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MG MGF Technical - FAO Will Munns - EPAS cut-out circuit

Hi Will,

Yes I know I'm slow, but I've finally got all the components ready to build your EPAS cut-out circuit.

* Switch YUG101720
* Relay QC58N from Maplin.)
* Bullet Connectors
* Wire

I have studied the diagram, the switch and the relay.

The switch is easy as it's connectors are numbered 1 thru 5 as per your diagram. The relay is more difficult - it has connectors, in pairs, numbered 1&4, 5&8, 9&12 and 13&14 reading each pair from left to right and the pairs top to bottom - if you follow me. Anyway, the relay case is transparent and so I think I can work out from the circuit diagram which connectors to use. However, if these numbers mean anything to you and you can be certain of matching them up to your diagram, please let me know.

My real question is about the connectors on both the switch and the relay. They are very narrow. How should I connect wires to these small connectors? I found the smallest female spade connectors I could, (2 amp rating, compared with 5 amp rated wire and 10 amp rated relay - ???), but these are too small.

Dummy question coming up - do I need to find some proficiency with a soldering iron? Oh, and while I'm at it - even with bullet connectors and spade connectors, do you solder wires in place or just squeeze the connectors with pliers?

TIA,

Dave

Dave

The relay wires are best soldered-
The easy way to do this is to strip a very small amount of sheth from the wire (the heat will push it back later)
Then heat the wire and add a little solder, the wire should clean up and the solder should flow and cover the strands in a nice shiney coat of solder, if this doesn't happen it could be the wire is dirty or not hot enough, just add more solder and flick off the excess (use a sheet of paper for a target)
Then go around the legs of the relay in the same way, just a little solder on each one to clean up the leg.
Once this has been done secure the relay with some blu-tak and touch the wire to the leg (so the side of the wire runs along the side of the leg) and heat breifly, the solder should melt, remove the iron and the wire should be nicly secure to the leg, wrap with tape to ensure it doesn't short against anything.

The switch wires I used spade connectors on, i brought slightly bigger and squashed gentely with a pair of pliers (don't overdo this or you wont get them on the switch!). I could only get unsheilded spades so I covered the ends with tape as well.

The spades and the bullets can be soldered on, but I just crimped them, the bits attached to the car you will only want to crimp!

Do not worry about the spade connector rating, the currents going thru the switch are in the order of milliamps, only the green wire thru the relay is at risk of pulling anything larger.
Will Munns

Thanks Will, I'll give all that a shot. Can you get smaller spade connectors than the 2 amp rated ones I've found? Even squashing one of these looks as if it'll be too big.

Dave
Dave

I think I used the 2 amp ones, what matters is they dont hit each other (and on the switch they are mounted sideways so this shouldn't happen) and they dont fall off (which is the squishing)
Will Munns

Thanks again Will.
Dave

Will,

OK, this weekend I honed my soldering skills (they actually turned out much better than my crimping skills - not that you'd notice if you looked at the state of the relay now!)

Anyway, it was all good fun, but I must have done something wrong as it doesn't quite work ...

It nearly works!! Here's what happens.

1. Turn on ignition - EPAS warning light comes on as normal.
2. Start engine - EPAS warning light stays on and EPAS is not working
3. Press the toggle switch - the light on the switch comes on and the EPAS warning light goes out (I can also see that the relay has thrown), but EPAS is still not working.

So with all my wiring in place the EPAS doesn't work whatever position of the switch. If I reconnect the two original EPAS wires (the green and the Pink/blue trace) everything reverts to normal with EPAS working. So, I know I have cut the right wires!

Any ideas?

I have used position 4 on the toggle switch (rather than the alternative position 3) as per your circuit diagram instructions. With this position, what is the expected situation regarding the EPAS warning light on the dashboard and the switch position/light?

Hope you can solve this one for me as I'd really like to use the switch on Wednesday at a track day!

Thanks,

Dave
Dave

>I have used position 4 on the toggle switch (rather than the alternative position 3) as per your
>circuit diagram instructions. With this position, what is the expected situation
>regarding the EPAS warning light on the dashboard and the switch position/light?

Using the alternate connection you should get the light on the switch when the relay is on(epas off) , rather than the way I have it which is light on when epas on.
Sound like you have wired the relay incorrectly, try taking it out and testing that the right things make and break when you toggle the switch, do you have a multimeter, if so use the continuaty test, if not then wire a small bulb and battery and use that.

Will
Will Munns

Will,

Just got back from London, hence the delay in my reply.

A little clarification please:

When I press the switch, the relay moves and the dashboard EPAS warning light goes out - is this what you mean by

>>the way I have it which is light on when epas on.

i.e. EPAS should be on if the EPAS warning light is out - although in my case the EPAS isn't on at this point because I have the relay wired incorrectly.

