BMW X5 Runs Rough Experience Request

Jordan Owner/Technician Ontario Posted   Latest   Edited  
Updated
Electrical
2012 BMW X5 xDrive35i 3.0L (N55B30A) 8-spd (8HP70)
P0306 — Cylinder 6 Misfire Detected
Running Rough

Hello DN

Please forgive me in advance if some of my explanations are hard to follow,

2012 X5 3.5i 160K 

codes from Autologic are attached. 

I am currently working on this vehicle, that another previous shop had worked on, from my fellow tech, the previous shop had done coils, plugs, VCG, and PCV I believe. Not sure what else if anything. 

Client came in to us 2hr away, (we are the only euro shop in our radius) So I really want to get this client taken care of efficiently. It came in as a running rough, with a cylinder 1 and 6 misfire, my tech found the coil grounds (brown wire) loose. Tighten the grounds (for the coils, all the nuts were loose and the grounds loose..and cleared the codes. Cyl 6 was the only one that returned. We found it has an issue with intermittent no starts. The Autologic Energy diagnostics showed a battery replacement at 125K but barely any travel time. I looked at the battery and found both sides were rippled like the battery had vacuum attached to it and sucked in (Sorry for the bad analogy) you could physically see each cell, and running your hand down was like a washboard. Also cranking voltage dropped to 8.6 when cranking. So we replaced the battery.. 

Swapped ignition coil from 3 to 6. No change. He went to change the #6 plug, and when it came out it was rusty and water was in the hole. I did some research and found there is a common problem with those vehicles with the COWL that leaks water, and there is no Foam insulation underneath either. Apparently the client (after speaking with him) said he “has” the updated BMW cowl that is taller.. 

I did a resistance check of all injectors (while it was slightly difficult as I didn’t have proper female terminals, I backprobed the injectors (circuit off) and got around 2.5-3 Ohms each injector. And being GDI Low impedance Peak and hold injectors I couldn’t find a spec, but I assume this was ok from other research.

The vehicle when you clear the codes will run great for about 2 minutes then develop the Miss, and it feels like a dead miss. After I scoped the injectors, it then was not running great even after the clearing of codes and now has an ESP stability/chassis control light on that I can’t figure out what it is, I get incorrect steering angle sensor but never touched that? 

I checked compression static and dynamic 200+ static and 50-75 Dynamic.

Lastly I opted to scope the injector and I have attached waveforms. I think I know how the peak and hold injectors work…. But I am using this old Hantek Scope for the first time today. And for the life of me don’t think I had it setup right and or got good captures. My time base/Voltages might of been off. It doesn’t give you a reference voltage on the x or y axis so I couldn’t even tell what voltages or current was. Only by moving the trigger. Is this a crappy scope? Channel 1 is the control with a 20:1 attenuator I believe I set time base at 2 ms I don’t remember.

Channel 2 was current ramp set at 50mv my Current Clamp was set to 1mv/100ma. Also Hantek Clamp. Time base of 200us.

Please any insight would be great. I’m still learning with my scope, I’m a new business owner and just getting into scopes etc, and I was trying to teach my fellow tech and feel I have failed. I really appreciate the input and or steps or what voltage/time base I should of been using.

Thanks, 

Attached are captures. I have 2 cylinders that are known good (they might be bad waveforms but I just figured if I kept time and voltage the same or each cylinder even if I didn’t have it set right I should roughly see the same which they did. But 6.. 

which i’ll edit to show and then Cyl 6 which just looks horrible (To me)

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Maynard Technician
Ontario
Maynard
 

Jordan I dont have many answers for you but I would say it looks like cylinder 6 is not working at all…. Do both injector wires go to the DME? You may need to also put your scope on the other wire of the injector to see if it has a command on it. If both wires go to DME there could be control on both wires. If there is no command to the injector it would seem likely the DME is shutting down the…

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Jordan Owner/Technician
Ontario
Jordan
   

Hello Maynard, I was awaiting your response. Both wires do go to this junction, and then to the DME. All injectors have a white wire and 3 have a white/grey 3 have a white/blue. I will try and scope the other line and current ramp the other. I do not see any adaptations or relearns on my Drive-Pro(Legacy) I will try my Verus tomorrow. Or my Launch. I 100% agree the DME is shutting down the…

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Caleb Diagnostician
Indiana
Caleb
 

Couple questions. 1: Does the misfire occur under load, at idle etc? 2: Only a P0306 sets when the misfire occurs or does the injector circuit fault set also that you posted? 3: Is there corrosion in the DME connector/connectors?

