High CO and MOT fail M100SE 1991

[Twayblade]

Here we go again I can here you say ! well yes and thanks to all the previous threads on this Forum related to this topic over the years I have reached the conclusion after a lot of investigation that I need to upgrade my SE ECM memcal which is currently 9929
This is the first MOT under my ownership (37K miles from new). Failed twice now on high CO 5-6%, you can smell its running rich. CO pot is adjusted more or less full anti CW -ive even checked the CO signal voltage 0.65v
I don't have a reliable exhaust Gas analyzer, a friend had a very old Sun tune unit that gave an indication 1.5% but did not correlate to readings from MOT testing station, anyway this was used as an indication of CO level for CO pot adjustment.
I'm no expert but Elanscan data looks ok to me, once its warmed up and fans are cycling ,coolant temp 110c, MAT 75.1c, MAP 0.35 bar injector pulse 1.5ms, spark advance 11.6, IAC 27 I have checked the base timing (which was ok) and reset the base setting for the IAC.
The car starts and drives well with no issues, although Ive only covered a couple of hundred miles since I acquired the car. The one thing I need to do is to fill up with fresh fuel. Anyway I'm wondering if Ive missed any thing? because my thinking is leaning towards the memcal version and not having the CO adjustment range with 9929. Lotus obviously had an issue with the CO adjustment range which is why they released memcal 9930.

What options are available? Mountain chip? or 9930 ? are these available? or I could consider going closed loop?- what do I need for that?

Any advice or guidance would be gratefully received

[Rambo]

Try new, high octane E5 petrol, add some additives to the tank, go for a blast and make sure your engine is red hot just prior to the test

[lotustonybassplayer]

The wikiLec has all the info you need for going closed loop.

[chrism]

Hi Twayblade.

Yes, I'm a newbie owner of a '90 SE blessed with a 'smelly' exhaust and a suspicion of fuel thirsty-ness so I'm beginning to think like you.

Looking on PROM id decoder (Mountain Chips) it seems that the SE PROM development went from 9239 (which is mine) + 9929 to 9930 that had revised CO pot calibration - which is where, it seems, we'll both need to be (more necessary for you tho' atm...)

Mountain Chips seems dead-and-gone but SRSports have a 'MEM-CAL' that would be an upgrade when you send yours to them. I phoned up this morning to ask about it and all I got from that was that it was a 'Lotus part'; I was hoping to hear that it was a 9930 upgrade but this didn't seem to happen and I was advised to 'look at your car on a computer'. Perhaps you can get further and report back? It might well be that this enables the more accurate CO recalibration that we both need. I'd be hesitant to go 'closed loop' in the interest of originality - and if this upgrade works I think it'd be better v-f-m than changing other expensive 'exhausty' stuff.

MEM-CAL A100E0097S.jpg

Do let us know how you fare and if anyone knows more about this SRSports MEM-CAL please chip in ( no pun intended)

[Blaster]

I had the same issue last year so initially went for the later map then added the O2 sensor. I still have the later map if you want to try and an old Gunson CO meter that seems to read about right.

[chrism]

Hi Tony, thanks for that kind offer - and, yep, I turned out a garage cupboard today and was delighted to find my old yellow Gunson CO meter (that cost £49-95 ages ago...) with a view to getting a CO reading later.

(The Elan passed its MoT just before I bought it recently - but I can't rationalize how it passed with totally-seized front calipers and pistons, let alone smelling so richly-fuelled. Anyway I sorted braking and now need to address the smelly bit...)

I'm a real newbie to Elans. I've only just got ElanScan working. The figures apart from rpm and prom-id mean nothing atm but finding that my prom was even earlier than Twayblade, smelling stale/rich exhaust, seeing sooty plugs and feeling she was gulping the fuel down made me look at the forum's Mountain Chips folder for a solution - but to no avail, unfortunately...

I'm trying to get the latest map (9930) w/out the closed loop/O2 sensor solution which I gather would 'fix' myself + Twayblade giving us more CO adjustment (and keep us 'standard'), which is why I phoned SJS.

