E90 330i Trouble Starting

Hi Gents

Ok as the title shows, I'm having trouble starting my 330. The problem occurred recently and is only doing it when the car is hot/at operating temperature.

The funny part is that if you got a problem with the battery/coils/injectors and so on the vehicle will fail or battle from cold starts.

Mine only does it after its been parked for a few hours after being driven. If its parked for say 5 minutes or you allow it to cool for an entire day it starts fine, but leave it for 3 hours and it will start but as it gets up to an idle rpm it splutters and the swings for like a second or two longer than normal. A tap on the accelerator helps (now I'm thinking Vanos Solenoids?)

I've ruled the starter out because once it swings and splutters, I immediately switch the engine off and within a second or two I start it again and it starts up normally. Tried this about five times in a row.

I'm confused, need help before I get it checked so I know I'm not being taken for a ride. But for now I'm not really worried about it because the car drives normally. :thumbs:

Crankshaft position sensor perhaps? :dunno:

Sounds like you have a leaking injector (or two) that drips fuel into the piston after being driven, which causes the hard starting when hot.

If the car has been standing for a while, the dripping stops because the fuel pressure drops. When the fuel in the cylinder has evaporated, the car will start normally.

I had this same problem with an X3 3.0i (M54 engine) which was caused by a leaking injector.

Take you car for a diagnostic check to see if any fault codes are logged.

Blue Shirt said:

Sounds like you have a leaking injector (or two) that drips fuel into the piston after being driven, which causes the hard starting when hot.

If the car has been standing for a while, the dripping stops because the fuel pressure drops. When the fuel in the cylinder has evaporated, the car will start normally.

I had this same problem with an X3 3.0i (M54 engine) which was caused by a leaking injector.

Take you car for a diagnostic check to see if any fault codes are logged.

Click to expand...

Problem is that if parked for say 15min its starts fine, won't the fuel still drip by then?

Just remembered now that a few days ago I pulled it out of the garage and parked it outside for the entire day. It moved like 20 meters max and probably ran for under a minute max. So end of the day I had to put the car back into the garage and when I started it, it struggled again. This was the only time it battled on a cold start, but it was a very hot day :bangdesk:

Currently there's no engine light on the dash.

As I said, I had the identical problem. First start in the morning was fine, also after stopping for short periods (say up to 30 min).

If the car stood for an hour or more, it was hard to start and sounded like a misfire (idle stumbling) for a short while (until the excess fuel burnt off).

Here is a short video of the symptoms on my X3:

[video=youtube]

Blue Shirt said:

As I said, I had the identical problem. First start in the morning was fine, also after stopping for short periods (say up to 30 min).

If the car stood for an hour or more, it was hard to start and sounded like a misfire (idle stumbling) for a short while (until the excess fuel burnt off).

Here is a short video of the symptoms on my X3:

[video=youtube]

Click to expand...

Thanks for the video :thumbs:

But mine splutters whilst swinging and then idles like normal. I booked it in for a diagnostic check on friday. Fingers crossed hope its nothing major.

I would do the following:

Clean and swap the Vanos solenoids (posted a DIY for this some time ago), then clean the MAF sensor with some MAF cleaner. I would also remove the engine cover and inspect the Eccentric Shaft Sensor plug for any oil that may have leaked past the gasket (this is a fairly common problem).

When they run diagnostics, ask them to check the Smooth Running of the engine, this will check the injector timing for any discrepancies - I had some dirt in the fuel rail on mine which was causing injector 1 to stagger all of the other injectors, so there was an over-correction on cylinder 1 that was being picked up. But it was only when the injector was removed and the fuel rain inspected that the dirt was found. The injectors and fuel rain was then cleaned in an ultrasonic bath and the injectors were running perfectly within spec again. This was done at Garage 808 down here. What was a concern was that this problem could have been anything as simple as a dicey coil pack, plug or injector, but then even more worrying, a leaking valve! Luckily it was just some dirt in the fuel system! So worth running some injector cleaner every now and again, and DON'T allow your fuel tank to run very low, certainly not much after the reserve light has come on!

Hope they can sort this out for you. I am still battling with a pinging issue on mine! :nonono:

Much appreciated Philip. Will certainly check on these items that you pointed out.

In fact I did search for your thread when this issue did start last month.

Will let you guys know what's the outcome.

One good point thou is that the vehicle's running normal once started, no complaints there.


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ASH M said:

Much appreciated Philip. Will certainly check on these items that you pointed out.

In fact I did search for your thread when this issue did start last month.

Will let you guys know what's the outcome.

One good point thou is that the vehicle's running normal once started, no complaints there.


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Keep us posted! :thumbs:

So I got the car checked out today. Only got one fault on the ECU.

