Have I got a VVC inlet manifold??

[tomward]

I've been doing lots of tinkering since the cam belt failed in September and am nearly there with putting the whole thing back together and I discovered there was no way of fitting the standard inlet o-ring type gasket into my inlet manifold.

Having dug a bit further I've discovered I need one of these gaskets instead, which the Rimmer Bros website tells me is a VVC inlet manifold gasket.
https://rimmerbros.com/Item--i-LKJ100821

Does this mean the previous owner fitted a VVC inlet for some kind of performance boost? Or is this something the factory may have done? Nothing I can find suggests I should have to buy this gasket for my car which is a 2004 non VVC version.

I've fitted a new head with valves pre installed from Rimmer Bros - a Land Rover genuine one it turns out. Is there anything else I might need to be aware of?

Ever since owning the car (about 4 1/2 years now) I've had an engine warning light on the dash. Previous investigation hasn't revealed much and it didn't affect the performance of the car but at last years MOT with the rules changing I decided to see if something could be found, the local garage - not an MG specialist - diagnosed a faulty Lambda sensor which I didn't believe but they fitted it, passed the MOT and it was no surprise to me when the engine light came on about an hour down the A12 - it's always during long runs at steady revs like a motorway.

Am I right in thinking if a different inlet was fitted without a re-map this might have caused my engine warning light error?

[Mykel]

TFs all came with the alloy manifold, even the non-VVC ones. So the correct gasket kit would be the one sold as VVC, which comes with the correct inlet manifold gaskets – one between plenum and manifold, the other for the mating face on the cylinder head.

As to the MIL coming on, this might have a plethora of reasons, eg one of the lambda’s faulty, the cam shaft sensor or the odd misfire from a knackered plug, h/t lead or coil. Or a broken wire to one of the sensors. Best to be investigated by hooking the car up to an EOBD reader, or even better, a PScan unit.

Probably a broken lambda sensor would be hardly noticeable, while a cam shaft sensor gone awol would surely lead to a considerable lower mpg figure, somewhere below 30, as this will set the injectors to “grouped fueling”. Ignition faults will definitely be felt at tickover, and maybe through reluctant acceleration.

[tomward]

Interesting, I wonder why the o-ring type gasket comes in the kit then rather than the one I need?

As for the MIL. The lambda sensor and the Cam sensor have both been changed over the years without success, the engine (until the cambelt jumped a tooth) ran perfectly without particularly awful mpg so I never worried about it too much until they changed the MOT. I need to plug it in with someone who has specialist knowledge rather than my local MOT/exhaust centre. Any recommendations in the Suffolk/North Essex area?

[Rob Bell]

EOBD readers are as cheap as chips on fleabay, but I agree with Mykel, pscan is the one to go for if you plan to keep your MG for a while

As the MIL is on, it means that there is an emissions-related fault. Any EOBD reader can give you what codes are stored on the ECU, and will also clear the errors (to see whether the problem is current or historical). Let us know what the stored codes are?

[tomward]

I've got a cheap Amazon EODB reader. It's never told me anything useful or even found a fault - I just use it to turn the light off every now and again. My local garage as said above just told me the first code error they saw and changed a part accordingly. I don't think there was anything wrong with the Lamda sensor or the Cam sensor they changed because the error light came on within an hour of driving it after the change which in my view is an expensive method of fault finding.

It needs proper diagnostics using a PScan and someone who understands the system. I think the ECU is expecting to see something it isn't. The dealer who sold me the car suggested the exhaust isn't entirely standard so whilst I've got it apart I'll try to find out what I'm looking at before randomly plugging an OEDB into it.

I need to get the engine started first though

[ArntyR]

tomward. I've got a TF 135 and had the same gasket conundrum as you. Imo Mykel's advice is spot-on since if you look in the Rimmer's cat some TF 135 ally manifolds are stamped VVC and others are not. They are exactly the same otherwise, and need the same gaskets - but NOT the rubbery O ring that I've seen offered erroneously...(your TF might be a 1.6 115 which a previous owner might have upgraded to alleviate the 115's plastic IM which was prone to warping, I wonder? This rubbery double joined up 'O 'ring is the 115/plastic version gasket)

I was being nagged by a slightly high tick-over, some exhaust steaming and hot coolant smell after fitting stainless pipes recently. (My previous TF 115 did the same and I changed that (plastic, remember) IMG - NEVER AGAIN!!!). I bit the bullet and ordered the 2 TF 135 gaskets from Rimmers. The bottom gasket isn't commonly listed by 'non-MG parts people' but I found a Euro unit that listed the top one (as THE inlet manifold gasket, interestingly) - so it being a Saturday I took the old gasket with me - checked the number of stud holes + pattern etc - picked it up and fitted it; EASY PEASY!! I could see some white leakage-ish tracks into a couple of the manifold tubes so I crossed my fingers that I'd solved the problem and put it all back together (after cleaning out the throttle body, air flow sensor and idle valve - they're really easy to get to with the top of the IM off...) The bottom manifold looked 'solid' and worth taking a gamble on. The nuts/studs/bolts also looked a real 'blighter' to get at, much 'beefier' and there were more of them than the 115 so I actually chose to wimp out. Anyway...I'm happy with the outcome since that messy bleeding process is also likely to cause a hot coolant smell for a while. Tickover is slightly reduced, and steadier, as seems steaming from the exhaust, so my wimpyness might have paid off, I hope.

