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MIL Light On and Rev Problems
Posted: Thu Jul 28, 2011 9:30 am
by scotboy15
I’ve owned my S2 Elise for about 5 months now and everything was going relatively smoothly.
Recently though it has been going through a lot off coolant and seems to need topping up every 3 weeks or so.
Then two days ago I was driving and found that at idle the revs were sitting slightly higher than normal (1500 instead of 1000) and sometimes when driving, if you pressed the accelerator it would struggle before kicking in.
Last night I was driving home from work and the MIL light came on (steady orange and not flashing) so I haven’t driven it since. From the manual it indicates that an engine sensor has picked up a problem and it can only be fixed by a dealer yet up here in Aberdeen there isn’t a nearby dealer.
Does anyone know what could be up? It’s a Rover engine, done 40,000 miles and it had its head gasket replaced before I owned it at about 25,000 miles.
Any help, advice, pointers or good garages that could help would be great.
Thanks
Re: MIL Light On and Rev Problems
Posted: Thu Jul 28, 2011 9:36 am
by Shug
Take off the oil cap and check for a mayo-like substance, would be my first check. The replacement of a head gasket does not mitigate against it happening again - especially if all that was done was to whip off the head and slap a new one on - lots of checks like head hardness and liner heights should also be done as these tend to be the root cause that swapping a gasket only temporarily masks.
If the light is a steady red, it's not a terminal "STOP NOW" kind of fault (if it starts flashing - stop), so driving it to a garage should be fine. I'll let some of the aberdeen boys suggest the best options up there. Anyone with an OBD reader can read the faults and any decent garage has one - again, ABZ boys, who'd you suggest?
Re: MIL Light On and Rev Problems
Posted: Thu Jul 28, 2011 9:49 am
by alicrozier
I have an OBD reader if you want the code read.
Re: MIL Light On and Rev Problems
Posted: Thu Jul 28, 2011 8:20 pm
by mac
Rover engined S2's the MIL light would come on when something was out with the defined limts, a flashing MIL light indicates a Mis-fire ( which could lead to cat damage & possible fire)
Has the engine been soaked recently?
Check the plugs & plug wells for dampness and while your there might as well check the coil packs and lead ends for signs of corrosion
Cheers
Mac
Re: MIL Light On and Rev Problems
Posted: Fri Jul 29, 2011 9:32 am
by scotboy15
I'll be honest, its starting to look like it is gonna be the head gasket. Checked under the oil cap and there wasn't any of this famous mayo like substance. Decided to check the dipstick and there was a bit of mayo like residue at the top. Top off the coolant cap and there was some on the bottom of that as well.
I then dropped the coolant cap in the engine bay and haven’t managed to find it- what a moron!
Alicrozier - if I could get a shot of the reader then that would be a great help. I presume once I get the error code things start to become a bit clearer? How easy is it to use?
Re: MIL Light On and Rev Problems
Posted: Fri Jul 29, 2011 10:00 am
by alicrozier
scotboy15 wrote:I'll be honest, its starting to look like it is gonna be the head gasket. Checked under the oil cap and there wasn't any of this famous mayo like substance. Decided to check the dipstick and there was a bit of mayo like residue at the top. Top off the coolant cap and there was some on the bottom of that as well.
I then dropped the coolant cap in the engine bay and haven’t managed to find it- what a moron!
Alicrozier - if I could get a shot of the reader then that would be a great help. I presume once I get the error code things start to become a bit clearer? How easy is it to use?
I'm around Sat late afternoon and evening or all Sunday (in Newburgh), I could pop into town though if you dont want to drive it. Reader is easy 5 mins to do. Dongle plugs into my laptop though so I can't leave it with you. I have the error code lists too.
Tip on the coolant cap (and oil cap for that matter), been there, also felt daft.

It'll likely be sitting on the undertray...roof bars are great for hooking them out from the wheel arch.
Edited to add: does sound ominously like HGF but may just be residue gunk from the last time that wasn't flushed out properly...