Picked up an Catalytic converter fault. Seems when it gets hot and is parked something expands and blocks the exhaust.

Anyway I got the codes cleared and was instructed to check if the car still has the problem, if so I must let it log for a few days and get it hooked up to the diagnostic machine again to see if the fault appears again.

I can see myself doing the exhaust and software here. Wanted to do it but decided against it as I want to sell the car later in the year. Now it looks as if I'm probably going do to it anyway.


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That's very interesting! I know that there are some cats that begin to fall apart or collapse inside which can cause a rattle, but possible restrict exhaust gases to a degree. But I gather this is maybe something else in the exhaust system somehow that is causing this blockage in the exhaust system.

Keep us posted! :thumbs:

Got the car on the diagnostics again, the catalytic fault is gone. However I'm getting a Thermostat open fault code. Now I know that these cars have a water pump and thermostat problem but that's not going to cause my starting issue.

Now after some research this is what I found,

"Q
I have a 1998 528i touring with 115,000 miles that starts fine when cold, but starts hard (cranks about 2-3 seconds) when hot. If I start it in the morning it starts immediately. When at operating temp (after driving to work), if I turn it off and then try to restart, it will start right up. However, if I let it sit 30 minutes to a couple of hours, it takes some cranking to fire up (will sometimes kick when cranking but takes much longer than is normal). Problably been this way for 3 or 4 months. When it does start, there a fuel smell in the exhaust like it’s running rich …. only on start up. When it’s running, it runs fine; smooth, good idle, good power. No lights lit on dash (Check engine, etc). Spark plugs and all coils (from you guys) were replaced about six months ago. Air filter is a K&N drop-in filter and is clean. Everything else is stock. Fuel filter is about a year old. O2 sensors were replaced and Mass Air Flow sensor was cleaned three weeks ago. I replaced a couple of cracked air hoses around the intake and idle control valve. I’m all out of ideas. Any help would be greatly appreciated.

A
The symptoms that you’ve described would be consistent with a faulty engine temperature sensor. All BMW models with electronic fuel injection (L-Jetronic, Motronic and all late model applications) use a temperature sensor that monitors the engine coolant temperature and reports back to the ECU (Engine Control unit). In this case, the net effect is that the sensor is “cooling down” too quickly and causing the engine management system to richen the fuel mixture (because it thinks the engine is colder than it is) which floods the engine. The short shut down periods are OK, as the sensor has not started to detect a slight drop in engine temperature yet. However the mid-length shut down periods allow the sensor to start to detect that the engine temp is decreasing and the faulty sensor changes its resistance too quickly …. showing a signal to the ECU that is incorrect. Finally, the longer periods, allow the engine to actually cool down to the point where it can handle the sensor’s resistance change (and corresponding ECU mapping)"

So I've decided to change out the sensor but before I do so I'm going to BMW to have them do their bit and get a second opinion.

Not to disappoint or prevent you from doing this, but these temp sensors rarely fail, well, this is what I was told long after replacing both on my 330i which of course made no difference with regards to my car's issues. There is a oil/coolant temp sensor located at the filter housing / heat exchanger, and then another one from the radiator hose - have to drain the coolant to change that one.

Out of interest, have you checked the engines operating temperature via the hidden menu? This will show the coolant temperature in real-time. Ideally one needs to have live data read which will show the engine oil / coolant temperature and then also the coolant temperature from the radiator.

I am battling with a pinging issue for the last two year almost and have been to many places including BMW when it was doing this and still under motorplan (they could not fix this and started with their "this is normal BS"). Have already replaced a multitude of costly parts and just not winning. I do have a cooling issue which can only be the thermostat being partially stuck open, but this is not causing the pinging since it does this even when the engine is still cold, and is particular bad with this hot weather when at operating temperature. The thermostat is not throwing errors, but the engine is running cooler than it should, so will eventually replace this, but first want to sort out the pinging - not willing to throw more money at this car until then!!!

Thanks Philip, will look into the hidden menu information.

But I'm willing to change the sensor first as a trial and error repair. Because BMW themselves don't know what to do and want to charge me an arm and a leg to keep the car for a week minimum.

The sensor in the hose you talk about doesn't effect the ECU so I'm ruling that out for now. Sorry to hear about the pinging issue. Have you checked the vehicles timing or fueling system? Corroded fuel pump relay maybe.


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ASH M said:

Thanks Philip, will look into the hidden menu information.

But I'm willing to change the sensor first as a trial and error repair. Because BMW themselves don't know what to do and want to charge me an arm and a leg to keep the car for a week minimum.

The sensor in the hose you talk about doesn't effect the ECU so I'm ruling that out for now. Sorry to hear about the pinging issue. Have you checked the vehicles timing or fueling system? Corroded fuel pump relay maybe.


