I'm sure there could be a book written on this Issue!

At the moment we've got:

With all 4 plugs clamped onto a metal bar on the exhaust and a jump lead to the -ve on the battery to be sure, with no compression on the engine they all spark perfectly.

If you then put an old set of plugs back into the engine to give it some compression, on the test bed on the exhaust 1&4 fire ok but 2&3 are very erattic if they fire at all. 2&3 also after a second or 2 of cranking just fire constantly, even for a few seconds after cranking has stopped.

Its possibly made worse when the battery is running low.

We've just swapped spark A and spark B a few inches from the Megasquirt unit and the problem follows then onto 1&4.
Then Megasquirt has been back a few times now to be tested and were assured everything is working ok.

The engine turns over at between 200 and 300rpm but on the computer there is sometimes a spike to very large RPM's.

Everything did work ok and all the wiring was fine i.e no interference etc until the car conked out and left me stranded about a month ago and we have'nt got it to work since. With megasquirt being very experimental just before in conked i'd updated the temp sencor info on the latop, stopped without the fan running so it got quite hot.. and then whilst trying to get it re-started flattened the battery and the starter motor got very hot.

Were trying to narrow down whats happend and work and test our way through the system but getting nowhere fast.

Any ideas or pointers?

Hi.
Are you using the EDIS unit?

Sorry I forgot to say.

Its firing the coil pack directlly using its onboard coil drivers and Megasquirt n Spark version 29y4.

I'm thinking of wiriring up and EDIS unit inplace of the Megasquirt to see if it will spark properly in Limp home mode atleast.
That would also prove all the Crank position sencor, coil pack and HT leads etc are functioning correctly

Then maybe if it comes to it getting the Megasquirt convierted to run the EDIS as it seems lots of people have been having bother and resorting to this.

I'm just puzzled as it all worked correctly before.

[Edited on 1/12/07 by MkIndy7]

If it gets worse when battery goes low I can only think of the supply to the MS. When you crank it without plugs, the starter motor needs less current ot get the thing going, but with compression higher current draw resulting in lower battery voltage.

Easy test is to wire up a second battery wich only feeds the MS as a test.

Afterwards you could have a small sealed lead-acid battery to supply the ECU only, charged from the main car electrics via a diode, and possibly a resistor to limit the charging current. During cranking this would hold its volts cos it couldnt discharge into the starter motor. A relay would also be needed to isolate the ecu until the ignition key was turned on.

I'd thought that aswell but the Megasquirt never loses power, or loses enough to loose the connection with the laptop and the same power scource feeds the rev-counter etc.

I've tried connections straight to the existing battery to try and remove the ignition circuit load and hopefully less of a voltage drop.

Also jump starting it from another car doesn't seem to make it any better, but yes its worth a try.

We have seen the wire to the coil pack drop to around 10.5V under cranking but it is still sparking just at the wring time etc, and megasquirt gives it a -ve feed to make it spark, both sides of the coil share the same +ve feed so it should effect both of them really.

A bit of an update but no soloution as yet.

Tonight i've wired up a spare EDIS unit to prove the Crank sencor and Coil, plugs etc were all definately ok even though I was quite happy they were.

And it sparked perfectly, obviously only in Limp home mode but still, they were all perfectly timed good strong sparks and no conctant sparking.

It was even sparking well when the engine was turning over VERY slowly as the batterys about had it me thinks.

Oooh the wonders of Megasquirt

Hi there,
been giving this some thought.
Are both pots fully counter clockwise? Are you using resistive plugs? Have you fitted the Ford suppressor next to the coil pack? Where is your ECU earth compared to the battery earth?

I guess when you test this with plugs out of the engine there are still a set of plugs in the engine so the engine still rotates under compression?

Phil

I've never altered the pots from how they were supplied (and they worked before).

The plugs are Bosch Sierra Injection plugs as your limited with the thread size on the pinto, There coaded 7R .

I've never seen a Supressor on any of the Coil packs I've taken off as I get them from Fiesta 1.1i as there kept out of the weather under the inlet manifold.
They've always worked without on previous Megajolt instalations and on this Megasquirt unit.

