E30 Zone

Hi Guys,

I am new to your forum from Australia. I have had starting problems for awhile now and am keen to fix it cause it is really annoying. A few months ago i took my car in for a service to try and fix the problem and it came out fine. They replaced the rotor cap, ignition leads and spark plugs etc. the usual stuff on an ignition tune up. The car was fine but now two months down the line the problem has come back. When the car is hot it takes a very long crank before the engine starts. Before the tune up i would need to crank twice in order to start. Now its just once, but its a very long crank and its getting worse. 90% of the time it starts straight away on a cold start, every so often needing a long crank. But the problem occurs nearly all the time on a hot start. Also, when it does start after a long crank, most of the time it gives a bit of a splutter then idles.
It is really annoying and need it fixed. I am hesitant to take it to my BMW specialist and have him work on it and cost me a fortune without having an idea what the problem is. Before the ignition tune-up he said he fixed some loose wiring which fixed the problem for a couple of days then it came back. After that he did the ignition tune-up, worked fine for two months, now its back. I can't afford to keep taking it to him every time, its costing me a fortune.

Any help please. I have heard of it possibly being the crank position sensor.

Welcome boo. Not sure if it,s relevant to your problem, but my 325i suffered from something very similar recently.
The removal of a an aftermarket immobiliser has cured it, What model E30 do you have mate?,

I have a 320i sedan. I don't have an immobiliser though or any other alarm system installed.

hi boobouna,
Check all your hoses, and make sure they are not perished. You could have a split in an air/vacuum pipe causing the problem, though you would expect to see some kind of problem when cold too.

Small hose to your vacuum advance (if car is L Jetronic - though from the 88 age it shold be motronic) and the big pipe from the AFM to the throttle body are a good start.

Has anyone adjusted the idle speed or any other settings (AFM etc)??

Yeah its Motronic. I don't believe anyone has fiddled with the idle speed or settings, all i know is the work that has been done on it without going into details like setting adjustments.

Thanks for your help mate

Could be the Blue temp sensor?

I've got a similar problem with mine - fires up when really cold, but when warm it can take several attempts, which is embarrassing. The problem is much worse in summer. From what I've read here it would seem to be the blue sensor. I'm having the valve clearances done soon and will get the sensor changed as well as replace any suspect hoses/pipes.

Sound like a fueling issue perhaps. Might be worth checking the fuel pressure from the fuel pump. I had exactly this problem, car would start fine in cold or 1st thing in the morning, but once warm would take a hell of a longtime to start. I bought a pressure gauge and plumbed it inline after the fuel pump and found out that the pump wasn't holding pressure, hence having to crank the engine over and over while the pump would build the pressure back up.

Sounds good guys, i will take these all on board. It is embarassing trying to start it and everyone is looking at me. I also researched and found out it could be the fuel system check valve.

If you manage to get a pressure gauge, you can eliminate a lot of things of your check list through the process of elimination, as you'll be able to test if you have a fuel leak in the system, a pump fault, injector fault, fuel regulator fault. Def a good tool to have.

before you start pulling you fuel rail apart, as eko says the first thing to check is the blue temp sensor, its located toward the front of the engine just under the inlet manifold on top of the cooling water thermostat. (when viewed from your drivers side)

you will find two sensors, one brown which send the signal to your dashboard temp gauge and one blue which tells the ECU how hot the engone is and this alters the fueling accordingly.

remove the plug from the blue sensor and with the engine cold (or as coldd as you can get it in Oz) and using a multimeter set to ohms measure the resistance across the two pins, it should be around 2000-2500ohms. then start the car and let it get to temp or hot. then stop and remeasure, the result should be lower or around 250-350ohms.

perform this check first and come back to us - fault finding is best done one step at a time.

fianlly dont forget you should NOT push the throttle when starting the car - cold or warm

and welcome to the zone!!

mrlee

Any help please. I have heard of it possibly being the crank position sensor.

if it were this it would not start at all