adrianreeve
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| posted on 10/2/12 at 09:20 AM |
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Megasquirt weirdness! Help please
Ok, so thought I'd have another quick go at getting the car started. Until now, all is well, fuel pump does its thing for 3 secs, engine cranks
over, few coughs and splutters, not quite there though. Up the req fuel a bit and try again. Suddenly as I'm cranking, the fan kicks in (
it's -2 in my garage!), and I lose comms to the ecu. Now if turn the ignition on, the fan comes on straight away. As I said, it was all wired up
properly and working as it should, and I haven't changed any wiring. The car hasn't moved under its own steam yet, so I don't think
anything could have shaken loose or moved.
Does anyone have any idea where I should start fault finding here? Megasquirt or wiring?
Anyone got an emerald or Omex they want to sell me?!
Any help much appreciated.
Cheers
Adrian
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MakeEverything
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| posted on 10/2/12 at 09:28 AM |
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Is the fan wired to the ecu or a thermostatic switch?
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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adrianreeve
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| posted on 10/2/12 at 09:33 AM |
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Through the ecu via a relay, wired as per the extraefi drawing.
Cheers
Adrian
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ashg
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| posted on 10/2/12 at 09:33 AM |
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is the fan setup to be controlled by the ecu or is it a separate switch in the rad?
if its controlled by the ecu chances are you have just got a pin misconfigured in the software.
Anything With Tits or Wheels Will cost you MONEY!!
Haynes Roadster (Finished)
Exocet (Finished & Sold)
New Project (Started)
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adrianreeve
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| posted on 10/2/12 at 09:37 AM |
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That's rhe weird thing ash, it wasn't doing it, and now it is! If it was a pin config problem, would have thought it would always have
done it?
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MakeEverything
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| posted on 10/2/12 at 09:39 AM |
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quote:
Originally posted by adrianreeve
Through the ecu via a relay, wired as per the extraefi drawing.
Cheers
Adrian
Depends what version you've got as to what drawing youre referring to! Mine is on a rad switch, not the ecu as per extra efi drawing.
Have you tried unplugging it all and plugging it back in again? Same as removing the 12v feed really. May be the relay pulled in throu a glitch in
the software?
[Edited on 10-2-12 by MakeEverything]
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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scudderfish
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| posted on 10/2/12 at 10:07 AM |
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Is the +12v side of the fan relay that the MS grounds connected to a perm feed? I originally had mine set up like that and when I plugged a BT module
into my serial port the fan would switch on and the MS would do weird things as it pulled power through the floating 12v. With just a serial
connection, the ECU would occasionally drop into boot mode when you tried to switch it off.
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adrianreeve
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| posted on 10/2/12 at 10:07 AM |
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I tried disconnecting the battery, but it still does it.
Cheers
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adrianreeve
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| posted on 10/2/12 at 10:09 AM |
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Can't remember scudderfish, I'll have a look, cheers
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rachaeljf
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| posted on 10/2/12 at 10:34 AM |
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If you've lost comms the ecu has lost its mind. You might need to reflash it.
Cheers R
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matt_gsxr
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| posted on 10/2/12 at 10:54 AM |
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What temperature is it reading?
No need to give up yet, but if you do I am sure your MS will fetch good money.
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britishtrident
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| posted on 10/2/12 at 11:21 AM |
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I know it might seem too obvious but is the ECU earthed properly ?
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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adrianreeve
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| posted on 10/2/12 at 12:06 PM |
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Pretty sure the earthing is ok. Any reason the ecu would lose its mind? All I've done is crank the engine over!
Cheers
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rachaeljf
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| posted on 10/2/12 at 12:13 PM |
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It is unusual to scramble the processor, but it happens. I believe voltage spikes getting through to the cpu, often caused by the ignition, can do it.
Are you using ignition drivers inside the MS case?
What software are you using? Is your MS a bought one or did you build it?
This could easily grow into a huge Q&A thread; it's probably best to search in the MS forums for answers!
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scudderfish
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| posted on 10/2/12 at 12:28 PM |
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My MS used to give the impression it was dead (unresponsive, TS wouldn't talk to it), but it was in boot mode. Power cycling didn't
appear work because it was getting a feed through the fan relay.
In TS go to Comms menu, Mini Terminal, connect and press Return. If it responds with "Boot>?" (or something like that), press X and it
should then be ready to go.
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adrianreeve
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| posted on 10/2/12 at 02:01 PM |
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Thanks for the advice guys.
It was built by Bill Shurvington originally for Flak Monkey on here, then freshened up by Phil at extra efi last year, so I'm confident of the
build quality. It's running with coil drivers, no edis.
Cheers
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kemills1
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| posted on 24/2/12 at 09:32 PM |
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MS
Hi.
if the fan is going at switch on, does the fan status indicator on the PC interface show the fan is activated? If not, maybe you have a stuck fan
relay. Also back emf from relays can fry transistors. Does you MS have diode protection on the relay drivers?
Kev.
BTW, there should be a jumper fitted to go into boot mode. Is this fitted?
[Edited on 24/2/12 by kemills1]
Kev
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