206cc 2.0 cam sensor

[jgra1]

hi all, SWIMBOs 206 broke down yesterday. we towed the thing home, I have already lost all love for it over the years.. anyway.


planet said multiple misfires on all cylinders - but I didn't dig any deeper, my other scanner said camshaft sensor out of coherance issue. (P0345)

My simple question, if the cam sensor is ok, the only other thing I can think of is a belt slip on one of the cams, or at the far end of the scale an ECU failure..

or to put it another way, what could cause all the rough running, misfiring etc if not the sensor or the belt slipping? (that also throws a cam sensor error? think it was 0345)

The Cam and Crank sensors were removed, looked ok but not easy to test.. Cam sensor seemed to show open circuit on all 3 pin combinations (if that is what the '1' means on all ohm scales)

hateful car, and bad timing to break down (no pun intended)


I will buy a sensor, and a sledgehammer

[wheeler]

What engine is it? Is this a diesel? If so and it cut out while running it wont be the cam sensor at fault, it is only used for initial starting. If you unplug the sensor once the engine is running it will stay running till you turn it off. You cant really resistance check the sensor as its Hall effect. It should have a power supply, earth & 12v pulse when the engine is turning.

[jgra1]

thanks Wheeler, sorry its a petrol. the 135HP 2.0 from around MY2000

I think I have no option but to orded a new sensor, and do a compression check (easier than further dismantling of the timing cover, crank pulley.. if a tooth had slipped it would show odd compression I hope.

I will check for line voltage and earth at least before replacing sensor.

If the ECu has given up the ghost I think it's a straight scrapper..

[wheeler]

OK, I think it may be the same in that it doesn't cut out if the cam sensor is disconnected.
I suspect is may be the earlier 2.0 (what is your engine code?) with the timing hole on the crank pulley?
If this is the case it is really easy to check the timing. Only 3 allen screws holding the top timing cover & pull the wheel arch liner back to access the crank pulley to peg it. 8mm rod to peg the crank & 6mm pegs for the cams. Have you checked that the camshaft is at least turning when you crank the engine?
Cam sensor & ECU failures a very rare on PSA engines however (premature) timing belt failures on the 1.8 & 2.0 16v engines are definitely not uncommon.
What actually happened to the car? did it cut out when driving or did it just fail to start?

[jgra1]

thanks Wheeler!

Engine is the EW10J4 (I think it was superseded by the EW10J4S)

Car was following me up an incline and suddenly lost all power, stalled etc. I turned around, and it was obviously misfiring everywhere.. exhaust and engine rocking and banging.. it would start but badly, and I could almost keep it running (enough to get off highway) but it wasn't pleasant.

A similar thing happened once before, it turned out the crank sensor had met its end arguing with the flywheel teeth.. I went straight to that sensor hoping for the same issue but was fine.

I did the belt and tensioners myself - probably about 2 years and 30,000 ago

Cams both turning, can see the ex cam is half a tooth out when the inlet cam is able to be pinned (this could just be the belt pulling / valves acting)

my quick code reader said P3045 , my pplanet just said a lot of multiuple misfires, knock sensor, ECU (I may put this back on again and see if there is anymore detail)

I will check for continuity of the three wires to the plug later, and voltages.. I really dont want to jack up and remove wheel etc in the dark, but I know I may have too..

I will get to the bottom of this and also tell her to buy something more suitable like a hatchback thats a bit newer.. Ds3 maybe?

John

ps top timing cover took actual hours to remove! 4 allens, recessed, and no room .. just spend your time picking up all the tools that keep dropping.. hateful design.. taking ECU out helps a little

[wheeler]

Ahh, Im thinking of the engine when its fitted in a Xsara which is a totally different lay out. The ECU is behind the battery for starters, so might just be a little more awkward.
Is it like the XU10 engine with adjustable cam pulleys? You might be able to reset the timing out half a tooth with this.
The XU10J4RS (VTS) engine was also known for breaking valve springs, not sure if the EW10 enignes were also affected?

