (Had forgotten already the roundness of this engine, a real workhorse with +170k km).

The good news is that the dealer requested the mass air flow sensor from Lotus with urgency. So shouldn't be long hopefully.

Thank all for the help

[JayEmm]

The BMW S54 is one of the greatest engines ever put in a road car, it's phenomenal. 343PS from a 3.2L NA unit, revving to 8000rpm. Major disadvantage is it is a very heavy unit, being an iron block.

[Henrique Vilar Gomes]

There's still no forecast for Lotus factory to send mass air flow sensor... is this normal?

In fact there is still no reply for the urgent e-mail that was sent by the Portuguese importer requesting the part last monday...

I've got a 170.000km car replacing a 3000km new car ?.

What's going on?

Colin, how much time was your car in the shop?

Best regards

H

[Colin G]

I was told it was a really quick fix, I could've literally just driven in and back out again shortly after. Can't give an exact time on how long it took as I just left it with the dealer for the week while I was in London working.

[JayEmm]

Assuming it isn't in a difficult-to-access place, MAF replacement is usually just unplug, plug in, reset computer, that's it - on my BMW the time taken is definitely in minutes rather than hours.

Obviously the packaging in the Evora is quite different to any front-engined car though, so it's a bit trickier.

[JAWS]

@Henrique Vilar Gomes check the plug going into the MAF sensor on the top of the airbox is not loose. Push it in to see if it has come unclipped.

 

[Henrique Vilar Gomes]

The thing is that it's taking a week only for the reply to the mail asking for urgency in the part....

Tks

[JAWS]

3 hours ago, Henrique Vilar Gomes said:

The thing is that it's taking a week only for the reply to the mail asking for urgency in the part....

Tks

Are you certain it is the actual part causing the problem? Have you checked the connection to the MAF sensor to see if it is compromised? it's not unheard of to cause this issue, as experienced by Colin G. @Colin G - does your MAF sensor and clip have a zip tie around it?

[Henrique Vilar Gomes]

It's what the mechanic diagnosed, tomorrow I'll phone the dealer and draw their attention to this.

Thanks a lot

[Colin G]

No idea Jaws, couldn't even tell you where it's located! (And away with work for two weeks now)

[DanChantler]

I had a similar issue. Hesitation in some low revs and almost stalling at times. Mentioned the MAF issue at my 1,000 service (I had been keeping B&C in touch with my issue while I waited for the service to come up so they were aware) and B&C said Lotus had now issued a MAF bulletin which I'm pretty sure was as @JAWS has described. The fix was quick and easy and I have had no issues since. 

@Henrique Vilar Gomes - ask your dealer about the Lotus bulletin for the known MAF issue

[Henrique Vilar Gomes]

Thanks everyone

The part will be here next Tuesday (hopefully), 15 days with the car in the shop

 

[JayEmm]

@DanChantler Glad you mentioned this. I just checked with Lotus and my MAF has been secured, but not had the sensor replaced. So that's going to be done at my service too as per the bulletin. I don't *think* it has caused me any issues, but evidently there is a problem with them.

[Henrique Vilar Gomes]

Brought the Lotus home yesterday, and the problem is gone ?

Thank all for the interest in my problem

Best regards

H