You also said:

>>try taking it out and testing that the right things make and break when you toggle the switch

I'll try. Using your diagram's terminology - I presume that there should be some current flowing from A to A' and from B to B' when the switch is toggled so that the switch light comes on? And no current flowing on either wire when the switch is toggled off? Is this assumption correct?

Because the relay case is transparent, I can see the dual poles throw when I press the switch. Can I therefore assume that the wiring from switch to relay is correct and my problem must lie with the other 4 connections to the relay (A, A', B, B')?

If I swap around the connections A, A', B and B' on the relay, in a trial and error fashion, can I do any damage?

Thanks for your patience Will,

Dave
Dave

>When I press the switch, the relay moves and the dashboard EPAS warning light goes out.
Errm, if you have it using connection 4, then the light on the switch will be in the same sense as the relay, ie the light is on when the EPAS system is disabled (which i think is the opposite to what I said before).
So if you have wired correctly then the dash light should be off when the system is bypassed (switch light on)

>I presume that there should be some current flowing from A to A' and from B to B' when the
>switch is toggled so that the switch light comes on? And no current flowing on either wire when the
>switch is toggled off? Is this assumption correct?

Nope, when the switch is on then both circuits should be 'broken', when the switch is off both 'green' wires should be connected and both 'other' wires should be connected.

>If I swap around the connections A, A', B and B' on the relay, in a trial and error fashion, can I do
>any damage?

I would not recommend this, it may well be protected, but I do not know.

Will
Will Munns

>>I would not recommend this, it may well be protected, but I do not know.<<

Some how I doubt if it is protected from the likes of me!!! ROFL

Hopefully you'll be able to get this all ready by Thursday Dave? At the moment, I am having something of a tyre nightmare... :o( Shall explain when I see you.
Rob Bell

Rob, Will,

The good news is that the circuit now works. I didn't change the wiring - it just worked when I put it all back together. I maybe moved a wire attached to the relay which might have not been a good connection or something, but anyway it just started to work.

The bad news. I went out tonight and decided to give the switch a try. As I was driving along I started to hear a regular thump coming from the boot. I couldn't understand it. Of course my mind immediately went to the epas system and started to try to imagine what possible connection there could be between epas and thumping at the rear of the car. Nothing came to mind!

By now I'd naturally lifted off the gas. The thumping stopped. I put my foot on the pedal again and as the car hit the higher speed the thumping returned, sort of regular thumping with the speed of the vehicle. Lift off - went away - foot on the gas - it comes back.

By now I'm trying to find somewhere to pull over on the side of the road and then I saw it - a huge cloud of steam in my rear view mirror. I turned the engine off and coasted to a stop. Got out, lifted the bootlid and pulled out the dipstick. Mayo all down it.

So, this evening my car rolled of the flatbed onto my drive with a perfectly funtioning epas cut-out switch and a HGF. One day before the Kemble track day. :-((

Anyway, Rob, if you want to put some more detail on the web pages about the epas ciruit I can let you have the numbering system used by QC58N relay so that you can match these against Will's diagram. This might help others using the same part.

Maybe see you at Kemble, if I can get a lift as a passenger.

Dave
Dave

Dave, glad to hear about the Epas mod, gutted about the car, and the track day.
Whilst the heads off why don't you have it ported - you know it will make you feel better!

Will
Will Munns

Will,

>>Whilst the heads off why don't you have it ported - you know it will make you feel better!

I've already got the email from Dave Andrews to say he can do it! Has to be some compensation for the disappointment. Just don't mention money.

Dave
Dave

Dave, I can pick you up if you like, and we can both blat about in my car :o)

We're off to an airfield, so if the weather is dry, I may decide to leave the semi-slick S-02s on, and slap a pair of F1s on the boot rack for the journey home ;o)

Let me know what you want to do mate :o)

Soooo - what are you getting dear old DVA to do for you? Are you going for the 'solid cam' option and Emerald ECU or simply some gentle breathing and retaining the VVC mechanism?
Rob Bell

Rob,

>>Dave, I can pick you up if you like, and we can both blat about in my car :o)

You're too kind. I'm a bit out of your way - especially with such an early start! But, thank you, and if all other means of getting there fail, I'll get back you. At the moment I'm trying to contact another 'Fer who lives fairly close to me, to see if he can give me a lift.

>>We're off to an airfield, so if the weather is dry, I may decide to leave the semi-slick S-02s on, and slap a pair of F1s on the boot rack for the journey home ;o)

Sounds a fun idea and I would be only too happy to help turn the semi-slick bit to slick!

>>Soooo - what are you getting dear old DVA to do for you? Are you going for the 'solid cam' option and Emerald ECU or simply some gentle breathing and retaining the VVC mechanism?

