[GEOS07335i]

First off I have a 2008 E93 335i with 124K miles. So I've been having a bunch of issues with misfire on cyl 4. I've swapped out plugs, coils and fuel injector with cyl 1 and keep having multiple misfire and misfire on cyl 4 its a constant. I have also done a walnut blast with in the last week. They were pretty bad but did not help the misfire issue at all. I even cleaned the Vanos solenoids and this did help with lifter ticking but did nothing for the misfire issues. So next thing on the list I ordered a compression tester 14mm.

Questions:
1) What compression should the cylinders read?
2) How much variance is acceptable?
3) Where is the fuel pump shutoff relay?

This was my plan.
1) Disconnect all Coil plug connectors.
2) Disconnect Fuel Pump relay (where is this located)
3) Start on cyl 1 and remove the plug
4) Insert compression tube
5) Turn over car for 5 seconds
6) Write down compression numbers for each cylinder and compare

[MysticRob]

I can't answer all those Qs, but I can give you my results.

All 6 cylinders were between 150 and 160 PSI, with 134k miles on it before I bought it. I've always been told no more than 10% variance between cylinders is good.

[feuer]

Have you checked the ECU mofset? If that is OK then is probably the head. I'm sorry that the 425whp isn't panning out easily. It would help if you provide more details of this misfire. When it happens? In boost? All the time? Maybe you can post a log?

[GEOS07335i]

Originally Posted by feuer

Have you checked the ECU mofset? If that is OK then is probably the head. I'm sorry that the 425whp isn't panning out easily. It would help if you provide more details of this misfire. When it happens? In boost? All the time? Maybe you can post a log?

Yeah my quest to 425 RWHP is pretty far off at this point. I though I had all of my maintenance issues under control but I cant get the car to run right.

The misfire happens when I start the car. It never goes away. It just run's really rough. I have INPA running and while the car is running in german I can decipher misfire on cyl 4. So what I did was swap out injector on cyl4 with cyl1 and clear codes and try again. I did this with plug's and coils and it never leaves cyl 4. Hence why I think I need to do a compression test. What other info can I provide? I'm attaching log file I took last week. Car is dead in the water at this point.

I did take out the DME to check the mosfet on the Fuel Injector drivers but it was held in with clips not screws or bolts so I decided it was not a good idea to pull out the tabs as I dont think I could ever get it sealed 100% again. So I had put that on hold.

[feuer]

Originally Posted by GEOS07335i

Yeah my quest to 425 RWHP is pretty far off at this point. I though I had all of my maintenance issues under control but I cant get the car to run right.

The misfire happens when I start the car. It never goes away. It just run's really rough. I have INPA running and while the car is running in german I can decipher misfire on cyl 4. So what I did was swap out injector on cyl4 with cyl1 and clear codes and try again. I did this with plug's and coils and it never leaves cyl 4. Hence why I think I need to do a compression test. What other info can I provide? I'm attaching log file I took last week. Car is dead in the water at this point.

I did take out the DME to check the mosfet on the Fuel Injector drivers but it was held in with clips not screws or bolts so I decided it was not a good idea to pull out the tabs as I dont think I could ever get it sealed 100% again. So I had put that on hold.

Pry open the ECU and check the mofset for cyl4. Also, INPA can give you a read out showing if the ECU is internally shorted. Common code for this is 30BA (cyl 4-5-6) 30BB (cyl 1-2-3) Although good idea I would skip the compression test. It will not tell you why the car is misfiring.

[YoungBlood]

What index injectors? How does the plug look? What about swapping around coils or replacing them?

[YoungBlood]

But check those mosfets. Mine did lots of weird stuff before it finally fully shit out, and I had a whole bank of bad ones at once. Didn’t do anything on start up tho, only under load. And when you swapped injectors around did you code them?

