mems1 to mems3

[webba]

Hi I am wanting to change a car from mems 1 to mems3 ,could anybody help me with a complete parts list as I know 1 or 2 people have done it.

Ady

[sniperpenguin]

Hi Ady,

Not an easy job - But one I'm looking at since I want to eventually remap via ZnF tuning.

From the looks of things, you will need:

- New "T-piece" at the exhaust-side of the head (with the extra sensor)
- A MEMS3ECU (with matching 5AS, I assume)
- A later inlet manifold with all the sensors
- A later Alternator
- Coil Packs (VVC's shouldnt need this)

Your biggest problem will be the loom, as IIRC the TF160 loom would not just plug'n'play........ This is what has stopped me so far, as Im crap with electrics

[Mykel]

Hi Ady,

is yours a Mk1 or Mk2? From my experience with the engine wiring harness, it should be quite easy on a Mk2 car, as all the relevant connections are alread there. IIRC there is even a MIL lamp in the instrument block which is wired to the back of the car.

So it would be
- a suitable engine wiring harness
- the MEMS 3 ECU
- a rocker cover for use with ignition coils
- those coils
- later style inlet plenum with different MAP sensor
- cat plus backbox with post-cat lambda sensor
- a different inlet camshaft plus blanking plate for the dizzy cap assembly
and a testbook to get the ECU mated with the rest of the car's electronic.

That should be it, but I am not sure about the injectors. On a Mk1 you would also have to change the main harness, I'm afraid. There will be some lights missing in the instrument block for example, and then there's the issue with the manual speedo drive.

hth
Mykel

[Rob Bell]

Guys, I have chatted to Mark about this, and the parts list isn't as comprehensive as you'd think

Yes, you'll need a pair of VVC ignition coils if you want to convert an MPi so you can use the MEMS3 wasted spark ignition system, but you certainly don't need the second Lambda sensor (bear in mind that early MEMS3 cars did not have this feature)...

Matt Parker will, for a small fee, modify your wiring loom so you can plug the MEMS3 to your engine, and then you just need Mark to upload a suitable map.

I've intentionally left out quite a lot of detail, but I am very tempted to go this route for Project Shed. Probably will delay this until after PPC999 2012

[Mykel]

That sounds interesting to me, Rob, but for a completely different reason:
After changing the ht leads on my VVC, I wowed to myself, never to reach down there again, to keep my precious arm skin as lovely as it still is in most places

So taking it that a VVC coil pack could be used with the MEMS3 ECU, how about changing the rocker cover on the head to fit the later style waisted spark coil packs? Would my MEMS2J unit accept them? Rerouting the wires from below the inlet manifold up there shouldn't be that hard, and I still have that old loom in the basement to tinker with. The question is, would it work?

Might be a good base for a later swap to MEMS3 anyway ...

[Rob Bell]

One day I'd like to put together a nice clear how-to page on converting MEMS1.9/MEMS2J to MEMS3 specification. There is huge flexibility in the MEMS3 configuration, and is perfectly happy to run multiple throttle bodies on VHPD K-series engines without any namby-pamby emissions stuff - so could be an ideal route to engine tuning. But I think that if you are looking at multiple engine specification changes, you'd probably be better off with an aftermarket ECU.

Any way, I thought it might be useful to post some of the conversations that I've had with both Roger Parker and with Mark Stacey. I haven't included my many conversations with Mike, who has now converted his MEMS2J VVC to MEMS3 for racing in the MGF Trophy Cup, but ultimately he got Matt Parker to do the splicing of the two looms (MEMS2J to MEMS3) for him...

So now for a bit more detail on the conversion - the following information very kindly provided by Roger Parker (which largely relates to MEMS2J to MEMS3, but does touch upon MEMS1.9 to MEMS3):

Hi Rob,

Yes MEMS to MEMS conversions is something that Matt and I have done and I have further experience of the MGOC Race series cars.

The simple conversion route is to get a MEMS3 engine loom, which will save you the hassle of getting one of the two VW plugs for the ECU and the fiddly fitting of them. This will cover the larger of the two ECU connectors, but the smaller one will have to be cut from a MEMS3 main harness with a length of loom so you can then splice this into the main body loom of the car by the ECU mounting. This is a bit of a fiddle and more so if you get a non MGF/TF one as some wiring colour codes are different. This is not a major issue, it just means you need the wiring diagram for the donor car to interpret the different colour codes, although the wire function is in most cases the same.

