More 5,500 rpm stutter questions I'm afraid ....

Help required from the Exige gurus please.

Had the car a few months now and had 190 conversion done by Lotus dealer few weeks and so far so good which has include road use and one trackday at Brands.

Yesterday did 2 hour motorway run to Mallory followed by day on track in 7 or 8 20 min sessions then 2 hour drive back. When I got back i stopped with engine running for 5 mins to chat but when went to pull away sufferred from the 5,500 rpm limiter I’ve heard spoke about. Stopped the car and turned it off for 2 mins and it cleared.

Therefore a few questions:

  1. Could this be a one off or the start of problems ?

  2. Did turning it off clear it and that’s all I have to do if it happens again ?

On a different subject… since 190 conversion I’ve just noticed the aircon doesn’t seem to want to chill the air at all - it was crap before I know but now is worse than hopeless as it’s putting out warm air !! I understand it’s ECU controlled so any chance the reprogramming of the ECU ( it was sent to Lotus) could have caused this or is another problem all together ???

Advice much appreciated.

David

David

You ‘went to pull away and suffered from 5500 rev limit’ so you did a drag run eh…??

Anyway, did it only do it once or did it rev-limit at 5500 all the way home after it did it the first time?

If it was a genuine mis-fire then ECU would have put 5500 rev limit (assuming its the ‘recall’ s/w which i guess it will be?) and switching it off for 2 mins would have cleared it provided original mis-fire problem had cleared.

Can’t comment on con-air tho’ but did you look see if the pipe was broked??

David,

the 5500 rpm stutter is a safety measure. When the ECU detects a misfire, it limits the revs to 5500 so that the Cat doesn’t build up unburnt fuel.
Switching the engine off and on resets the ECU, that’s why you didn’t feel it anymore.
Now, why did you have a misfire to start with? don’t know, would check the wheel sensor, the sparkplugs, if it was too hot, etc. But it’s just a matter of maintenance.

OTOH the aircon is not connected to the ECU, only the secondary fan is controlled by it AFAIK.
If it worked before and not now, there’s something wrong with it, like the infamous brolen pipe or… something.
I don’t have an airCON, so not so qualified to speak.
But AFAIK, it’s never been so good.

Uldis

Thanks guys - car was pretty hot after 2 hours on the motorway and then sat running for 5 +mins so maybe that was it - once it had limited at 5,500 it wouldn’t go past until I switched it off and then it was back to normal.The plugs are the proper titanium 190 jobs and only about 2,00 miles old so shouldn’t be them but if happens again will get the electrics checked over.

As for a drag run I was just pulling out into traffic officer so had to accelerate hard - honest !!

As far as the aircon was concerned I was told it was ECU controlled to cut out when on full throttle so no loss of power was suffered or is this just bollox ??

Better it checked out at service anyway - don’t need it now anyay !!

Forgot to ask what’s the broken pipe problem with and aircon and what do I look for - please remember that I’m mechanicaly inept before giving and answer to this one !!

[Looking from the back of the car] To the right rear of the engine, at the top, there are two pipes with black nipples on clamped next to each other, these are for the air con. They break at the end! Particularly the front narrower one.

Because it is a design fault Lotus can be begged to fixed them for free. Mine’s just returned from the dealer having it done, although I haven’t tested it yet because, well, there’s not really been much use for more cold air this week!

Ian

Ian,
You should run the aircon for a while even in winter to keep the seals flexible.

Cheers Phil

The plugs are the proper titanium 190 jobs and only about 2,00 miles old so shouldn’t be them but if happens again will get the electrics checked over.

And what do you mean the proper titanium 190’s? the plugs in the std car and in the 190 are the same, normal Champion RC6 6YCC, not titanium tipped.

As far as the aircon was concerned I was told it was ECU controlled to cut out when on full throttle so no loss of power was suffered or is this just bollox ??

Bollox. At least I never heard of that. But then, I don’t even have an AC

It seems to me that you have been listening too much salesman talk.

The aircon compressor IS switched out on full throttle and that is ECM controlled - as is the increase in idle speed required when the AC is on.

Just read the service notes on aircon

David

The stutter can be induced by the ignition coilpack overheating eg waiting in the pitlane for 5 mins or so, before going out on track.

Aircon - probably a broken pipe - get the dealer to fix it & re-gas the system - Lotus should pay for this! Unlikely that you will use it whilst out on track, so don’t worry about any (? much) power loss when it’s switched on. However, you will find it useful a) in winter when demisting the screen & side windows, & b)in summer when you’re stuck in traffic jams

Ooops, but who would have believed Lotus was clever enough for this…
And I keep on learning.

The 5500rpm stutter is a real pain. I still have this problem intermittently even though I have new plugs/leads and have also rebuilt the speed sensor. There appears to be no obvious reason why it occurs as it will happen at any time - hot, cold, dry, wet, fast or slow. Most irritating. I also have the air con problem which Im yet to have fixed, I think it is possible to get rubber hoses to replace the aly ones which crack. Im sure someone else here can confirm this.

Did you get the ECU reprogamming done at Lotus, you know, the recall?

I beleive mine went in for the recall just before a bought it. From what I have heard the changes to the ECU on the recall introduced a 5500rpm rev limit if a missfire is detected, this is to stop any damage to the CAT (which has been blown out of the back of my car anyway). I assume a misfire can cause unburnt fuel to get through into the CAT which can be a fire hazard. I don’t think the recall addressed the cause of the misfire itself. The only cause I can think of for my misfire is that the coil is a bit dodgy, I may try insulating it to see what happens.

I thought it also had a revised set of conditions for the 5500 limit to kick in, as in not as easy as before.

It did, there were changes to the way it reads the timing pulses, Mark Barrett detailed it in a post a while ago.

Uldis - I could be wrong about the titanium plugs but I know they were NGK’s fitted by a Lotus specialist as there seems to be a debate about Champion vs NGK and I don’t know one plug from another so was happy with anything that got me mobile again was on a trackday at the time !!

If they are titanium plugs could this cause damage or is it just that it might be the cause of the detected misfire ??

Thanks again for the advice.

If they are titanium plugs could this cause damage or is it just that it might be the cause of the detected misfire ??

Thanks again for the advice.

David

Tell us the model number of your NGK plugs… the number on em should be 7 or higher and… they shouldn’t have a tapered seat.

Also do you mean Titanium ? or Iridium ? plugs

Rox Teddy - I’ve no idea and I’m in Edinburgh at the mo so it’ll have to wait 'til I get home and dig out my plug spanner to comeback to you on that one - thanks for your help.