[GEOS07335i]

Here are picks of my DME I have the MSD81 can't find any info on which is the driver for cyl 4 although I did a continuity check on the six chips and they all reacted the same. I get 0 when touching positive terminal to center pin. So that rules out the DME.

[GEOS07335i]

Originally Posted by YoungBlood

What index injectors? How does the plug look? What about swapping around coils or replacing them?

There INDEX 9 injectors. Plugs are brand new less than 20 miles but they look black now. A little carb cleaner cleans them right up. I already swapped coils 1 and 4 around cleared codes and it came back with in 1 minute of running the car. Coils are bosch brand new from FCP Euro so are plugs. I did place a new order for Bosch Plugs. The plugs in it now are NGK gaped at .22 95770 because I was starting to prep the car to do some high performance mods. But I think I will go back to stock plugs until I get the car running. Yes I coded them with INPA 5.0.6 coding went with out a hitch. Swapped injector from Cyl 1 to cyl 4 and same misfire on cyl 4.

[GEOS07335i]

Originally Posted by feuer

Pry open the ECU and check the mofset for cyl4. Also, INPA can give you a read out showing if the ECU is internally shorted. Common code for this is 30BA (cyl 4-5-6) 30BB (cyl 1-2-3) Although good idea I would skip the compression test. It will not tell you why the car is misfiring.

Do you recall what sequence in INPA to do this? I also have set up ISTA+P and it goes through it's internal checks. I see DME shows yellow but if you dig in it tells you misfire on cyl4. I'd like to use ISTA +P to diagnose what's wrong but not

[feuer]

Originally Posted by GEOS07335i

Do you recall what sequence in INPA to do this? I also have set up ISTA+P and it goes through it's internal checks. I see DME shows yellow but if you dig in it tells you misfire on cyl4. I'd like to use ISTA +P to diagnose what's wrong but not

Just read the fault codes. But you having msd81 pretty much rules out internally bed ECU. Only way it could have happened is if you were installing injectors with battery and ignition on. Post the codes here. Hopefully isn't the head.

[GEOS07335i]

Originally Posted by feuer

Just read the fault codes. But you having msd81 pretty much rules out internally bed ECU. Only way it could have happened is if you were installing injectors with battery and ignition on. Post the codes here. Hopefully isn't the head.

E R R O R M E M O R Y
----------------------- Date: 16.01.2018 14:38:24
Model: E89X
Scope: all control module
JobStatus: OKAY
Quantity: 26
----------------------------------------------------------------- ADR Gen. name JobStatus Number of errors Error code Kind of error
00 JBBF OKAY 1 Error stored
A6CF 61 01 MRS OKAY No Error stored
12 DME/DDE OKAY 2 Error stored
2AAF 62 29D0 D2 17 EKP OKAY No Error stored
18 EGS OKAY No Error stored 20 RDC OKAY No Error stored
24 CVM/CTM OKAY No Error stored
27 PGS OKAY No Error stored
36 TEL/MULF OKAY No Error stored
37 AMP OKAY No Error stored
3F ASK OKAY No Error stored
40 CAS OKAY No Error stored
47 ANTTU OKAY No Error stored
54 RADIO OKAY No Error stored
55 ISPB OKAY No Error stored
56 FZD OKAY No Error stored
60 KOMBI OKAY No Error stored
62 MOSTGW OKAY No Error stored
63 MASK/CCC OKAY No Error stored
67 ZBE OKAY No Error stored
6D FAS OKAY No Error stored
6E BFS OKAY No Error stored
72 FRM OKAY No Error stored
73 CID OKAY No Error stored
78 KLIMA OKAY No Error stored
A0 CCC OKAY No Error stored =====================================

[feuer]

What the fault codes? Shows 2 store at DME. Also 1 in the junction box buy the fuses.

[GEOS07335i]

Originally Posted by feuer

What the fault codes? Shows 2 store at DME. Also 1 in the junction box buy the fuses.

