[Brey335i]

I'm a master-mechanic-genius. Your misfires are caused by your RB turbos. I will be glad to take them off your hands. Simply mail them to me... and I'll get rid of them for you at no charge

[dzenno]

Originally Posted by TrackRat

It could be the injector spray patterns or possible fuel pressure sensor malfunctioning? Unfortunately these types of issues are not easy to resolve. It often requires R&R of components unless something tests bad.

High or low fuel pressure sensor?

It's hard to say that it'd be the "high" pressure sensor as fuel pressure at the rail goes up at the onset of WOT as well to the same peak levels as up in the high RPMs, there's logging for that on the procede and I never get low rpm misfires...

It'll be a party if changing the fuel injector doesn't fix it then i'm pretty much out of reasonable options...

[Penn999]

My engine was also running roughly..i took it in to bmw and they replaced my vanos solenoids and the car feels way better. ive been following your efforts to fix this misfire...it sounds depressing with all of the time and $ you have put into your car. I know vanos solenoids is a farfetched idea but I don't remember reading that you have gotten new ones lately if ever...also what brand gas do you use? again, I know it sounds simple but the only gas that works flawlessly for my car is shell vpower. Any other gas and it misfires and stumbles throughout the entire rpm band. Let me know your thoughts on these suggestions.

[luca335i]

Did u try doing a pull without meth. Too much flow would cause a high rpm misfire as well. Also your valve cover gasket could be leaking oil. Did u check the plug on cyl 5 to see if it's wet with fuel? Also see if your 02 sensors are still good.

[Joshboody]

Originally Posted by dzenno

High or low fuel pressure sensor?

It's hard to say that it'd be the "high" pressure sensor as fuel pressure at the rail goes up at the onset of WOT as well to the same peak levels as up in the high RPMs, there's logging for that on the procede and I never get low rpm misfires...

It'll be a party if changing the fuel injector doesn't fix it then i'm pretty much out of reasonable options...

Check your fuel pressure logs again. If this changes by more than a couple tenths, i would suspect an issue. Mine stays very steady with maybe 1/10th volts up or down. Especially if you see variations from mid to upper rpms.

I thought i remember somewhere reading that if the pressure sensor on the low side fails, the pumps default is 100%.

[dzenno]

I'll check it out but the question is why at high rpm only for a sensor? I've always suspected it around fuel pressure but I think cyl 5 injector will be the first to diag/change...

Problem i have is with the piggies that hijack canbus the BT tool stops functioning so I can't datalog all the 10-15 params around fuel injection (inj dc, inj voltage, inj pwm, low pressure fuel pump voltage/rpm)...all these are available with the BT tool but inaccessible as soon as you turn procede/jb into non-passthrough mode...

I've put Cobb back on as that at least let's me run higher boost and datalog with BT..I'm trying to get a jb+ from somewhere as well for a touch more boost so I can trigger the issue...it's hard with only 12.5-13psi up top...need 14+ minimum to have it happen...

Anyone know anyone willing to lend me their jb+?

[dzenno]

Originally Posted by luca335i

Did u try doing a pull without meth. Too much flow would cause a high rpm misfire as well. Also your valve cover gasket could be leaking oil. Did u check the plug on cyl 5 to see if it's wet with fuel? Also see if your 02 sensors are still good.

Hey man how's it going? Been a while

Yeah all these are pump 94 sunoco, meth off at UT50/IC50 or IC0...same on meth but boost has to be higher than UT50...

Another person on *********** (oddjob I think) just today reported a very similar issue on cyl4 and it was his injector where some clip was broken that I guess holds it in place?? Maybe it's the spacer that goes on the bottom?? Not sure, but his issue sounds exactly the same as mine...

Valve cover gasket is brand new just recently replaced, engine bay is bone dry, 3x checked...front o2 sensors replaced 2 months ago, rear are still original...AFR looks great on both banks (mid 12s at 6500rpm) confirmed through procede logs AND external wideband...think shiv has gotten the procede AFR catalogs calibrated much closer now to true wideband readings, they're now VERY close to a point where I can consider them just as reliable as external wideband lc-1 units I have...

[Joshboody]

Originally Posted by dzenno

I'll check it out but the question is why at high rpm only for a sensor? I've always suspected it around fuel pressure but I think cyl 5 injector will be the first to diag/change...

Problem i have is with the piggies that hijack canbus the BT tool stops functioning so I can't datalog all the 10-15 params around fuel injection (inj dc, inj voltage, inj pwm, low pressure fuel pump voltage/rpm)...all these are available with the BT tool but inaccessible as soon as you turn procede/jb into non-passthrough mode...

