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E36/7 Z3 (1996-2002)
E36/7 Z3 Roadster, Z3 coupe, Z3 M Roadster and Z3 M Coupe talk with our gurus here.

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  #1  
Old 09-03-2013, 09:57 AM
mikeijay mikeijay is offline
One Eyed King
Location: London...Baby!
 
Join Date: Dec 2007
Posts: 23
Mein Auto: 2002 318CI & 2001 Z3 2.2
Q? Cam Shaft & O2 Sensors = Stitch in nine?

Experiencing an intermittent slight loss of power at the lower end. No stalling or misfires or check engine light (yet) but I can feel that responsiveness is a tad down at times. As its intermittent and temperature related (better when cold!) ... sensors!

After checking with the diagnostics I had a P0161 (O2 heater Circuit malfunction) and a P0369 (cam shaft sensor B bank 1 intermittent). The cars on 115k on originals sensors.

Was going to go for Bosch (O2S) and Vemo (CSS) - but Before I hit the trigger on ordering replacements, are the OEM worth a punt? I can get both OEM for the same price as a single Bosch O2S meaning I could afford to replace all sensors.

Also is it worth replacing all O2 sensors and both Cam Shaft sensors at the same time or is it an overkill?

Last edited by mikeijay; 09-03-2013 at 09:58 AM.
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  #2  
Old 09-03-2013, 10:29 AM
Blacklane Blacklane is online now
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Location: Springfield, Ohio, USA
 
Join Date: Jun 2011
Posts: 1,052
Mein Auto: 1998 Z3 Roadster
You have a known bad o2 sensor, so I would certainly replace that. My 2.8 only has two sensors, so if the other one were the same age, I would replace it as well since it would be convenient and I would be fairly sure it will fail soon. They are expensive, however, so I would hesitate before buying more than that, but it's a judgment call.

You probably had one cam shaft sensor event, so I would reset that fault and see if it comes back. Maybe you should have one on-hand, since they're not expensive. Cam and crank sensors don't degrade or wear-out, so they don't have a predictable life. They just fail randomly.

When I hear of loss of power at the low end, I think of a VANOS seal failure. And the fact that it's better when cold might be due to thicker oil. There is no diagnostic code for VANOS. You might want to look over the info here: http://www.beisansystems.com/
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  #3  
Old 09-03-2013, 12:13 PM
mikeijay mikeijay is offline
One Eyed King
Location: London...Baby!
 
Join Date: Dec 2007
Posts: 23
Mein Auto: 2002 318CI & 2001 Z3 2.2
Thanks for the advice on the VANOS seal - wouldn't have thought of that and will check it out. I think your right about the Cam shaft event. I had it in the garage a couple of weeks ago and assumed they would have reset the error code the previous week during diagnostics. I'll reset the code and go for a drive this evening. I completely forgot until this morning I had an OBDII reader in the glove of my suddenly very neglected E46. I had never seen a fault even appear before on my E46.

VANOS for bed-time reading it is!
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  #4  
Old 09-03-2013, 08:34 PM
mikeijay mikeijay is offline
One Eyed King
Location: London...Baby!
 
Join Date: Dec 2007
Posts: 23
Mein Auto: 2002 318CI & 2001 Z3 2.2
Interestingly after 2x20 minute drives after reset of all codes On the first drive I had P0369 as pending (expected within 40 cycles). Re-set code and drove around for another 20 mins and P0369 showed as a fault this time not pending.

No sign of O2 sensor / P0161 fault as yet. Expected it to be the other way around!
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  #5  
Old 09-05-2013, 04:20 AM
wilem wilem is offline
fixin stuff
Location: south carolina
 