Re: MIL Light On and Rev Problems
Posted: Mon Aug 01, 2011 9:14 am
by scotboy15
alicrozier wrote:scotboy15 wrote:I'll be honest, its starting to look like it is gonna be the head gasket. Checked under the oil cap and there wasn't any of this famous mayo like substance. Decided to check the dipstick and there was a bit of mayo like residue at the top. Top off the coolant cap and there was some on the bottom of that as well.
I then dropped the coolant cap in the engine bay and haven’t managed to find it- what a moron!
Alicrozier - if I could get a shot of the reader then that would be a great help. I presume once I get the error code things start to become a bit clearer? How easy is it to use?
I'm around Sat late afternoon and evening or all Sunday (in Newburgh), I could pop into town though if you dont want to drive it. Reader is easy 5 mins to do. Dongle plugs into my laptop though so I can't leave it with you. I have the error code lists too.
Tip on the coolant cap (and oil cap for that matter), been there, also felt daft.

It'll likely be sitting on the undertray...roof bars are great for hooking them out from the wheel arch.
Edited to add: does sound ominously like HGF but may just be residue gunk from the last time that wasn't flushed out properly...
Sorry Ali, was busy most of the weekend so didn't get online at all.
Managed to get help from my dad in finding the coolant cap, I knew it hadn't dropped onto the under tray but still couldn’t find it. After taking the air filter out found it lodged behind the fitting bracket for that. God knows how it got there.
Yeah, I'm not entirely sure it is HGF upon looking at it a bit more over the weekend but we will see. If you are available around the city centre anytime this week Ali then that would be a great help.
Re: MIL Light On and Rev Problems
Posted: Mon Aug 01, 2011 11:17 am
by Rich H
A bit of mayo might jsut be residual oil in the system fomr last time if you haven't looked for it.
Clean everything and see if you get more.
Get the codes read (Or buy a reader they are only £20 off e-bay) it might be trivial.
Re: MIL Light On and Rev Problems
Posted: Mon Aug 01, 2011 7:28 pm
by scotboy15
Yeah , I'm not sure as after looking at it at the weekend it's possible that it could jut be left over from last time. here's hoping anyway.
Hopefully I can get the code red and then take it from there.
Re: MIL Light On and Rev Problems
Posted: Tue Aug 02, 2011 9:41 am
by alicrozier
scotboy15 wrote:
Sorry Ali, was busy most of the weekend so didn't get online at all.
...If you are available around the city centre anytime this week Ali then that would be a great help.
I work in Bridge of Don (opposite AECC) so could bring it in any day...traffic a nightmare to get into town or out here tho' with the roadworks.
Re: MIL Light On and Rev Problems
Posted: Fri Aug 19, 2011 9:41 am
by scotboy15
Ok, to progress this problem a bit I bought a fault code reader and when connected to the car it comes back with :-
P0121 - Throttle Position Sensor/Switch A Circuit Range/Performance Problem
Anyone any idea what this could be when combined with the symptoms mentioned above?
Thanks
Re: MIL Light On and Rev Problems
Posted: Fri Aug 19, 2011 11:31 am
by campbell
A lot of our amateur experts are "on annual leave" this week tearing up half of France and select bits of Holland etc. Might be next week before you get some feedback! Although a couple of them are still here (before I get a slap).
Re: MIL Light On and Rev Problems
Posted: Fri Aug 19, 2011 11:41 am
by Rich H
TPS reset - does that work on the S2?
Or pull the plug off the tps and clean it out.
Failing that a replacement TPS.
Re: MIL Light On and Rev Problems
Posted: Fri Aug 19, 2011 12:30 pm
by steviej
I have a spare throttle body with tps if you want to try it, be at fintray / abz over the weekend.
Try the reset first and check the wirings not broken at the tps plug.
Re: MIL Light On and Rev Problems
Posted: Wed Aug 24, 2011 12:38 pm
by scotboy15
Cheers for the feedback guys.
So basically it seems like I should just replace the TPS and this should fix the problem? How much is a new TPS and are they difficult to fit?
How do you do a TPS reset?
EDIT:- Just checked and a 52mm throttle body is about £120. This seem about right?