Camshaft sensors keep blowing

[Seagullrestorer]

Hi

I’ve got a problem where the camshafts sensor keep blowing in my 1.9jtd doblo.. is it a short circuit on the wiring somewhere do you think or something else? Also where is the ecu on a doblo mk1

 

[varesecrazy]

How do you know they are faulty..?

Rough running..error code..??

 

[Seagullrestorer]

Hi I don’t know they are did for sure but when I fit a new one it starts straight away ( crank and non start before)

2 days of faultless driving with new sensor and then the engine light starts to flicker on the second day but engine still runs perfectly until I turn it off, then won’t restart and error code p1320 is back

Engine just cranks now like before with no start. Has power to these sensor both 12v and then 5v to signal but when you plug the sensor in that voltage then drops to 1.3v

 

[varesecrazy]

Not sure if jackwhoo has seen this before?

Are these ebay replacements .. or a good brand?

 

[Seagullrestorer]

It’s a brand new Bosch sensor, is somehow the ecu blowing them (if they are blowing which I’m pretty sure they are) so strange

 

[portland_bill]

Try refitting one of the 'broken' ones, to see if it then starts.

The code is just saying that the ECU is not getting the signal it expects. This can be due to the sensor, or the wiring and connections between it and the ECU. Each time a new one is fitted, the wiring and connector get disturbed, so those need checking very carefully, especially where the wiring might be stressed at a corner, or in a clip, or where it may chafe on something. Check earth points, any on the engine, and the ECU earth.

When a 'broken' sensor is removed, what does it look like? Is it the same as it went in, or is it physically damaged, or contaminated? Is there a spacer gone missing, and it is hitting the camshaft? Or is there something else adrift inside that is hitting it?

If the ECU powers it, the voltage these work on is usually around 5v, I think, so it is unlikely to be the ECU causing a problem. It is likely that it generates its own current, from a magnetic field inside. The ECU just reads the signal.

 

[varesecrazy]

Try refitting one of the 'broken' ones, to see if it then starts.

When a 'broken' sensor is removed, what does it look like? Is it the same as it went in?

That was going to be my next question..

 

[jackwhoo]

Hi all , worth checking meaning of code p1320 is it crankshaft sensor or camshaft sensor?
Jack

 

[jackwhoo]

Link incorrect

 

[jackwhoo]

I am leaning towards theory that there could be an intermittent break in one or more of the wires connecting to the sensor. Replacing sensor could cause broken conductors to touch for a while.

a flickering mil light was mentioned by someone with jtd who incorrect crank cam signal correlation due to incorrect belt fitting.

 

[jackwhoo]

Oh and don't ignor the mention of broken key on cam pulley that engages with cut out on cam shaft- have seen this a few times

 

[Seagullrestorer]

Ok so the camshaft sprocket is very slightly touching the camshaft sensor where there is a slight bend in the ring.. it’s not worn the sensor itself, would this cause it to kill sensors?

 

[jackwhoo]

Is the key on the cam pulley that engages with the cam shaft intact?

 

[varesecrazy]

Ok so the camshaft sprocket is very slightly touching the camshaft sensor where there is a slight bend in the ring.. it’s not worn the sensor itself, would this cause it to kill sensors?

If we tapped you on the forehead once a second for a few hours.. would you feel better for it...

It will set up damaging vibrations

So.. it looks like you need a spacer in there.. or attempt to cure the runout you are seeing.

Googling the CODE brings up Multiair failure.. and other totally unrelated things.. as well as the relationship of timing signals.. odd

 

[Seagullrestorer]

Hi the key is fine it’s just the thin metal ring in slightly deformed so lightly rubbing on the sensor

 

[jackwhoo]

Multi ecu scan may well tell you if you have a missing signal from crank or cam sensor or if problem is crank /cam signal correlation problem(incorrect valve timing)

The free version of Multi ecu scan may do this.

Did the fault first occur after any work done on vehicle?

If you clear the code and do nothing else does that enable vehicle to restart?
Does the code return?

May well be time for cam pulley that doesn't touch the cam sensor(-:

 

[Seagullrestorer]

On closer inspection it has worn through to the metal in the sensor so I guess it shorted it out.. new cam gear and new cam sensor on order.. thanks for the help

 

[portland_bill]

Ok so the camshaft sprocket is very slightly touching the camshaft sensor where there is a slight bend in the ring.. it’s not worn the sensor itself, would this cause it to kill sensors?

Hi the key is fine it’s just the thin metal ring in slightly deformed so lightly rubbing on the sensor

On closer inspection it has worn through to the metal in the sensor so I guess it shorted it out.. new cam gear and new cam sensor on order.. thanks for the help

The sensor works by the ring passing by, setting up an alternating magnetic field. If it touches, the magnetic field will be disturbed, or in the wrong place, so a 'different' signal.
What we're talking here is physical damage, not an electrical or electronic fault.
Take care replacing the pulley, ensure it is running true.

As asked above, has work been done recently that caused the damage? I'd expect this to be so, as these things don't just bend on their own.

 

[jackwhoo]

1.9 Jtd cam shaft position sensor is a hall effect sensor rather than an inductive sensor. Its signal output is dc .

The crank shaft sensor is an inductive sensor as Portlandbill describes.

 

[Seagullrestorer]

The original sensor was blown (just old age) so I replaced it and in the process must have bent the thin ring accidentally very slightly for it to rub on the sensor which wore away the sensor breaking it (blowing it I assume) I will be very careful with the next pulley and sensor