Engine stuttering upon start up?

[Tj303]

Hi all

I'm not sure if it has always happened, but i noticed now especially when starting the car from a cold start that the engine seems to stutter a little every 5 seconds or so. It's almost like the engine is being momentarily starved of fuel.

It's most audible as an interuption in the exhaust burble, but doesn't really seem consistent with what noise should be coming from an exhaust burble i.e. a constant sound.

Could this potentially be a fuel pump issue? Or is it quite normal?

Cheers

[Si-M240i]

mine has always been a little "lumpy" at tickover, but it goes like Sh*t off a shovel, so I don't worry about it.

[crex]

I noticed mine is starting to do this as well. It is probably the hpfp that seems to plague these engines.

[RPM90]

I've test driven 2 135i's in the past week. 1 vert and 1 coupe. Both, had an surging and rough cold idle. However, after about a minute to warm up, both engines calmed to a dead steady and creamy smooth inline6 idle.

These new direct injection injections require ultra high fuel pressures & pumps. So, if the engine sits cold for a certain amount of time, cold start idle is off/odd until the whole system warms completely, which takes no time at all.
My A4 2.0T has this cold idle condition if I don't drive that car for at least 2 days.

[BrokenVert]

My car has a missfire when its cold. But I do notice a bit about what you saying. I guess we need to wait until the thing finally goes.

[bimmerboy]

i notice the same thing, during a cold start/idle, for the first 20-30secs it sounds like the engine is knocking or cutting out very quickly, but once it settles down its fine. Performance is still fine too, so i'm guessing its normal?

[lacrosse]

I have a similar problem. My car starts hard (long cranks) especially when cold/damp and sitting for more than an hour and will occasionally be very rough at idle until warm. Then it is OK. It is going in Friday (5/15) for a check up by the dealer. I am not too hopefull as the dealer said over the phone "Are you sure you are using the right octane gas?" WTF I've had the car for a year and I suddenly forget what gas it takes? He then said he had never heard of a 1er doing this. Again WTF? Doesn't he know that the N54 is used in more than the 1?

Note: There have been no CELs at all. This is a recent phenomenon.

[crex]

Originally Posted by lacrosse

I have a similar problem. My car starts hard (long cranks) especially when cold/damp and sitting for more than an hour and will occasionally be very rough at idle until warm. Then it is OK. It is going in Friday (5/15) for a check up by the dealer. I am not too hopefull as the dealer said over the phone "Are you sure you are using the right octane gas?" WTF I've had the car for a year and I suddenly forget what gas it takes? He then said he had never heard of a 1er doing this. Again WTF? Doesn't he know that the N54 is used in more than the 1?

Note: There have been no CELs at all. This is a recent phenomenon.

Let us know what they say. Mine runs fine after warmup so I have not taken it in yet but will soon.

[xantdieselx]

I swear mine sounds a bit raucous when I first start it (cold). It's almost un BMW-like but after about 30 seconds it's totally mellow and relaxed. I actually like it. It makes me think that the beast within needs a minute to wake up...kinda like me when I haven't had my coffee yet.

[RPM90]

Originally Posted by lacrosse

I have a similar problem. My car starts hard (long cranks) especially when cold/damp and sitting for more than an hour and will occasionally be very rough at idle until warm. Then it is OK. It is going in Friday (5/15) for a check up by the dealer. I am not too hopefull as the dealer said over the phone "Are you sure you are using the right octane gas?" WTF I've had the car for a year and I suddenly forget what gas it takes? He then said he had never heard of a 1er doing this. Again WTF? Doesn't he know that the N54 is used in more than the 1?

Note: There have been no CELs at all. This is a recent phenomenon.

It's the fuel system pressurizing, that's what I think.
DI requires HIGH pressure. On a cold engine start, the air/fuel mix needs to be even richer to atomize fully. So the computer is requesting more fuel, but the pump isn't fully up to pressure, so it takes a bit time for things to normalize.

I can why where a fuel pump that might not to fully up to spec could cause this condition on every cold start, and not just when the engine hasn't been started in an couple of days, and thus the system needs to be fully pressurized to give a good cold start.

Your fuel pump might be having some issues, and this poor cold start everytime could be an indication of a pump that will eventually need repair or replacment.

My A4 2.0T FSI has an issue where sometimes it won't start on the first try. This happens a LOT on very cold mornings, or when the car sits for longer than day. This happens on a lot of the 2.0T FSI engines.
One thing I've done is to turn the key to the "on" position and let it sit there for a 10-15 sec count. This helps pressurize the system, and the start is always hardier and smoother. If I simply insert the key and go straight through to start, I get this cold start issue.

I can see with the push button start how this can be a problem, because don't have a clear way to pressurize the system before a cold start.
But, try pushing the start button without pushing on the brake or the clutch, before you start the engine. This should help pressurize the system, then push on the brake or hold in the clutch and start the engine normally. See if the cold start is smoother and easier.
Report back.

[JHZR2]

I noticed this on my first test drive of the 1-series, on an AT coupe M-sport at a dealer.

My second test drive was an MT, and didnt exhibit this!

[JHZR2]

Deposits. See my other posts on oil and DI deposits. I'd get Redline SI fuel injection cleaner in there in all 135i vehicles. The chemists at redline have indicated that it makes its way through the combustion process, and so it will go through the crankcase ventilation, etc., to keep injectors, valves, etc clean.

[RPM90]

Originally Posted by JHZR2

I noticed this on my first test drive of the 1-series, on an AT coupe M-sport at a dealer.

