Long post not to be read if you don't have time, Part iii

[jokiin]

Is it really this easy to bypass the alarm and remove the problem? :
https://www.elise-shop.com/immobili...els-with-cobra-alarm-up-to-my08-p-502822.html

scary easy (and cheap) if it is

 

[Nigel]

scary easy (and cheap) if it is

I'm not sure what that does, I wouldn't expect the ECU to enable without the correct codes transmitted from the alarm unit, so I guess this just disables the Cobra's own fuel pump and starter cut-off.

 

[jokiin]

I'm not sure what that does, I wouldn't expect the ECU to enable without the correct codes transmitted from the alarm unit, so I guess this just disables the Cobra's own fuel pump and starter cut-off.

I would expect that also, people still want the convenience of remote unlocking so may not want to remove everything, the fact that this pre made bypass plug even exists may be some sort of indicator that this is not the first Elise to have some type of alarm gremlins with the factory fitted Cobra unit

 

[SawMaster]

Just waking up here and haven't read everything so please excuse any duplicity or errors. What I'd do here is first check all ground connections- not just look but undo and look for corrosion under the connectors. Then disconnect all non-factory wiring and return to stock confhuration. If no malfunctioning after this add one electrical change back at a time and the culprit should be apparent.

I once had a rather odd problem with my old Buick- it ran perfectly but would sometimes stop when hot just like turning the switch off, and would not restart till cool again. This usually occurred when braking or cornering hard. No power to ignition or injection when this hapened. I replaced countless parts and still no good. I spent days taking the dash apart to check the miles of wiring and connectors there and everywhere. I studied the wiring diagram and finally came to one part I hadn't replaced.The oil pressure sensor worked fine on the computer-controlled gauge, but GM had thoughtfully included an ignition cut-off under loss of oil pressure there.I replaced it al all was OK for awhile then it began again. This time I bypassed the switch there and no more problem after that. I finally concluded that the oil pressure was dropping momentarily under braking or cornering and at cranking speeds the pump wasn't making enough pressure to close the switch so it wouldn't re-start, and the computer-controlled gauge wasn't accurate. cooler oil being thicker gave just enough pressure to start it. I fought that car literally a year to find this driving it gently to keep it going where it ran fine.

Don't know if the Elise has an oil pressure switch like this, but look at the wiring diagram and determine where the power enters the ignition and injection, and have jumpers on hand to hook to them as close to the components as possible, and when an anomaly hits clip the jumper in. If this does the fix, start working backwards toward the power source similarly till you find the culprit. If the alarm is malfunctioning just toss it and get another instead of trying to fix it- they're reasonably priced these days.

HTH, need more coffee, and hope you get sorted out quickly and easily.
Phil

 

[Nigel]

If the alarm is malfunctioning just toss it and get another instead of trying to fix it- they're reasonably priced these days.

Not so easy since it is encoded to the Engine Control Unit, one will not work without the other, so replacing it requires someone capable of reprogramming both units using equipment that is not widely available for security reasons. Maybe a reasonable cost, but not exactly cheap.

While an earth problem is definitely feasible, on a car made with very little steel it is less likely than on most vehicles. Plastic doesn't cause earth issues, and the aluminium is glued together so is not suitable for use as an earth either!

Since it is either working or not working, with no struggle to work in-between, it is most likely to be a faulty relay, maybe in the alarm, maybe powering the ECU.

 

[kamkar]

it ran perfectly but would sometimes stop when hot just like turning the switch off

We once had sort of the same problem with a ancient seagull outboard engine, it would start and run no problem.
BUT ! once hot if you stopped it, you would not be able to start it again before it was a lot colder.

British Seagull - Wikipedia

en.wikipedia.org

 

[mollydog]

@Nigel, yes I fitted that immobiliser bypass just before setting off last summer, and is still on the car now, a funny thing, on the Elise (maybe other Rover cars too) taking off the brown coolant sensor that goes to the ECU will set the rad fan todefault mode and switch on

well disconnecting the brown coolant sensor didn’t switch on the fan

as I have a fan over ride switch I thought I’d press the switch and see if the fan was working (with ignition ON)

to my amazement pressing this switch also primed the fuel pump, so I thought I might as well and see if the engine will start

well the engine turned over and started, the fan over ride is set to run for approximately 30 or so seconds then cuts off and when the fan cut off so did the engine, I tried this 3 times so wasn’t a fluke, the other thing is/was that the rev counter was not working, and when I pushed the accelerator peddle the engine cut out, the alarm light was on but I still have the EP immobiliser bypass fitted so once I clicked the fob the light went off on the stack

 

[Nigel]

Can't suggest much from that information, unless you have a circuit diagram for the car?
I don't think the circuit diagram for my MEMS 3 MG ZS is going to help much, although it does have that brown coolant sensor!

I'd be checking all those earth cables, looking for one with a fractured conductor. Maybe time to get a new multimeter to check for zero resistance.

 

[dash riposki]

OMG, is Lucas Electronics back in business and supplying Lotus?

 

[jokiin]

OMG, is Lucas Electronics back in business and supplying Lotus?

repair kits are still available

 

[mollydog]

I think this is the time where I call in an auto electrician to go over all the wiring I'll add part 4 later

 

[Nigel]

OMG, is Lucas Electronics back in business and supplying Lotus?

