OK.. after doing some research, I think my rough idle, miss/sputter is caused by one or more faulty fuel injectors.

I can most definately smell that the car is running a bit rich, when I WOT the engine on the road, it performs fine.
I'm guessing I have one that is dripping or not atomizing the fuel correctly, thus the mixture is all wrong for one cylinder, or more.. that cyl has too much oxygen that passes on to the exhaust(liquid fuel wont burn, thus extra oxygen).. the O2 sensor sees the extra O2 and thus makes ALL the injectors run more rich(it thinks it has to, its too dumb to realize there's an injector issue).. thus I smell the rich exhaust

so,
What injectors can I use on my M30? It's a 1986 model.. I'll check build date later on.. but I've seen on ebay sellers saying you can use 19# injectors that are used on Ford Mustang 5.0's

Anybody in the know, know about all this and give me some info?

Thanks!

we had one of these discussions just last week: http://forums.bimmerforums.com/forum/showthread.php?t=796677

i've been thinking the same thing. also have a slightly rough idle(have been over the whole engine looking for a vacuum leak), and when mine us at WOT the problem is gone. i was thinking atomization as well. high doses of injector cleaner have not helped.

i've been thinking the same thing. also have a slightly rough idle(have been over the whole engine looking for a vacuum leak), and when mine us at WOT the problem is gone. i was thinking atomization as well. high doses of injector cleaner have not helped.


yea.. if they are gunked pretty bad or have a large foreign particle stuck in them, the injector cleaner wont have any effect.

The rough idle you have.. can you also hear/feel the roughness/miss when you bump the idle up a bit? Say at 2000-3000 rpms? Can you smell the exhaust a bit on the rich side?

thanks for the link above, it helps to know others have used the Mustang injectors and gotten good results.
I've seen the mustang injectors for 50-100 for a set of 6. While rebuilt, its a ton cheaper than buying new OEM's from BMW vendors or perhaps even cheaper or similar cost to having the current ones on the car professionall cleaned via either MotorVac or Removed/Rebuilt.

Now MotorVac may still be a good thing to do though.. because it will clean carbon deposits off the valves and piston. I've had MotorVac done to a 351 engine with a ton of miles on it and I def. noticed a signifigant improvment in performance.

I've been looking around because I need to do something with my injectors also, here is what I've found:

WitchHunter - Complete Injector tear-down, cleaning, rebuild and flow testing, they send back a chart showing the flow before and after the cleaning - $17/injector or $102/set +$8 shipping. Go through their website, they have a lot of interesting info on injectors and their cleaning process with pics. Make sure you read the section about the difference between a proper cleaning and remanufacturing, there is none!: http://witchhunter.com/ (http://witchhunter.com/)


Alternate site, also $17/injector but don't get sucked in to their " Remanufactured" injectors here, see above: http://www.accurateis.com/products.php?cat=10


FiveOMotorSport - A set of the newer replacement #19 "Mustang" injectors, $240/set of 6 +$12 shipping ($252): http://www.fiveomotorsport.com/Injector_SetsBMW.asp (http://www.fiveomotorsport.com/Injector_SetsBMW.asp)

They also have sets of the "Design III" injectors, but don't recommend them unless you've done engine work.

The #19 "Mustang" injectors also come up on eBay for around $75 to $100 but they are used and I'm not sure I would want to put them on my car with out knowing anything about them, so if you send them out to get cleaned and flow tested for another $100 you might as well buy the new ones. There was a set for $135 that was supposed to be cleaned, but I'd want to find out more about the "cleaning", remember, you get what you pay for.


AutoHausAZ - OEM replacement, Bosch 0280150714 - $295 (free shipping) http://www.autohausaz.com/search/pro...=%200280150714 (http://www.autohausaz.com/search/product.aspx?sid=fzwojsahtgpdke45wxuigh45&partnumber=%200280150714)

i do have the slight miss even off idle. at idle you can hear it at the rear of the exhaust. i've replaced many parts, compresion is good and even, engine vacuum good, valves adjusted, throttle plate adjusted and cleaned, TPS adjusted.
i do not have the rich running smell. but it always gets a little smoother at WOT. can just feel it when the pedal is pushed.