The ECU Earth is earthed in the same place as the rest of the sencors on an earthing post that it tapped into the Chassis less than a foot from the battey and can run a 300W inverter for the laptop from the same source so power wise that shoud be ok.

Yes an old set of plugs is put back into the engine to maintain compression when testing.

Hi,
check that the pots are fully ccw, check you have resistive plugs, you must be able to get them for that setup. Also ensure you have resistive leads and also fit a 20uF cap (all Ford Zetecs have them on the coil pack bracket)

Phil

I've never looked at the pots but have seen them discussed so I'll have a look.

According to your website if the plugs have got an R in their coding then they'll be resistive, and the HT leads are to suit that coil pack so they should also be resistive.

Would this type of capacitor be suitable as I can't get to a scrapyard till the weekend
http://www.maplin.co.uk/search.aspx?MenuNo=12472&MenuName=Tantalum&worldid=3&FromMenu=y&doy=3m12

Or would a Bigger motor run style capacitor be better just to test with?

Does it have to be exactly 20uF or just around there?.

Thats really not a suitable cap, you really need one like this:

I would guess those are resistive plugs too. So at least that eliminates noise, the EDIS module is not really prone to noise like an ECU is, thats why I try to push people to EDIS8 when doing a V8 as with 4 directly driven coils noise can be a pain.

Another thing to try is to use the edis module connected to the plugs in the engine and have the MS firing a set of plugs on your test thing.

Also, whats the gap on the crank sensor??
Phil

Would a much bigger 20uF motor start type capacitor be ok to try?

Hmm I haven't got 2 coil packs to test with 1 set sparking in the engine and on set in the car on EDIS.

Could I substitute a pair of bulbs so the coil drivers had a load on them and somewhere to disharge to?

Also there would only be one incoming CPS sencor signal, would it be ok to split that and feed the MS as well?.

Or would the pip-saw cable from the EDIS be used as a CPS feed into MS?.

The TPS gap is exactly 1mm, checked that the other night with the feeler guages.

Also how do you know when the pots are fully CCW? as they just turn and turn and turn in both directions, not coming to a stop in either direction.

[Edited on 5/12/07 by MkIndy7]

Hi there,
youll know the pots are fully clockwise as they click, see here:
http://www.extraefi.co.uk/vr_setup.htm

Another thing worth trying is move the ground onto the engine. You can share the VR sensors signal, they are both high impedance inputs so they should be ok,
Phil

So if i'm using the EDIS to spark in Limp home mode, and then feed the MS with the CPS signal as well to see how the Ms behaves then:

Could I substitute something like a bulb or LED onto the Megasquirt Spark A and B wires to see if/when/how there sparking.

I suspect the Pots were already as CCW as they would go.

For the Capacitor would 1 like this:
http://www.maplin.co.uk/Search.aspx?criteria=20uf&source=15&SD=Y
be suitable to try as i've got one in the garage.

Hi,
yes you could try leds but as they will pulse for around 6mS during cranking and 3.6mS when running your not really going to tell much. I would use an old coil pack.
I have a 20uF cap you can have, give me your address, I dont think that maplin one would be much good, but you can try it by all means,
Phil

Right.. I think I'll be able to borrow or get another coil pack at the weekend to run both the EDIS and the MS and see whats happening.

I haven't tried the capacitor or trimming the pots yet.. too busy and too damned cold!. But I will try them when I get chance at the weekend.

But if that doesn't work I can't help thinking that in this instance the MS seems a bit unreliable (i.e it has worked and now for some reason won't).
What if anything would I lose in having it dumbed down just to run the EDIS module.. can it still do all the MsnSextra code features without directly controling the coil drivers?

I can assure you that it is far from unreliable!! I bet it will end up being something youve missed or are not doing, Ive sold 300+ of these things and have had 2 people that didnt get them running, 1 guy blew it to peices by wiring it up wrong and the other was a guy who just refused to plug a laptop into it. Both I refunded the money to.

Lets face it, it works on your engine, it has to be something that changes when your engine is under compression as it works when its not under compression, so it cant really be an MS fault,
Phil

Oops I think that got taken the wrong way.

