Jellybean Posted July 9, 2013 Share Posted July 9, 2013 (edited) Hey We are painting the weld-in rollcage in the car so we have taking out the dash, disconnected the Dash from the Loom etc, we changed the TBelt Q: The car wont start , she turns over but wont fire up; would taking out the dash cause this? The Fuel pump is not priming and the no spark, check all the fuses , all are fine,all engine sensor connections look good, nothing is loose Edited July 9, 2013 by Jellybean (see edit history) Quote Link to comment Share on other sites More sharing options...
TheTurtleshead Posted July 9, 2013 Share Posted July 9, 2013 Check your crank position sensor and it's circuit with a continuity tester/multimeter. Common failure point on an MX. They can fail randomly and without warning. James Quote Link to comment Share on other sites More sharing options...
Jellybean Posted July 9, 2013 Author Share Posted July 9, 2013 thanks James, will do , but we were thinking it just seems like too much of a coincidence no? Quote Link to comment Share on other sites More sharing options...
TheTurtleshead Posted July 9, 2013 Share Posted July 9, 2013 thanks James, will do , but we were thinking it just seems like too much of a coincidence no? Could be, very easy to check so worth ruling out though, and they really do just fail on a whim. I'd look for; Poor earths after paint, plugs left unconnected, and make sure the timing is correct also. Quote Link to comment Share on other sites More sharing options...
Jellybean Posted July 9, 2013 Author Share Posted July 9, 2013 Could be, very easy to check so worth ruling out though, and they really do just fail on a whim. I'd look for; Poor earths after paint, plugs left unconnected, and make sure the timing is correct also. Good points We still need to paint the cage so the Dash is still out , was hoping somebody would say; Yeah having the Dash disconnected from the loom will break the circuit So what I was thinking Paint cage, get it done and dusted Install dash, reconnect to loom Check the Crank position Sensor as you said Hopefully see if it works Quote Link to comment Share on other sites More sharing options...
TheTurtleshead Posted July 9, 2013 Share Posted July 9, 2013 Ahh the dash is still out! Not sure but the crank position signal may go via the tacho, probably a break in the circuit there oe elsewhere. I wouldn't worry about it. Quote Link to comment Share on other sites More sharing options...
Jellybean Posted July 9, 2013 Author Share Posted July 9, 2013 Thanks again! Quote Link to comment Share on other sites More sharing options...
viper Posted July 11, 2013 Share Posted July 11, 2013 Are you sure you have the belt on correctly? timing? etc? as being a non interference engine it will still turn over and not fire if you have the cam positions crank wrong, i made that mistake once on my MK1 mx5 Quote Link to comment Share on other sites More sharing options...
Jellybean Posted July 11, 2013 Author Share Posted July 11, 2013 Are you sure you have the belt on correctly? timing? etc? as being a non interference engine it will still turn over and not fire if you have the cam positions crank wrong, i made that mistake once on my MK1 mx5 Eoin is a VAG mechanic and by what he went through on putting the belt on (setting the Cam markers etc turning her over by hand 3-4 times), I doubth its the belt; just something stupid like a ground The fuel pump is not priming and no spark Quote Link to comment Share on other sites More sharing options...
Jellybean Posted August 6, 2013 Author Share Posted August 6, 2013 The little MX has electrical problems, spend 8hrs on her yesterday! You could say the MX5 has 2 engine looms , one half of the loom is attached to the Dash and the other to the firewall, to make things easier for us we disconnected the loom from the Dash and took the dash out of there so we could trace and diagnose issues a lot easier. The only items not connected are the two footwell lights (either side of the centre console) and cigarette lighter (all three are integrated to the dash) but these will not cause the car not to start. Issues Early morning Scenario · The fuel pump was priming and we had dash lights ( was a ground behind the passenger dash area) · no spark · Could not find any continuity within the harness between the ignition coil loom pins and the corresponding ECU loom pins ( forget the wire colors but I can get them) · No relay clicking · No revs on the tacho when trying to crank her Current Scenario · In order to trace the wires for the ignition coil we removed the dash and harness from the dash, reconnected everything minus two footwell lights (either side of the centre console) and cigarette lighter · Now we have no dash lights, Charge, Brake .. but it will show the symbol if we turn on the headlights, indicators · No fuel pump working Any advice, we are thinking a relay is gone, fuses are all fine , inside and out plus all grounds are triple checked. Quote Link to comment Share on other sites More sharing options...
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