Emissions! Normal CO, high lambda, high HC

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Emissions! Normal CO, high lambda, high HC

Postby gaskethead » Wed 25.04.2018, 17:08

Problem with emissions.
Any advice on what next to change or do first please.
Just had emission test. At fast idle CO is about half max, HV about 3 times max (550), and lambda is 1.47.
I've changed plugs. Looked all similar. Air filter changed and checked timing. Should I next change leads, then injectors , then Oxy meter? Engine runs very well over 2.5k rpm , a bit lumpy up to 2 k. Smells high HC. It also does the 3000rpm thing at cold similar to another post. Any advice gratefully received before I try swapping over some injectors?
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Re: Emissions! Normal CO, high lambda, high HC

Postby Fredjohn » Wed 25.04.2018, 18:05

Guess from reading your post you have the closed loop system, ie with an O2 sensor. Given what you have already tried, try the following:

Whether open or closed loop, allow engine to warm up and cycle the fans on/off once or twice, then take readings.

Putting some injector cleaning fluid through the system should also help before you go to the expense of fitting new injectors, or even have them hi frequency cleaned.

Similarly, if my understanding of the closed loop system is correct, the O2 sensor should adjust the mix appropriately. Perhaps therefore the sensor is faulty. Replacements are not that pricey, but are a b*******r to remove. Again do this before any injector replacement.

If however you have an open loop system, apart injector cleaning, adjust the CO pot hidden behind the glovebox. See WikiLEC for how to do this.

Sure others will be on here soon to post other items to check.

Good luck.
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Re: Emissions! Normal CO, high lambda, high HC

Postby gaskethead » Thu 10.05.2018, 10:04

Many thanks for this. I haven't replied before as I had hoped to have time to look for the O2 sensor. Unaware that sometimes it is not fitted. Also useful to know that you can get injectors ultrasonically cleaned. So far putting through injector cleaner has had some improvement but not complete. I'll search out the sensor as soon as time allows unless one can see it from above? Cheers
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Re: Emissions! Normal CO, high lambda, high HC

Postby Fredjohn » Thu 10.05.2018, 10:34

If you have an S2, it will have the O2 sensor. It is located immediately left of the heat shield (turbo written on it) at the front of the engine, visible when you open the bonnet. Wires come out of it!

If you have an SE, then it may or may not have a sensor, depending on what mods previous owners did. Same location, but if not fitted there is a large headed bolt (19mm??22mm??) ilo the sensor to plug the hole.

Suggest you download the WSM and parts manual: great source of finding things and identifying them. Available from http://www.lotusm100.com/manuals/

As you are very near, it maybe worth heading to Castle Combe for the annual Club Lotus event at the end of the month and meet about 20-30 M100 owners and cars. See separate thread re attendance.
La vie passe vite: vivez la avec elan(s).

Elan S4 DHC 1969
Elan SE turbo 1992
MB CLK 320CDi 2007
Boardman Elite SLR Endurance 9.8 carbon road bike
Evora 2010
VW T4 Campervan
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Re: Emissions! Normal CO, high lambda, high HC

Postby gaskethead » Sat 19.05.2018, 10:08

Hi, I will be at castle combe in the morning from about 9 (I need to get to Eastbourne by 6 pm) and I'll look out for you. Planning to do some track laps.

My reg is H591XYL, and its a red one.

cheers
Chris
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Re: Emissions! Normal CO, high lambda, high HC

Postby gaskethead » Sat 19.05.2018, 10:44

and no O2 sensor fitted to my vehicle - so I think its injector swap or refurb next? Although still cant understand why it runs at 3000rpm on cold start up for approx. 30 seconds? that cant be injector issues can it?
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