Sorry can you explain. Junction box? you mean behind glove box? Can you tell me how you determined that. Wich fuse in the Junction box? How can I read this for my self?

thanks for the help.

[feuer]

Originally Posted by GEOS07335i

Sorry can you explain. Junction box? you mean behind glove box? Can you tell me how you determined that. Wich fuse in the Junction box? How can I read this for my self?
thanks for the help.

Junction box is mounted under the fuse board. Both mounted behind the glove compartment. See blue and black connectors? That is the this box! There aren't fuses in/on the junction box. It's a module and you have 1 active fault there.

[feuer]

Originally Posted by GEOS07335i

Sorry can you explain..

Read the ECU memory. The screen with the history of all fault codes will look like this. That is what we need to see.

When swapping injectors, were all decoupling elements present?

Were all injector hold down brackets properly installed?

[GEOS07335i]

Originally Posted by FCobra94

When swapping injectors, were all decoupling elements present?

Were all injector hold down brackets properly installed?

Yes all decoupling elements were present and fairly tight.

I believe so getting the brackets properly seated were a pain but I made sure the small tab on the fuel injector was seater as far down as it could go.

[GEOS07335i]

Originally Posted by feuer

Read the ECU memory. The screen with the history of all fault codes will look like this. That is what we need to see.

Ah starting to make more sense. Ok It may take me a little to put the DME back in. I'm at work will try to do it during my lunch break and capture the ECU Memory screen. I know where that's at. However if I recall correctly mine is in German. I'm using INPA 5.0.6 (bimmergeeks). Give me a few and I'll get a screen shot.

Thanks for the help :-)

[arkie6]

Back to the compression test questions. I would do the following:

1) Put a battery charger on it (not a tender) so the battery voltage stays consistent and the starter spins the same speed from cylinder #1 to #6.

2) Remove all 6 spark plugs before testing the first cylinder.

3) Rather than remove the power supply to the fuel injectors, if you have a remote starter switch you can disconnect the starter solenoid input signal, connect the remote starter switch, and turn the engine over directly at the starter with the ignition switch off.

4) Ideally, you want to have the throttle plate wide open when checking compression, but I'm not sure of any easy way to do that with throttle by wire. If you are just looking for consistency from cylinder to cylinder, it probably doesn't matter. But if you are trying to verify compression per manufacturer's specification, you typically need the throttle to be wide open, clean or removed air filter, etc. I'm thinking the simplest way to open the throttle on the N54 would be to loosen or remove the 4 throttle body bolts and pull the throttle body away from the intake manifold a 1/2" or so.

[GEOS07335i]

Originally Posted by feuer

Junction box is mounted under the fuse board. Both mounted behind the glove compartment. See blue and black connectors? That is the this box! There aren't fuses in/on the junction box. It's a module and you have 1 active fault there.

Finally got the DME installed. I cleared memory and pulled the following

[GEOS07335i]

Originally Posted by arkie6

Back to the compression test questions. I would do the following:

1) Put a battery charger on it (not a tender) so the battery voltage stays consistent and the starter spins the same speed from cylinder #1 to #6.

2) Remove all 6 spark plugs before testing the first cylinder.

3) Rather than remove the power supply to the fuel injectors, if you have a remote starter switch you can disconnect the starter solenoid input signal, connect the remote starter switch, and turn the engine over directly at the starter with the ignition switch off.

4) Ideally, you want to have the throttle plate wide open when checking compression, but I'm not sure of any easy way to do that with throttle by wire. If you are just looking for consistency from cylinder to cylinder, it probably doesn't matter. But if you are trying to verify compression per manufacturer's specification, you typically need the throttle to be wide open, clean or removed air filter, etc. I'm thinking the simplest way to open the throttle on the N54 would be to loosen or remove the 4 throttle body bolts and pull the throttle body away from the intake manifold a 1/2" or so.

Dont have a starter switch. Where is the fuel pump relay? dont want to vapor lock. i have a batteryt charger I'll put on it.