Rough running 4.8is

[panchosouth]

Guess who changed their mind about selling- Sigh.

What can I say. I started surfing for parts-porn and found a pair of black comfort seats....And I'm off to the races. Now my current plan is to install the comfort seats in front, move the sport seats to the back, get rid of the bench seat, and install one of those nice shiny M3 paddle shift steering wheels. Oh and hard wire in some radar/laser stuff…Oh and get rid of the OEM GPS, remove the Dice media bridge (no likey) and install that thing on Ebay (Dinavin?). Oh and go with some new sporty bushings….And new sway bars….And possibly….Well I’m sure you know where I’m going with this…..

Rough running:

The Uber Donkey ran a wee bit rough when I first picked her up. It was really hard to get a good read because (using my ass-o-meter) the suspension was doing the low-rider bob and the DINAN tail pipes were giving me new-owner orgasmic sound woodies, so every time I went to sus out the rough running I would end up getting lost in the DINAN burble then forget what I was doing. That didn’t last very long because a week into owning it (this is amidst getting new tires, suspension etc sorted) I began to notice a stumble on throttle up. Once noticed, it seemed to jump from back ground irritation to CEL almost immediately.

A trip to the shop showed the usual culprits you see on here: multiple miss-fires, or cyl 2 or 5 or whatever misfiring.

First remedy:

All new plugs. Ran great for about 3KMs before the stumble was back onboard.

Back to codes- Same as last time.

Second remedy:

Replace indicated coils (in this case it was showing 2 and 5) Spent 200.00 on coils locally (lesson learned; ordered the next six from ECS Tuning for the price of two local ones). Ran great for about half an hour. Finally got a taste of how it was supposed to run and …..sigh.

Back to the shop. Same codes. So. Start from scratch. Check for vacuum leaks. Nope. Check for loose connections (more on this in a bit), discover that PO had some sort of sub-woofer set up in back, and check splice and tap in points. All good. Replace remaing six coils.

Third remedy.

Carbon build up is the suspect du jour. Run a cleaning agent through injection system. Lots of smoke from pipes. Lots of male grunting in shop as we all nod like spastic bobble heads, a collective agreement that this, this is the culprit. It is decided to run only 94 octane and take a couple of long trips (200kms or so) to blow out carbon.

CEL returns, however, it is usually a flashing engine light, and the rough running can be somewhat mitigated by pulling over and cycling the ignition. This done, light disappears, and if introduction of throttle is steady and limited, stumble is all but gone.

It should be noted at this point, that the issue seemed more prevalent when cold and damp (early morning), and under mild to medium throttle you could set your watch to the CEL coming on. Also, and this is why I said “more on this” when I mentioned connections….The airbag light in instrument pod and on sunroof/light control area started to come on….This was also the period when I was trying to get the suspension sorted out, so the pod looked like a Christmas tree on crack. Whenever the suspension inactive light came on, it was always simultaneously joined by the TPS light (tire pressure). Don’t ask me why, it just did, and the only way to get it off was when you re-set the codes. The airbag light would show itself, for maybe 5 or 10 minutes, then go off…..as in when the truck seemed to be producing enough heat….but that is again supposition on my part.

Back to shop.

Fourth remedy:

Check all vacuum lines again. Again with injection system flush, new fuel filter, also a Hot Oil Engine Flush (basically a blow-the-crap out of it scrub-a-dub-dub). Once more 94 octane and long drives. I can tell you that the head bobbing and grunting was far more pronounced this time, as the smoke was akin to the Hindenburg. Oh the Humidity! Thankfully the shop had just completed a compression test with flying colors so no sudden rectal convulsions were ensuing when I saw the great clouds of smoke billowing out of Uber Donkey.

So where am I at? Well, I still have the rough running and CEL. Last day I had it on the road (I work overseas so it was going into storage) it was rainy and somewhat cold aaaaannnnnd on comes the CEL and the airbag light. It also sounded like it was knocking, but I was on my way to the airport and couldn’t really hang around to get a handle on it. No luck with ignition cycling either. CEL stayed on. Air bag intermittent. Somewhere over the Atlantic I decided I wanted a turbo. Decided to sell the X5. Posted same. Contacted Otto’s BMW to go pick up the X5 and get it sorted. Was told I had to wait two weeks for someone to be able to pick up and then get it diagnosed. Accidentally looked at parts porn. Bought seats. Sigh.


Let’s hear your thoughts, and add any similar experiences to this post, and remedies! We should have a sticky on this so we can save some moolah to others who come up against this…..

Will let you know what I hear next week.