I need advice so I don’t go around in circles, and lose my sanity in the process.

My new camshaft sensor replacement is not reading the rotation of the camshaft. It’s the same Bosch part number as the one before, (which also seems to be still working properly), but this one comes with a translucent plastic tip that’s just begging to be pulled off.

there are 3 wires, one is ground, one is the reference voltage, and the signal wire. After backprobing, I believe the reference voltage is 5V and the signal wire voltage is the one that oscillates in a square wave pattern between 0 and 12V. Testing the cam sensors ( both old and new) show the Hall effect to be in working order with the metal proximity test.

The problem is when it’s installed. The new one shows 12V and doesn’t change. Tried using an oscilloscope when cranking the car. I tried pushing the car backward in reverse gear: nothing. Pushing the car forward in 3rd gear: nothing.

My question is what could be the problem? If it’s not the sensor, then what? Is the camshaft worn out? Wouldn’t I have noticed a difference before my MCS decided to quietly quit on me at a traffic stop? Do i need to inspect something inside the engine? It’s my understanding that the DME uses the readings of the camshaft position sensor to determine when to inject fuel and when to ignite a spark.

if it helps, my car is currently a crank, no start condition. just shut off that day at a traffic stop after 2 hours of HWY driving. Spark seems to be ok. I’ve manually checked each spark plug and coil by taking the plugs out and connecting a spark plug tester between the coil and plug. I saw both a light and a spark for each coil and plug. Supply voltage at coils show battery voltage-0.2 V, so still around 12v. The control signal however is at 9V with ignition on. Not sure this makes a difference or if it’s by design. My current concern here is if this method of physically testing didn’t account for a return ground while the spark plug is inside the cylinder.

My timing chain was supposedly replaced almost 4 years prior to the car shutting off, which was about 15K miles ago. By all accounts, it should still be good but who knows.

Other vaguely pertinent info:

My valve cover was changed twice by the same shop as the timing chain in a span of a few months and 2K miles, but it’s highly possible they swapped it for a used one the 2nd time around, just like they gave me a really used battery as well. There was a whole fiasco with that shop and i think they didn’t charge me for the 2nd valve cover replacement, which leads me to believe this, considering the bolts also look really old. Anyway, I digress.

i have a right fuel level sensor fault, in both the JBE and KOMBI. I may have even had it in the DME the first time I was able to scan for codes long after the incident happened. I had already fiddled with the filter before then so it’s unclear when the fault appeared. I also replaced the JBE (still unprogrammed) with a used one between the incident and the time I scanned for codes. I do remember my instant MPG acting wonky a couple of months prior to the incident, but don’t remember if it was sustained. While accelerating and showing instant mpg in the 20s, it would suddenly pop up to the 50s and 60s.

Preliminary testing seems to point to an extremely high resistance between the positive and ground wires for the right fuel level sensor attached to the fuel filter. I’ll be checking it tomorrow while also replacing the fuel filter. Please let me know if this resistance is a possible cause for no start. Supposedly it should only fall within 19-220 Ohms or so.

Hmm..I think I need to check the voltage readings again while turning the crankshaft. Can’t trust my brother’s word for it. I wasn’t the one with visibility to the multimeter at the time. I noticed a couple of times he had accidentally hit the HOLD button, freezing the reading, so it’s possible the same thing happened there.

 

It's my understanding that the crankshaft sensor is responsible for timing the coils and injectors and the cam sensor(s) are only used for VANOS operation. So the engine should still start and run (albeit in limp mode) with a faulty cam sensor.
Are there any error codes in the DME? Are you getting pulses to the injectors when cranking?
The fuel level sensor issues would make me want to check the pressure on the low pressure pump.

 

Close but not entirely correct.

The DME does not know which phase the engine is in until it has position data from the cam (s). The DME needs to know if cyl #1 is at TDC on the compression stroke or the exhaust stroke.

 

Hey all, thanks for replying,

2982 for the cam sensor. This one only came on after replacing the sensor and returns after clearing.

initially, when I had a bad battery, I had 2968, 2982, and 2983 for cam sensor fault codes with only 2983 present. After I cleared the codes, these never came back. I hadn’t replaced the sensor then.

With the new sensor, 2982 persists and pops back up as present after clearing now. 2983 still listed but not as present.

FRM faults all claim to be open circuits, so I’ve checked the wiring diagrams and it’s a matter of investigating where it might be.

KOMBI fuel claims it’s a short circuit to positive as with DME fuel one

JBE Pitch and Passenger sensors listed as open circuit, RLS (rain-sensing on the interior rear view mirror) listed as short to positive,

and finally, JBE fuel is listed as signal implausible

My understanding was that it won’t run with a faulty crankshaft sensor, but not necessarily the case with a faulty camshaft sensor. However, it’s still possible it won’t run.

According to the sensors, the injectors are firing off at 21 ms.(fuel injection timing)

Engine speed when cranking: 174.00 1/min. (RPMS?)

Fuel pressure at the rail: 1.15 MPa (High-pressure fuel system). =11.5 bar=166.8 PSI

According to the graph of a healthy HPFP, which seems to show a nearly 1:1 ratio between engine speed and PSI fuel pressure, this seems to be ok, assuming the sensor 1/min is RPMS (tachometer has me guessing between 100-200 RPMS).
It’s proving extraordinary difficult to obtain a live reading with a fuel pressure gauge due to the difficulty of accessibility of the fuel feed line. Might have to lift the car and remove the panel from underneath.


I expect more codes to pop up if I ever get it running, such as a bad O2 sensor.

I can post all the DME sensor data if needed. (Taken without MAF connected)




Ignore Air-mass faults. I have the MAF disconnected and entire air filter intake/silencer removed for the moment.

 

In my case, is it bad enough to prevent the car from starting?

 

The camshaft sensor works with the vanos solenoid, yes? The solenoid, in turn, controls the supply of pressurized oil to the Vanos actuator? If there’s no fault code from the solenoid and the camshaft sensor is fine, do I need to look at the actuator motor or perhaps the non return valve that’s near the solenoid?

wouldn't I receive some sort of fault code if there was an issue with the actuator motor? Also, would the jamming of either solenoid (which would show up in a code readout) or actuator cause the motor to quietly die and the car to never start again? I’m talking about not even a hiccup when cranking.

 

try swaping the cam sensors. intake and exhaust and see if the error moves from one cam to another. Try using another known working sensor or another new one.

 

Thanks for replying. The N14 engine only has 1 cam sensor, the intake. N12,N16,N18 have both intake and exhaust though.

Anyway, I did swap it with a new one. The code changes from 2983 to 2982 depending on the sensor.

P.S. fixed all the fuel level sensor faults

 

Found the source of my camshaft position sensor fault code. I was in denial. No way that the timing chain would be a problem since it was relatively recently replaced, and the valve cover replaced twice. Well… fool me once..I should have known not to trust in the work of a euro shop that caused me so much grief with my car.

I present to you a sheared bolt that secured the exhaust? Cam sprocket in place. I’m crossing my fingers but it looks like the damage is minimal, providing I can remove the sheared bolt from the shaft. The bolt head was even resting nearby so optimistically speaking, perhaps it was a controlled failure when it happened, considering the car was idling in neutral at a light. I didn’t even notice damage to the plastic tensioners or sprocket. Actually, that’s not true, there are some nicks in the plastic where I imagine the sprocket must’ve landed but it doesn’t seem like it’ll be an issue.

The cause seems to be a seized vacuum pump connected to the other end of the camshaft. Woe to caution: periodically check your vacuum pump to prevent this from happening. Simple to remove in principle but a hassle because of the location of the bolts.