The Rimmers gaskets were delivered this morning, tho'...(LKJ100860 top + LKJ100821 bottom). Hope this helps.

ps the original gasket seemed to be a very hard, brittle piece of black plastic, the new replacement seems much more pliable and flexible.

[Rob Bell]

Yes, Mykel is 100% right: the alloy inlet manifold was fitted to both the VVC and the higher-performance 135PS MPi variant. All other versions of the K-series used on the MGF and TF used the plastic inlet manifold (including the 120PS used on the CVT Steptronic)

[Rob Bell]

I've got a cheap Amazon EODB reader. It's never told me anything useful or even found a fault - I just use it to turn the light off every now and again. My local garage as said above just told me the first code error they saw and changed a part accordingly. I don't think there was anything wrong with the Lamda sensor or the Cam sensor they changed because the error light came on within an hour of driving it after the change which in my view is an expensive method of fault finding.

It needs proper diagnostics using a PScan and someone who understands the system. I think the ECU is expecting to see something it isn't. The dealer who sold me the car suggested the exhaust isn't entirely standard so whilst I've got it apart I'll try to find out what I'm looking at before randomly plugging an OEDB into it.

I need to get the engine started first though

Might be worth the investment in a better EOBD reader Tom - you should be able to get the error code. Do you remember what it was before the garage went into random-part replacement mode?

The pscan is pretty good - it'll give you live data, but you're absolutely right, it doesn't give diagnoses - just the numbers as they appear on screen - and it is up to whoever is using it to interpret the data. Shame you're not closer to north London!

[Tipper]

TFs all came with the alloy manifold, even the non-VVC ones. So the correct gasket kit would be the one sold as VVC, which comes with the correct inlet manifold gaskets – one between plenum and manifold, the other for the mating face on the cylinder head.

Just for accuracy and being picky(!)...except the lower output models, ie, Stepspeed and 115 which have plastic inlet manifolds.

[tomward]

It's a bit odd though, even the official service manual* doesn't seem to refer to any other inlet manifold other than the plastic one on the non-VVC engines - mines definitely a 135 hence the alloy manifold. The correct gasket has just arrived a work so I'll fit it at the weekend I hope.

* Although I need a manual on how to understand the manual most of the time

Rob Bell - I don't know the fault codes I'm afraid, I'll get it plugged in somewhere. How close to North London? My sister lives in Tring and my brother in Wood Green I drive to Tring round the M25 fairly often.

[Mykel]

* Although I need a manual on how to understand the manual most of the time

Welcome to the club!

Rob Bell - I don't know the fault codes I'm afraid, I'll get it plugged in somewhere. How close to North London? My sister lives in Tring and my brother in Wood Green I drive to Tring round the M25 fairly often.

I think we’re on to something here …

[Rob Bell]

The manual was written for the MGF and updated for the TF. Guess what they didn't bother updating...

I'm very near Wood Green (Alexandra Palace) - so that could work?

[tomward]

Not only that but I've just seen your ad for the ZS - I must not be tempted

[Rob Bell]

That's currently in Manor House (and has the plastic inlet manifold! ) - you're more than welcome to have a look

[tomward]

I've been digging through the cars history file and have found the exhaust came from MIJ Performance in Walsall. I needed a gasket anyway so have rung them up and they suggest a Lambda sensor spacer might solve the problem. Apparently with a higher flow catalytic converter in my pipe the sensor will get a faulty reading. Mounting it in a spacer will remove it from the higher airflow and might remove this problem. The alternative might be that the catalytic converter itself has begun to break down but I'm trying the spacer first as that is a cheaper fix!

[Rob Bell]

That explanation doesn't work for me. Remember that the post-cat sensor is an oxygen sensor. An error is driven either by an incorrect voltage or a signal with a high oxygen oscillation (as will occur with a failing catalyst).

If you connect up your car to a pscan, you can save the data into telemetry file and have a look at it. This is what I find with my EU3 FL1 with the 1.8MPi K-series engine:



The blue tracing is the pre-cat signal, the orange tracing, the post-cat lambda signal.

Some minor oscillation is expected from the post-cat sensor (picking up unused O2), but the signal should be well damped compared to the pre-cat Lambda - largely because oxygen is being used to oxidise NOx and CO.

If you can get this data, you can get a good idea of what your problem is.