Engine starting Issues. Help! :(

[calbens]

Hi guys
It's been a long time since I've posted on here so I hope you are all still going strong and loving your Zeds

As some of you may know, I've owned my 22 yr old, 2.0L Z3 for many years and most of them it's been my daily drive and it's been faultless, until now.

Over the last few months its started playing up where it won't start straight away even though I'd started it first time then drove to the supermarket, come back to it an hour later and it refused to start. When it did finally start, I put my foot on the accelerator and the engine cut out. I turned it over again and it basically cut out again.
My husband over the phone said try putting it in reverse, start the engine and see if it will go and it did but the acceleration was really poor and it felt like it was trying to cut out on me.

So I managed to drive it with lots of revving across the road to our regular garage and switched off the engine. 5 minutes later the mechanic came to look at it and it started first time, no problem.
The mechanic seemed to think it was because I wasn't using premium fuel (since the changes) so he recommended swapping to premium which I did and after at least 2 full tanks it's not made a bit of difference.

If anything the fault is getting worse and it's continuing to be random. If the engine starts first time I know I'm going to get to my destination fine but, there's no guarantee that it will restart once I've turned the engine off and come back to start it.

On the occasions it has faltered when I've started it and got it where the engine doesn't cut out on me and I'm able to drive it with a very heavy foot it's ok ish, but as soon as I come to a low speed, say coming up to a junction, the engine has died before I've come to a stop....It's actually done this twice now and I was lucky not to have an artic in the back of me on the first occasion. Very scary?

So now my poor zeddy is sat on my drive going nowhere as I really can't trust her.
The garage doesn't seem to want to do anything because nothing is showing up when it's been plugged in for diagnostics. So I though as a last resort before it goes for scrap, which would truly break my heart, that I would ask here and see if anyone has had anything similar happen to their Zed and if so were they able to rectify it? Or does anyone have any suggestions that I could try?

Cheers guys and sorry it's a bit long winded
Bex

[LaRy]

My guess is that you could have a problem with the idle air control valve. In idle and low speed, the intake air is using a totally different way at idle. It is really a bypass.
This control valve is controlled by two electrical coils, in order to get a seamless control . It can be broken or just dirty and stocked. I had to clean mine a couple of weeks ago, because the engine reved up to almost 2000rpm straight at start, just for a short moment. Especially if the car had not been driven for a week.
The valve can be changed or cleaned in an hour. The valve is rather expensive from BMW, but you can find a lot of copies, much cheaper.

If you are looking for fault codes, the valve has no feedback if it is working. The fact is also that an engine not starting is not setting any fault codes, especially not in the old days. Reason, the time from starting to running would set so many fault codes, that it would been useless

Of course, you could also have problems with fuel supply, like fuel pump pressure. Fuel pressure has no supervision or fault code.

[LaRy]

Someone else had problems. Starting and dying. It was the air mass flow sensor. No fault codes.

[Robert T]

Hi Bex. It doesn't sound terminal, just needs a little bit of fiddling to find the fault. MAF issues are known to cause starting problems and the simplest test is to just unplug the MAF. The car will then run on default values and should start and run. Camshaft and crankshaft sensors can cause similar problems and they can be intermittent. They don't always log codes when they start to go bad. ICV would be another possibility. Do you have a decent BMW indy you can take it to? I can pop over and read codes for you, but it sounds like you've already done that.

Cheers R.

Sent from my SM-G991B using Tapatalk

[calbens]

Thanks LaRy and RobT for your help, I feel more optimistic now that I've read your replies that it can be sorted.

We do have an independent BMW garage but after previous experience with them I wouldn't entrust any car with them again.

We've always used our local garage and they've looked after the Zed for all the time I've had her.
I think when we asked them to look at her they we're overwhelmed with cars coming in after covid and staff shortages that I think they probably passed the Zed off as too much hassle.
I must add that when it went in for its full service about 5 months ago they said the spark plugs had seized in.
So I think with them telling us that and this random starting fault which they don't believe has anything to do with the plugs, We've thought it's probably not worth fixing. But I can't bare to part with it because when she start first time she sounds and runs beautifully.
I will admit to a good few tears at the thought of not being able to keep her going.

Thanks again for your suggestions. Neither of us are mechanically handy so we're going to book her in and get them to check and change the sensors you've suggested. Fingers crossed it works
I'll keep you posted
Bex xx

[LaRy]

RobertT wrote: MAF issues are known to cause starting problems and the simplest test is to just unplug the MAF. The car will then run on default values and should start and run.
You don't have to be handy. Look at my picture showing a MAF unit. The unit itself is probably looking the same as in mine. You see my hand. Just twist the connector 90 degrees counterwise und drag out the plug when it doesn't start. If the engine starts, buy a new MAF. That is the square box with the connector, fasten by two screws. fasten to the round unit. Simple as that.

A lot of technicans cannot repair cars, if they don't get a fault code. That is a problem. The fact is that all values are crazy before it actually runs in a proper way after a few seconds. For that reason, the system does not record initial starting problems. The technician has to use the brain and old fashion methods for trouble shooting.

[calbens]

Cheers for the photo Rob
I've had a look and I think I've found it but mines a clip not a screw (I'd post a pic if I hadn't forgot how to lol)
I've tried googling and youtubing to see what I do with the clip but I can't find anything and I don't want to prod or pull in case I break it .
I'm going to see if I can add a photo, I might be a while

Ok I haven't worked the photo out but I did manage to get the plug out. It was a simple push the clip down and pull the plug out... Result! So now I just need to be patient and wait for it to not start so I can try and eliminate it.

[LaRy]

Maybe your connector is looking more like the connector shown above my hand in the picture. In that case you just press the metallic clip down, at the same time as you pull out the connector.

[calbens]

So since my last reply, sods law, the Zed hasn't faltered
I'm puzzled as to why not, because prior to being sat unused on the driveway for 2 months, the fault was a regular occurrence to the point I would dread having to stop the engine in case it wouldn't fire up properly again.
The only difference now, apart from me not driving it, is Vivs using it to commute to Carrington every other day for work so it's getting a fair blat down the motorway.
Could it be the battery is getting a better charge rather than me doing local 8 mile runs daily? Because the only other thing I've done is unplug the maff plug and re plugged it in. Sigh!
I'm sure we'll find out sooner or later and when we do, you'll be the first to know

[LaRy]

Great that it is working again. Could be a better battery, could also be that the idle control valve is not getting stocked because of sticky dirt. The reason I had to clean my valve was that the engine went up to almost 2000rpm at start, if the car had not been used for a couple of weeks. It could be stocked "in the other direction", in your case. If I started it every day, no rpm rush at start. So I believe it was a sticky dirt problem in the idle control valve.

But it can also be the connector. When I cleaned my idle control valve, I had to get some new hoses, so I made the job twice. Second time the engine went so poor that it actually stopped. Reason and solution, disconnect and connect the electric connectors again, to get a proper connection.