My orange engine management light has come on a couple of times, then gone out. The first time it stayed on for about 20 miles,. The second time for about 5 miles. The car drives perfectly, oil pressure and water temp are normal. Any ideas what will cause this, is it something I should be concerned about ?.
Cheers.
Not 100% sure what it will be on your car, but I had something similar on my JDM Subaru Forester ST/b, in the end it was the o2 censor that needed replacing. I guess some knowledgeable member will be along shortly to give you a better diagnosis
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Probably a good idea to get this checked out. One of the components in your car is not behaving as expected. The car’s ECU is warning you in advance of a possible complete failure.
Find someone with a suitable OBD-II scanner (or buy one, they are only £20 - £30 on Amazon or ebay). This will tell you the fault codes that have been logged by the ECU.
Cheers for that. Is there anything that is particularly common, bearing in mind its a vts sport.
O2 sensor, as already mentioned by Marcus. There are probably a few other common ones but I couldn’t tell you what they are, there are literally hundreds of different diagnostic codes that can be stored and reported by an OBD-II ECU.
The most common cause of MIL illunimation on 1800cc MX-5s is the VVT valve sticking intermitantly. DTC P0012. Another code that seems to be getting more common recently is a misfire code, P0300, P0301, P0302, P030 or P0304.
Thanks. What exactly does the valve do, where will I find it, and can I dismantle it and clean it / replace seals ?
The valve controls the amount of oil that’s fed to the VVT actuator to control the amount of cam timing advance and retard. It stick out of the side of the cam cover with a black connector on it. It’s held in with a 10mm bolt. You can’t dismantle it.
ok. thanks for replying.
Check for water under the carpet in the passenger footwell (caused by blocked hood drains). I’ve seen a few where this has caused shorts in the ECU connectors.
Thanks, I’ll have a look at that.
I have also had this code P0012 appear and get a startup rattle sometimes. My post here
On searching around various forums it appears that the 2.5 models with VVT have an Oil Control Valve Filter which could be blocked. MX5 parts list a replacement. Where is this and how do you get it out to clean? Might be worth a try?
If you remove the VVT oil rail from the top of the cam cover the filter is under there. I’ve not checked one for blockage before but sounds like a good place to start.
Right, Thanks. I’ve had a quick look, it doesn’t look too much of a hard job. 5 bolts and a oil union connection. Might do it on my next oil/filter change.
Not sure whether it would need new gaskets or can re-use the old ones? - don’t want any leaks!
What I find strange is that it doesn’t seem part of any Mazda service item but MX5 Parts say it should be cleaned regulary.
Anything (tips) I should be aware of?
If you are not sure what you are doing I would recamend you take
it to a gararge to get it checked with a proper diagnosis computer
it will save you money in the end. It will cost about £40
(head turning black)
Don’t take the whole thing off, I think from memory that you can just remove the oil rail to get to the filter. Remove the oil union at the back then just remove the rail. The filter is just below that.
Thanks Robbie.
Although you said earlier that you cannot dismantle the Oil Control Valve, if you take it out as per your post here - can it be tested/cleaned in any way?
You could clean it with brake cleaner or something if you like. From memory I think it does a clean cycle when you turn the igntion on or off. It cycles fully open then fully closed. If you remove it, leave it plugged in then turn the ignition on and off I think you’ll see the internals move. I’m not aware of a way to bench test it, only a dynamic test where the diagnostic tester operates the OCV and you can check for a change in cam timing. Don’t quote me on any of the above, I don’t have my manuals handy to confirm it.
OK I’ve done all this now.
Removed the oil rail and OCV filter. Looked very clean as it was but I did clean it with white spirit before putting it back. The workshop manual says the filter has a ‘projection’ keyway but there was none on my flange, the filter just sits snugly in it. Any way put it all back using the original washers.
Thought I’d have a look at the OCV itself while I was there. Disconected the connector and undone the bolt but the OCV was rather reluctant to come out, had to give it quite a pull - Robbie??? When out, that too looked very clean, O-ring looked OK. I checked the resistance as per the manual and it checked out OK at about 7 ohms. I then checked the operation with a 12 volt supply as per the manual and the valve went to advance (12v applied) and returned to retard (12v off) OK. Put the valve back which slid in quite easily this time, bolted up and reconnected.
Started up and all seemed OK with no apparent leaks. So couldn’t find anything wrong really but then again I haven’t had the MIL on again recently either. Next thing I’m going to do is change Oil and Filter but with 0w/40 synthetic instead of 10w/40 semi this time, but I’ll have to do that outside and it’s tooooo cold at the mo.