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Francisco Diagnostician
Maryland
Francisco
 

Most likely you have a bad DME and injectors. It is very common on this N55. As far as the grounds being loose for the coils, that is a big problem with BMWs, which cooks the DME. As far as your captures with the oscilloscope I don't think your 1mv/100amps is possible. So you have 50mv =5000 amps? You need to get a better oscilloscope, one that you can use cursors and see the values. Also, see…

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Jordan Owner/Technician
Ontario
Jordan
   

I agree I believe this vehicle needs a DME. Injectors I believe are okay but I would definitely change #6. I believe the driver for #6 is bad. Which makes me want to open it up and test the transistor legs (if it’s like a regular driver) and check for a short to one of the 3 legs. *Reference to pictures 3 and 6. Which I believe is 50mv division which I now see is impossible..I don’t know. This…

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Francisco Diagnostician
Maryland
Francisco
 

Also, be careful when removing the injectors. If they have water intrusion because of the cowl, they got corroded and probably seized to the cylinder head. I have one in my second bay that will most likely be declared as a total loss by insurance for the same exact reason, injector 6 was bad because of water from the cowl being broken, which corroded injectors and burnt the DME. Do a visual…

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Jordan Owner/Technician
Ontario
Jordan
 

The injectors and bores do look fairly rusty and corroded. You are correct. Thank you for advising me on this precaution.

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Fred Owner/Technician
Ohio
Fred
 

I watched a YouTube video (pine hollow auto diagnostics) on a BMW where grounds weren't connected after vcg job and it killed some coil or injector drivers on dme.

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Jordan Owner/Technician
Ontario
Jordan
 

Fantastic. I’m going to look into it!

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Fred Owner/Technician
Ohio
Fred
   

This one I believe, 12 min in youtu​.​be/zM694Wi8sTM

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Jordan Owner/Technician
Ontario
Jordan
 

The misfire occurs at idle, The P0306 isn’t actually present. It might be with another scan tool, but not with my drivepro, the only codes were what was posted.. but on DN I couldn’t type in those exact codes because they were not found. So I just put p0306 because thats a generic misfire on #6..which is my problem…If that’s improper to do please advise because I couldn’t type in my original…

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Obie Technician
Washington
Obie
 

I can't help with your scope problems. I do know this. BMW shuts off injectors after misfire is detected. There are many updated injector series for those engines. All the injectors must match. You need to verify the injectors are updated. Autologic can give you the installed injector info and you check it with the latest info. All 6 must be replaced and the DME adapted if any are replaced. This…

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Jordan Owner/Technician
Ontario
Jordan
 

Wow thank you. That was very informative. I have researched and realized if you don’t code injectors into the DME, it will run rough. I just don’t know if any were ever changed.. I ALSO forgot to mention when I went to scope the injector #6, the crevices IE in the head was full of rusty water. I had to blow it out with an air gun. So for checking stored codes for injectors, this means…

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Cody Diagnostician
Illinois
Cody
 

It sounds like a misfire turns into a misfire that the computer turns off the injector for. If spark is good, compression is good then the only thing left is fuel or a strange, semi-rare type of air flow out of cylinder(lack of valve liftish?). Main question is what is a comparative compression from another cylinder that is not misfiring? If you found a rusty spark plug, did you swap it? Im…

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Jordan Owner/Technician
Ontario
Jordan
 

Can you explain what a current flow test or injector flow test is? yes the rusty spark plug was replaced with brand new. When you say controlled by power and ground I’m not understanding. I thought only a driver could be low side or high side switched not both? Thank you.

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Kirk Owner/Technician
California
Kirk
 

I think he meant both wires come from the DME directly.

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Jordan Owner/Technician
Ontario
Jordan
 

Correct they do. It is not an independent ground.

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Francisco Diagnostician
Maryland
Francisco
 

Hi Jordan, You are correct a driver can only be low side or high side ( N-channel or P-channel) but since both wires are going to the DME, then there are two drivers one for each wire of the injectors. If you want to learn more about ECM and internal, please visit my youtube channel at youtube​.​com/channel/UC5fa7… I take the time to explain in deep the internals of the automotive…

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Jordan Owner/Technician
Ontario
Jordan
 

Thank you so much!! I’m definitely going to do this. Just a quick response if you may. Why would an injector need to be low and high side controlled. IE.. a driver for each wire? Thanks.

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Kirk Owner/Technician
California
Kirk
 

Nice! Do you repair N55/S55 valvetronic circuit?

