Hi, if the oil supply to the Mivec feed or the signal from the ecu to the oil control valve fails, does the inlet cam lock in position to stop damage occurring? If this is so, how is it then unlocked....is there a mechanism on the pulley that has to be manually released, or will restoring the correct oil supply bring the pulley back to life?

I believe my Mivec system isn't working, and can't figure out why , but this is just one of 3-4 possibilities I'm currently looking at.

Thanks, Andy.

 

According to the service manual, if there is a Mivec cel, then the gear will lock into position. 0* I believe. I'm not sure if it can lock without oil pressure though.

What makes you think it's not working?

 

+1 I too would like to know why you think your Mivec s locking up?

 

Hi, I've put a 9 head onto an 8 block....when we tried to map it, it would only make 17 psi boost, and needed a lot of load to do it. To eliminate a problem with the Mivec, we put a lot of ignition advance into the map, and the mapper told me to be ready for the idle to be very high when I started the car, as the Mivec pulley would immediately advance.

When I started the car however, the idle remained at 850 rpm which makes me think that the Mivec is not receiving either a sufficient oil feed or ecu signal. My next problem will be figuring out how to be sure it is working if I fix something, as I'm not sure I'll feel much difference....the Mivec is supposed to be very progressive, and I don't know how to check for certain if it starts to work. My main concern at the moment is that the cam pulley is mechanically locked into a sort of failsafe position and that I somehow need to manually release it, rather than just relying on sufficient oil pressure.

I haven't ruled out something as simple as a boost leak on this, and a mis-diagnosis by the mapper, but it's starting to get a bit depressing now, as I've been having difficulty with this swap every step of the way...it'd be nice just to have it running right now.

Edited to add that I haven't had a CEL, but I don't think one comes up if there's a fault with the oil control valve.

Thanks, Andy.

 

Hi, anyone got any more info on this...specifically, does the inlet cam pulley on a ix have the facility to mechanically lock into one place as a failsafe against no oil feed/ecu signal, and does it have to be manually dismantled to be released?

Any info appreciated, thanks, Andy.

 

There is a cel if the oil control valve fails. Just unplug it and find out. It doesn't "mechanically" lock into place. If the ecu sees a malfunction, it will regulate oil pressure to keep the cam at the same position "locking" it into place. Once the ecu sees the problem cleared it will "unlock" the cam. So no dismantling.

In my experience, if it's not working, in addition to a cel, you can hear a very distinct clicking from the control valve solenoid.

What headgasket did you use when you did the head swap? VIII gasket or IX?

 

are you sure about this? how can it regulate oil flow to the mivec gear when the oil control solenoid is faulty? Is the clicking the mivec internal gear bottoming out? i should have taken pics of when i pulled mine apart last weekend

 

Hold on you put a 9 head on a 8 block? Did you tap the 8 block for the Mivec oil feed?

 

omg lol, surely he has oil going to it...

 

It's got an external oil feed from the oil filter housing to the head, so yes, it has all it needs in theory....I removed the connector from the oil control valve and put 12 volts through the valve, whilst breifly touching the other terminal to earth ( whilst the valve was still bolted in place ) and can't hear it doing anything. Not sure if it's meant to make much of a click when it activates, and I'll take it out and look at it if necessary, but it's awkward to do that as the alternator bracket ( still the one from the 8 ) is in the way.

I'd like to test the wiring from the ecu to the ocv...am I right in thinking that if I put a test light across the terminals of the ocv connector it'll light up if the car is revved to the point where the signal wire starts to pulse to operate the Mivec...I'm worried I backfeed the ecu and fry it with this method.

Haven't had any cel lights since the car has been run with the ix head and Mivec, just became apparent there was a problem when we tried to map it.

Edited to add, it has the ix head gasket.

Thanks, Andy.

 

evo 8 or 9 headgasket will work.
id recommend pulling out the solenoid from the head, and testing it on a bench. if it's not moving when you apply 12v, it's cooked. Pretty sure it's just a 10mm bolt and it comes out

 

O.K., I just disconnected the ocv connector and got a cel, so that eliminates the ecu to valve wiring....as you say, next step is valve out and have a look. It's also been suggested that it may have an incorrect cam sensor fitted to the inlet side....I've had a look, and the exhaust and inlet fittings appear identical apart from the actual wiring colours. It would be possible to mix these sensors up, although again, I would have thought a cel would come up.

Spoke to a tuner earlier who had an inlet cam pulley in front of him....it would appear from him that the variable part of the pulley does have a mechanism for self locking in extreme cases, and that dismantling the actual pulley is the only way to release it.

Lots to think about!

Thanks for the replies so far, keep 'em coming, Andy.

 

If the ocv fails, does it automatically default to the closed position....I'm trying to figure out what the hell has gone on here, 2 different people over here are saying that the pulley can physically lock into position depending on what the problem is, and furthermore, that the pulley has to be removed and dismantled to it's component parts in order to be manually released!

I'm thinking I need to see this to believe it. I get the worrying feeling my pants are being removed in preparation for a stiffing!

 

eliminate the easy stuff first, and go from there.
i pulled my mivec gear apart the other weekend, cleaned and reassembled. Took 30mins. Very simple. I didn't see any mechanical "lock", but there is a stopper to limit the movement.
I doubt that the cam angle sensors are different, but if you have it all there, give it a go!

 

Hi, did you actually disassemble the 2 halves of the Mivec pulley to the point where the star type fasteners were off and the centre was seperate from the outer...I'm led to believe that there is something within that causing this problem.

Don't believe it can be anything else now, if the cam sensor was wrong or faulty it'd give a cel, likewise any wrong connections to the ecu. I just put on a smaller diameter oil feed pipe to up the pressure to the ocv....the only thing I don't have fitted is the factory check valve, but it seems like people are fitting a line without it with no problem now, so we'll see.

Thanks, Andy.