I'm not sure if your 'latest map' is a 9930 or what I could do to try it* - but I'd really love to find out!!! I'm wondering, tho', if yours is the even later 1499 - which according to the Mountain Chips info was S2-based or US spec(?) and needed a cat and/or O2 sensor?

As you can appreciate I'm trying to get my head around what's been left behind after the discontinued stuff. I came too late to the Mountain Chips story and would have loved to have 'had a go'

* doesn't the Elan chip have to be sent away to be professionally re-mapped? (I was re-mapping my MGTF135 ecu a short while ago, but didn't think the comparable d-i-y hardware + software package was available for the Elan)

Oops, I've just realised you were probably offering your map + CO meter to Twayblade, not me

[Twayblade]

I had the same issue last year so initially went for the later map then added the O2 sensor. I still have the later map if you want to try and an old Gunson CO meter that seems to read about right.

[/color]

Thanks for the offer Tony, I may be able to move forward and at least know what will reduce the CO %. I can collect as it looks i'm not that far from you. P.M. me when convenient

[Twayblade]

in my first post I should have given credit to Tim from lakeside Engineering who I phone asking for advice and pointed me towards the ECM PROM Memcal version being a possible hurdle to fixing my high CO% issue- my SE having 9929 and 9930
made available by lotus to give a wider CO% adjustment range
Thanks for your time Tim

[Fredjohn]

Chrism
The 1499 Eprom was used for both the S2 and non-Californian models. You do need the O² sensor and wiring, but you do not need to fit a cat.
IF Mountain Chips were available you would just buy the upgrade you want eg Everest,in the Eprom format you want eg 9930 or 1499. This is a fit it yourself plug and play mod. The latter plus O² sensor will give you closed loop and end of emissions issues.

[chrism]

Thanks Fredjohn. It's all making much more sense now due to your input, thanks.

So, it seems that to enhance fuel economy and reduce over-fuelling or partial-burning smell a 9930 or 1499 + O2 sensor upgrade would be the way to go - but neither are available now and probably won't be offered used, either(?)

This brings me back to the SJS MEM-CAL as (perhaps) the only currently available option to enhance the ability to more accurately tune CO. Is it merely a more sensitive Lotus supplied potentiometer or does it have any roots in, or connection to, the 9930/1499+ upgrades that aren't available to latecomers like me? (This is what I didn't get to find out...)

I'm a little worried that Mr MoT will turn around to me next year and pronounce a failure that I won't have a clue about sorting since the fuelling upgrades have become personalised, then died with little motivation for support being offered to Elan-latecomers

[Simon_P]

Would you like you post your scan file (you need to zip it first).

[TorqueHorse]

Hey just catching this thread, but this quoted part stood out...

So, it seems that to enhance fuel economy and reduce over-fuelling or partial-burning smell a 9930 or 1499 + O2 sensor upgrade would be the way to go - but neither are available now and probably won't be offered used, either(?)

The 1499 IS still available; just attached as part of a new ECU. I got one myself a few months ago. https://deroure.com/partinfo.asp?MAK=0& ... PBID=62084

The O2 sensors are available too from various sources. SJ has them it seems https://www.sjsportscars.com/parts-and- ... E6024S.htm, and you can look through old threads and find parts cross-references to others available on other sites too.

Good luck

[chrism]

Screenshot (16a).jpg

Simon_P. If you mean me, thanks I screen-shotted my first 'Scan attempt, which was to primarily check that the coolant sensor was working. Fans came on ~105C, coolant temp reduced to ~ 93C, tickover was ~950, air:fuel ratio ~14. I haven't done a log file yet; very time I go to look at forum logfiles WinRAR tries to sign me up and charge me(?)...(steep learning curve...)

TorqueHorse, I looked at your suggestion, thanks, and saw 'Turbo catalyst (except California)' Mine is an SE w/out a cat or wiring loom(?) which I suppose would make it extremely complicated to go 1499 via that ecu(?) I'd have to install an S2/Fed exhaust, for starters (?)

