Crank speed sensor

gagge

Member
Hi
I have bought an 1.4tdi 75 hp AMF engine. I actually don´t know much about the engine. But it turns around and the oil looked good. Previous owner said that it worked before he took the engine out.

Before I fitted it in my car I changed the timing belt.
When I tried to start it up for the first time it did not start and I got 16706 no signal from crank speed sensor. So I bought a new speed sensor and tried to start it once again. This time I got another fault code 16705 implausible signal from crank speed sensor.

Does anyone have a idea of what might be wrong here? What would the fault code be if I got the timing belt wrong? 20210402_122532.jpg20210327_185746.jpg
 

spike

Member
If the cam timing is not spot on the crank and camshaft sensors send conflicting signals to the ECU and the engine won't start.
A quick check is to disconnect the camshaft sensor so the engine relies solely on the crank sensor signal.
It may take a few more revolutions to fire up as the engine works out which cylinder is on the firing stroke but if it runs then you need to re check the cam timing

Cheers Spike
 

a2roger

Member
I had the same problem with the crankshaft sensor but the car started fine. I got the light deleted and the fault has not come back on am going to wait to see if it dose and then go from there, as the car was sat for a few months before I bought it so it might just need a long drive on the motorway.
 

gagge

Member
Hi thanks for all your tips and advices. Today I tested starting the car without the camshaft sensor connected. It did not start but I did not get a new fault code either. So then I tried with the old crank sensor. Immediately fault code No signal as before, so that one is probably broken. Unfortunately I do not have a good multimeter to check out the ohm. So I fitted the new crank sensor once again, and connected the camshaft sensor aswell and Voila. Now it started!
I do not now why it did not started with the new sensor the first time, perhaps I did not manage to get the sensor to the bottom of the hole?
 
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