Join Date: Feb 2013
Posts: 64
Mein Auto: z4
before you replace sensors, put a scan tool on the vehicle, watch the cross counts, and if the pre cat sensor has an appreciable number of cross counts say, 28 maybe, don't waste your money on sensors. to replace both because one has failed is not really necessary. the post cat sensor is measuring cat efficiency and should be nearly flat lined. it if it is swinging wildly like the pre cat sensor the cat has likely failed and you would have a three way innnef code. the life of one sensor is not indicative of the other. sensors seem to be allergic to coolant and other things like old type silicone sealers. you could have a vacuum leak, or restricted fuel filter. TPS that has a flat spot or a coolant sensor that is telling the computer the engine is warmer than it is so it reduces the fuel output via a narrower PW. ever notice how peppy it is when it is cold. that is partly due to increased injector pulse width for cold driveability and to get to cat up to 600 degrees so it can go into closed loop. good luck with your diagnosis

the heater ckt is only to allow the sensor to come on line sooner, it is like a cigarette lighter element within the o2 sensor. your problem is likely in the cam sensor code. as far as one sensor being better than the other, i doubt that. if it is crossing a 500mv threshold 28 times a second i would say that no sensor is gonna make a difference...just don't think so.

NOTE: you can check the cat but shooting the inlet and outlet with a temp gun. if the temps are equal the cat aint doing jack and the sensor is likely bad..BUT that really doesnt matter to you because you have a heater code. just info.
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Last edited by wilem; 09-05-2013 at 04:27 AM.
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  #6  
Old 09-05-2013, 10:20 AM
mikeijay mikeijay is offline
One Eyed King
Location: London...Baby!
 
Join Date: Dec 2007
Posts: 23
Mein Auto: 2002 318CI & 2001 Z3 2.2
Thanks William

Thats is extremely helpful. Tomorrow is my 'diagnose my car day' so will certainly check it that tomorrow.

So far the O2 P0161 code has not reared its face again however I did get a 'Pending' P0014 "B" Camshaft Position - Timing Over-Advanced or System Performance (Bank 1) code yesterday. Still have the P0369 error.

Its annoying as she seems to Idols perfectly, start up sound is gorgeous and on the button every time but feels slow until 3k revs. When it was back from the garage after my blunder with the MAF she was perfect. Couldn't wipe the smile off my face. My mechanic was dubious and asked me to drive it for a few days and report back. Felt a bit stogy (assumed ECU reset) and after X miles was superb for a few days consistently then relapsed :S !

I know its not phycological as I have a 2.0 E46 with a N42B20 (Auto) that right now would thrash me in D mode in a 0-60 race
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  #7  
Old 09-06-2013, 11:20 AM
mikeijay mikeijay is offline
One Eyed King
Location: London...Baby!
 
Join Date: Dec 2007
Posts: 23
Mein Auto: 2002 318CI & 2001 Z3 2.2
Sorted :)

All sorted - thanks guys!
Changed the failed O2 sensor and the exhaust side Cam Sensor today.

Can't believe the difference. Happy to report she now purrs like a kitten and responds like she's telepathic
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  #8  
Old 09-14-2013, 08:18 PM
wilem wilem is offline
fixin stuff
Location: south carolina
 
Join Date: Feb 2013
Posts: 64
Mein Auto: z4
Quote:
Originally Posted by mikeijay View Post
she's telepathic
they certainly seem that way don't they? for future reference Mitsubishi Motors (diamond star motors) teaches us that 97 percent of electrical problems are poor connections. I don't think it is that high but it is ridiculously high.
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  #9  
Old 09-16-2013, 09:52 AM
mikeijay mikeijay is offline
One Eyed King
Location: London...Baby!
 
Join Date: Dec 2007
Posts: 23
Mein Auto: 2002 318CI & 2001 Z3 2.2
I can certainly believe that! Its gone back to how it was

So far I have changed...

MAF
CSP sensor (Exhaust)
O2 (Pre Cat)
Air, Oil & Fuel Filters, Sparks

And after making any sort of change the car springs to life and drives perfectly for 24 hours. However in every single case the next day the car seams to revert back to its unresponsiveness under 3,000 revs. It did exactly this when I first changed the CSPS - felt amazing and then reverted back 2 days later. Then the MAF - felt the best its been and reverted back to its original state the very Next day.

It starts perfect, idles perfect but feels heavy and slow at low revs. It was so peppy after the CSP sensor & maf change before it reverted.