If it was fitted with the Lucas 5AS alarm system which was fitted to the Lotus Elise as standard instead of this optional Cobra alarm then it would probably still be working fine

 

[mollydog]

it’s weird, my (and many other) Elise uses 5AS immobiliser/alarm (which was used wth Rover engine cars) and also the Cobra immobiliser/alarm

why have the two I’m not sure, maybe something to do with the 5AS was/is inter winded with the Rover ECU, as Rover is no longer with us maybe someone at Lotus has the answer

 

[jokiin]

why have the two I’m not sure

supply issues I would think, it's common for car companies to have multiple suppliers of some components

 

[Nigel]

I think the standard alarm didn't achieve a Thatcham 1 security rating, maybe because it didn't have the unnecessary fuel pump and starter motor cut-off, and so made the a new Lotus Elise rather more expensive to insure. I guess new ones where quite expensive to insure anyway, presumably reasonably cheap now. For Lotus, the Cobra made an easy to sell money making option. The engine and ECU where bought from Rover and wouldn't run without the 5AS, don't expect Lotus had the ability/money to get around it, although I think they did for the Mk 2 when they used a non-Rover ECU with the Rover engine.

Also, not sure the Lucas had the ultrasonic proximity/intruder sensor which some people found attractive for a soft top.

 

[mollydog]

I think you have a good point there Nigel, I heard the first year or two the Elise didn’t come with the Cobra alarm and as you say would of made the car a lot more to insure without the Thatcham classed Cobra, as even now at renewal time I’m asked what alarm system it has

for sure Lotus didn’t have money to do much with the Rover engine and I heard the Elise S1 was the last throw from Lotus, and miraculously it did save Lotus for a few more years

I’ve read (rumours on the net) Lotus were looking at fitting in the Honda engine but due to Lotus requiring low volume engines, Honda would only sell the engine at a retail price to Lotus,

having said that, power to weight ratio the K series engine was very good in its day

just a shame Rover never sorted out the head gasket, even our MG TF we bought new and was well looked after, but at just over 39K miles it had HGF

I’ve heard when Ford took over Land Rover, Ford spent lots of energy developing a better head gasket for the Free Lander that used the K series,

 

[crabu2]

I just want to see Part IV please.

 

[SawMaster]

Can't suggest much from that information, unless you have a circuit diagram for the car?
I don't think the circuit diagram for my MEMS 3 MG ZS is going to help much, although it does have that brown coolant sensor!

I'd be checking all those earth cables, looking for one with a fractured conductor. Maybe time to get a new multimeter to check for zero resistance.

Does seem a likely possibility- I've seen poor grounds cause weird issues elsewhere. There would be enough connection for current flow to light a test lamp or to carry the tiny current of a DMM, but when higher load were drawn there wasn't enough connection to allow the necessary current flow and the resistance caused an out-of-spec response from electronics. Ditto with dirty relay contacts, clean those with plain cardboard wet with Isopropyl alcohol slid between the contact points. One other possibility could be a failing fuel pump drawing excessive current when hot which overheats the relay arm and reduces contact pressure- I've seen that a few times on various cars and now I replace the FP relay anytime I replace a pump as cheap insurance.

I didn't know the alarm was integrated, thought it was an aftermarket thing. As it seems to be a heat-related issue it could be an electronic component failure in an encapsulated module somewhere. To locate those gremlins, when things get hot and the problem occurs, cool the module by spraying it with a can of air like you clean conputers with, but held inverted so you get a liquid spray and not gas. We used to do that with canned Freon before we knew it harmed the ozone, and with a defective module it would restore function till it warmed up again. The XJ6's with the ECM mounted on the engine block were particularly bad for this kind of failure and this was the best diagnostic tool for them. I could never figure our why they decided a hot engine was a good place to mount electronics not meant for those heats.

Best of luck with this- the Elise is just too darn nice a car to be sitting instead of being driven and enjoyed.
Phil

 

[Nigel]

I’ve read (rumours on the net) Lotus were looking at fitting in the Honda engine but due to Lotus requiring low volume engines, Honda would only sell the engine at a retail price to Lotus,

having said that, power to weight ratio the K series engine was very good in its day

just a shame Rover never sorted out the head gasket, even our MG TF we bought new and was well looked after, but at just over 39K miles it had HGF

I’ve heard when Ford took over Land Rover, Ford spent lots of energy developing a better head gasket for the Free Lander that used the K series,

The original Elise was developed to be lightweight, there was no way a heavy Honda engine would have gone in the original, the Rover K series was the right choice and in it's more powerful variants plenty powerful enough for an 8??Kg car.

And the head gasket issues were sorted out in the end:
"As of 2015, with more than half a decade in the market, there have been no reported issues of head gasket failure on cars using the Kavachi engine."
https://en.wikipedia.org/wiki/SAIC_Kavachi_engine

Although I had one of those gaskets in my engine, it failed, the polymer coatings disintegrated and the centre steel layer rusted despite using nothing but proper OAT coolant! I'm back with an original Rover version now, working fine and at only £16 to replace I thought it was good value. Of course you have to replace it yourself, a dealer will try to charge you £1000s