Engine not starting causes.

[emarkey]

So your mx5 won't start. It's turning over, fuel is going in, your spark plugs are fine, it might fire once but not enough to start the car. When it does start however, it runs well.

Thoughts?

[MX5Spares]

Hi Eoin ,possible fuel issue?? Pump maybe.Bypass the fp and gnd??(confirm yourself please)pins in the diagnostic box and see if you can hear the pump coming on.Have you the turbo set up tuned correctly.Could be temperature sensor giving inaccurate readings to ecu re extra fuel when cold etc.

[emarkey]

I think everything on the ecu looks reasonable. See, all was well before I swapped the engine. So it must be something I did.
It SEEMS like it's not getting a big enough bang on start up. I will Brap hold of a compression tester at some point and seem what's up there.
Which reminds me, I still have your piston ring compressor

[MX5Spares]

Oh yeah I have to noted here !!

[emarkey]

Say the head gasket was blowing between two cylinders, and there was low compression in those cylinders, would that cause it not to start properly ?

[emarkey]

https://www.dropbox.com/s/ffegkajez3for ... 9.m4v?dl=0

This is what its like every time.

[Fergus]

Sounds electrical to me, maybe a wire shorting somewhere or faulty coilpack/wire.
Did you connect back up the grounding wire at the back of the block near the downpipe?

[emarkey]

You think?
I'll check all grounds next. Maybe grab a known good coil pack for a test.

[sidewaysreilly]

You say you swapped out the engine. Did you swap out the sensors too?

[emarkey]

What sensors exactly?
Also, I'll try changing the coil pack. I loaded a new map onto it and put the ignition cold advance to 0. Think it helped a smidge. Not idling and misfiring now though even when it warmed up. Seems vacuum or coil pack related.

[sidewaysreilly]

the later mk 1s were obd 2 I think , but I know when I put in the later engine, I had to use the sensors( temp, op, etc) off the old engine to allow it to start.
What static timing figure have you got the ignition set to?

[emarkey]

I am using the original temp and oil pressure sensors and they work as they should.
I think I'm at 10 degrees. Need to check again.