When I said it I tried to make a point in me saying "in this instance" to try and clarify myself and not put the onus completely on the MS. But if the EDIS works (even though there maybe a small fault on the system somewhere) and the MS doesn't then it must be something thats over sensitive or not as robust.

There has been a few occasions i've read about where people have had unexplained problems and resorted back to running the EDIS module, I was just testing the water incase I have to resort to this.

I know how tricky electronics and fault finding can be I'm a Service and Maintainance Engineer so I can appreciate the difficulties, but I have very systematically checked all of they system and they've all proved to be working ok, feeds where they should be etc.
But in the end quite rightly it may turn out to be something thats just not quite right, a crimp that internally only half the strands of wire are connected or anything but again the EDIS can run through this and the MS can't.

I had noticed the 20uf capacitor in the drawings but presumed that as it hasn't been present in any of the EDIS/coil pack installs i've come accross or fitted (2 lol) that it couldn't be that vital.. there also appears to be no specs on what type, voltage, material its made from if you haven't got the Ford one from a Zetec engined car.

1 Last thought, could it be on the Advance side of things that the MS has a fault?, When its on the car its not reporting that side correctly where it wouldn't be spotted on a test bed where it may only run at higher speed, say 3,000rpm where its sparking that fast a small problem in the spark timing might not be so visable.

My tone may have been a little off but it has been well over a month with little progress in getting my baby running again as i'm sure some of you can sympathise with.


So my apolgies to Phil he's been nothing but helpful on this matter, he's had it back twice now to test it and replaced the coil drivers just incase, all without accepting payment and classing it all as part of the service and you can't ask anymore from somebody than that.

Ian

[Edited on 7/12/07 by MkIndy7]

Hi Ian,
sorry if I jumped a little there, Ive spent something like 4-5 years on the MS project so Im a bit sensitive about it as I know it works and works very well indeed.
Pop the ECU back to me and I will test it again to see if I can figure this out. I have a spare coil pack somewhere and a cap, I will put it in the post for you to try when I send the ECU back. You can use the coil pack to run EDIS and the MS ECU together so you can then see whats happening with the spark,
Phil

[Edited on 7/12/07 by daxtojeiro]

Thank you for that offer, I'm sure there's a very many people out there that are thankful for all your years of development and hard work.

To try and speed things up this weekend we'll return the MS to its original instalation and try to get a CAP from the Scrapyard to eliminate that and see if it works correctly then.

If that doesn't work we'll wire up both the EDIS and Megasquirt and borrow a coil pack off a friend with a Megajolt install.
Atleast that way we can see how it reacts Running off the EDIS on a second set of plugs andwith some descent RPM readings etc and take a log of them.

Then will get back to you with the info and we can take it from there.
Hopefully they'll be some light at the end of the tunnel!

Anything else you or anybody can suggest or think to thy imbewteen feel free to add.

And sorry again for any misunderstanding,

Ian

[Edited on 7/12/07 by MkIndy7]

Well we've been out and had another try with it and even bought a new battery to eliminate that and give us more testing time.

With them both connected the EDIS fire the plugs fine,
but the MS firing another set of plugs (with the capacitor on) still has the same fault. (whilst there is still a 3rd set providing compression to the engine).
If its any use knowing, with the EDIS running in limp home mode and the MS firing the injectors it doesn't even sound like its going to start either.

But thinking about it, things like the live to the EDIS are coming direct from the fuse box and not from the exact same wire that goes to MS, So were now considering making up a new plug to the MS, just incase there is a break in a cable close to the MS for example, as thats 1 part that you don't get back when testing it. We have looked inside the plug but there's nothing other than some very neat soldiering in there!.

What would be the basic connections to get Just the sparks running on MS.
IGN live, Earth, CPS, Spark A, Spark B? should it run ok without the aux sencors like temp and 02?.

Because again when we first connected it up and turned it over for the 1st time it sparked properly!.

Hi there,
give me a ring and see if we can discus this better over the phone,
Phil

Please could you U2U or email me your telephone number as I can't find it anywhere.

Thanks,
Ian