I've put Cobb back on as that at least let's me run higher boost and datalog with BT..I'm trying to get a jb+ from somewhere as well for a touch more boost so I can trigger the issue...it's hard with only 12.5-13psi up top...need 14+ minimum to have it happen...

Anyone know anyone willing to lend me their jb+?

I mean a fueling capacity issue, not the sensor. Any noticeable drop in pressure is bad of course.

[badass335]

Hey Dzenno, sorry to hear. This is what i was trying to say before. Keep in mind, it may not be the exact same thing but in your case it could be possible that the install wasn't correct and when you applied the extra boost with the Shiv dyno runs, you could have 'blown' something out of place?

Originally Posted by M3 Eater

hmm I had a misfire issue nobody could solve until a tech looked at my injectors to find that the last tech forgot to install couplers to hold them in place. stock trim the fuel pressure wasn't hard enough to cause the misfire but even a little more boost and misfire...BT was telling me which cylinder and everything. I took about 4 months for Bmw to figure out that the new injectors that they installed were not the cause, but that becuase they weren't installed properly that i was misfireing.

EVERYONE (TECHS, MECHANICS,) THOUGHT IS WAS THE TUNE! (especially the tech that made the mistake) Terry assured me that it wasn't but it was so hard to tell because it wouldn't misfire on map 0.
Fuel injection service is a waste because the fuel never really touches the valves. I removed my manifold and scraped the valve myself trying to find the cause. If you can find someone to remove your manifold and manually clean the valves.... go for it! The DI injectors rarely get clogged without failing but I found a place that services our injectors. It is an experimental service offered by a company that works on race cars if you insist on cleaning the fuel system. Direct Injection is a totally different animal that any shop is used to working on. Make sure if you pay someone to work on you fuel system that they know its Direct Injection and make sure they explain how their service is DI specific. Otherwise you will be wasting your time and money.

I found 1 place in the country that was ready to do it and that when a Foreman at the 3rd dealership I brought my car to realized that the injectors were installed wrong.

[R1000K3]

Originally Posted by TrackRat

Sorry the new coils didn't resolve the issue. Could be an injector or many other possibilities.

For reference a sparkplug only draws whatever voltage is required to arc the gap, thus more potential voltage won't be used if it's not needed. A higher output coil will not change performance unless the higher voltage is required to fire the sparkplug.

It isn't all about voltage. I'm not saying this to criticize your post, just to put things into perspective.

Voltage is the electrical parameter that determines when a spark jumps over a certain air gap. This is typically 1 thousand volt per millimetre (about 1/16 inch). But this is in free air and in an engine the voltage requirement is proportional to the cylinder pressure, which of course is much higher in a tuned N54 engine than for a stock one. It takes from a couple of kilovolts (low compression lawn mover) to several 10 thousands of volts to make a spark depending in the actual cylinder pressure.

It is also important that the current is strong enough and have the necessary duration, i.e. that the energy of the spark is sufficient. It is very easy to make an ignition system that provides high voltage but it gets more and more of a challenge the more energy it has to deliver.

The main difference between conventional ignition systems and a system for tuned engines is the primary side of the coil is feed by 12 volt in a standard system and several hundred volts like e.g. 400 volt in a high performance ignition. I don't know whether N54 coils are driven by 12 volt or if the ignition coil module steps up the voltage to the coil. I guess it is still 12 volt since the coil pack is small and high performance ignitions are bulky since they also include a large transformer and large capacitors.

Back to Okada's...The reason I've had a very limited believe in these coils is they seems to use the same principle as the stock ignition. This means there is not a lot to gain regarding the spark energy. Okada shows on their site that their coil generates a bit more energy and duration but the improvements they claim are the least to say very minimal if we talk about what a real high performance ignition would be vs. a stock ignition. This in combination with the high price makes them give little or none back for the money for the majority of users. In most car they will not make any change at all, if the fuel mixture ignites on stock coils there is not a single horse to gain even if we would use Top Fuel ignition system. This is a fact that many suppliers of ignition systems are prone to hide since the market for these and similar components is huge. There are millons of car enthusiast on the globe that willingly will put their head in the sand bag and buy just about any component they want to believe will provide power gains, as long as it is very easy to install and can be financed without too much effort. Some degree of over pricing also works to trigger buy mechanisms since it may make the product to appear more advanced than it is.

