JB4, dp fix and the ensuing misfires/limp mode

[breakfastreatre]

Hi guys,

purchased a 135 as a second car/track toy.

catless downpipes, ams intercooler, active autowerks bov.

I got it cheap knowing that i would be spending some money on something soon.

Test driving the car with the jb4, it felt great and I had no issues. Full throttle multiple times and no hiccups. Only issue with the car running was a rough idle at times, presumably from carbon buildup as a blasting hadnt been done recently.

Now that I have the car in my possession, problems show up.

driving around normally, the car exhibited zero issues.

but, WOT would occassionaly put it into some sort of limp mode. The car was missing really bad, and it sounded like a boxer engine. Turning the car off and then back on would bring things back to normal

I had a generic code reader at the time and got the code:
p0365 cam position sensor B circuit bank 1

The car was still not stickered at this point and I needed an etest, so I threw in a JB fix into the jb4 wiring. Car still exhibited no issues driving around normally.

Passed etest.

drove the car for about a week with the DP fix in. Maybe put 300kms on it in that timspan.

Talking to some friends, they mentioned the vanos solenoids could be an issue. They are an easy fix, so I purchased two new ones, and threw them in.

I also removed the DP fix at this point.

reset the ecu, removed the negative, held brake pedal for 30 sec.

This is when things starting getting worse.



Between 2000-3000 rpm, partial throttle, the car would surge really bad. RPMs not building smoothly.
anything more than partial throttle up to WOT would be smooth but WOT conditions would produce the misfire/limp/boxer engine sound more frequently.

I removed the JB4 and replaced it with a mhd flash.

Now, im getting misfire codes in cylinders 1, 3, 4 as of most recently.

what should my plan of attack be?

Is this something I can diagnose with the monitoring package through mhd before I start pulling parts?

Plugs were replaced recently but maybe are already fowled? replace
coils are an unknown. replace
pull plugs, check for fuel, possibly leaking injector?

if that has no effect, change upstream O2 sensors.

then, injectors, hpfp


anything Im missing? Should I try anything else before swapping parts?

[drwillb]

I'd start with cam position sensor, plugs (and coils, cause you're in there), and walnut blast.

Post a log to MHD thread to get their opinion.

[HawkeyeGeoff]

Originally Posted by Get Inline

1. walnut blast

2. all 6 new spark plugs

3. replace ignition coils on misfiring cylinders

report back and let us know if this fixed the issue.

good luck

Agreed with this course of action.

Do the cheap stuff first...you can make your own walnut blasting kit for about 300 bucks with a compressor:
http://www.bimmerhelp.info/DIY_N54_Valve_Blast.html

If you have access to do it, reset all your adaptations after sparkies+coils+walnut blast.

What index injectors do you have? You can see if you take off the engine cosmetic cover.

[breakfastreatre]

Originally Posted by HawkeyeGeoff

Agreed with this course of action.

Do the cheap stuff first...you can make your own walnut blasting kit for about 300 bucks with a compressor:
http://www.bimmerhelp.info/DIY_N54_Valve_Blast.html

If you have access to do it, reset all your adaptations after sparkies+coils+walnut blast.

What index injectors do you have? You can see if you take off the engine cosmetic cover.

They are all index 8. The car is a 2008 so im assuming they were replaced at some point. Previous owner (2nd) didnt know. Car does not exhibit hard starts at all

[HawkeyeGeoff]

Originally Posted by breakfastreatre

They are all index 8. The car is a 2008 so im assuming they were replaced at some point. Previous owner (2nd) didnt know. Car does not exhibit hard starts at all

They're probably fine then.

You got a laundry list of stuff to do, get to it.

[breakfastreatre]

Small update.

Replaced leaking oil cap because that was the first thing that came in.

Drove ok for 2 minutes and then misfires. Cylinder 2 joined the misfire family.

Ordered a new valve cover gasket and the RB upgraded pcv valve

[rominun]

I'd replace the spark plugs first. If that doesn't fix the misfire, then buy new coils. Along with the spark plugs, i would do the carbon intake cleaning. And if that doesn't fix it, then you're injectors are most likely faulty.

[ajoosten]

Take a log and check your fuel rail pressure.
If under WOT your feel a hesitation do not continue to WOT. You are most likely detonating at WOT and will cause internal damage. If you are running an aftermarket map and have high boost this can happen easily if not tuned correctly.

-Pull and inspect spark plugs
--If black and smell like gas that cylinder has a leaky injector
--Check for signs of damage to the plugs, it sounds like you may have been detonating in the cylinder
--Spark plugs should all have a gray coloring on the tip if everything is okay
-If leaky injector is diagnosed by gas smell and black tip of spark plug, replace said injector and recode that injector to the DME
-Buy a new set of Bosch Coils of Amazon and install they are cheap.

Your DP fix does not affect the way your engine runs. The fuel adaptations are only controlled by the pre cat O2 sensors. All you are doing with the DP fix is telling the DME that the Cats are working.

Take your tune back to stock! Log, Log , Log. Get stock running right. Step into your more and more aggressive tunes and log log log.

If it is not running correctly there IS a reason.

I'm currently rebuilding my N54, don't get too aggressive with the tune to quickly. Good luck.

[breakfastreatre]

Originally Posted by ajoosten

Take a log and check your fuel rail pressure.
If under WOT your feel a hesitation do not continue to WOT. You are most likely detonating at WOT and will cause internal damage. If you are running an aftermarket map and have high boost this can happen easily if not tuned correctly.

