320i l-jetronic no start/cutting out

Post Sun Oct 19, 2014 7:42 pm

car is a 1987 320i running on the primitive l-jetronic engine management.
We bought the car knowing it had a cold start issue, previous owner had aa check it out and was told its the afm?
It starts up and runs but after say 5mins at idle it will cut out and then will just crank no start, come back after 2hrs and symptoms will repeat their self.
we have given it a mini service i.e oil, filters, spark plugs etc.
cambelt is 3000miles old
ive been researching for the past 2 days with no luck please help

Post Sun Oct 19, 2014 10:43 pm

No very little about this really old stuff, but is it possible that it's running on the fifth injector alone, and the main four aren't working at all?
No idea if this is possible, but it would explain the symptoms - cutting after 5 mins when the cold start injector shuts off, and then not starting until completely cold.

Post Sun Oct 19, 2014 10:46 pm

The air slide valve is a common failure item - they seize up:

http://www.e30zone.net/e30zonewiki/inde ... lide_Valve

However, normally, this just results in an overly high idle speed, of over 1,000rpm.

Post Sun Oct 19, 2014 11:02 pm

thanks for the reply gents its an m20 but i don't think it has a cold start injector its the last of the l-jet, today we drove the car round the block all seemed fine until we switched the car off and then it wouldn't start.
I did read about the airslide valve but the car idles perfectly when it does start, could it be the blue temp sensor? as i believe l-jet only controls fuel

Post Mon Oct 20, 2014 9:58 am

You need to ascertain whether it loses spark or fuel when it cuts out and refuses to start and investigate accordingly. Over the years I have replaced a few ignition control units which iirc are on the drivers side inner wing in front of the strut tower.

Post Mon Oct 20, 2014 7:43 pm

ok spent sometime with the car today and it has both spark and fuel when the no start symptoms occur, it seems to be over fueling as their is a strong smell of fuel when it cuts out.
I removed fuse 11 to disable the fuel pump and the car starts and burns off any left over petrol, replace fuse and it will fire up for half a minute and cut out seems to mainly do this when cold.
i'll add a video of it cutting out, im no expert but im thinking fpr or afm?

Post Mon Oct 20, 2014 8:03 pm

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Post Mon Oct 20, 2014 10:04 pm

BMW_E30vert wrote:could it be the blue temp sensor?

Yes, it could well be - a common problem on older BMWs.

Post Thu Oct 23, 2014 9:06 pm

Just an update a new blue temp sensor sorted the problem out, now starts fine all the time every time thanks

Post Thu Oct 23, 2014 10:19 pm

Good to hear that.

Post Thu Oct 23, 2014 10:52 pm

OP said it had a "cold start issue". Duff blue sensor causes anything but a cold start issue. It should start happily when cold (colder the better), and begin to falter shortly after. It will have a "hot start issue", not a cold start one.
OP also says that plugs have been changed. Wasn't anything relevant noted about the condition of the ones that came out!

Post Thu Oct 23, 2014 11:25 pm

Sorry but i may have caused some confusion but yes brian it was a hot start issue the previous owner was consulted by AA that its a cold start issue and this is what we were told when we bought the car.
The car would start but cut out after 5mins(once warm) and then refuse to start, spark plugs were showing signs of engine running rich.