Was running the car a little a couple of weeks ago - trying to get her ready for the summer... when she just died. Now have nothing - wont start and fule pumps don't run.

Started off looking at the Loom and have actually re-worked all the engine bay wiring as it was a bit of a mess.

However, still nothing

have proved that the pumps will run if power is supplied and that the fuel pump relay is working OK.
Have continuity for wiring back to MS
Confirmed that I have 12v supplied to correct pin on MS

Tried connecting a laptop to the serial port on the MS and cannot connect.
tried port checker and it cant make a connection either

so have come to conclusion that my MS may be dead
I do however have another issue which started at the same time but I cant see how it is related to fuel pumps not running:
Engine wont turn over I can occasionally here the starter relay click over but not always, can see a voltage drop when i try to start. but engine does not run over.... like i say -0 i think that is a separate issue and haven't started on that yet - just interesting it started at the same time as the other issues

So..........

Does anyone have a suitable STIM and could maybe test my MS to see if it is truly dead?

It is a V3 board running as MSnS running MSExtra code so no EDIS unit involved - driving a Zetec coil pack on my 2.1l Pinto.......
Unit is about 9 years old

first thing I would check is if there is 5volt on the board.

Yeah get it open and see if the main fuse or power circuit has failed internally - should be an easy fix if the fault that caused it has been removed.

[Edited on 16/5/16 by coyoteboy]

OK... I'm an electronics numpty

Needless to say I bought this fully built by someone competent!

So... any indication where I should check between on the main board for +5v ?

I can just about wield a multimeter but when faced by a circuit board like this my mind runs away to hide in its happy place!...

quote:

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Originally posted by coyoteboy
Yeah get it open and see if the main fuse or power circuit has failed internally - should be an easy fix if the fault that caused it has been removed.

[Edited on 16/5/16 by coyoteboy]

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quote:

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Originally posted by DaveFJ
OK... I'm an electronics numpty

Needless to say I bought this fully built by someone competent!

So... any indication where I should check between on the main board for +5v ?

I can just about wield a multimeter but when faced by a circuit board like this my mind runs away to hide in its happy place!...

---

Have a word with ExtraEFI or James Murray Engineering.

Not trying to learn electronics just want to see if the MS is toast......

anyway.. the only place i could find +5v on the board was at the top of the proto area...
just tried testing from there to the Gnd next to it and get 0.51v ....

Tested the pin at the 37 way connector and currently have 11.89v there

conclusion? As I said in my first post, think i need someone with the right setup and STIM to test it properly.. Just knowing what a great bunch of knowledgeable guys we have on here I thought I would check if any of you had a test rig before going down the potentially expensive route.....

Find polyfuse F1

http://www.msextra.com/doc/ms1extra/MS_Extra_Hardware_Manual_files/v3board1.gif

Check for voltage either side of it. If you don't get 5v at either side of it, check for power at Pin1 of U5. Report back

Everything on an MS1 v3 board is replaceable by a monkey with a club fists - I'm pretty sure we can diagnose and instruct a repair The problem is if the fault still exists it'll be trickier to track down.

[Edited on 17/5/16 by coyoteboy]

OK...

Both sides of polyfuse F1 read +0.5v ....

Pin 1 on U5 has nothing at all

I would question my multimeter or my stupidity but I get 11.89v at whatever pin that is in the 37 way plug (i opened it up to be certain which connector the red wire was connected to )

Any ideas ?

much appreciate the input so far!

0.5v on the input indicates a fault on the psu side of things, - hence you don't need an ms specialist to help fault find, it's (probably) before it gets that technical.
I shall try to take another look at the ms v3 schematics to see any likely fault that might bring input 5v to 0.5

edit: do you have any higher res pictures of your board? so we could look for scorched components and such like?

[Edited on 17/5/16 by gremlin1234]

I can take more pics... I had a good look for any scorching and also took the board out and looked at the other side... couldnt see anything

Voltages on this what you have?