-Pull and inspect spark plugs
--If black and smell like gas that cylinder has a leaky injector
--Check for signs of damage to the plugs, it sounds like you may have been detonating in the cylinder
--Spark plugs should all have a gray coloring on the tip if everything is okay
-If leaky injector is diagnosed by gas smell and black tip of spark plug, replace said injector and recode that injector to the DME
-Buy a new set of Bosch Coils of Amazon and install they are cheap.

Your DP fix does not affect the way your engine runs. The fuel adaptations are only controlled by the pre cat O2 sensors. All you are doing with the DP fix is telling the DME that the Cats are working.

Take your tune back to stock! Log, Log , Log. Get stock running right. Step into your more and more aggressive tunes and log log log.

If it is not running correctly there IS a reason.

I'm currently rebuilding my N54, don't get too aggressive with the tune to quickly. Good luck.

Car is currently sitting with a partially disassembled motor. I was hoping to get the parts before I went away for work, but didn't get a chance so I won't until probably September.

Valve cover was leaking bad, so I'm going to pull that and replace gasket.

I got new coils, plugs. They are pretty cheap on rockauto.

Upon removing the top engine cover, I found some water sitting in cylinder 6 plug recess
That didn't help either I'm sure. It rained once while I had the cowl off. Whoops.

I'll report back when I get all of this stuff in and have a chance to look at the plugs. Then logging.

[breakfastreatre]

Ive been working nights and staying out of town, so I hadnt had much time to work on the car, but I was home for the past 2 weekends so I got the car buttoned up.

The cam sensors i got from rockauto dont work.

I replaced the valve cover gasket, plugs, and coils.

Car drives very nice at WOT and close to wot. Any part throttle puttering around is complete garbage.

Looking at the mhd gauges shows that the two primary o2 sensors are fighting each other. Readings are inconsistent between the two and jump around wildly.

Ive attached a couple wot logs as well, 1 3rd gear, 1 4th gear. I didnt redline but the car felt great in both instances.

Current map is stage 0, effectively stock.
I have two new primary o2 sensors on order and will hopefully get the walnut blasting done tomorrow as well.

http://datazap.me/u/breakfasteatre/s...ata=3-12-22-23

http://datazap.me/u/breakfasteatre/s...og=0&data=3-23

[breakfastreatre]

Got the car walnut blasted, replaced the 2 primary O2 sensors

Car still surges at light throttle. Heavier throttle and wot, the car runs well.

Any thoughts? The car is on stage 0, so it's not currently running a hot tune.

What kind of behaviour does a bad injector exhibit?

[ajoosten]

I still think this could be an injector issue. Pull the new spark plugs that you put in the car. Look at the ends. It should be a light grey color. If you have black on the ends of the spark plugs I would suggest new injectors. I know it is a chunk of change but by new ones and you will be happy.

[breakfastreatre]

1 to 6, left to right.

one interesting thing. The car does not surge before it has warmed up. If anything, i would think that the car would run worse cold because of the fuel leaking into the cylinder.

as well, if the injector spray pattern is wonky, I dont see why the difference between cold and warm.

I will do two logs tonight, one cold, one warmed up. Light throttle, a couple shifts, it will be interesting to compare the two.

here is a warmed up, 4th gear steady cruise

http://datazap.me/u/breakfasteatre/s...og=0&data=3-19


I wonder what changes from cold to warm?

edit: speaking to a friend of mine, i should have realized this. Vanos solenoids move oil. I bet they arent triggered until the oil is warmed up. I hadnt noticed but my intake vanos solenoid that I just changed out looks bunk. I will swap the two sensors and see if the bunk-ness follows and I will report back

[ajoosten]

Originally Posted by breakfastreatre

1 to 6, left to right.

one interesting thing. The car does not surge before it has warmed up. If anything, i would think that the car would run worse cold because of the fuel leaking into the cylinder.

as well, if the injector spray pattern is wonky, I dont see why the difference between cold and warm.

I will do two logs tonight, one cold, one warmed up. Light throttle, a couple shifts, it will be interesting to compare the two.

here is a warmed up, 4th gear steady cruise

http://datazap.me/u/breakfasteatre/s...og=0&data=3-19


I wonder what changes from cold to warm?

edit: speaking to a friend of mine, i should have realized this. Vanos solenoids move oil. I bet they arent triggered until the oil is warmed up. I hadnt noticed but my intake vanos solenoid that I just changed out looks bunk. I will swap the two sensors and see if the bunk-ness follows and I will report back

You are right, leaky injectors can cause an initial start up “surge” a very quick start due to extra gas, they can also cause longer cranks due to flooding.depending on how long the car has sat. I’m not sure what you mean by a “bunk” looking solenoid but even my bad solinoids I changed out looked brand new, so you might be on the right track. Are you getting any vanos codes? Have you resolved the issue with new vanos solenoids?

[breakfastreatre]

Originally Posted by ajoosten

You are right, leaky injectors can cause an initial start up “surge” a very quick start due to extra gas, they can also cause longer cranks due to flooding.depending on how long the car has sat. I’m not sure what you mean by a “bunk” looking solenoid but even my bad solinoids I changed out looked brand new, so you might be on the right track. Are you getting any vanos codes? Have you resolved the issue with new vanos solenoids?

I did resolve the issue.

It was one of the vanos solenoids. Mhd Logs showed requested and actual vanos values were way off from each other. Swapping the solenoid from Intake to exhaust showed the issue follow.