Stalling & stuttering S2

[David_F]

Hi I’ve just bought a 95 m100 S2 no 660. Drove it back home over 200 miles with no problems. Took it for another 70 mile round trip last week and everything went well. Got a break in the rain yesterday and thought I’d go for a drive after car been sat outside for about 5 days in the rain but with a shower cover on. I got about a mile down the road and stopped at a red light. After about a minute of idling fine the car just stalled without a splutter literally just cut out. Started up again first time but cut out again as soon as got back to idle revs. Started again fine but had to keep the revs up to keep engine going and when lights changed the car ran ok a few hundred yards to get some petrol. Filled her up and set off back home and the car would be ok for a bit then particularly at low revs would lose power but would then catch up again with a few more revs. Tried taking her down a long straight at 50 mph and again ran fine at times but even cruising at 50 every now and again would lose power and then pick back up. Car was already booked in to local lotus specialist for a ‘check up’ but couldn’t get in until early next month so would like to try and understand what the problem might be. Does anyone have any thoughts on where to start as there seems to be some very knowledgeable people out there? Thanks for any advice you can give.

[esprit888]

So as you didn’t mention it I assume the CEL didn’t come on showing any codes? When you turn the ignition on (but don’t start the car) does the CEL illuminate? (Common trick is to remove the CEL bulb to hide an issue) if it illuminates then I would look towards water on the coil packs, what your describing sounds like an electrical fault, one bad injector will also drag down the same one on the pair.

[Rambo]

I would agree with the initial diagnosis. So, check.....

1. CEL ie does it come on and stay on or go off ?
2. Do the paperclip test anyway and check for any error codes - see http://wikilec.com/view/Check_Engine_Light_(CEL)
3. Investigate coil packs (under header tank) It may be that water has pooled there or there is a bad electrical connection
4. Check all plugs are sparking and HT leads are in good nick

This may help you on the electrical side of things http://wikilec.com/view/Electrical#Earthing_points

Might be worth taking it for an extended run again now you have a full tank of fuel. It could have been some dirty petrol. Stick in some injector cleaner whilst you're at it

[Rambo]

Also search here viewforum.php?f=38

There have been quite a few problems ie coils, injectors, bad earthing etc... recently where cars have been laid up

[David_F]

Brilliant thanks looks like I’ve got my weekend jobs sorted. Really appreciate your help.

[David_F]

Ive now checked the CEL and this comes on and goes off as expected. Ive done the paper clip test and no error codes found. Ive added the injector cleaner and taken it for a few long runs which appears to have stopped the odd misfiring I had previously.

I now seem to be able to recreate the stalling and am no longer having any problems when the engine is fully up to temperature albeit my temp gauge never gets above the first mark (is this normal?) The stalling seems to occur consistently as the car is getting up to temp so starting from cold it starts first time and idle is around 1200rpm. After about 6 mins if the car is just stood, the idle will drop as if the choke is coming off and then stall with battery, oil and cel light coming on. It will start up again first time but won’t idle and will just stall. It requires revving to keep going past this point for about 1 min until idle then stabilises at about 950rpm and I don’t have any more problems while the engine is warm.

Any thoughts most welcome.

[GeoffSmith]

#660 - Gazza's old Midnight blue S2?

I would start with checking the base timing is correct.

[Simon_P]

And the idle while you are at it - instructions for both in the wiki.

[ShaunM]

my temp gauge never gets above the first mark (is this normal?)

Yes, that's normal. Should sit the needle's width under the first mark.

Good luck sorting your issue.

[GeoffSmith]

… gentle 50mph cruising it can drop as low as half way to the first mark…

I suggest you check that your thermostat isn't stuck open.

[ShaunM]

… gentle 50mph cruising it can drop as low as half way to the first mark…

I suggest you check that your thermostat isn't stuck open.

Was expecting someone to post that. Had this discussion with other established LEC members a few years ago. Definitely not stuck open as would drop to zero in winter which did happen one year when a thermostat failed and stuck open. I've had 3 thermostats in 13 years of owning the Elan and all do the same when cruising at 50mph on very low throttle. You should try it...5 miles on "rolling road" throttle (and before you ask, yes I've fitted the correct themostat, the last one was fitted by Long Stratton Lotus when they fitted the new radiator)

[GeoffSmith]

… gentle 50mph cruising it can drop as low as half way to the first mark…

I suggest you check that your thermostat isn't stuck open.

Was expecting someone to post that. Had this discussion with other established LEC members a few years ago. Definitely not stuck open as would drop to zero in winter which did happen one year when a thermostat failed and stuck open. I've had 3 thermostats in 13 years of owning the Elan and all do the same when cruising at 50mph on very low throttle. You should try it...5 miles on "rolling road" throttle (and before you ask, yes I've fitted the correct themostat, the last one was fitted by Long Stratton Lotus when they fitted the new radiator)

Mine behaved similar to how you describe when it wasn't closing fully, but it was barely discernible and it was only when I ran ES that it became obvious what was happening. That's one reason why I corrected the non-linearity of mine - it now reads ½ FSD at normal operating temperature and running cool is a lot more obvious.

[Simon_P]

It would be interesting to see a scan of temperature vs what the gauge reports. The gauge is just an indicator and the CTS is much more accurate.

