Help, x5 running strange

[we350z]

I thought I had a bad IAC valve on my Nissan. After removing it, dissasembling, cleaning the solenoid, and then reinstalling with a new gasket which was a total knuckle buster i realized that it did not solve my erratic idle issues. It ended up being a faulty injector that was working intermittenly for me, though this symptom can be caused by many things.

[we350z]

yep this is how i found my faulty injector before I ended up replacing the entire fuel rail assembly and injector set completely. Not sure if you can do easily on X5 without removing valve cover gaskets but on my Z i could unplug each coil pack one by one, then once you isolate the problem IF you do you can try swapping spark plugs (check to see if its fouled) and then lastly switch injectors (required removing upper plenum on my Z). However, unfortunately when I was installing my new 740cc injectors i didn't realize that one of them ended up being faulty since I had no way of flow testing them so I ended up taking the car to a mechanic. Had I switched the injectors around I would have found the problem moved too.

Originally Posted by weasel56

Anything is possible... Especially if you haven't changed them yet at 107k.

Also, since you apparently have a code reader... you can take the misfiring cylinders, switch the coil with a known good one (cyl. without misfire code stored) and the spark plug to another.... clear faults, drive it till they come back. See which one the misfire follows. If it stays put, swap the injector with another and try again. That's just one way to figure out what component is giving you the trouble.

But just changing the spark plugs is a safe place to start, simply because you're due for them at 100k anyways... and the whole spraying the hoses trick to find vacuum leaks works great with substantial vacuum leaks, but not with the smaller ones. The computer compensates for it really quick. If your code reader has "data flow" you can read the upstream O2 sensor voltages. At idle at operating temperature they should switch in the range between 0.2 and 0.8 volts about every second. spray it all down with the cleaner while reading this, when you hit the tiny little leak, the voltages will stick at 0.8 volts for a few seconds. That's how I gotta track them down sometimes...

[Weasel]

The fuel rail isn't that hard to get off on the 3.0i, easier than the Z for sure! Just the microfilter bulkhead (4 torx screws) and the plastic engine covers. (2 10mm bolts/nuts each). Then just unclip the extra harness shit from the top of it, and the front sensor wire... then the 4 10mm bolts that hold down the rail itself.

But hopefully all it is will be the overdue sparkplugs...

[we350z]

Ya I saw a write up on the valleypan replacement and I was surprised at the ease in which the fuel rails comes out. I have to say this engine looks like a dream to work on compared to the VG30DETT on my Z (even after i did all the stupid throttlle body water line deletes that intricately lined the underside of the upper plenum. I still have nightmares about this

Originally Posted by weasel56

The fuel rail isn't that hard to get off on the 3.0i, easier than the Z for sure! Just the microfilter bulkhead (4 torx screws) and the plastic engine covers. (2 10mm bolts/nuts each). Then just unclip the extra harness shit from the top of it, and the front sensor wire... then the 4 10mm bolts that hold down the rail itself.

But hopefully all it is will be the overdue sparkplugs...

[culthero]

I will try plugs next and post results

[culthero]

So, I put in new plugs, and the problem was still there. So I then swapped the coils off of cyl 5 & 6 with 1 & 2. Still have the same rough idle issues on the same cylinders. Got my codes reread:

P0313
P0300
P1353
P1351
P0171
P0313P
P0300P

Before the new plugs and swapping of coils....I had the following:

P0300
P1353
P1351
P1083
P0171
P0300P

Any more ideas or am I at the mercy of a BMW Tech now?

The weird thing is that if I turn it on and drive off and not ever stop for longer than a short stop sign....it will run and idle fine. As soon as I stop a a traffic light for instance...it will start to idle rough. Sometimes it even goes away after driving for a bit, stop a a short light its fine...then after stopping at a longer traffic light...it will come back.

[Weasel]

If you get tired of trying to figure it out yourself, then hopefully you would only have to pay the BMW techs once... Just make sure they drive it enough to make sure its gone and doesn't come back! Even if it does, bring it back to them saying its doing the exact same thing and they should stand by their work and go at it again. If they try to make ou buy more parts, tell them you already paid to have this problem fixed once, and they missed... not you!

Otherwise, keep plugging along! But these problems can be a bitch to find sometimes...

[culthero]

I think I might have a faulty injector(s) after all.

Last night I cleared my codes, drove home, it started shaking and the codes came back.

This morning I start up my X, the codes are cleared, and I decide to drive to work, but instead of being idle at traffic lights, I put my X in Neutral, and revved up to about 1K RPMs. I never let it idle on its own. I was able to drive about 20 miles to work without it hesitating and without any codes coming back on.

Can I swap injectors without swapping the entire rail? If so..how hard is it?

I'm really not ready to give up yet.

[Weasel]

Once you pull your fuel rail off, the metal clips that hold the injectors to the rail will be easy to pop off. After that, just wiggle and pull the injectors out. They just push in with o-rings and are held in place with the clips. Just BE SURE the clips are fully/properly seated when you put it back together. And the o-rings should be the same size as most multiport fuel injection systems. (bosch style injectors)... so if you want to replace them you can go to the local parts store and get them.

Some people even use 5.0 mustang injectors in old 318ti's as an upgrade...

[culthero]

Awesome! Thanks!

Is there any precautions I need to take before pulling off fuel rail other than d/c the battery? Any lines I need to remove and clip shut or anything?


Thanks again for all the help!