Could my ECU be on the fritz?
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  #10  
Old 09-16-2013, 10:40 AM
Blacklane Blacklane is online now
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Location: Springfield, Ohio, USA
 
Join Date: Jun 2011
Posts: 1,052
Mein Auto: 1998 Z3 Roadster
An intermittent electrical connection or ECU issue would likely be random, not RPM-related. If it has worked fine before, I don't think that's your problem. I'm still going with VANOS for your low-end performance issues. That is also consistent with the over-advanced timing error code and the other camshaft error code, although generally a bad VANOS rarely sets codes. Coincidentally, you also had an O2 sensor issue which has now been corrected, but that was for a heater so would have little effect other than at start-up.
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  #11  
Old 09-16-2013, 10:09 PM
wilem wilem is offline
fixin stuff
Location: south carolina
 
Join Date: Feb 2013
Posts: 64
Mein Auto: z4
Quote:
Originally Posted by mikeijay View Post
I can certainly believe that! Its gone back to how it was

So far I have changed...

MAF
CSP sensor (Exhaust)
O2 (Pre Cat)
Air, Oil & Fuel Filters, Sparks

And after making any sort of change the car springs to life and drives perfectly for 24 hours. However in every single case the next day the car seams to revert back to its unresponsiveness under 3,000 revs. It did exactly this when I first changed the CSPS - felt amazing and then reverted back 2 days later. Then the MAF - felt the best its been and reverted back to its original state the very Next day.

It starts perfect, idles perfect but feels heavy and slow at low revs. It was so peppy after the CSP sensor & maf change before it reverted.

Could my ECU be on the fritz?
some codes are pending codes and perhaps causing the problem prior to illuminating the SES light. some codes take several drive cycles and/or days to illuminate the SES light. for example a generic po 447 sets as pending then after the engine cooolant and ambient air temperature equalize this sets it upo to check for the condition again. If the problem is still there the light will illuminate. Some codes may take days to satisfy the computer before turning on the SES light. You need a scanner to check for pending codes. Are you clearing the codes after each repair? then after an overnight it go crappy again? I would clear the codes when it does this and see if it clears up. If it does then there is a pending code/ condition that needs attention. I am not very familiar with Bimmers and the Vanos system so i cant offer any help there. Sounds like Blacklane may have more model specific information from that stand point. I would certainly inspect all the mentioned terminals and connectors. especially the female sides of them. they are often splayed and loos and cause intermittent problems. Ground connections on the engine block and frame are a good staring point. anytime the ground ckt is poor and there is resistance in the junction anything can happen. I would check the Engine coolant sensor closely for inaccuracies when cold.
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Last edited by wilem; 09-16-2013 at 10:11 PM.
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  #12  
Old 09-19-2013, 01:46 PM
mikeijay mikeijay is offline
One Eyed King
Location: London...Baby!
 
Join Date: Dec 2007
Posts: 23
Mein Auto: 2002 318CI & 2001 Z3 2.2
Thanks guys, both give great help and advice as always!

I tend to clear the codes after each repair, usually one at a time so that I can work out which could be the problematic area. I will shamelessly admit that I was talked into an aftermarket MAF at the motor factors that made it 100 times worse. Replaced it straight away with a genuine article. I also had a bit of bad luck with the Camshaft position sensor. When I received it from the internet wing of EuroCarParts the bag that said 'unreturnable' if opened' was wide open. I informed them of its condition on arrival and said that I would give it a go. Still at the back of my mind I couldn't trust it, so to completely rule this out I replaced it when I installed the genuine MAF and everything is almost back to how I would expect.

Now all the easy electrics stuff is done I made some enquiries today with regards to getting the VANOS seen too.

I would love to have a crack at it myself but i know my self only too well!
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  #13  
Old 09-20-2013, 08:20 AM
mikeijay mikeijay is offline
One Eyed King
Location: London...Baby!
 
Join Date: Dec 2007
Posts: 23
Mein Auto: 2002 318CI & 2001 Z3 2.2
I've got the garage on standby to do the VANOS seal replacement and about to order the bits and bobs from Rajaie. will report back soon!
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  #14  
Old 09-20-2013, 10:03 AM
Blacklane Blacklane is online now
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Location: Springfield, Ohio, USA
 
Join Date: Jun 2011
Posts: 1,052
Mein Auto: 1998 Z3 Roadster
You might want to consider getting the VANOS seals from Beisan Systems: http://www.beisansystems.com/
The OEM seals break-down over time while the Beisan ones do not.
They will ship to the UK.
As a DIY, their instructions are amazingly detailed and accurate, if you choose to go that way.
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