Sudden crankshaft sensor failure?

[colesy]

Hi everyone,
Did a track day in my 172 yesterday, was all going well until the second session when the car just electrically shut off and wouldn’t restart.

Plugged in the RSTuner and the only code I had stored was an engine speed sensor code (presume this is crank sensor) has anybody had such a sudden failure of a crank sensor before?
I had no prior symptoms, no misfires and the car was even on a dyno for 3 hours 2 weeks ago with no issues shown.

Currently the car will crank forever, immobiliser light goes out, fuel pump primes but it will not run, which I guess would point to a crank sensor issue with no spark.
Now it does still have the ‘old’ style crank sensor fitted so I am going to get the updated one with new loom.

Cheers

 

[JamesBryan]

Are you getting any rpm reading when cranking?

That'll be one way to tell if it's the sensor.

 

[colesy]

Are you getting any rpm reading when cranking?

That'll be one way to tell if it's the sensor.

On my very ropey data logger thing I have when cranked no RPM speed is shown

 

[JamesBryan]

On my very ropey data logger thing I have when cranked no RPM speed is shown

Looking like the culprit then.

 

[colesy]

Looking like the culprit then.

Fingers crossed it’ll be that easy 😅

 

[colesy]

Did some more searching tonight, on my data logger at rest it’s showing 184rpm, when cranked this went up to 200rpm.
Checked the compression 180psi across all cylinders.
Plugs look good
Fuel pump primes
Immobiliser light goes out as it should
Got a new style sensor coming tomorrow to try and we’ll go from there.

 

[Adamm.]

This thread gives me flashbacks. Hopefully it will just be the crank sensor as you said.

 

[colesy]

This thread gives me flashbacks. Hopefully it will just be the crank sensor as you said.

I hope so 🤞🏻 I wouldn’t mind so much but I’m meant to be racing it in 2 weeks so I’m on a bit of time crunch to get it sorted lol

 

[npt]

Are the newer style wiring crimp fit or solder?

 

[colesy]

Are the newer style wiring crimp fit or solder?

They come with those heated solder joints from Renault.

But for those interested the crank sensor was not the problem. Fitted the new updated one last night and no change at all.

Now all along this process I’ve heard the fuel pump priming so I wrongfully assumed that was all good. Took the pipe off the rail and was met with no residual pressure, I thought that’s odd. Put a bowl under the the disconnected fuel line primed the pump absolutely f**k all came out.

Screw it I’ll take the sender out. Took that out and found the pipe that connects to the top of the fuel pump had rattled itself off. Put it all back together and started first time, ffs! All sorted now though!

 

[JamesBryan]

They come with those heated solder joints from Renault.

But for those interested the crank sensor was not the problem. Fitted the new updated one last night and no change at all.

Now all along this process I’ve heard the fuel pump priming so I wrongfully assumed that was all good. Took the pipe off the rail and was met with no residual pressure, I thought that’s odd. Put a bowl under the the disconnected fuel line primed the pump absolutely f**k all came out.

Screw it I’ll take the sender out. Took that out and found the pipe that connects to the top of the fuel pump had rattled itself off. Put it all back together and started first time, ffs! All sorted now though!

That's mad, never seen that before.

 

[colesy]

That's mad, never seen that before.

I should add it’s got a kemso fuel pump in it that @GrahamS fitted when he had the car so I guess years of abuse and vibration just got too much!

 

[JamesBryan]

I should add it’s got a kemso fuel pump in it that @GrahamS fitted when he had the car so I guess years of abuse and vibration just got too much!

Was fuel spraying out around the pump?

 

[colesy]

Was fuel spraying out around the pump?

Yeah it was just coming out the top of the pump in the tank but not obviously being delivered to the rail. Anyway sorted now 😃

 

[GrahamS]

Thats my shoddy workmanship! I don’t recall how I did that pipe but think it was removed and pushed back on the barb with some heat.

 

[colesy]

Thats my shoddy workmanship! I don’t recall how I did that pipe but think it was removed and pushed back on the barb with some heat.

I don’t even think it was that to be honest, just lots of running over kerbs 😏