Intermittent EML...any ideas

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rosewellian
Joined: Mon 02 May, 2011 20:27
Posts: 75

  Z3 roadster 1.8 TU
Location: Tadley

Intermittent EML...any ideas

Post by rosewellian »

Hope someone can help with this. Intermittent EML issue. Took Z to BMW specialist who's diagnostic tester highlighted a temperature sensor showing minus 40 degrees which was clearly incorrect. Incidentally the sensor was replaced 2 years ago as a fix for the heater not working.
Technician also commented that if he was being critical he could feel a very slight miss with engine idling.

No parts were replaced and the fault code was cleared. The next day I did 150 miles of spirited driving on the Dorset cruise with multiple stop/starts and EML stayed off. Day after, as soon as I started car EML came on but then mysteriously cleared itself after a few days, stayed off for a week or so but has now come back again!

Can't understand the above as even if what's causing it to come on is intermittent I didn't realise it would reset itself without a tool.

Has anyone else experienced anything similar or have and ideas on how to resolve.

Thanks
Ian
Ian Rosewell - Near Basingstoke
1999 Topaz Blau 1.8
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Del
Joined: Sat 19 Nov, 2011 18:35
Posts: 2136

  Z3 roadster 1.9

Re: Intermittent EML...any ideas

Post by Del »

As far as I know your car (M43 engine?) has two temperature sensors. A coolant temperature sensor which acts as a form of “choke” in conjunction with the fuel control sensors and an air temperature sensor which on the M43 is an integrated part of the MAF sensor. For the ECU to properly know about the mass of air going into the engine it needs to know the air temperature. From what you say, the latter might be “on the blink”. They can get damaged by small airborne contaminants flowing past them over the years.

In my experience, MAF sensor faults can sometimes start off being a bit intermittent. Generally if a sensor performs OK for about three stop/start running cycles, the engine fault light will go off.
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colb
Joined: Sat 05 May, 2012 22:46
Posts: 690

  Z3 roadster 1.8 TU
Location: Newport South Wales UK

Re: Intermittent EML...any ideas

Post by colb »

Ian
Snap same car as mine.
You really need to read the codes the car has set to point you in the right direction as to what is amiss.
As to temp sensors I can only think of intake air temp sensor and outside air temp sensor. As far as I know neither of these would stop your heater working. Check the diagnostics thread to see if someone is near to you to get the codes read.

Just seen post by Del, he is right the intake air temp sensor is part of the Maf sensor, I had Maf problem with mine and dodgy Lambda sensors, replaced with OEM Maf and Bosh Lambda solved my problems.

Colb
Colb
1999 BMW 1.8 Z3
2003 BMW 2.5 Z4
1998 Honda Deauville NT650V
Mike Fishwick
Joined: Fri 19 Jun, 2009 10:27
Posts: 2093

  Z3 roadster 2.8
Location: Daglan, France

Re: Intermittent EML...any ideas

Post by Mike Fishwick »

You do not tell us which air temperature sensor is suspected of being the problem.

If you have air conditioning the outside temperature sensor will cut it out when the ambient temperature falls to +4 degrees C, to prevent the fins of the evaporator from icing up. This will, of course, have no effect on operation of the heater or the engine.
A Z3 is not just for Christmas - it's for life!
rosewellian
Joined: Mon 02 May, 2011 20:27
Posts: 75

  Z3 roadster 1.8 TU
Location: Tadley

Re: Intermittent EML...any ideas

Post by rosewellian »

Thanks for you comments guys, in the last 6-12 months both lambda sensors have been replaced by bmw specialist and I replaced the maf with an oem bosch one. Looks like another trip to the bmw specialist is due unless I can fined someone in the Basingstoke area with a fault code reader
Ian Rosewell - Near Basingstoke
1999 Topaz Blau 1.8
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rosewellian
Joined: Mon 02 May, 2011 20:27
Posts: 75

  Z3 roadster 1.8 TU
Location: Tadley

Re: Intermittent EML...any ideas

Post by rosewellian »

Forgot to say It was the coolant sensor showing minus 40 degrees
Ian Rosewell - Near Basingstoke
1999 Topaz Blau 1.8
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colb
Joined: Sat 05 May, 2012 22:46
Posts: 690

  Z3 roadster 1.8 TU
Location: Newport South Wales UK

Re: Intermittent EML...any ideas

Post by colb »

Rather than pay someone to read the codes use the cash to buy yourself a code reader, since you say you changed the Maf and Lambda sensors 6-12 months your problem may well be elsewhere in the system. Mine did have a dodgy Camshaft sensor that set codes and lit the EML.
OEM part fixed that one for me. Don't chuck any money at it until you get the codes read.

Colb
Colb
1999 BMW 1.8 Z3
2003 BMW 2.5 Z4
1998 Honda Deauville NT650V
rosewellian
Joined: Mon 02 May, 2011 20:27
Posts: 75

  Z3 roadster 1.8 TU
Location: Tadley

Re: Intermittent EML...any ideas

Post by rosewellian »

Good idea Colb, as you have same 1.8 as me do you know what model of fault reader I need for engine issues?
Ian Rosewell - Near Basingstoke
1999 Topaz Blau 1.8
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Del
Joined: Sat 19 Nov, 2011 18:35
Posts: 2136

  Z3 roadster 1.9

Re: Intermittent EML...any ideas

Post by Del »

I replaced the coolant temperature sensor on my 1.9 (M44). First I bought an aftermarket one from GSF which neither fitted the ECU connector very well nor sealed the coolant in. Took it back and bought an OE BMW one (under £15) which was fine. I am guessing that the M44 and M43 parts are similar if not identical.
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colb
Joined: Sat 05 May, 2012 22:46
Posts: 690

  Z3 roadster 1.8 TU
Location: Newport South Wales UK

Re: Intermittent EML...any ideas

Post by colb »

Ian

Have a read through this thread http://www.zroadster.net/forum/viewtopi ... cs#p380672

Some details in there on what I use on my 1.8

Have you got the 16pin socket under the steering wheel and the Pacman socket under the bonnet?

The 16pin OBD2 under the steering wheel will only talk to the engine if using the BMW INPA software, the Pacman Socket will access all modes in INPA.

I started off using my Gendan Engine Check software on my Laptop which worked fine for the engine and Lambda sensors, reads codes and allows clearance.

I then bought the INPA package off ebay and loaded that on the Laptop, if you load all the programs it takes a big chunk of disc space.
Some helpful threads on installing and using in the forum if you search.

I have now been playing with DashCommand using a ELM 327 wireless Interface to my Ipad, that works either connected to the OBD2 socket under the steering wheel or with the Pacman socket in the engine bay, using that you do need the BMW cable to allow the ELM 327 to be connected to it (Pacman Plug to OBD2 16 pin socket. I use the cable that came with my B800 Airbag tool to make the connection.)

Cheapest way to go is via the Ipad using the Dash Command software, downloaded as an App for about £6 and buy the Interface from ebay for £12 or less. The Inpa package is also on Ebay.

You will save yourself what you would have spent getting someone else to read codes the first time you use any of these setups.

Colb
Colb
1999 BMW 1.8 Z3
2003 BMW 2.5 Z4
1998 Honda Deauville NT650V
Bi11
Joined: Mon 05 Nov, 2012 21:26
Posts: 150

  M roadster S54
Location: Bedford

Re: Intermittent EML...any ideas

Post by Bi11 »

+1 for Dashcommand and the ELM327. With an intermittent fault you can read the code, clear all error codes, and reset the light each time it comes on. You can then see if it is the same error code occurring each time without having to spend £60 to get it read.
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