The MEMS3 ECU small connector (body loom) has more functions than apply to the older 2J set up so some will be redundant, but in essence the wiring from the two smaller connectors (green and blue) of the Trophy wiring loom has to be unpicked so you have loose wires and pins, then these loose wires/pins, together with the loose wiring from the smaller MEMS3 ECU plug has to be inserted to the original MGF body connection wiring plugs (obviously some new pins will have to be fitted to the bare ends, or solder the wires to removed MGF wiring pins.)

Some prefer to cut the plugs off the MGF wiring a couple of inches from the plug ,and then do the same for the MEMS3 wiring, followed by splicing the common colour coded wiring together.

Then you only have to consider coils, IAC valve, lambdas and oil/coolant temp sensors.

Coils
You can redirect and extend the MEMS3 wiring, which normally feeds coils mounted on the cam cover, down to the original twin coils under the inlet [on the VVC], but I suggest it is easier and better to convert to MEMS3 coils (the longer necked ones with the red banding specific to VVC) and just plug the new wiring to them. Shorter HT wires on just two plugs with the other two having direct feeds from the coil is much better than the 4 long HT leads of the MEMS2J VVC. The MEMS3 cam cover is universal and you only need to make sure the non VVC cam sensor hole is filled to stop oil leaks.

Sensors
All sensors are the same aside from the temp sensors and lambdas mentioned. Simply replace the oil temp sensor on the HCU with the MEMS3 type, but note that the HCU mounted one will not screw right in as the machined face has a tighter radius than the MEMS3 cut out and the sensor has a bigger diameter face. Simply leave the original sensor in place whilst you file the alloy to give clearance. Original Lambda should work but note comments later. The oil filter housing sensors are different on some engines and I can't recall the exact detail, but the new engine loom should indicate the differences with the different plugs, so just change as needed. You should replace the main ECU coolant sensor with the later black one (brown being the early type, just like the oil sensors on the HCU) otherwise all other sensors and actuators are common.

Lambda sensor(s)
There being two on MEMS3 engines and only one on the MEMS 1.9 and 2J systems. You can add the wiring between the sensor plug and the small ECU connector for the after cat sensor if you wish, as we have done for simplest full engine management operation, or ask Mark to disable the after cat lambda on your ECU so that it doesn't flag faults. Alternatively you can fit a PTP MIL eliminator which at £20 seems expensive for a resistor, a bit of wire and a few connectors. Unfortunately I do not know the value of the resistor so I can't help any deeper here.

You may also find that the main lambda sensor wiring plug is different, but that is only a quick cut and crimp change. What may crop up though is that MEMS3 is more sensitive to the actual lambda sensors used and I have seen a need to replace previously new universal sensors for dedicated MEMS3 only sensors. This is worth bearing in mind in case you find an issue with fault codes around these sensors.

Note the MEMS3 engine loom wiring plugs around the HCU have different colour codes so you just need to get these in the right position.

Idle air control valve - IACV
Lastly the IACV is a 5 wire on the MEMS2J (and 1.9) and 4 wire on the MEMS3. It is a simple matter of swapping the whole IACV and also the connector hose between the throttle body and the valve as the angle of the pipe connection on the IACV is different.

Converting an MPi with MEMS1.9 to MEMS3
If your thinking of MEMS3 for a MEMS1.9 engine then the process is much the same with the exception of not needing any VVC related connections. You may want to remove the dizzy cap, rotor arm and the rotor arm peg from the end of the cam.

Fitting the new engine loom to the car shouldn't (as I recall) offer any incompatibility problems with plugging straight into where the old loom came out, but that obviously applies only to looms from the same models and looms from other MEMS3 cars will need some changes, which is not beyond your skills to change if you wanted to go that route.

Cam Position Sensor
Cam sensors for MEMS3 non VVC engines are simple and incorporated into the cam cover so the change to top mounted coils and cam sensing was cleverly incorporated in the need for just two component changes, the cam cover and exhaust cam with an extra lobe.

This means any MPi head can be converted to MEMS3 operation by just changing those two items and adding the cam sensor.

In summary...
With MEMS3 there is much greater scope for Mark at Z&F to tweak the settings and I have found his tweaks to be quite effective, especially on the VVC.

Rog

I also tackled Mark Stacey about this - and here's a summary of his response:

Coils and Cam Sensor
You will need the plug top coils and the cam sensor if easily fitted - however the cam sensor may not be a necessity as it is mainly for sequential injection emission control and if necessary I can set banked injection without it...

