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Old 05-16-2017, 08:12 AM   #31
john318isau
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Do you have a boost or vacuum/boost gage installed?
Yes I do have a cheap digital gauge that does both. I haven't watched it though when the problem is happening, usually too busy finding a place to pull over...

On my way home from work today the problem was much worse than usual. Happened about ten times. Stalled a few times, once when stopped waiting at some lights. I guess its good its getting worse as it should make it easier to diagnose, but I'm not going to drive it to work as it is now as it's to stressful wondering when and where is going to happen next.

(My drive to work is country type highway roads but with quite a bit of traffic, and also a narrow mountain pass. There's lots of places where there is no room to stop, and there are lots of large trucks that use the highway. So far I've mostly been lucky where I have had to stop, and sometimes I have been able to keep moving at a slow pace, but I also want to avoid damage from backfiring.)

I think I'll try a crank sensor if I can find a cheap used one, as from research that seems like a likely cause too. I did measure mine and it showed around 650 ohms but maybe it could have an intermittent fault. I would like to check the wiring more as suggested here, but it's hard to get to. Would be great to remove some of the DASC parts to get access but probably a big job and new gaskets required?

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Old 05-17-2017, 02:20 AM   #32
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I noticed when I last was checking codes, with the ignition on but engine not running, INPA was showing a voltage reading of 11.75 volts. With the engine running it's 13V+.

I understand a good battery should be reading 12.5V when fully charged.

Could I have a battery or charging issue that might be causing ignition problems too?
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Old 05-17-2017, 05:19 AM   #33
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Quote:
Originally Posted by john318isau View Post
I noticed when I last was checking codes, with the ignition on but engine not running, INPA was showing a voltage reading of 11.75 volts. With the engine running it's 13V+.

I understand a good battery should be reading 12.5V when fully charged.

Could I have a battery or charging issue that might be causing ignition problems too?


It is possible I guess as it's all computer controlled and susceptible to voltage issues.

I would try testing at the battery posts and again at the actual attached terminals with a reliable voltage meter. Testing the posts and then the terminals lets you know if corrosion maybe blocking some of the current.


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Old 05-17-2017, 10:22 AM   #34
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Ok, had some more time to look at the car.

Battery is ~12.5V at rest so that is okay.

I received my new coil (looks like it has been dropped in transit though) and the car would not start at first. It did start after a few attempts but stalled. Then it ran for a little while and I was able to check with INPA while it was running. No change to any of the readings and smoothness is way out on cylinder 2 and less so on cylinder 3.

Then it died again and wouldn't start.

INPA was reporting cam sensor fault code again (112) so I unplugged the sensor and it started next attempt. I turned it off and re-connected the cam sensor and it started fine again.

Cam sensor fault code is appearing almost immediately now. As mentioned I had replaced it with a second hand one so maybe that one is faulty?

Is there anything else that can cause this error code (unplausible value it says)? Timing chain slackness or mis-firing perhaps?

I may have to try another cam sensor but I am getting sick of spending money on things that may not be needed.
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Old 05-17-2017, 12:52 PM   #35
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Quote:
Originally Posted by john318isau View Post
Ok, had some more time to look at the car.

Battery is ~12.5V at rest so that is okay.

I received my new coil (looks like it has been dropped in transit though) and the car would not start at first. It did start after a few attempts but stalled. Then it ran for a little while and I was able to check with INPA while it was running. No change to any of the readings and smoothness is way out on cylinder 2 and less so on cylinder 3.

Then it died again and wouldn't start.

INPA was reporting cam sensor fault code again (112) so I unplugged the sensor and it started next attempt. I turned it off and re-connected the cam sensor and it started fine again.

Cam sensor fault code is appearing almost immediately now. As mentioned I had replaced it with a second hand one so maybe that one is faulty?

Is there anything else that can cause this error code (unplausible value it says)? Timing chain slackness or mis-firing perhaps?

I may have to try another cam sensor but I am getting sick of spending money on things that may not be needed.


Thinking outside of the box.

Okay this all started after an engine cleaning. You are still getting unusual readings on the cam sensor that you swapped and the problem persists.

What's the chance of water getting into the harness someplace? One thing that wouldn't cost you maybe ordering another unneeded part would be to make sure no water got the DME itself. Unlikely but stranger things have happened.




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Old 05-17-2017, 12:58 PM   #36
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I agree that there is a good chance it is related to the engine bay cleaning, except that the car started and ran fine after the cleaning and then drove at least 50km the next day before failing in this way for the first time.

I have had a look inside the dme compartment and it was dry. I haven't pulled apart the dme itself though.

I wish the wiring under the intake was easier to get to so I could check out better than I have. I also wish I had a known good cam sensor to try without having to buy another one.
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Old 05-18-2017, 03:45 AM   #37
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When I measure the wiring socket for the camshaft sensor both the +12V and GND pins measure short circuit to ground, but with ignition on I see 12V. I'm not sure if this is normal or there is a short circuit. Any ideas?
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Old 05-18-2017, 10:24 AM   #38
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With the ECU/DME disconnected that possible short circuit disappears. Not sure if this is how it should be or not.

Pin 54 of the ECU is where this connects to. It measure short to GND when the ECU is connected. When I disconnect the ECU there is no short from 54 to GND. If I check for short to GND for all the other sensors and devices that share the 12V from pin 54, none of them measure short to GND. I am confused.