My second test drive was an MT, and didnt exhibit this!

I drove a sportronic and it did this, a few days later I test drove a manual coupe and it did it too.

As I said, my 2.0T does it too, but not to the extent that the TT 3.0 does.
The 2.0T does it mostly when it's also very cold and the ECU/ECM wants more fuel. The BMW seems to do it even when the weather is warm.

Is the oil change interval still 15k, even with the turbo's?

You've mentioned this "gunk" issue on a few threads. There is "blow-by" in every engine. FI engines tend to get more of this due to the fact that the combustion chambers see an extreme amount of pressure.
But, in every engine there will be some fuel that seeps into the crank case, just like a bit of oil may find it's way into the combustion chamber.
FI engines would have more of tendency to seep fuel into the crankcase due to the high pressure intake.

Over time the oil can become more diluted than a NA engine. So, I am curious if BMW still does 15k mile oil changes. Synthetic oil is amazing stuff, but it can't do much about fuel in the oil.
Sludge though, tends to build in hot spots of the engine in the oil path where there are tight bends and it tends to get very hot in those areas. Over time sludge builds. But, sludge is typically created by dirt/dust contaminated oil, not from diluted oil.
Not changing the oil filter enough, or not changing the air filter often enough is what leads to more solid contaminates building in the oil. Then, as this thicker solids filled oil move through the oil pathways, it tends to stick easier and starts to create blockage. This very much blocked arteries in blood stream.

Blow by fuel dilution will make the oil thinner and not as viscous as it should be, so it can't protect as well, but sludge is a different problem.

Now, with turbo's and their high heat can create more "coke", which is created by oil that reaches it's flash point, and then burns leaving behind a residue called "coke". Coking is awful for bearings, especially turbo bearings as it will cause excessive wear. This same coke will also contaminate the oil with it's solids and it can add to a potential sludge problem. But, if you are using synthetic, the it is very unlikely that you will get a coking issue, because synthetic has very little "ash" content. These are solids typically found in non-synthetic oil. Mobile 1 has nearly 0% ash content, so it's not likely to create a coke issue under high heat, thus not likely to add to a sludging problem. Check the synth oil you are using and make sure it has 0 to nearly 0 ash content.
This was a much bigger problem with older turbo setups where the oil would sit on the bearings once the engine is shut down. After a hot run the turbos can be orange/red hot, and if you shut off your engine without a cool down, you took a chance on letting the oil sit on the turbo's bearings and literally cooking, and creating coke.
Thus, the reason why turbo timers were a big thing, as it would circulate the oil after shutdown. Modern designs use methods to keep the oil circulating so as to not sit and cook on the bearings.

Do you really think this engine is prone to sludging?
It's been out for at least 3 years, and I haven't heard much about sludging in this engine.
Audi did have an issue with the 1.8T engine, but it was related to the type of oil used and the longer drain interval, but it was also traced to people not cleaning or replacing air filters as they should. Toyota has this problem too on their highly regarded V6.

[lacrosse]

Thanks for all the comments. I'll be sure to report back!

[JHZR2]

Originally Posted by RPM90

Do you really think this engine is prone to sludging?
It's been out for at least 3 years, and I haven't heard much about sludging in this engine.
Audi did have an issue with the 1.8T engine, but it was related to the type of oil used and the longer drain interval, but it was also traced to people not cleaning or replacing air filters as they should. Toyota has this problem too on their highly regarded V6.

RPM,

long story short, yes, and more. The lack of ability to operate as stratified charge, and given the multitude of issues that are well known ans starting to be disclosed by VAG, mitsubishi, and others who offer DI engines makes it more compelling. Ill post more data tonight or tomrrow.

[RPM90]

Originally Posted by JHZR2

RPM,

long story short, yes, and more. The lack of ability to operate as stratified charge, and given the multitude of issues that are well known ans starting to be disclosed by VAG, mitsubishi, and others who offer DI engines makes it more compelling. Ill post more data tonight or tomrrow.

I look forward to it. Thanks.

I'm very interesting in seeing how DI is affecting "sludging".
I'll look up some stuff on it too.

[lacrosse]

Confirmed victim of the HPFP failure!

[cagekicker]

hpfp?

[JHZR2]

Originally Posted by RPM90

I look forward to it. Thanks.

I'm very interesting in seeing how DI is affecting "sludging".
I'll look up some stuff on it too.

I put a decent amount of information into the thread here:
http://www.1addicts.com/forums/showthread.php?t=262365

Most of the data pertains to VW DI engines, so it may be of use. The last thing I posted in that thread, was more or less an acknowledgment of the issues on part of VAG. Mitsubishi has started making claims about issues on theirs, and toyota still has a port injector in their designs because of the inherent issues with straight DI.

[lacrosse]

Originally Posted by cagekicker

hpfp?

HPFP = High Pressure Fuel Pump (something insane like 30,000 psi).

[mattssi]

I've noticed the same thing the past few days on my 2010... just over 500 miles. When I started it in a garage today, it was very noticeable due to the acoustics... rev'd high, and was smooth, but for a couple seconds got rough, car shakes a tad, exhaust sounds funny, but eventually it calms down, gets quieter and is ready to go.

Sort of worrisome.

[Simsims]

Liquid RARELY compresses at all


Once the pump spins the pressure will immediately be at maximum

Unless there's something about the pumps taking time to spin up/down (which I can't see happening), the gasoline in the lines should be under pressure as soon as the pump starts.