Potential fails

We can repair it for you if you like?
We build / modify / repair / install megasquirts

I'd thoroughly recommend Bailey Performance....


on another note, I have a stim which worked to test mine a while back, Geoff from on here, used to have the v8 viento wilkingj made it.

don't ask me if it is what you need tho!

I'd post it to you for 30quid.

pic of stim

[Edited on 18/5/16 by Chris_Xtreme]

[Edited on 18/5/16 by Chris_Xtreme]

No garage time now until the weekend,,,, but will report back my findings as soon as i can spend more time on it

Thanks for all the advice...

My current thinking.... I have a couple of things to check further and may well take you up on the STIM...

If i prove that the MSnS is dead then I will see what you guys at Bailey can do to hopefully repair it


I have had one thought.... bearing in mind that I also cant get the engine to turn over....

Could I have toasted the battery in some way? I have checked it is pumping out 12v and have had it on a trickle charger.... The rad fan works (i have an override switch) and lights work... but just wondering if it could still be knackered? going to try to get hold of another batt to test with - although the wife is oddly reluctant to let me take the one out of her mercedes.. cant imagine why!

cheers all

You haven't disconnected an earth lead by any chance?

I did check them all after I reworked the engine bay wiring.. but it is on my list to check everything again.... you have me thinking now and doubting myself!
I rewired the Alternator and to get at it had to remove the engine earth strap.... I'm sure I would have put it back!!!!

Don't take the battery out of the Merc , it'll probably cause you all sorts of grief with lost codes etc

as it turned out - i did get a little garage time tonight

Good news is I am not a total numpty and i did reconnect the earth straps to the engine!

So...

checked all 5 earths coming from the MSnS - all good.

carefully checked all wiring in the plug - no issues i can see

tried checking all above again - no dice




as for the turning over issue... gave the solenoid a whack and can now here it click but still no attempt at turning over. removed plugs (managed to snap ceramic on 2 whist doing so! god they were tight!) and turned engine over by hand - so it isn't siezed at least!
intend to remove starter motor at weekend and see if there is another issue there....

As for the MSnS...

Think I might just send it off to be checked...... at least I can be sure then....

cheers for all your advice guys

Just fitted brand new Odyssey battery... still no joy...

going to contact Bailey and ship my MSnS to them to check/repair

A big thumbs up for Tayna batteries BTW... New Odyssey 680 battery. order at lunch time yesterday and delivered at 9am this morning! £85 including delivery

[Edited on 21-5-16 by DaveFJ]

Well I have an answer on the starter motor anyway... Its fubar!

tried to get ti to turn on the bench but nothing
cracked open the casing and large chucks of copper started falling out!
I can see that quite a few of the thick copper wires that run up to the windings have disintegrated....

so - Now looking for a replacement on eBay....

well that's one mystery solved at least!

strange coincidence that it should fail at the same time as the apparent failure of the MsnS !

If the engine is not turning over megasquirt may appear to be dead as no revolutions causes it to shut down, best get it cranking first.

Fuel pump would kick in anyway, default action is to prime the pump (unless it's been disabled for some weird reason).

If there's 12v across the incoming pins of the MS at the DB37, it's the MS PSU that's at fault.

Now dispatched to Bailey Performance for check/repair...

My fuel pump is only triggered once it sees the engine cranking, needs a couple of turns to kick it off.

I,m sure Dale will sort you out anyway.

Well that's one issue resolved

New starter motor fitted and now it turns over...

Just waiting to hear from Dale now about the prognosis for my ailing MSnS.


Just to add to my woes however.... My laptop HDD has died with my only backups of the MS config ... looks like I might have to start from scratch once Dale has performed his wizardry

let Dale know, he should be able to copy it down off the MS for you, assuming the chip is still sound and there was some issue around it at fault.

you never used it with a phone? or tablet? there will be a copy their too.. ever email it to someone or upload it to a forum? (just trying to think of places you may have left it hanging around!)

re the hdd dying, you could try plugging it into another computer and seeing if it will let you get onto it to copy files off.

All fixed!

On its way back to Dave now, with map intact.

www.facebook.com/baileyperformance

What was wrong with it in the end Dale?