[Fredjohn]

TorqueHorse, I looked at your suggestion, thanks, and saw 'Turbo catalyst (except California)' Mine is an SE w/out a cat or wiring loom(?) which I suppose would make it extremely complicated to go 1499 via that ecu(?) I'd have to install an S2/Fed exhaust, for starters (?)

Chris some later SEs had the wiring already in place. Look for an unused socket with 2 wires: slate/green and brown/yellow to the left of the turbo looking from the front. Just a question of unscrewing the blanking plug near the turbo,, screwing in the O² sensor and then plug in the leads to the unused socket nearby. Then upgrade the ECU. You do NOT need an S2 exhaust or cat, the existing exhaust is perfectly fine.

[chrism]

Aw...that would've been the best news ever Fredjohn but my SE was reg'd on 3/12/90 and doesn't seem to have a blanking plug near the turbo that I can see.

Mind you, I'm not sure I'd recognise it so I took a couple of pics in case you might recognise anything I missed. There are 2 or 3 plastic multiplugs to the left of the turbo but they're all connected to something...

_DSF0303a.jpg

_DSF0305a.jpg

Mine must've been too early for that upgrade Do you know of any additional wiring that might make the upgrade viable, I wonder? Thanks for that info though - it would've made that 1499 conversion a 'piece of cake'...

[Twayblade]

Aw...that would've been the best news ever Fredjohn but my SE was reg'd on 3/12/90 and doesn't seem to have a blanking plug near the turbo that I can see.

Mind you, I'm not sure I'd recognise it so I took a couple of pics in case you might recognise anything I missed. There are 2 or 3 plastic multiplugs to the left of the turbo but they're all connected to something...

_DSF0303a.jpg

_DSF0305a.jpg

Mine must've been too early for that upgrade Do you know of any additional wiring that might make the upgrade viable, I wonder? Thanks for that info though - it would've made that 1499 conversion a 'piece of cake'...

hi Chris, I'm pretty sure its the big nut in your first turbo shield Photo

[Twayblade]

Hey just catching this thread, but this quoted part stood out...

So, it seems that to enhance fuel economy and reduce over-fuelling or partial-burning smell a 9930 or 1499 + O2 sensor upgrade would be the way to go - but neither are available now and probably won't be offered used, either(?)

The 1499 IS still available; just attached as part of a new ECU. I got one myself a few months ago. https://deroure.com/partinfo.asp?MAK=0& ... PBID=62084

The O2 sensors are available too from various sources. SJ has them it seems https://www.sjsportscars.com/parts-and- ... E6024S.htm, and you can look through old threads and find parts cross-references to others available on other sites too.

Good luck

Hi TorqueHorse, on the B&C site why would the Turbo non cat ECM be £740 and the Turbo cat ECM be £144? seems a huge difference

[chrism]

Hi Twayblade. Thanks, I can see the rusty blanking nut on the turbo where the actual O2 sensor screws into - but I can't seem to find out where there's a loom connector/unused socket for the black plastic m/plug on the other end of the sensor connecting lead is attached to:-

A100E6024S.jpg

"Chris some later SEs had the wiring already in place. Look for an unused socket with 2 wires: slate/green and brown/yellow to the left of the turbo looking from the front."

I've looked everywhere behind the r/h headlight near the orangey boost control thingy and I can't see anything (apart from 3 populated small m/plugs) which is why I took the pics in case anyone else could see what I'm not. There's nothing I can see that's ready to accept the O2 m/plug connector

[Fredjohn]

As Twayblade rightly says, it's the big rusty "bolt" next to the aluminium heat shield with turbo stamped on it in photo one.
I would guess your car is too early for the extra wiring(mine's a '92). But you can add in the 2 wires. Think there's instructions either in Wikilec or the Mountain Chip tab.
You just need to find a 1499 Eprom!

[RonR]

Chris, I think the O2 sensor wiring/plug is hiding behind your engine mount - see photo:

Image1.jpg