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Well, that sensor is not too expensive and easy to replace, so worth a shot! Have zero faith in the agents! They let me down hugely with this problem that my car has!

The only way to physically check the timing (assuming there are no error codes to show a timing issue) is to remove the valve cover and set it with the timing tool - not going to fork out R5k plus for labour if there is no proof that the timing is out. Fuel system is something that I considered and had the injectors and fuel rail cleaned end of last year. Somehow this feels more like a sensor issue than fuel starvation - has no problem if you gun it.

Frustrating problem - even Garage 808 is at a loss with this one!!

Sensor changed and the fault is still there, no idea where to go from here :thumbdo:

Sorry to hear that there is no change - I know how this feels!

Have you tried checking the hidden menu to see what the engine coolant temperature is doing (menu 7 after unlocking menu 19)?

I wonder if there is not an issue with the fuel pump or fuel filter/regulator??

Yep thanks for that suggestion, I did monitor it for a while.

It goes up to 80 degrees and more or less stays around there. It moves to just over 90 in traffic on a hot day but then the fan kicks in and immediately drops back into the 80s.

My second suspect was the fuel pump relay with dirty/corroded contacts, causing havoc with getting too hot an cold again. But these cars don't have a relay, rather a fuel control module.

Next on the cards is to hook up a fuel pressure gauge via the test port on the fuel line before the injectors. Check if it's holding its pressure and if the pressure is constant at "warm" start up.


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ASH M said:

Yep thanks for that suggestion, I did monitor it for a while.

It goes up to 80 degrees and more or less stays around there. It moves to just over 90 in traffic on a hot day but then the fan kicks in and immediately drops back into the 80s.

My second suspect was the fuel pump relay with dirty/corroded contacts, causing havoc with getting too hot an cold again. But these cars don't have a relay, rather a fuel control module.

Next on the cards is to hook up a fuel pressure gauge via the test port on the fuel line before the injectors. Check if it's holding its pressure and if the pressure is constant at "warm" start up.


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Click to expand...

Yours is then suffering from the same "over cooling" issue that mine is - sitting around 80 degrees mostly and maybe briefly going up to the mid 90's for a few seconds before shooting back down again. Except my car does not show any faults saying that it is a faulty thermostat! But obviously it is - and even a few minutes after a cold start I will hear the cooling fan come on, so will just have to replace the thermostat and coolant one of these days.

Correct, the best is to have the fuel rail hooked up to a pressure gauge so that the pressure can be tested from the fuel pump, and then they should also perform a bleed test which means leaving the pressure gauge connected for an hour or so after the car has been just sitting - there should not be a massive drop-off of pressure from what I understand. There is a vid of youtube where a guy shows this test - luckily our engines don't have the high pressure fuel pumps that I gather the N53 have...

PROBLEM SOLVED!!! :rollsmile:

Thanks for all the help guys, much appreciated. :ty:

However this ordeal has left me feeling some what depressed :thumbdo:

Basically I haven't driven this car for 3weeks now. My brother is using it from the weekend and its back to its normal self.

A few weeks ago after a long trip with the car, I noticed that the engine fan was always on when I stopped at a toll road. Even after this 5hour run the bonnet was cold to the touch. Now I did get a thermostat fault on the diagnostic the second time round and Philip did warn me that the car was running too cold. So I just ignored this for a few weeks saying to myself that I'll get around to it soon.

Anyway after the long run the car's fan was immediately kicking in on start up. So I knew the thermostat was at its end. Used the car for a day that weekend where it failed to start with white fuel pouring out of the exhaust and a smell of un-burnt fuel, had to get it towed home. Parked it for a few hours were it did start up as per normal. So during the week I had the thermostat changed out and again once the car was started the fan was kicking in. This leads one to the water pump. Lucky I never change it as I allowed the car to adapt after a few km's, so the fan actually started working normally.

Come next day even from cold start the car refused to start with keeping your foot on the accelerator, even with your foot on the accelerator it was misfiring badly and immediately after taking your foot off the engine will die.

Up till this point there were still no engine light on. I then got it hooked up to the diagnostic machine again, cleared the thermostat code but noticed that there were two codes of the temperature sensor, yes the same sensor that I previously changed. Cleared all the codes and one of the temperature sensor codes popped back up. This lead me to change out that sensor again and get the codes cleared.

All in all the problem has been solved:joy::joy::joy:

So basically the thermostat and temperature sensor caused the engine to run too cold making the fuel mixture way too rich even when the engine was hot (after the thermostat was changed and the engine was running at normal temp).

Hope this helps guys as BMW and independent mechanics or so called BMW specialists failed with the car. :thumbs: