Vanos or injectors. Not necessarily fault codes if they are faulty. Also PROPERLY check all the other air hoses. 80% chance its still an air leak. The simplest thing to check is to remove cable from MAF and see if it affects on idle.

 

Vanos or injectors. Not necessarily fault codes if they are faulty.

Yes VANOS can be considered. But how its injectors, as the jerk goes away after few seconds of engine start..?

Also very rare , i feel the car accelerates with much strain rather than the smooth peppier acceleration.

 

Not the injectors and doubtful the VANOS seals are the primary problem.

Suggest you read all my comments here - http://forum.e46fanatics.com/showthread.php?p=16727145

 

I had gone all through that (Thx for the whole write up). But really no time & provision to carry out all those and that is why i wanted a quick resolution.

try resetting your adaptations via PA Soft. I have a similar issue on start up whenever the weather cools down here (ambient below 50). Car acts like it wants to stall, then catches itself and smooths out for a few seconds, then the idle skips again. No codes, ever. Last winter, I replaced every suggested maintenance item, had the car professionally smoke tested and even went so far as to delete my SAP thinking I might have a vacuum leak within that system. After I did the delete, I had the local bmw dealer reset my adaptations as part of flashing EU2 onto my DME. This solved the problem. This year, as the weather has cooled off again the idle hiccups returned. Made a quick trip back to the dealer, had them reset my adaptations and no more hiccup. Long story short, since you have PA soft, reset your adaptations if you haven't already done so.

Ahh. That is my favorite one. Always does that . But it doesn't solve the problem in my case as mentioned by jfoj , as its some thing mechanical. My car never acts like it wanna stall. Its only a jerk on the engine for a few sec's. And it goes away 95% once the engine is warmed up within the first 20~40 Sec's. Remaining 5% jerk always there on idle. But however, there is no fluctuation on the engine rev needle on idle. That 5% jerk completely goes away if i accelerate the car past 3000 RPM.

Resetting Adaptions is only a partial/short term solution IF it actually improves things.

Everything maintenance wise, even a weak fuel pump can cause cold start problems.

Really have to do your homework to also rule out even a bad/leaking power brake booster.

Fuel Trim values give a lot of insight as to what may be going on.

a tired fuel pump gave me those symptoms

So far two votes for fuel pump. Keep coming guys impin:

@jfoj

You always mention about fuel trim and stuff. Tbh , i have no idea what it is and how to measure it.:tsk:

Can you please elaborate on that ? :hmm:

 

try resetting your adaptations via PA Soft. I have a similar issue on start up whenever the weather cools down here (ambient below 50). Car acts like it wants to stall, then catches itself and smooths out for a few seconds, then the idle skips again. No codes, ever. Last winter, I replaced every suggested maintenance item, had the car professionally smoke tested and even went so far as to delete my SAP thinking I might have a vacuum leak within that system. After I did the delete, I had the local bmw dealer reset my adaptations as part of flashing EU2 onto my DME. This solved the problem. This year, as the weather has cooled off again the idle hiccups returned. Made a quick trip back to the dealer, had them reset my adaptations and no more hiccup. Long story short, since you have PA soft, reset your adaptations if you haven't already done so.

 

Resetting Adaptions is only a partial/short term solution IF it actually improves things.

Everything maintenance wise, even a weak fuel pump can cause cold start problems.

Really have to do your homework to also rule out even a bad/leaking power brake booster.

Fuel Trim values give a lot of insight as to what may be going on.

 

a tired fuel pump gave me those symptoms

 

What's the mileage of the car and are the coils original? Reason I ask is because many people have experienced similar symptoms and it ended up being a coil going bad. It hard to diagnose but if you have high mileage replacing the coils may not be a bad idea regardless.

 

Its ~185000 KM.

Unfortunately with these cars there is no silver bullet or easy solution.

You are dealing with a 14-15 year old car and I have to assume in the region you are located with the high ambient temperatures a lot of the plastics and rubber parts under the hood are shot and in need of replacement.

With cold start problems for the first 30 seconds or so the engine is not even in Closed Loop so anything that will cause a Lean mixture will cause a rough/uneven idle.

Something like a fuel pump will get weak and not seem like an obvious problem. They are cheap enough, at least here in the US that it is wise to get this out of the way, replacing it rules out the pump as a problem.


Here is the deal, once you can gather data there may be a glaring problem that will jump out at you, or there may be things you can rule out. This is a game of Treasure Hunt. You sometimes find the Treasure by following the clues, sometimes you find the Treasure by looking under each rock and ruling things out. It is not an exact science. Also many times it is kind of funny how people have spent time and money with professional shops that get nowhere and with a cheap smart phone App and some common sense and using the process of elimination someone with little technical skill can either identify and/or repair the problem themselves.
.

If you want things done properly you remove the injectors and send them out to a specialty shop for cleaning and refurbishment. Most better shops do a flow rate before and after testing so you will know that there were a few questionable injectors or there was not much of a problem. Again, does your car need this, do any cars need this. You will only know if and when you perform this service.

Most things start with basics of fresh filters and spark plugs. Looking for oil in the spark plug wells, looking for questionable coil boots or a coil that looks like it should be replaced. Smoke testing the engine and crankcase are important. Making sure the oil fill cap and dipstick O-rings are in good shape and tight. Using a OBDII tool and removing the oil fill cap while the engine is running and warmed up to see what the Short Term Fuel Trims do.

Monitoring the Fuel Trims and Logging data from cold start, at idle and highway cruise. We have found a lot of car with replacement or degraded MAF's. These are hard to identify because a MAF degraded by 4-10% it really hard to flag. There are also a LOT of counterfeit Asian sensors on the market that do not work properly. Things like the DISA need to be removed, inspected and the large O-ring needs to be replaced. We have seen failing/leaking power brake boosters. The power brake boosters are starting to fail around year 12 on these cars and are often overlooked. Sometimes you need to plug the line to the power brake booster or the sucking jet pump and try a cold start to see if any of these things improve the cold start problem.

First of all big thanks jfoj for your time and help.

Yes its damn hot on summer in our country, reaching up to 50C & above.

As you advised, i have bought the OBDFusion and connected it with the bluetooth adapter. Seems to be that the app is real professional and informative. However i have no idea where to start on it.:eeps: . Perhaps you expert can help on it . On a glimpse, it showed no stored errors and some where i saw the fuel trims value as -40% or something.

By the way i checked my MAF, and its the real siemens stuff. No asian or 3rd party MAF there.

 

Unfortunately with these cars there is no silver bullet or easy solution.

You are dealing with a 14-15 year old car and I have to assume in the region you are located with the high ambient temperatures a lot of the plastics and rubber parts under the hood are shot and in need of replacement.

With cold start problems for the first 30 seconds or so the engine is not even in Closed Loop so anything that will cause a Lean mixture will cause a rough/uneven idle.

Nothing lasts forever, some parts you replace/PM just because they wear and will fail at some point. Some parts do now impact cold start as much as others.

Something like a fuel pump will get weak and not seem like an obvious problem. They are cheap enough, at least here in the US that it is wise to get this out of the way, replacing it rules out the pump as a problem.

As for Fuel Trim info, you need an OBDII tool. I highly recommend an smart phone/tablet App called OBDFusion.

OBDFusion for the iProducts it is $9.99, for Android is is $3.99.

For iProducts you NEED a Wifi adapter, for Android you can use the Bluetooth adapter.

iProducts adapter - http://www.amazon.com/dp/B00WPW6BAE/...BWNPO9BZ&psc=1

Android adapter - http://www.amazon.com/dp/B00WPW6BAE/...BWNPO9BZ&psc=1

So for the basic OBFusion, you are at $30 or less for iProducts and under $20 for Android. Very worth while once you find out what you can do with these Apps.

Here is the deal, once you can gather data there may be a glaring problem that will jump out at you, or there may be things you can rule out. This is a game of Treasure Hunt. You sometimes find the Treasure by following the clues, sometimes you find the Treasure by looking under each rock and ruling things out. It is not an exact science. Also many times it is kind of funny how people have spent time and money with professional shops that get nowhere and with a cheap smart phone App and some common sense and using the process of elimination someone with little technical skill can either identify and/or repair the problem themselves.

Professional shops rarely have people that think outside the box or think at all. They often have people that barely understand the workings of vehicles and engine management systems that have been around for 20 years.

Again, on a car that is 14-15 years old there is a lot that has degraded and a lot of past history this is unknown. You may be dealing with a lot of parts that have degraded only slightly, maybe 4-10% but the problems may add up. Also you have to understand regionally what some of the common problems are. In the UAE you may have more problems with fuel injector varnish build up due to the fuel additives or lack of fuel additives and/or the warmer temperatures. Here in North America we do not seem to have a lot of fuel injector related problems, but shops charge a lot of money for on car fuel injector service that is questionable.

If you want things done properly you remove the injectors and send them out to a specialty shop for cleaning and refurbishment. Most better shops do a flow rate before and after testing so you will know that there were a few questionable injectors or there was not much of a problem. Again, does your car need this, do any cars need this. You will only know if and when you perform this service.

Most things start with basics of fresh filters and spark plugs. Looking for oil in the spark plug wells, looking for questionable coil boots or a coil that looks like it should be replaced. Smoke testing the engine and crankcase are important. Making sure the oil fill cap and dipstick O-rings are in good shape and tight. Using a OBDII tool and removing the oil fill cap while the engine is running and warmed up to see what the Short Term Fuel Trims do.

Monitoring the Fuel Trims and Logging data from cold start, at idle and highway cruise. We have found a lot of car with replacement or degraded MAF's. These are hard to identify because a MAF degraded by 4-10% it really hard to flag. There are also a LOT of counterfeit Asian sensors on the market that do not work properly. Things like the DISA need to be removed, inspected and the large O-ring needs to be replaced. We have seen failing/leaking power brake boosters. The power brake boosters are starting to fail around year 12 on these cars and are often overlooked. Sometimes you need to plug the line to the power brake booster or the sucking jet pump and try a cold start to see if any of these things improve the cold start problem.

Again, no easy solutions. At the age many of these cars are at now, these are contenders for "restoration" meaning you replace things to put the car back into top shape because many small things are worn out. Some people do not want put the time or money into "restoration" and in this case maybe it is time to pass the car onto someone that will "restore" the car to its original performance.

Did this answer your questions, no, but maybe it gave you some ideas or things to think about.

Keep the thread up to date what you do and what seems to help your specific problem as others can learn from this information.

 

You are moving in the correct direction, you will find OBDFusion is a very good little App and for the money you will find that it can do some amazing things.

You need to take some time to play with the tool and find your way around the menus. If you get codes, make sure you get the Freeze Frame info. I would also like to know the warm idle Fuel Trim info. You can generate a Report from the Diagnostics Menu. Report is the last tab and you may need to swipe sideways or change your device to Landscape mode to find the Report tab. Generate the report while the engine is running.

You can read my comments in this thread for Logging info, just note that OBDFusion used to be called Touch Scan. http://forum.e46fanatics.com/showthread.php?t=1080334

You can do screen grabs, but it is best to set up DropBox Free and use this to store the Logs, Screen Shots and Reports. NOTE, DO NOT DOWNLOAD AND INSTALL THE DROPBOX SOFTWARE ON YOUR COMPUTER. Unless you manage the DropBox software it can be a problem. When you set up your DropBox Free account, when you are prompted to install the software, just click the back browser arrow and you will be in your DropBox Free account.

More to follow once you have figured out how to Log. Note that anytime the App is open and connected to the car it will Log. The .CSV files can be found under Logs, Files.

Do not even bother to try and graph on the App, it is a waste of time. All Apps are horrible for graphing as are even Pro level tools. I just need the .CSV files and we will discuss this once you have set up and mastered Logging.

 

Hi jfoj,

As discussed, i have managed to upload the report on the dropbox which was generated on the Warm-Idle condition (Engine Running). Please find the link below :-

OBD Fusion Report -5 Minute Cold-Idle

Please let me know, if you want a report generated on the highway as well as i need to take the vehicle a bit far.

FYI, i am using the OBDFusion on my inline android nav system with ELM adapter and it seems pretty simple and easy rather than playing on the phone.

 

Had the same/similar issues on my 328i. changed, vanos seals, lambda, crankcase vents,plugs,filters. Finally solved it by getting a new fuelpump.
Get the pump pressure checked.

 

Ah. So you meant to say that , only fuel pump actually fixed your jerk/rough problem ??. But all of these = [changed, vanos seals, lambda, crankcase vents,plugs,filters.] were waste of time and money ?

 

Had some consistent codes. Diagnostic made after each thing I changed. Codes finally cleared permanently after I changed fuelpump. Surely the things I changed before weren't a waste of money.

 

Ah! But i did not have any codes to start with . that is why i had to go the other way around. :hmm:

 

I didn't get any codes before either, but it got worse and eventually threw codes. I don't remember exact code numbers, but it had smtn to do with bank1 2 trim and something else. So that's why I changed those things before the pump.
Just get the pump pressure measured by a pro.

 

DropBox link now works, thanks.

From the Report, the only thing I can really see is this:

A. LTFT for Bank #1 is negative, which means it is removing fuel or attempting to Lean out the Bank because it thinks the Bank is running Rich. Most Rich conditions I run into tend to be bogus or incorrect. I will need to see Log data from Cold Start and Warm Idle for 4 minutes each to get a better idea as to what may be going on.

B. LTFT for Bank #2 is pretty much as expected.

C. Most other parameters look pretty good.

DISA inspection and replacement of the large O-ring would be something to consider.

Need to see Cold Start and Warm Idle Logs next.

 

Okay will do that. I assume,now you want the .CSV format data from the engine cold start till the next 4 minutes ?

DISA already inspected and its in good condition. Also had cleaned it with the WD40 and replaced the O-Ring as well :thumbup:

 

Cold start 4 minutes, do not touch the throttle or drive the vehicle.

Warm idle for 4 minutes, do not touch the throttle or drive the vehicle. Manual trans in park or neutral if a manual.

.CSV files for both. They cannot easily be attached to a forum post. Usually easiest shared by DropBox Freem and then post the share like, but others have used Google or Amazon Cloud storage with the share link posted back the thread.

 

Got it.

Below is the link to the CSV file

Cold-start-CSV-5min

tbh, i cannot understand anything from that

 

So from the Cold Start Log it is very clear that the Bank #1 Pre-cat O2 sensors is very lazy. This is causing the Fuel System Status to have problems around the 40-55 second window on start up. Note that this is adjusted because the tool is connected and gathering data before the engine is actually running.

This is also likely why the Bank #1 LTFT is negative or removing fuel. This is probably part of the problem with the cold start rough idle. There may be more to the problem, but the Bank #1 Pre-cat O2 sensor needs to be replaced. I would suggest replacing both Pre-cat O2 sensors for the best results as O2 sensors are considered "consumable" parts.

Not sure how old the spark plugs are, but they may need to be replaced if they have not been inspected or replaced recently.

Once the Pre-cat O2 sensors are replaced and the car has been driven about a week, see how the cold start is and we may want to look at Logging again.

I also have some concern about the MAF, but I would like to wait until the Pre-cat O2 sensors are replaced and the also see a 4 minute warm idle Log as well. Soft fuel pumps can also cause cold start problems as well. But lets start with the Pre-cat O2 sensor replacement. Suggest Bosch direct fit O2 sensors.

I assume your car does not have the SAP system due to its age and the market it was sold in? If it does, it does not appear to be working properly.

Here is a DropBox link for the graphs that show what is going on - https://www.dropbox.com/sh/lyf8irpssz517iw/AAAOr_0Bi_A0tToGfMrhBbHna?dl=0

Please download and post the graphs back here so you and others can reference them. I do not have any more attachment space on the forum.

 

So from the Cold Start Log it is very clear that the Bank #1 Pre-cat O2 sensors is very lazy. This is causing the Fuel System Status to have problems around the 40-55 second window on start up. Note that this is adjusted because the tool is connected and gathering data before the engine is actually running.

This is also likely why the Bank #1 LTFT is negative or removing fuel. This is probably part of the problem with the cold start rough idle. There may be more to the problem, but the Bank #1 Pre-cat O2 sensor needs to be replaced. I would suggest replacing both Pre-cat O2 sensors for the best results as O2 sensors are considered "consumable" parts.

Cool. Yeah will replace both for sure

Not sure how old the spark plugs are, but they may need to be replaced if they have not been inspected or replaced recently.

Spark plugs were replaced with NGK-Iridium.

Once the Pre-cat O2 sensors are replaced and the car has been driven about a week, see how the cold start is and we may want to look at Logging again.

I also have some concern about the MAF, but I would like to wait until the Pre-cat O2 sensors are replaced and the also see a 4 minute warm idle Log as well. Soft fuel pumps can also cause cold start problems as well. But lets start with the Pre-cat O2 sensor replacement. Suggest Bosch direct fit O2 sensors.

Okay lets do it accordingly.

I assume your car does not have the SAP system due to its age and the market it was sold in? If it does, it does not appear to be working properly.

SAP System ? . I wonder whats that now :hmm:

 

SAP=Secondary Air Pump or air injection system that only runs on cold start for up to 90 seconds or around 104F engine coolant temperature. Not sure your car actually came with this feature.

When you get a chance post the graphs up and you will be able to see what is going on.

 

SAP=Secondary Air Pump or air injection system that only runs on cold start for up to 90 seconds or around 104F engine coolant temperature. Not sure your car actually came with this feature.

Interesting. Well, how can i check that & confirm then ?

 

Please download and post the graphs back here so you and others can reference them. I do not have any more attachment space on the forum

Sure.

Both file as PDF in the attachments.

 

All this is soon familiar. I was also told to change the precat sensors. That didn't change any thing.

The cheapest thing you can do,is to let someone measure your pump pressure before u start to change any parts

 

I have PROVEN the Pre-cat O2 sensors need to be changed. They WILL resolve the Bank #1 thinking it is running Rich and incorrectly Leaning out Bank #1.

Your situation has nothing to do with the OP situation.

Look at the graphs and LEARN!

 

I'm just putting this out there...
I have two 2004 330i sedans.
Both had this issue.
Both ended up having an injector that would leak when the fuel pump charged the fuel line.
After shutting off the engine... the one leaky injector would slowly leak. It would stumble the worst on starts after leaving for >1.5 hours for about 20 to 30 seconds and then everything was perfectly fine. That is, until the next time the car day long enough to let the bad injector leak down.
I solved this by removing the injectors while still connected to the rail and turning on the ignition (but not starting) so to charge the fuel line. The bad injector would dribble out fuel.

I didn't have any codes thrown. Maybe something to look into, maybe not.

 

Cool. Great input Simmsled. Sure let me have a look at the injectors as well then. But did you check the graph above as 'jfoj' advised. Same kind of graphs expected for the problem you had as well ? :eeps:

But thanks for it :thumbup:

 

jfoj,

Any point in checking the voltage of O2 sensors as shown below ? Can it also confirm whether the sensors are weak ?



I found that the Voltage was fluctuating on O2 Sensor 1

 

jfoj,

Any point in checking the voltage of O2 sensors as shown below ? Can it also confirm whether the sensors are weak ?

I found that the Voltage was fluctuating on O2 Sensor 1

No, absolutely not. This is the problem that people do not understand, even Professional Auto Techs/Mechanics. A single snap shot of data is pretty just useless for O2 sensors as they are constantly changing in Voltage if they are working at all, even lazy ones change Voltage. Additionally because the O2 sensor Voltage is changing, you have no idea when the during the Voltage change the snapshot was taken. Even if you have the ability to grab Min and Max Voltages, you still will not have a big picture about what is going on with the O2 sensor health.

O2 sensor graphing from cold has been my 100% way to confirm lazy O2 sensors for some time. Sometimes even the lazy O2 sensor that show up when cold will look pretty normal once fully warmed up, but will if you know they were lazy when cold and analyze them more closely when warm you can often find tell tail signs of problems, but on a cursory first glance you might otherwise miss a problem.