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Kirk Owner/Technician
California
Kirk
 

A few points from me: the loose grounds are a big problem, but these are coil grounds, not injector grounds. If a DME damage has occured it will be permanent and the cylinder will never fire. 200+ compression for a high mileage engine is kinda not typical, ~175 would be more normal. I would put the camera in this cylinder to verify no mechanical damage. Changing one injector with used or new…

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Jordan Owner/Technician
Ontario
Jordan
 

Hello Kirk, I have a snap on borescope and I did look into the cylinders, I noticed carbon on-top of the piston and backside of valves, but I am not really familiar with how much is too much.. it didn’t look like the carbon was on the seat area. Or margin of the valve just the throat.. now I’m thinking this could just be a carbon clean job. But why the short to ground code? Should I keep the…

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Kirk Owner/Technician
California
Kirk
 

If you don't see any fresh oil in this cylinder don't bother anymore with a boroscope. The wet/damaged injector looks like a plausible theory. Possibly the DME may overheat after a few minutes running a shorted/damaged injector and shutting it down, or driver shutting down after overheating. If you install a new/used injector but not code it the engine may run a bit rougher, but not a…

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Mehboob Owner/Technician
California
Mehboob
 

Check intake port for #6 cylinder is not restricted by broken disa valve flap . I found too many time causing only #6 cylinder misfire. FYI only. good luck.

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Jordan Owner/Technician
Ontario
Jordan
 

I had never even heard of that or know what that is.. is this a variable flap for runner length? Thank you. I’ll do that tomorrow morning.

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Mehboob Owner/Technician
California
Mehboob
 

Broken pic.

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Jordan Owner/Technician
Ontario
Jordan
 

Great! Thank you. I will definitely check that out.

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Kirk Owner/Technician
California
Kirk
 

You will not find DISA in the N55 engine.

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Jordan Owner/Technician
Ontario
Jordan
 

Thank you.

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Francisco Diagnostician
Maryland
Francisco
 

N55 don’t use DISA valve. Don’t waste your time!!

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Justin Mechanic
Tennessee
Justin
   

Here’s a bulletin that may apply.

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Jordan Owner/Technician
Ontario
Jordan
 

Thank you Justin, that is extremely helpful.

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Ilya Owner/Technician
New York
Ilya
 

Check injector harness to dme for green wires. Recently had same proble . found water intrusion at dme plug

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Shaun Owner/Technician
Florida
Shaun
 

This may be a little off topic but I noticed you said you have a Drivepro from Autologic, have you tried their tech support on this issue? If so I would be curious as to what their thoughts were. Thank you

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Jordan Owner/Technician
Ontario
Jordan
 

I have called into IVS360, They assumed it was an injector. Physical issue. Which I wasn’t sold on.

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Shaun Owner/Technician
Florida
Shaun
 

have You tried swapping it with the cylinder next to it to verify?

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Jordan Owner/Technician
Ontario
Jordan
 

I have not because I am afraid of the injector being stuck. And causing a bigger issue. But with it dropping RPM as I command it off I assume it’s good.

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Shaun Owner/Technician
Florida
Shaun
 

If this were in my shop I would sell the time to swap and let customer know the risks. If they did not want to proceed then good luck, here’s your current invoice have a nice day. You can’t pay for someone else’s vehicle issue. CHARGE them and go through the proper procedures. Not every person is your customer

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Jordan Owner/Technician
Ontario
Jordan Update
   

Just an update the old owner of the shop that I’m purchasing has requested that I go ahead and try and change the injector so we have one on our way I will keep you all updated. The vehicle started this morning and died several times while trying to move it out of the shop. The DSC 4x4 lights are on and flashing CEL now.

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Stephen Technician
Tennessee
Stephen
   

GDI and CRD injectors are controlled, switched on, by both wires to the injector. Each output is connected to 2 or more injectors. A certain injector only fires when both of it’s sides are activated at the same time. I suggest connecting a 3rd channel to the other side of the injector to get a full picture of it’s drive. I don’t think that the “bad 6” shows anything meaningful because the…

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Eric Mobile Technician
Quebec
Eric
 

Hi Jordan, engine partitions are often broken and water leak in the cylinder 5-6 recess and on the DME. There are updated parts from BMW. For the injectors 1-6, one driver is controlling those 2, the injector 6 is probably grounded, affecting both cylinder. Please check from connector on DME to injector if it is short to ground. Probably #5 is no good too. The DME is probably gone too if water…

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Andrew Owner/Technician
Australia
Andrew
 

disconnect wires at DME and Load test individual injector wires. FYI - DME is fitted on the intake manifold (for cooling purposes) special tools are required to pull injectors. injectors have plastic bodies and can crack if too much force is used to remove them. please read repair instructions As engine fires can occur if cracked injectors are refitted. If injector wires test ok it will…

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Jordan Owner/Technician
Ontario
Jordan
   

Hi there, thank you for the reply, may I ask how do you “load test” injectors? Thanks. Are you referring to voltage drop testing the wires We also have the special tool for the injectors.

