I have a 2011 x5 335i and for the past several months anytime I accelerate anyway other than very gently I get pretty significant stuttering and shaking followed by an engine malfunction message. sometimes after the message the car will simply have a small loss in power. sometimes the performance is awful, the stuttering and shaking will remain. sometimes I'll start my car and that's just the way it decides to run. it always goes away on its own when I shut the car off. sometimes after an hour sometimes after a week. there doesn't seem to be any consistency. I know the obvious solution is to take it in but I live in the middle of nowhere and the nearest BMW dealership is about 3 1/2 hrs away. I have already replaced the fuel pump, the plugs, coils, and the air filter. any thoughts?
No CEL or error message displayed on the OBC? Could be a throttle position sensor, a clogged catalyic converter, the fuel filter, an o2 sensor (although those normally function only in closed loop i.e. while accelerating gently or idling). Have you tried going WOT or in other words "stepping on the gas pedal"? If it does not stutter when you do, but does stutter when you accelerate "a little more than gently", it could hint at an o2 sensor.
At this point and unless you solve the issue by replacing the fuel filter, you'd better buy a quality diagnosis tool (around $150 I believe) and identify the issue than keep changing parts with no improvement.
Last edited by Breeze1; 08-20-2018 at 05:37 PM.
"If you have integrity, nothing else matters. If you don't have integrity, nothing else matters." Alan K. Simpson.
5spd E46 "3XX": 328i engine, 330i Intake and exhaust, CAI, 323i diff.
the CEL does come on with the engine malfunction. is there another fuel filter other than attached to the fuel pump? BMW told me that when they replaced the fuel pump that the filter was included. when in park I can put the throttle to the floor and it revs just fine. the problem only presents when under acceleration and it happens a lot easier going uphill and under load.
I was not aware that the filter came with the pump on your model. It leaves me dubious regarding maintenance costs and/or reliability, but I have to say I couldn't find a reference to a separate fuel filter other than an "activated charcoal filter under the "ventilation" section of "fuel delivery", so that one is just the filter used by the breather in the tank:
https://www.realoem.com/bmw/enUS/par...-X5_35iX&mg=16
If they replaced it with the pump, that's one thing out of the way. If you want to try to rule out the catalytic converters, you could locate them, go for a spirited drive or rev it up in "P" until the engine warms up pretty good and then quickly look at the cats to see if they're glowing red. If they are (or one of them) they're most likely clogged (please be careful and have a fire extinguisher handy because clogged cats present a fire hazard). Lastly, you could locate the TPS, clean it and see if things improve significantly.
You can double check my link to make sure it's your model or browse www.realoem.com from scratch using your car's serial number to locate the parts.
Edit: since it's an auto and the car revs fine in P, it could also be something related to the transmission, such as a sensor.
If I were you, if the "guesswork" tests above fail to produce results, I would buy a scanning tool to help identify the defect.
Last edited by Breeze1; 08-20-2018 at 06:25 PM.
"If you have integrity, nothing else matters. If you don't have integrity, nothing else matters." Alan K. Simpson.
5spd E46 "3XX": 328i engine, 330i Intake and exhaust, CAI, 323i diff.
if we suspect cats, let's test them correctly...
'95 325iS - auto to manual swap done!
"If you have integrity, nothing else matters. If you don't have integrity, nothing else matters." Alan K. Simpson.
5spd E46 "3XX": 328i engine, 330i Intake and exhaust, CAI, 323i diff.
gather data - do a pressure test, etc. in this case, we're way cart before the horse here - we're still not sure which vehicle were even trying to diagnose....
'95 325iS - auto to manual swap done!
You're right about the fact that it's always best to gather data and do things "by the book", but in this case and given what the OP said about his whereabouts, I thought I would share with him my impressions and a few "tips" that I believe could narrow things down or possibly even identify the issue if it just so happens to be one of those things. Next step would indeed be to at least get a scanner, and/or do a smoke/pressure test.
I'm assuming the car is an X5- 35i, based on what the OP said.
"If you have integrity, nothing else matters. If you don't have integrity, nothing else matters." Alan K. Simpson.
5spd E46 "3XX": 328i engine, 330i Intake and exhaust, CAI, 323i diff.
Sorry, breeze, but shadowpuck is correct. That is not a valid way to test cats, at all. To test a cat, you screw an adapter into the primary O2 sensor port, then hook up a vacuum/pressure gauge to that adapter. Then rev the engine to ~3500 rpm. Backpressure must read less than 2 psi.
To confirm the problem is STILL just the cat, and not all the cat's honeycomb having been blown into the muffler, you repeat the test at the post-cat sensor hole. If you have almost zero backpressure there, and significantly over 2 psi at the pre-cat port, you have a clogged cat.
Note that a clogged cat won't get very hot, because there's not much flowing through it.
Too lean, or even too rich a mixture can show as an overheated cat. That doesn't necessarily mean the cat is bad...yet.
Of course, after backpressure testing is done, if and when it's confirmed that all air/fuel parameters are correct, and O2 sensors are operating properly, cat efficiency codes will point to a cat that's no longer doing its job.....but not in such a way that it'll stop the engine from running correctly.
Eisenbrandt, the 335i is a 3 series car. There's no X5 335i. You need to drop one of the threes.
But, the most crucial thing:
You need to own a BMW specific scan tool which can converse with every computer in your car. Without this, you can't possibly diagnose your issue.
I suggest this, as an easy alternative:
https://www.ebay.com/itm/For-BMW-MIN...-/172319102926
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
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