Probably not related, but I also had a closer look at the piggyback computer that is mounted above my ECU (photo below). I never looked at it properly before but I see that it is not actually connected. The connector has been unplugged and some wires very poorly jammed in the connector to short some pins together (presumably re-connecting some of the ECU wires that were being modified by this unit).

I have found someone with a wrecked E36 who is sending me a cam sensor, crank sensor and O2 sensor, so will have these to try next week.


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Old 05-22-2017, 10:11 AM   #39
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Just tried another cam sensor and a crank sensor. The crank sensor bolt was loose which I hoped might be the cause. But no good, I still have a constant cam sensor fault code being reported. I didn't bother driving it.

So I need some help from a fellow M44 owner.

My 12V line that is shared with most sensors measures short circuit to ground. This may be normal, but I don't think so. Can someone with a multimeter check if there's is the same. This is simple to do - just pop off the plug to the idle speed motor and measure the middle pin (pin 2) to ground and see if it measures short circuit (use continuity test or ohms/resistance check).
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Old 05-22-2017, 12:22 PM   #40
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I found if I disconnect the O2 sensor the short circuit goes away. Another O2 sensor does the same thing, though, so this must be normal.
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Old 05-23-2017, 06:30 AM   #41
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Still trying to figure this out. Has anyone ever heard of the camshaft sensor reference marker falling off or something like that, so the cam sensor cant pickup the position?

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Old 05-23-2017, 05:57 PM   #42
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Still trying to figure this out. Has anyone ever heard of the camshaft sensor reference marker falling off or something like that, so the cam sensor cant pickup the position?





I have never known of any such failure of it falling off, it's a pretty solid piece.

If my Compact was operational I would gladly do the testing you asked for. Someone should be able to oblige you I would hope.

The sensor wiring isn't something I have messed with much but something doesn't sound right about the way it seems to be working on your car but I can't be sure.

Sorry


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Old 05-24-2017, 11:06 AM   #43
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I decided to finally actually check a camshaft sensor (should have done this first, but seemed pointless with an intermittent fault).

I read on Pelican Parts website to connect 12V and GND, and watch for 12V on the middle pin with a multimeter when something metal passes in front of the sensor.

I just did this with one of my sensors and it did not show any output on the middle pin (0V) when I pass a large spanner in front of it.

So it appears to be dead, unless I am testing it wrong.

I am afraid to test another one of my three camshaft sensors in case I am testing it wrong.

But I suspect I am testing it correctly and another fault is damaging these sensors.

My theory is that whatever short circuit I am measuring between pin 54 of the ECU and GND is not right. Someone kindly did a test for me and did not read a short circuit in the same place, although I'm not sure they tested the same way.

Has anyone ever heard of camshaft sensors being damaged electrically by something external, maybe the ECU?

My next request is if someone has an open spare ECU they can do some electrical tests for me as I measure short-circuit on a couple of the transistors in mine. Would require a multimeter with continuity and/or diode tests.
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Old 05-30-2017, 11:34 AM   #44
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To keep this thread up-to-date, I have been waiting on a second hand ECU to arrive to compare measurements. It arrived today and I did find that there was a short circuit that shouldn't be there.

It looks like someone in the past has attempted to repair the ECU but deliberately or accidentally soldered some parts together that shouldn't have been joined.

I have fixed these up and no longer measure a short circuit on the power run for the cam sensor.

But I am still getting a camshaft sensor error code within a few seconds of starting the car, and it keeps coming up every time I clear it.

However, I have tested my two cam sensors with 12V and checking for a voltage on the middle pin when a metal object passes across the sensor. Neither sensor showed any change so I assume they are both faulty.

They were both second hand so could have been faulty but seems unlikely.

I am guessing that they were damaged by this short circuit, and I now have to bravely purchase a third sensor and plug it in and see what happens, possibly destroying another sensor.

My only concern is that the problem I found with the solder must have been like that for the several years I have owned the car so why would it only cause a problem now?

Wish me luck...
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Old 06-09-2017, 12:23 AM   #45
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I finally received a new cam sensor. I bought a cheap Chinese made one because I couldn't bring myself to buy an OEM one knowing there was a good chance I would destroy it.

I thought I would test it first, using the Pelican Parts suggested test procedure, and it gave no reading at all, just like the other sensors.

I lost hope that the new sensor would fix the problem at this point, but, amazingly, the cam error code has gone, and I have now driven over 100km without any problems.

I am not sure what to put the problem down to, but it was either:

The two other second hand cam sensors I bought were both faulty, as well as the one that was in the car

OR

The short circuit in the ECU was damaging cam sensors (but it's been like that since I bought the car years ago)


The O2 sensor heater fault code I have had since I bought the car is gone now too, and this was definitely due to the ECU fault although I did replace the O2 sensor as well).

So, has anyone had any success in bench testing these sensors?

Anyway, I hope it continues to run well and that the problem is solved. I don't think concluding this thread is likely to be of much help to other people as the soldering problems on my ECU are probably unique, but one thing that can be learned from my experience is that you should trust your fault codes: I wasted time and money looking for fuel issues (so did my mechanic) when I should have concentrated on finding the cause of the cam sensor error code all along.

Thanks for all the help and advice.

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