I have no doubt though that the Okada coils provides a bit more spark energy than the stockers and that they will make a few tuned cars (not necessarily 335's though) to run much better than they are doing on stock coils. This is if the stock ignition system is just marginally too weak, then the problem may be fixed with Okada's. It seems however that the stock ignition in combination with other characteristics for the N54 engine can handle very high cylinder pressures without misfires. We need to remember that both FB_IS and hotrod182 have been using the stock ignition on well above 500 whp without misfires if a recall correct. There are also a lot of cars running at about 20 PSI on stock ignitions, which is about the same level as when dzenno's car misfires with upgraded turbos (on lower boost).

We still have to see at what level of tuning the stock ignition fails. It is really impressing it handles so good as it do but it has a limit, which may or may not be seen when 335's with upgraded turbos begins to run 20+ PSI. I'm willing to put a bucket of poop in a bet they will work

[dzenno]

^ that OR it's just my injector

[Irishace]

Sorry to hear the woes continue bro, I hope you manage to get it sorted. Still very anxious to get a lift in your beast when it is rocking.

[CobraMarty]

Have you done a compression check? One 'bad'/misfire #5 cylinder. Did it break a top ring landing? This is easy to check. I would also check a leak down. Both easy to check.
Then injector.
You can open the plug gap slightly to take advantage of those new coils.

[dzenno]

Originally Posted by Irishace

Sorry to hear the woes continue bro, I hope you manage to get it sorted. Still very anxious to get a lift in your beast when it is rocking.

We can go for a ride any time but for max bbost I'll shift 3rd-4th 6200rpm

Originally Posted by CobraMarty

Have you done a compression check? One 'bad'/misfire #5 cylinder. Did it break a top ring landing? This is easy to check. I would also check a leak down. Both easy to check.
Then injector.
You can open the plug gap slightly to take advantage of those new coils.

It's not motor related...compression test done March 29, 2011 at BMW dealer using their special tool:

[CobraMarty]

Thank goodness on the compression check. That becomes an expensive fix.

[dzenno]

Originally Posted by CobraMarty

Thank goodness on the compression check. That becomes an expensive fix.

For sure, I was pretty relieved seeing these results misfires started in February, doing the first pulls with RBs at 15-16psi...you'll see this mentioned in my very first review thread back then which at the time I thought was tuning related...

[luca335i]

New injector seals are required when injectors are swapped. Check your service invoice when u got it done to see if they did it.

[dzenno]

If they don't cover it under warranty I'll change it myself and just get it coded there...they charge an hour labour to code them so 130+tax...

Been talking to a friend to split the cost of BMW OPS (750) and just code it myself...BMW GT1 works only 2006 and older models...OPS is for 2007-2009...ICOM is 2010+...maybe offer coding to the local community at half dealer cost down the road for injector or any other related coding...Better tool many times than the BT...

[uberschnell]

You drive a 2008, correct? With how many miles?

Have you looked at the intake valves? I had my intake removed at 44K and they were clogged with carbon build up. 5 and 6 in particular were heavy and "harder" to remove.

There is a possibility that the airflow into that cylinder is altered enough to effect performance. This would not show on a compression test either.

Easy enough to have a shop borescope it.

Just a thought.

[dzenno]

Originally Posted by MteK

You drive a 2008, correct? With how many miles?

Have you looked at the intake valves? I had my intake removed at 44K and they were clogged with carbon build up. 5 and 6 in particular were heavy and "harder" to remove.

There is a possibility that the airflow into that cylinder is altered enough to effect performance. This would not show on a compression test either.

Easy enough to have a shop borescope it.

Just a thought.

Done not even 4 weeks ago pics posted on here...

[dzenno]

Is there any issues in pulling the injector and then putting it back in just for visual inspection? Do I have to replace the bottom spacer/buffer thingy if I do this?

[Elie335]

Originally Posted by dzenno

Is there any issues in pulling the injector and then putting it back in just for visual inspection? Do I have to replace the bottom spacer/buffer thingy if I do this?

whenever the injector was pulled out for visual inspection or anything, the O-ring on the " head " of the injector should be changed before plugging it back into the head gasket.



Check number item number 9.

Why?

Because this O-ring once pulled out and exposed to air, it does automatically oxidation and becomes so weak, so IF you don't change it 3 or 4 WOT pulls it might blow up and you would misfire. Remember, you would ALWAYS misfire, not just on high rpms.

I'm telling you from my own experience with injectors, had LOTS blown during my ownership to this car, and different cases were the reason.

hope it helped.