2004 X5 Injector issue

[Crazyc123]

So I was driving my car around a four hour trip about two hours into the trip I started getting a misfire in the engine I was doing about 80/90 on the freeway and the misfire made me slow down to 70 so I pulled over shut the car off restarted it and the misfire went away. about 15/20 minutes later the same thing happened and it got worse so I stopped at a auto parts store and picked up a coil because I had recently had to change one or two coils so I stopped and bought another two coils and started messing with the coils under the hood while I was running and found two cylinders that were misfiring so I changed both coils and ran fine again. Another 30 minutes later the same thing happened now I’m frustrated. I got to my destination only being able to go 55 mph and I went to the auto parts store and bought six new Denzō plugs and another coil.

I took all the plugs out and 2 plugs cores were burned and the tips of the plugs were burned right off. So I changed all the plugs did not use the coil in the truck ran fine. About a week or two prior I had went to a restaurant and came out of the restaurant to start the truck and the truck didn’t start for three starts about an hour later after I did the complete six plugs tine up and started miss firing again. Now the truck was cutting off and dying at lights .

So out of curiosity of it being a fuel problem and not a spark issue because I had just changed almost all the coils and all six plugs I started banging on the fuel pump underneath the passenger rear seat. To my surprise when I smacked in the fuel pump the trucks smoothed out and start running better. I then went and ordered a new fuel pump and fuel filter and change them the next day.

Truck ran great after that but after two or three days the misfire came back. Cylinder number four. Change the coil, checked the plug, bought a new plug and new coil, change them out, no change in the way the car ran, still had a misfire cylinder number four. So now I’m looking at a fuel injector issue. opened up the fuel injector harness and checked for computer ground to injector pulse on the grounding wire to the DME (I believe) and I seen injector grounding from positive battery to PCMDME injector ground. Check for power on the power side of the injector and had power on both injectors three and four (checked the one right next to it) when I start truck up runs fine but after a while fifteen minutes to twenty minutes of driving cylinder number four injector stops pulsing to ground on PCM / DME . check engine light illuminates and says cylinder number four misfire. pulled coil and coil is sparking every rotation of motor perfectly fine so it’s not the coil side it is on the injector side that the issues arising . while truck is running and check engine light is illuminated, cylinder number for injector does not ground flash. Truck can still be running amd while I clear codes , computer injector ground comes back immediately after clearing code. Same thing when I shut the truck off and start back up. Truck can be miss firing I shut truck off and start it back up and immediately the injector starts working again.

Question : is the issue the injectors self or is it an issue with the DME/PCM injector drive ground it’s obviously not a wiring issue or the problem would be persistent. where do I go from here ? do I blindly change the injector and hope for the best or is there a common problem with injector drive on the DME/PCM anybody who Is knowledgeable on these vehicles and the electrical injection system would you please point me in the right direction that would be great

[upallnight]

You have a misfire with fuel cutoff. That means the computer have detected a misfire or multiple misfires and have turned off the injection pulse to the injector(s). This is to prevent damage to the catalytic converter from raw gas that is being burned in the cylinders. Before throwing more parts at it, you should do a compression test of all the cylinders. You could have a cylinder that is lower in compression reading and thus will produce less power. Less power from a cylinder means a misfire to the Computer.

[oldskewel]

You could also try swapping injectors between two cylinders to see if the problem moves.

Also, most of the story sounds pretty normal, and your debugging is great. Except what about this: "2 plugs cores were burned and the tips of the plugs were burned right off" ???

I'd try to figure out an explanation for that one and not just hope it does not come back.

[upallnight]

Originally Posted by oldskewel

You could also try swapping injectors between two cylinders to see if the problem moves.

Also, most of the story sounds pretty normal, and your debugging is great. Except what about this: "2 plugs cores were burned and the tips of the plugs were burned right off" ???

I'd try to figure out an explanation for that one and not just hope it does not come back.

If you do swap out the injectors buy some new o-rings. The o-rings are probably pretty deformed from years of heat and cold cycles. Reusing old o-rings will just cause problems down the line. If you know anything about BMW's rubber o-rings is that you don't want to reuse them.

[Crazyc123]

Originally Posted by oldskewel

You could also try swapping injectors between two cylinders to see if the problem moves.

Also, most of the story sounds pretty normal, and your debugging is great. Except what about this: "2 plugs cores were burned and the tips of the plugs were burned right off" ???

I'd try to figure out an explanation for that one and not just hope it does not come back.

So from lack of fuel from the fuel pump being vad overheated the plugs and. Burned the resistors off the ends. It’s not a mechanical problem because it comes and goes and corrects itself immediately after restart. As far as the compression goes, I don’t think it can be a compression issue, unless I burned a valve from running lean, but I find that very unlikely as I’ve been driving all day and am currently sitting in truck now and it’s running fine. I understand the cylinder shutdown but even if it detected a misfire why would it come and go even while running and even when I clear codes or whatever. Sometimes it fixes itself while driving,

[Crazyc123]

Originally Posted by upallnight

If you do swap out the injectors buy some new o-rings. The o-rings are probably pretty deformed from years of heat and cold cycles. Reusing old o-rings will just cause problems down the line. If you know anything about BMW's rubber o-rings is that you don't want to reuse them.

So I was thinking of changing the injector but should I just change the one bad one ? They are pretty expensive and I’m only having a problem in cylinder 4

[upallnight]

Originally Posted by Crazyc123

So I was thinking of changing the injector but should I just change the one bad one ? They are pretty expensive and I’m only having a problem in cylinder 4

See this post.

https://xoutpost.com/1141378-post2.html

[oldskewel]

Originally Posted by upallnight

If you do swap out the injectors buy some new o-rings. The o-rings are probably pretty deformed from years of heat and cold cycles. Reusing old o-rings will just cause problems down the line. If you know anything about BMW's rubber o-rings is that you don't want to reuse them.

I actually just replaced all the injector seals on my M54, while rebuilding the top end at 186k miles. I found the o-rings to be pretty good looking, actually. I did replace them though, because they came in the head gasket kit.

Here are the part numbers:
6x lower O-Rings for Fuel Injector (7.52 X 3.52 mm) 13641437487
6x upper O-Rings for Fuel Injector (9.2 X 2.8 mm) 13641437486

[X5M62]

Hey guys, similar thing when I bought my 4.6is X5, was never wowed by it by performance during the test drive but I believed in it :-) On the way home at high RPMs the check engine flickered and the truck lost power...ran code and it was missfire cyl1 fuel cut off..after running slow for a while it ran fine until i pushed above 5000 rpm. So what could affect cyl 1 only? change injectors (all 8), plugs, and coils and? ran better but still happening...
Come to find out the CAT on bank 1 was all clogged up.. weird how it wasn t affecting all cylinders...
Anyway, tap your cat(s) with a fist or mallet, if you hear any sound i d change them (or it if only one on a 6 banger). $1200 a pop!! so I got a set of high flows aftermarket and oh boy...that wake it right up :-)