EML Help needed please

[Wavesong]

I have read much on here about EML woes but have not been able to cure mine so wonder if anyone can help please? The car is a year 2000, 2.0l

The story so far is that I left the car outside overnight and there was a frost followed by warm sunshine. When I started the car, it was lumpy and wouldn't respond to the throttle without trying to stall. I switched off, left it for a few minutes, restarted and all was well with no dash light on. The problem then repeated itself a couple of times, garaged or not. I found some splits in the small ribbed hose in the post MAF air intake hose and so logically replaced this and thought that all would be well after getting my local garage to clear the accumulated codes. I left the car out again on a cold night followed by warm sunshine and the problem came back with the same cure as before by switching off for a few moments and then restating. Since, I have driven to devon and back covering over 500 miles this weekend and no issues though power seems a little down and fuel consumption maybe be increased. Can anyone shed some light on this? The last error code was related to a throttle sensor though I didn't get a chance to write down the error code itself. Any guidance on this to avoid arbitrarily changing expensive sensors needlessly would be much appreciated.

[colb]

I would double check all the rubber hoses for cracks, if all ok no splits or cracks then I would be thinking towards the Maf being dodgy.
Did you do anything about the throttle position code it set?

My experience of fault codes are that one code may be the result of something upstream of the fault it is reporting being the cause hence my suspicion of the bad Maf.

Might be worthwhile investing in your own code reader to have instant access to read the codes rather than keep going back to the garage.

Colb

[Wavesong]

Yes, whilst replacing the one rubber hose, I checked all the others minutely and couldn't find anything else. My feeling too is the MAF sensor. As you say, the codes and descriptions are usually best taken as a rough guide and can be very misleading. Would the MAF sensor cause this issue most particularly on start up from cold though or is there another sensor more specific to air and fuelling from cold? In the car's history, there is evidence that an inlet cam sensor was replaced about a year ago. I wonder if it was replaced with a pattern part and would this sensor (wherever it is) cause these symptoms do you think?

[colb]

When I had Maf problem car ran but down on power like you describe, idle was not quite right either, changed idle control valve but that didn't make any difference finally bit the bullet and fitted a Bosch Maf and that solved the problem, also had Lambda issues which were resolved in fitting new pre and post cat sensors again Bosch items, don't waste cash on anything other than oem spec parts been there done that wallet much lighter as a result.
Suspect cam sensor if it sets a code otherwise my money is on the Maf as they don't always set a code in my experience, you could try cleaning it using Maf cleaner but dont touch the wire with anything just spray the cleaner on it and let it dry.
Colb

[Wavesong]

Thing is, the issues are really only with cold starting and clearly a temperature sensor as the frost plus warm sunshine suggest a cold start temperature related issue. Is there a temperature sensor connected with cold start?

[colb]

Yes there will be a temp sensor that will supply its reading to the ecu, best bet if you suspect this is to do a diagnostic check that you can see live data on ie see what the temp sensor is showing, have you access to a live data programme on a laptop?

Colb

[Wavesong]

No, don't have access to that and am reliant on my local garage code reading and clearing for me. I didn't know one could do this live and will have to ask if they can do that. However, its only going to show up on cold start under the circumstances I described. This morning, it was mild and damp, the car started exactly as it should and the idle is even. This is why I am trying to apply some logic and reasoning to the process rather than rely upon being led by the nose by what the computer says. Can you tell me how I identify the temperature sensor and is it straightforward to replace?

[colb]

http://www.realoem.com/bmw/enUS/showpar ... 3621739510

Temp sensor on the intake of the engine no3 in the diagram looks like it screws in with a rubber o ring as gasket.
On my 1.9 its in the airbox beneath the air filter.

A lot of people use the BMW INPA software for diagnostics but it can be a pain to put on a laptop other systems are available and capable of seeing live data from your car, I use Dash-command amongst others and this is simply an App you can use on a laptop or an iPhone using a Wifi ELM 327 interface with a BMW interface cable to connect it to the round diagnostic socket under the bonnet. You can download the software from the web and purchase the ELM interface from ebay. Investing in this as a minimum will save you pounds instead of paying out at a garage to get codes read and cleared.

Cable adapter - http://www.ebay.co.uk/itm/BMW-20-PIN-TO ... SwKIpWBqhP

ELM Interface - http://www.ebay.co.uk/itm/ELM327-WiFi-O ... SwGzlTwoH-

Dash command software - http://www.palmerperformance.com/products/dashcommand/

This setup is about the cheapest way to set yourself up for reading and clearing codes.

Colb

[Del]

My guess is that as you had an error code suggesting a "throttle position sensor (TPS)" error, it is actually the sensor at fault or I have encountered a sticking butterfly valve cause such an error. The valve gets black, sticky carbon around the edge that can cause it to stick. If it is the latter, a good clean with cotton wool buds and carb cleaner should do the trick. Personally, I haven't encountered problems elsewhere that cause a TPS error code.

Having to stop the car, turn off the engine and then turn back on again, is a situation often described by people with an intermittent TPS issue. "Fly by wire" cars often have two TPS sensors - one at the pedal and one on the throttle body. If your car has a manual, throttle cable I suspect it just has one at the throttle body. I am not sure if it can be removed/replaced separately or whether it is integrated into the throttle body?

[Wavesong]

As an update, I have now completed a 2700 mile trek around Britain including the Scottish North Coast 500, John O' Groats to Land's End taking in North and South Wales, over ten days. I saw three other Z3's together on the NC500 and their enthusiasm for seeing another Z saw no bounds. They were clearly having as much as I. The EML light hasn't come back on since or during the trip so I am hoping that whatever the glitch, its been thoroughly blown out by using the car as was intended. I mangoed to destroy two rear tyres whilst in Scotland and had to wait 24 hours for the replacements to arrive at the fitters. Both were worn down to the canvas on the inner edge. Looking at the car, it looks like the rear is low and sagging and wonder whether my rear springs are past their sale by date. Is this an easy job to do?

[Mr Silver]

Yes.
Usual safety stuff about jacks and axle stands apply here.
[1] Start by removing the handbrake cable support brackets either side so that the cables are free in the air. This will save any damage to the handbrake mechanism when you go to the next step.
[2] Remove the lower shock absorber bolt. It may be necessary to lift the suspension arm a tad to get it out, sometimes, sometimes not.
[3] The spring will come out by hand when you've pushed the suspension arm down as far as it will go.
Note1: Depending on what shock is fitted it may be necessary to compress it upwards to replace the lower fixing bolt after you've replaced the spring.
Note2: There may be a round pad under the spring. That is a height adjuster and must be put back.



Hope this helps.

Regards.

[Del]

The Z3 BMW OE coil springs are very high quality steel and whilst they can rust and break with age, I have not known them to sag. The wear you experienced on the inside edge of the rear tyres is often typically associated with cars that have been lowered. Is it possible your car has had lowering springs fitted that are less than premium quality?

[Wavesong]

I don't know if it has been lowered in the past but I doubt it. It sounds a relatively straightforward job to do though so will get a price for the springs and if reasonable, do it as a matter of course.