Some things that may be useful to gather snap shot date on are: Voltage, Temperature, LTFT, but any values are are very actively moving can only be captured and graphed for further analysis.

As I mentioned, you should get the Pre-cat O2 sensors replaced, then see how the vehicle behaves after a week, there may be more than one single problem and on cars that are 10+ years old this is to be expected.

 

No, O2 sensors are consumable. Like spark plugs only more sophisticated and sensitive. Money is they are original. They are less than $50 USD here in the US for Bosch direct fit units.

Lazy O2 sensors are not a function of being dirty typically, the materials in them are worn, damaged and cracked.

 

Hi jfoj,

As you advised, my new replacements Bosch O2 sensors are here. Before i install i would like to save one of the old O2 sensors which is good. Can you help me to identify , which one would be that ? The one close to the firewall or the one in the front of the engine ?

 

Not 100% sure one of the original Pre-cat O2 sensors is "good", however, the better of the 2 Pre-cat O2 sensors is the Bank #2 or the O2 sensor closest to the firewall or rear of the engine.

 

Okay. Cool. Big thanks for that :thumbup:

 

I am having the same issue. Rough idle at cold start pretty consistently all year and the throttle feels like it is inconsistent especially when cold (low RPM torque isn't there) I have run through jfoj's excellent list and even replaced a few things that looked newer just to eliminate them (bought the car used in February with 170k miles and the previous owner had definitely used some no name china brand stuff)

I have already replaced one of my pre-cat o2 sensors due to failure but I have not replaced the others yet (due to funds at the time).

I replaced, plugs, coils, injectors + o-rings (due to consistent misfire in cyl5), fuel pump, VANOS seals, vacuum lines, cyclone separator (unmarked china brand), valve cover gasket, lower intake hose (torn), MAF (unmarked china crap failed), intake cam sensor, inspected DISA. Im sure I am leaving something out but I think the only thing left to try is smoke test for any other possible vacuum leak and replace o2 sensors.

Anyway, not trying to hijack your thread, just wanted to share my similar experience. Very interested to find out what fixes your problem.

 

@ Jfoj,

Replaced both O2 sensors and its been 4 days now. As for the start-up jerk, its still there. But i believe there is a small improvement in MPG after the O2 sensor replacement.
What is the next step that i need to do ? Graph again on cold start for 5 minutes like last time ?



@omega112a,

No problem buddy. You are most welcome to hijack my thread as long as its on-topic :thumbup:
Ooops! That's a lot of things you replaced and still the "vibration" is not gone.

Sure i will keep this thread updated until the issue is resolved. So that others like me can get something useful from it.

 

@ Jfoj,

Replaced both O2 sensors and its been 4 days now. As for the start-up jerk, its still there. But i believe there is a small improvement in MPG after the O2 sensor replacement.
What is the next step that i need to do ? .

Like i said before , get Your Fuelpump pressures checked. Getting it checked will cost you next to nothing.
this is looking like my repair "adventure" all over again :facepalm:
They told me to change my O2's; MAF's and whats nots.

 

Lets see another 4 minute cold start Log.

But also keep in mind that everything from an engine mechanical problem to one or more small vacuum leaks can cause misfiring or rough cold starts.

We have seen some exhaust valves that are cracked or burned that cause cold start problems but do not seem to be much of a problem once the engine is warmed up.

Vacuum leaks in the intake air path or crankcase are also problems. Cracked valve covers are hard to find, leaking power brake boosters are getting common as these cars age, usually around year 12. Sometimes soft failing fuel pumps contribute to the cold start issues.

As for smoke testing, here is one quick and easy idea - https://www.youtube.com/watch?v=AsgB9eBl58I

 

Very cool! So will this smoke test point out vacuum leaks, is that the point of it? Looks like the DISA seal is leaking in this particular video, yes?

I also have the cold start rough idle until warmed up. I just ordered the bluetooth adapter for my android and downloaded the app. Should be in tomorrow, will start learning how to use and hopefully be able to figure out issues/post up reports.

Thanks jfoj! You've helped me in years past and I totally respect your diagnosis/opinion on these things.