I've found the lower end to be quite repeatable at on the 1/4 mark and with A/C fitted needle just above. The only time I've seen it below 1/4 is with a stuck thermostat. I've also noticed that as the sender fails it indicates fans-on temp nearer 1/2.

I've just unsorned the green car and it is stalling and the temp gauge is at half with the fans on, so I've got to investigate.

[David_F]

Hi thanks again. It is a midnight blue s2 and I believe it was owned by an active member on here which is one of the reasons I bought it as I hoped it had been looked after. It’s only done about 400 miles in the last 3.5 years according to paperwork and I’ve now had chance to spend a couple of hours with my local lotus specialist. He checked the base timing and tickover and was happy this was ok. Unfortunately I couldn’t leave the car with him to test from cold and I’m not having any problems when warm in fact she’s going pretty well. Looks like I’ll be getting to know him quite well though over coming weeks as the car I bought with no issues needs both rear wheel bearings, front upper ball joint, new track rod ends and a new sump after being grounded out at some point. I will have a really good car then though apparently!

Are there any instructions on testing the thermostat is working in situ anywhere please to try and rule this out? The car will now consistently stall when the temp gauge shows about half way to the first mark. Sat on the drive just ticking over it takes about 8 minutes to get to this stage. Today in damp overcast conditions I left the car ticking over on the drive for 20 minutes and the temp gauge never went over the first mark.

It will be going back into specialist so I’ll get them to look at this again from cold but if anyone has any ideas on what to look at I’d be really grateful. Someone has mentioned to me a regular issue with the fuel pump relay cutting off the fuel pump but not sure if that could show these symptoms?

[Rambo]

Sorry, can't help with the thermostat short of saying just buy another (relatively cheap and an easy fix), but I can assure you it would have been well looked after by Gazza. He only sold it to move on to a TVR (Tuscan IIRC ?) I was interested in it but dragged my heels and missed out

[Simon_P]

no issues needs both rear wheel bearings, front upper ball joint, new track rod ends and a new sump after being grounded out at some point.

Not sure who your "local Lotus specialist" is but with that list I'd be a bit wary.
The sump is the lowest part so find a pothole or a sleeping policeman and it will get dented and grazed = they are all like that. Does it have a hole in it? If not don't worry. The original ones are double skinned so can look bad but still be ok

Top balljoints wear out, new ones from Lotus lasted me less than a year as the grease was dry.

The rear wheel bearings are tapered rollers and should have some play. Back in the day Lotus issued a service bulletin for correct adjustment as dealers were overtightening them. Are they noisy? That would indicate that they are worn. They may need adjusting.

Track rod ends wear, unusual that both would fail. Do you notice it in the steering?

Other than the sump, none of these are difficult or expensive to fix read the wiki /manual and check yourself.

All of the points mentioned are MOT advisory or failure if sufficiently bad so there would be history.

I wonder if your Lotus specialist is a known M100 specialist? This work could be done by a competent local garage so I suggest that is your first port of call, ask them to put it on the ramp and check the items listed.

Does your Lotus specialist know that the timing and idle are set in service mode? You can check the idle with a paperclip a screwdriver and the wiki. You will need a strobe for the timing.

Buy an elanscan cable it will help no end troubleshooting your issue.

Testing the thermostat can be done with a saucepan and a thermometer, if it is at 1/4 it sounds ok. From cold with the heater off, start the engine, you should be able to feel the top hose get hot when it opens this should be when the needle is a fraction over 1/4 it should then drop slightly and settle at 1/4 Elanscan will tell you in fine detail!

[Rambo]

[David_F]

Thanks for the advice. Local specialist is performance auto care in knaresborough. Seems like a good guy that knows his stuff. The rear bearings and front top ball joint were advisories on the mot the previous owner shared. They showed me the sump and it has just started leaking oil slightly on a corner. Also showed me both track rod ends rusted to the extent they just need replacing as Ive asked for the tracking to be checked. I will get myself the elan scan cable thanks as it looks useful. Ive got another old kit car but very little technical knowledge or time at the minute so I’m just going to give it to them to sort I think as I just want to drive the Lotus as a second car. Hopefully will be a nice car again once tidied up a bit.

[Rambo]

They do appear to be the north and north east's top Lotus specialists and are sponsors of NYLOC so should know their way round M100's as well as the more exotic Lotus range. As Simon says, the jobs you need to do aren't particularly difficult or expensive but you need to factor in their hourly rates (expect north of £60 as a rough guide + VAT)

[David_F]

Been trying to use the Lotus regularly to see if the problem persists. Unfortunately it is still stalling when cold, restarting immediately but then running roughly, losing power for about 5 mins and after a few restarts and adding a few revs eventually the car will then run really well. Thought I’d try elanscan as suggested but looks like everyone is busy as I can’t seem to be able to buy an interface cable at the minute so watched the YouTube video and thought even though I have no idea what I’m doing I’d give it a go making my own. Failed at the first hurdle. Dusted off my multimeter and bought the Opel Vauxhall cable. As a complete newbie I’m expecting some ‘banter’ on this next question but I’ll never learn if I don’t ask so apologies if I’m being stupid. There appears to be only 9 wires inside but they don’t seem to follow the video and the pin on the top row 2nd from the right that would connect to the orange wire from the car doesn’t appear to be connected to any of the wires and the black wire connects to the pin top row 3rd from the left pin. Please be understanding as I’m just trying to get the car running well so I can use it regularly. Thanks