Cheap and cheerful I'm afraid. Dave said he would do some mild porting, retaining the VVC, but that it would be worth going for some reprofiled exhaust cams from Piper. Here's what he originally said when I made enquiries some weeks ago, when I thought the HGF was going:

"VVC heads ex factory suffer from poor production engineering which results in recessed seat inserts and poor alignment of the inserts to the ports, the minimum work on the head should include removing the recession in the chambers and correcting the port/throat alignment together with a little work on both inlet and exhaust ports. This should bring worthwhile gains throughout the rev range. More extensive porting will bring more gains but it will be diminishing returns at this level, still worthwhile but less cost effective. The exhaust cam is very mild and can usefully be replaced by one with a little more duration and lift to complement the variable inlet cam"

This was in response to my 'brief' which was:

"I'm probably not talking about anything other than some basic gas flowing to complement my ITG Maxogen filter, 52mm Trophy Throttle Body and Phoenix sports exhaust. I use the car throughout the year as my daily drive, but also do the odd track day. I'm therefore interested in performance through the rev range and not just high end."

So the decision to stick with the VVC was a natural assumption from this and Dave's recommendation for the mild porting and cams followed.

Dave
Dave

Okay Dave - keep me posted :o)

The DVA work sounds like a nice sensible progression. The flow work sounds subtle, but results can be highly significant. Similar work on a 105 bhp 1.4 K-series resulted in a cool 125!

The exhaust cam I have heard about - but I was not aware that it was yet available?

You must buy it - I want to know if it works!!! LOL

No need to re-iterate what to specify when the engine gets put together regarding HGs and locator dowls - but it may be seriously worth considering Carl's remote thermostat mod as a way of warding off future HGF - or at the very least, specifying the very latest spec of thermostat (Dave Andrews may have more information on this by now).

Hmm, the silver lining in a very dark cloud...
Rob Bell

Rob,

You make some good points and I'm keen to try and tie together as much as I can in the new 'project'. Gasket and dowels as you say should be standard fare now, but the new thermostat is worth exploring. My plan is to try to get Roy Forde on the case, using his expertise to co-ordinate things. I'll get him to talk to Dave Andrews on the cams etc. I don't have the knowledge to do it myself anyway. I'll try to be the catalyst, suggesting what I can and listening to their recommendations. Any check list in your head would be gratefully received.

Dave
Dave

I'm not sure what your budget is Dave, but if there is a possibility of spending an additional 400 quid, then an exhaust manifold may prove to be a very good idea. Typically 10% gains in power and torque... :o)

We'll put together a little check list (is it possible to convert your car to the OAT type coolant/antifreeze?)
Rob Bell

Hmm, additional 400 is a step too far for me. Besides, I didn't think there was a proper 4-2-1 solution for the F yet, because of the flexi-pipe.

I'm pushing the financial boat out with the mild porting. I'm only doing that because I want to take advantage of the head having to come off. But, little things that may not be incrementally too expensive are what I want to add in.

* Perhaps doing some work on the existing manifold, like Mike Satur has done for Andy G?

* Your idea of transfering to OAT coolant is another good idea. As is any new thermostat.

* I'm also tempted not to skimp, e.g. go for new head bolts and not re-use the old possibly-stretched ones, as Roger P has often warned.

These are the sort of things.

Dave
Dave

>>Hmm, additional 400 is a step too far for me. Besides, I didn't think there was a proper 4-2-1 solution for the F yet, because of the flexi-pipe.<<

That's fair enough Dave - makes sense. This is a bolt-on goodie anyway, so can be added at anytime on an as-and-when basis. I have a lead on a 4-2-1 manifold with flexi-pipe... will follow this up shortly.

Getting the existing manifold 'ported' is a good idea, and as you say, Andy G reports excellent results with Mike's grinding of the standard manifold.

Similar porting and 'blue-printing' of the inlet manifold can be done too - ensuring that the inlet ports match the inlet manifold and the plenum. Similarly, the match between the TB and the plenum is also often poor as Mike has previously reported. Again, potential gains to be had there.

Chase up Dave Andrews regarding the thermostat option.

I wonder if it might not be worth investing in Mike's "engine saver kit"?

Also, I would urge you, if not already done so, to change the under body coolant pipes, and look at the condition of the radiator - as I've found, it is susceptible to corrosion and failure - and thus contribute to HGF.

If I think of anything else, I'll let you know.
Rob Bell

Thanks Rob,

See you tomorrow.

Dave
Dave

Hi,

I promised to host pictures the other day.
Apology, I'm late.
Nothing very important, but who cares.
http://www.mgfcar.de/epas/index.htm

Regards
Dieter
Dieter K.

Hi Dieter,
those pictures most wellcome. And as a picture says more than 1000 words there are of course some questions....
1. How "stiff" is the naked unit to move when there is a steering wheel on the splines and obviously no electric power applied ?

2. Can You find out if the angled gear + one side of the clutch gives some additional "drag" to the system under the same situation as above ?

BR, Carl.
Carl Blom

Nice one Dieter :o)
Rob Bell

This thread was discussed between 11/09/2002 and 23/09/2002

MG MGF Technical index

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