I have these symptoms: <http://www.mx5oc.co.uk/forum/forums/p/3010/15143.aspx#15143>, now recurring regularly. The warning lamp
latches on when the engine is under load as it warms up to about 2/3 of
normal operating temperature. Unfortunately it is difficult to avoid
this as I have to get on to the A14 only about half a mile from work,
and however gently I try to accelerate along the slip road there is
always a (expletive deleted) rather large truck bearing down on me from
behind, and it’s a short slip road. Once the lamp is latched on, it
stays on for maybe 2-4 days, perhaps related to how many times I stop and start from cold. Then it clears. There are no obvious signs of poor performance, whether the warning light is on or off.
I also have these symptoms: <http://www.mx5oc.co.uk/forum/forums/p/225/386.aspx#386>
Does this suggest that the S-VT oil control valve is at fault?
I’ve been quoted £223 for a replacement OCV, plus fitting. Does anyone know anywhere else I can get one for less?
Hi Robbie,
Yes, that’s me. I’m just not sure what to do next, if it is worth spending the money on a new valve for something that is intermittent and appears not to cause any obvious problems.
Is it possible to remove the control valve, try taking it apart and cleaning it or flushing it?
Where on the engine is it?
Thanks.
Is on the top of the cam cover, drivers side. There is a pipe running from the back of the engine along the top of the cam cover to an aluminium block held down with 4 10mm head bolts. A cylinder (about 20mm diameter & 40mm long) sticks out sideways with a 10mm head bolt holding it in and a 2 wire connector on the end. The valve does a self clean itself, it doesn’t come apart. I took it out and operated it and the internals move OK, and I operated it while the engine was running and the engine stalled as it should so the rest of the system is working fine. Up to you if you want to spend the money (don’t pay any labour to get it fitted though do it yourself or you can run it round to mine and I’ll fit it on my drive). I’ve only ever replaced a couple as normally a good oil change sorts it. It may become less frequent as the weather warms up, has it come on again since I cleared it? The fault code is generated if the ECU sees the cam timing out of target range by a certain amount for over 5 seconds. You probably won’t feel any driveability concerns. It is most common cause of fault codes on the S-VT engine. Being an intermitant fault it’s a pain, it’d be better if the thing just gave up then you’d have to just get on a change it!
Thanks Robbie.
It hasn’t come on again yet, but I have been treating it gently until it’s warmed up. It did seem to happen more frequently as the winter weather got cooler last year, and in the cold stuff since new year it’s been coming back on as soon as it went off again. Seems to be just as it goes through a narrow, critical temperature range on the way up to normal temperature. I have tried keeping it below 2500 rpm until it’s warm, but even then gentle pressure on the accelerator in 5th or 6th gear to get up to speed on the A14 slip road can trigger it.
I’ll keep an eye on it. If I do decide to get it replaced, thanks for the kind offer to fit it. I will either take you up on that (worth a beer or 3, I should think or bring it to a tech day.
Thanks again for the advice and info, that’s a much better explanation than I got from the guys on the service desk.
or bring it to a tech day.