Technical Engine won't start. Will the engine start with the MAP sensor wires unplugged?

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Technical Engine won't start. Will the engine start with the MAP sensor wires unplugged?

Ian S

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I know the car will run with the air tube uncoupled once started, but will it start with the electrical plug unplugged?

I've spent hours now probing and am finding nothing wrong. All continuities that I've tried, inc the crank posn sensor to ECU plug, earth straps, earths from ECU plug, all OK.

The ECU seems to be choosing to not run the relay during starting. I've measured that it powered up the coils, etc, probably the fuel pump, for about 1 second then shuts them off, as I presume it supposed to during the key on 1st or 2nd position.

But then does not supply again when turning over with the starter with the key on 3rd posn. It's as if the ECU doesn't know the engine is turning.

200 miles old Magneti Marelli Crank sensor from Eurocarparts that I fitted only a few weeks ago. it does measure 1k Ohms though, instead of the 600 of the original.

Car was running very well, just cut out the dual carriage way at 40mph and won't re-start.

Thanks.
 
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If crank sensor is bad, engine light will come on while cranking. I had recently a new (less than 100 miles) crank sensor fail because the last repair man left its cable touching the radiator fan. The fan scratched it to death..
 
The light does not come on while cranking so that might be OK then.

He may have pushed it into the clips on the cam belt cover but it came out on it's own. Mine has done the same but it didn't touch the fan.
 
It was the crank position sensor.

It had come out of it's holes. And the bolt had gone missing.

It's a lose fit compared to the original and can rattle a bit.

The bolts threads might have been a bit tired when I fitted this replacement a couple of months ago but it did up tightly though.

Maybe the constant small movement of the sensor worked the bolt out. Maybe with some heat cycling. The original may have had thread lock glueing it in?

It's an M6 bolt with 10mm head. I found one of about the right length, which happened to be an 8.8 high tensile with nice sharp deep threads and 17 thread length. That was a tight fit and I had to spanner it all the way. I can't leave it there as it's from something else so I need to get such a bolt. And maybe use a dob of thread locker.
 
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