Manifold Air Pressure (MAP) Sensor - MPi only
Oh, and I'd forgotten, but those of us with MEMS1.9 will also need another MAP sensor - these as you'll recall are built into the MEMS1.9 casing, and is therefore thrown away with the bath water when you junk the MEMS1.9 for MEMS3.

I hope this helps, and I hope that Roger doesn't mind me posting his email to me here (I've emailed him to seek retrospective consent!)

Essentially, Mark can probably set your car up with the bear minimum of modifications, although coils are needed, and perhaps a MEMS cam cover is the easiest route forward, but not essential. Even the cam position sensor can be disregarded. But for a MEM1.9 swap, a MAP sensor will be required...

[Mykel]

Wow Rob!

Thanks a lot, this answers all my questions. Now I am really thinking about which way to go and in what order ...

Mykel

[sniperpenguin]

I am now in information overload....

PANDA will have this modification in future (MEMS 1.9).... Just got to figure out the easiest, cheapest way... especially now I've found out there are two looms LOL

[Dieter K]

One day I'd like to put together a nice clear how-to page on converting MEMS1.9/MEMS2J to MEMS3 specification.

Great, thanks mate, some final questions to be cleared, though.
... I think the German *Pensioner in making* has also something to play with in next year

[Rob Bell]

Just let me know how you get on chaps! I am thinking along the same lines, but won't be starting the project until Project Shed is up and running on MEMS1.9 - if nothing else to be confident that the engine is in okay condition, and the gearbox works!

[Rob Bell]

I may soon be making a start to this project - not least so that I can bolt on throttle bodies to the current MPi engine - which should be interesting

[chrisrigby]

Funny you've bought this thread back to life rob, with my VVC Frankenstien I was thinking of modding to MEMS3, jon and I a few weekends ago discussed it briefly. Having read this and also done some other research I think it can be done from the garage. The VVC looks the easiest to do?

Its also the thought of those dam midgets zipping about and how an F could be modded to get round something like that... few trips to the scrappies to be done.

[Rich in Vancouver]

Thanks for bringing this thread back Rob. I haven't seen it before.
That is a lot of useful information.
I may have missed this on my initial read-through but does the diagnostic port require any re-wiring?
It sure would be nice to be able to use the modern plug-in/bluetooth gadgets there to get real-time info.
(Although the re-mapping is what mainly appeals to me).

[Rob Bell]

The pre-2001 non-EOBD compliant car diagnostic socket wiring is covered here: viewtopic.php?f=8&t=15907 - but essentially it is the same. When you fit a MEMS3, you'll need to splice the data line into the main loom, which will go back into the correct pin on the OBD socket.

Chris, yes, this is do-able, and on the face of it, yes, the VVC does look simpler - if only because it is already equipped with dual coil packs (it might be easier to use the MEMS3 set up for for simplicity) - but a MEMS1.9 to 3 should be easy enough too.

Note that MEMS1.9 injectors have a higher flow rate than MEMS3 injectors (and quite possibly a different spray pattern) - so MEMS3 will either need remapping to adjust to the injectors, or you'll need to fit MEMS3 injectors to use the standard fuel map... if that makes sense?

PS Chris - I know what you mean about those pesky Midgets. Unfortunately hydraulic handbrakes are not permitted

[RobboMC]

I've just done this the other way as my new engine was MEMS3 and the car is MEMS1.9.

The electrical plug for the injectors is vastly different, and the MEMS3 has an air pressure sensor in the inlet manifold.

I would just change the whole inlet manifold, injectors included, if you can get one.

[Rob Bell]

Yes, that's certainly true for the MPi engines, good point Rob. The inlet manifold was adapted to accept an external MAP sensor, and I think you're right that using a MEMS3 inlet manifold is the easiest way forward - but alternatively, you could use a remote mounted MEMS3 MAP sensor...

I wasn't aware that the injector plugs are different on the two systems? I'll need to look at this, as most of my injectors are of the earlier type? Time for a rummage in the garage I think!

[quick_spider]

It's the loom end of the injector harness which is different, not the injector plugs.

[Rob Bell]

Ha! Thanks for confirming that Jon - I thought that it what Rob meant, but you've saved me the trip into the garage to check.

Hmm, so the question is whether the looms I have in the garage also include the MEMS3 injector loom...

[talkingcars]

I've just done this the other way as my new engine was MEMS3 and the car is MEMS1.9.

Why?

[webba]

i pm 'd and emailed Matt biut had no reply maybe he is away. is there anybody else that knows how to make a coversion lead?