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Ray Diagnostician
Ontario
Ray
 

Andrew said to disconnect the DME and load test the individual injector wires. Disconnect an injector and connect a headlight across the 2 wires, then run fused jumper wires from the injector wires at the DME, to a battery. The headlight should pull about 4 amps.

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Jordan Owner/Technician
Ontario
Jordan
 

Perfect information. Very informative. Thank you.

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Ray Diagnostician
Ontario
Ray
 

Hi Jordan, your welcome!

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Andrew Owner/Technician
Australia
Andrew
   

load testing wires - not the injectors themselves. This is my method. disconnect all wires from the DME And the injectors. Put a halogen bulb on the end of the wire you are testing and add ground to bulb also. Briefly Apply FUSED power to the wire At the other end. If bulb lights bright you can assume the wire is good. Leave connected and wriggle wires if you suspect intermittent short. When…

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Cody Diagnostician
Illinois
Cody
 

If im questioning a circuit, I add a multi meter or a scope to that formula to measure voltage drop, in my thinking if you are going through all that trouble to load test a circuit. Then you might as well spend an extra minute to have good hard voltage drop numbers.

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Jordan Owner/Technician
Ontario
Jordan
 

Thank you for this information. I will be doing this today.

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Kirk Owner/Technician
California
Kirk
 

Andrew, no one will install plastic injectors that have to hold a few hundred bars of pressure in a hot environment with added vibrations. They are metal “tubes” and there is some plastic molded around the tubes.

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Andrew Owner/Technician
Australia
Andrew
   

Hi Kirk, This is a safety issue so i was very careful to have my information correct. Do you have access to BMW repair instructions? If so please read carefully the instructions for removing the fuel injectors on N55 engine. I can assure you the injector has plastic parts that can crack if excessive force is used to remove or install them. If you do not have Repair instructions i would be…

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Kirk Owner/Technician
California
Kirk
 

Well, we rebuild BMW engines and we regularly have to extract stuck/rusted injectors from core heads. I can assure you that we have used forces that no plastic can whitstand. As you can see from the TIS instructions, the twisting force is what can cause a rupture, which is specific for a thin wall high strength steel.

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Andrew Owner/Technician
Australia
Andrew
 

The instructions give two values. One for twisting and another for pulling.

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Kirk Owner/Technician
California
Kirk
 

For your viewing pleasure here is a picture of a “dissected” injector. There is a plastic around it, but fuel flows in a steel tube.

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Andrew Owner/Technician
Australia
Andrew
 

Thank you.

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Jordan Owner/Technician
Ontario
Jordan Update
   

Just an update, the client finally came in, and wants to know if we can try swapping injectors? Is this something that is possible? I know the adaptive values may have an issue? As well as breaking them coming out?? The old owner of my shop I own who he has a lot of experience with this had said something about finding out the firing order. And attach the next cylinder that fires after 6’s…

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Obie Technician
Washington
Obie
 

Jordan, If you are positive the engine has NO mechanical problems then dealing with injectors may be a path forward. Simply removing and swapping injectors with possible unknown defects seems futile. I have lost track but are the injectors current series and are they registered in the DME correctly? Simply swapping injector leads is a non starter. If you are satisfied the wiring is okay then…

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Jordan Owner/Technician
Ontario
Jordan
   

Hi Obie, I appreciate your honest response. And you are right. This thread has led me to so much knowledge of these engines. And possible causes. I sincerely apologize for making it look misleadingly, I did not communicate that with the client. I 100% did. And he refused. I don’t have it in me as a new business owner to say ”sorry, but if you don’t want to follow my repair plan, I can not fix…

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Kirk Owner/Technician
California
Kirk
   

You can get one new injector and swap it. The X5 has early N55 with separate injector feed lines and you don't even have to remove the complete fuel rail. That would be a hour job for an experienced tech.

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Eric Mobile Technician
Quebec
Eric
 

Hi Jordan, do you have pictures of the injector 5-6 recess? Has water and windshield washer entered there by a broken engine partition? I just caught a shorted to ground injector 6. Be aware the injector is maybe stuck and fused into the cylinder head. I just did one and it was a nightmare to remove because the top fitting broke off when using the BMW tool. Did not need to remove the cylinder…

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Jordan Owner/Technician
Ontario
Jordan
   

Hi Eric, I mentioned in my OP that I had heard of the engine partition causing water intrusion. I definitely forgot to say.. it was FULL! Of water when we got it… I feel terrible in regards to not mentioning this.. Now I feel foolish, that I did not mention that my clients vehicle yes had water, in the recess of that cylinder.. Thank you, Jordan.

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