Apparently

"some damage due to reverse or overvoltage spikes to power input stage, repaired burnt track and replaced a diode."


I wonder whether the starter motor failing in such a complete way caused some sort of issue killing the MS.......

Note to self 'must swap that 5A fuse for 2A !'

Very happy bunny.... Thanks to all that contributed thoughts and ideas

Almost without a doubt - the power conditioning on the input to the MS is basic at best (but fully adequate most of the time). In the event of a giant inductive load failing mid operation it's a surprise other items haven't died.

quote:

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Originally posted by coyoteboy
Almost without a doubt - the power conditioning on the input to the MS is basic at best (but fully adequate most of the time). In the event of a giant inductive load failing mid operation it's a surprise other items haven't died.

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Most likely cause it incorrect grounding, the MS should be grounded to the engine block, the battery should be grounded to engine block and chassis.

If a failed / failing starter pulls a load of current then a potential difference could be seen between engine and battery negative or chassis (if grounding is too small or incorrect) this is one of the reasons why grounding MS to block is best. Unlikely the alternator has caused damage, MS will run at 20v without a problem, a diode failure in an alternator will stop it working completely or reduce its current capability. A regulator failure can cause over voltage but not normally more than 20v unless the engine was as high RPM at the time.

.... Just to add, an alternator regulates its output with ref to its case which is its ground, in a car the alternator is the source of power not the battery (with engine running obviously) bad alternator ground can cause weird voltage fluctuations.
Again, MS ground (if grounded to block) shares same ref as alternator, and same power as MS should be powered directly from battery via relay.

quote:

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Originally posted by BaileyPerformance
.... Just to add, an alternator regulates its output with ref to its case which is its ground, in a car the alternator is the source of power not the battery (with engine running obviously) bad alternator ground can cause weird voltage fluctuations.
Again, MS ground (if grounded to block) shares same ref as alternator, and same power as MS should be powered directly from battery via relay.

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quote:

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Originally posted by gremlin1234

my point about the alternator, was that if a failing starter caused damage to ms, it could have caused damage to the alternator too.. - but as you so concisely put it, less likely.

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MS is grounded to the same chassis ground point as the main earth lead from the engine.. therefore effectively is earthed to the block

quote:

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Originally posted by DaveFJ
MS is grounded to the same chassis ground point as the main earth lead from the engine.. therefore effectively is earthed to the block

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Switch that over as suggested - when you crank you'll see a voltage drop over the block->chassis>battery ground connections, this will cause the MS (which is grounded at the chassis/battery) to see a different (and varying) voltage reference.

The problem is that people assume a big braided cable is a zero-ohm link, which it isn't. And at low currents that's not really a problem, but starters (and alts) are really really not low current devices, so the ground strap becomes a resistor and the voltage across it screws with the reference for every sensor on the ECU and even risks situations where you get negative voltages at ECU inputs that shouldn't have them.




[Edited on 27/5/16 by coyoteboy]

To clarify... this is a diagram of how it is all connected right now.... I know the 300Amp earth cables are over the top - but its what i had available at build time and thought 'you can never have too much'

the braided earth strap I am treating as just a secondary earth for the block. the connectors for the MS earths and the main earth lead are in direct contact....

would there really be any benefit in me changing this???

Yes. Contact resistances are the killer here and multiple ground paths are never good. You may see little difference in normal operation, and it may work out just fine for you but you've just proved why it doesn't work.

That's the most tortuous ground scheme I've seen So much simpler to go battery > block, block to everything.

If you have 50 milli-ohms resistance across any single joint there you'll drop 10v across it with a heavy starter current. That's almost your entire battery voltage!

[Edited on 27/5/16 by coyoteboy]

Pleased to say she is now running nicely again

took the time to totally rework the LP fuel system and fix a few other issues which have been hanging around for a while. Found that for some reason my Coolant and Air sensor calibrations had 'fallen off' the MSnS so once I got those reprogrammed she seems to be running well....
Just registered my version of TunerStudio and hope to get some fine tuning done over the weekend, just got to pass MOT on Saturday first

Thanks to all who offered help and advice

Great stuff!