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SHE'S ALIVE: Battery – Reversed Polarity = Fried ECU? -

Posted: Sat Nov 12, 2011 9:25 pm
by Stewart
The car is a 2004 S2 Elise 111S

As you may have read here I managed to connect my battery back to front for a split second last night after having it on charge.

Now with the battery in the correct way round, I get a quiet chattering from within the engine bay when I turn the ignition to position II but the fuel pump primes as usual and dash looks normal although the orange check engine light remains lit. When I turn the key to position III the engine turns over but does not fire. There is a slight smell of fuel.

The lights etc work although I again notice a small chattering/whirring type of noise from what sounds like relays in the engine bay. This is only when the lights are on.

I am guessing a new or replacement ECU if I can get a hold of one but am also concerned about VVC solenoids. It appears that they too can get fried and if aren’t checked/repaired first you will just fry the new ECU when installed. Robin was kind enough to confirm this via PM.

If anyone has any ideas or can help with a replacement ECU please let me know. It is a Lotus K4 unit (part no. A117M0109F ) and is unique to the 111S I believe.

The car will either go to MMC or Falkland Performance Centre next week. FPC have their own transporter but I am not sure how to get it to MMC – I am in Cupar. My RAC cover doesn’t include home breakdown. Again if you know of anyone I can hire to move the car I would be grateful for suggestions.

Thanks

Stewart

Re: Battery – Reversed Polarity = Fried ECU?

Posted: Sat Nov 12, 2011 9:39 pm
by mainsy
Tow your car a few miles down the road then phone the RAC :thumbsup

Re: Battery – Reversed Polarity = Fried ECU?

Posted: Sat Nov 12, 2011 9:43 pm
by Stewart
Thanks. I am too honest for that and knowing the luck I have had of late I would rear end the tow car.

Re: Battery – Reversed Polarity = Fried ECU?

Posted: Sat Nov 12, 2011 10:46 pm
by tut
Stewart, give AA a call and they will add home start to your cover and then come out.

tut

Re: Battery – Reversed Polarity = Fried ECU?

Posted: Sun Nov 13, 2011 9:00 pm
by Rosssco
Sure you haven't just blown the ECU fuse or something - might be worth a check if you haven't already...

Re: Battery – Reversed Polarity = Fried ECU?

Posted: Sun Nov 13, 2011 9:14 pm
by Stewart
tut wrote:Stewart, give AA a call and they will add home start to your cover and then come out.

tut
I am with RAC - they will only tow you 10 miles. Also had a word with Craig at MMC (called me back on a Sunday evening - excellent service :thumbsup ) and advised hanging fire on recovering the car until we source an ECM.
Rosssco wrote:Sure you haven't just blown the ECU fuse or something - might be worth a check if you haven't already...
Yeah, thought of that and checked them on Friday night and they are all ok -bummer. I think I read on SELOC something about them not needing to draw enough to blow the fuses before frying the ECM.

Seems the biggest issue is sourcing an ECM new or used. Which guys carry out Honda conversions down South? Perhaps I could contact them to see if they have any kicking around. Again has to be specific to an S2 111s it is different form most of the others and is unique to Lotus.

Re: Battery – Reversed Polarity = Fried ECU?

Posted: Mon Nov 14, 2011 11:21 am
by simon
Try Essex Autosport (used to be Sinclairs) Stewart and see if they have any.
http://www.essexautosport.com/

Re: Battery – Reversed Polarity = Fried ECU?

Posted: Tue Nov 15, 2011 3:14 pm
by dov
hya,

Check the large 80A fuse on the bulkhead behind the engine. If the fuse is blown, try replacing it and starting the engine. If its starts and runs in limp home mode, ie idles up to 1800rpm and back down on its own, then the ecu's fried..if it doesnt start and the fuses are intact...you prolly also in deep sheet

Re: Battery – Reversed Polarity = Fried ECU?

Posted: Tue Nov 15, 2011 3:26 pm
by Shug
Shame it wasn't an R as I have a spare ECU sitting here now, after Elaine's upgrade.

Re: Battery – Reversed Polarity = Fried ECU?

Posted: Tue Nov 15, 2011 8:18 pm
by robin
The 80A fuse won't stop the engine starting as it just links the alternator output back to the starter/battery. Or am I wrong about that?

Re: Battery – Reversed Polarity = Fried ECU?

Posted: Tue Nov 15, 2011 9:10 pm
by tut
Doubt it.........

tut

Re: Battery – Reversed Polarity = Fried ECU?

Posted: Wed Nov 16, 2011 8:30 am
by Stewart
Thanks folks. I checked the 80a fuse last night but like the rest was fine.

I also posted on SELOC and a couple of guys confirmed that they had their ECUs successfully repaired buy www.autotekelectronics.com. I therefore removed the unit last night and sent it away today. Apparantley they have a very quick turnaround time.

I am still concerned about the VVC solenoids but not sure where they are located or what they look like. Can anybody point me in the right direction?

Good news is that the buyer is still keen and being very paitent and understanding through all of this :thumbsup

Re: Battery – Reversed Polarity = Fried ECU?

Posted: Wed Nov 16, 2011 9:22 am
by robin
The solenoids are the two lumpy things that live on the cylinder head at the back of the engine, driver's side.

http://www.deroure.com is a marvellous site!

Item 7 in this is the VVC control unit, items 2 are the two solenoid valves:

Image

Cheers,
Robin

Re: Battery – Reversed Polarity = Fried ECU?

Posted: Wed Nov 16, 2011 10:03 am
by tut
Brilliant site for research and checking prices, and then buying elsewhere.

My new steering rack £434 or £280 for the same one elsewhere.

tut

Re: Battery – Reversed Polarity = Fried ECU?

Posted: Wed Nov 16, 2011 11:16 pm
by Stewart
Thanks Robin.

I have just gone and had a look at the car and think I have identified the part(s). The only thing is I can only see one. Is the other one inside the chamber type thing?

Also, should I remove them to check them? Am I right in thinking that they are identical? With them removed am I looking for something like resistance of 8 ohms through them? Sorry if that isn't quite the right kind of terminology, it must be 25 years since I did my Higher Physics :oops: Fortunately my brother will be on hand this weekend to hopefully keep me right.

Only one solenoid in this picture?
Image