[jgra1]

I don't think the cams are adjustable, 99% sure they aren't (I remember that fun on V6's in 406 coupes in the past!)

I will dig some more, I still may do the comp test for fun, always nice to know.

The gap between the belt cover and the engine bay is a knuckle scraper, and its quite a big lump for such a small engine bay in all respects.. and, I always think the car is very front heavy - is a no from me

[jgra1]

hmm... My compression tester is old now, the flex pipe is not good..

However, i must have tried each cylinder 3 or 4 times! trying to be more 'tight' and certain each time ( I have extension tubes and so on)

for sure, I had readings of 8 to 10 bar at points on 3 cylinders, but nearest cambelt would never rise above 2 bar no matter what i tried..


is this it then, a valve spring maybe? something major anyway..

[jgra1]

daft question time..

What is misfiring? (I always assumed no fire was happening, but is it also the case that fire is happening at the wrong times)

A cylinder low on compression cant change when the firing occurs, just make it less of an event? .. so, is this possible compression issue a red herring and the cam sensor has actually gone after all (the code 0345)

still have a couple of fingers crossed, bruised as they are

[Hell Razor5543]

On an engine a misfire is one (or more) cylinders firing incorrectly (and this can be for a number of reasons). They are meant to fire in a specific order and at a particular moment (just as the fuel/air mix is at its most reactive). If, for example, the spark in one cylinder is too weak (caused, say, by a faulty spark plug) it might not cause that fuel/air mix to burn properly, so would not 'push' against that piston with the expected amount of force. For any piston engine to run efficiently the stages have to happen with precise timing, and with expected results.

[jgra1]

thanks James, what I am getting at is how OBD2 reports misfire? how does it know? fuel / air ratio at Lamda, firing order of plugs out of whack, knock sensor..

If the above, there is still a chance the engine isn't toast (and my compression readings are inaccurate)

The ECU cant measure compression, or sense anything happening in the cylinder, except by those 3 ways? plus injector open ratio, lack of camshaft signal, crank sensor coherance etc

I am just curious really - multiple cylinder misfire to me doesn't equate to a low-comp cylinder

[xantia_v6]

Modern engine management systems (with suitable crank position sensors) often measure the speed of the crankshaft several times per revolution so that they can detect the acceleration due to each combustion event and work out if on average one cylinder is not pulling its weight. Other engines have sensors in the ignition coils that measure the ionisation of the combustion gasses after TDC on the combustion stroke to check that the mixture ignited. Earlier systems would deduce a misfire from an unexpectedly high O2 reading (but that is a fairly rough assumption).

[jgra1]

thanks V6, interesting..


I did another few hours for fun... car is now under cover which helped..

I looked inside the cylinders with a cheap endoscope, I wasn't expecting to find anything much, and that's what happened. All cylinders look the same, not the cleanest things considering it's a petrol, but the last few mins of running have been very over fuelled..

I put the plugs in their unit and earthed them with some steel.. All i can say is they were all sparking in perfect rhythm, no surprises I could see.

I removed both rocker covers, and manually pressed the buckets, the suspect cylinder felt the same as the others.

Finally, i was measuring the voltage at the cam sensor.. there was a 0 volts, a green wire with continuity to earth that measures about 5V, and a 12V - oddly, the 12V would switch off when I placed a magnet at the sensor
!? (It did the same when I tried a spare sensor for the X7)

I am cool, just enjoying trying to find out what's gone on, knowing the wrecker is creeping closer

[Hell Razor5543]

Another possibility (which would also account for the compression issue) is if a piston ring has failed. That would allow some of the fuel/air mix to escape during the compression part of the Suck/Squeeze/Bang/Blow cycle. I remember (but I cannot say which show it was on; probably Car SOS) one engine being opened up, and the piston rings, while intact, were fitted so the gaps all lined up, providing an escape route. When you have two piston rings they should be 180 degrees for the gaps.

[jgra1]

thanks James.

I am going to try removing the injector plugs one at a time.. One bad cylinder could cause the bucking bronco engine maybe..