Rough idle andle black smoke?

[reconn]

I've been using these forums for a while now to help with projects on my 318i, but have just now registered cause I'm in great need of help. There has been an excelent amount of info. on here to assist with the other ploblems I've had, but can't find anything on this one.

I have recently rebuilt the top end of my 1.8 I4 myself including:
- all new valves, springs, oil seals
- head gasket
- ported and polished head and intake ports
- all gaskets and seals in top end
- cam sprockets
- injectors
- both knock sensors
- camshaft position sensor
- crankshaft position sensor
- o2 sensor
- plugs and wires
- cleaned the idle speed control valve
- replaced some vacuum lines
- flushed complete cooling system and installed new radiator, waterpump, thermostat
and housing
... and after all of this, I just can't get it to run correctly.

It idles a little rough and blows out small puffs of black smoke and soot. If reved while sitting it blows out quite a bit of black smoke and soot, but not very much when accelerating through gears. The engine just wants to run when driving and I notice an amazing difference with the rebuild while accelerating. But, like I said, it does have a rough idle and while keeping a constant speed on highway doesn't run a smooth as it should. With all knowledge I have of engines I know that the black smoke and soot is do to too much fuel to air mixture. What I don't know is what would make this happen after all the new parts that prevent this. It was also going through fuel like it was a Chevy big block, but I'm pretty sure that was fixed when replacing the o2 sensor, haven't driven it yet since, still smoking.

Any help given will be greatly appreciated and I'll be sure to return the favor of DIY knowledge in the forums since I'm finally registered and can post responces.

[jasonf860]

Perhaps you have the wrong size injectors?

[bimmer dot info]

leaking injector? possibly wrong fuel pressure. Is the check engine light on?

[Droopy9]

Hey reconn,
I have a 318i and these are the problem I have previously, I don't know if these will help you.
Sometimes when I was driving the rev were too high- The problem was a bad clip in the throttle body assy. The throttle body cable gets stock in this clip due to the normal wear and tear. the clip is call a "nipple" and the part number is 13541288013.

Also,
I am replacing my cat converter because I weird noise is coming out of it. I am assuming that my catalytic converter when bad (I order a new cat from Discountconverter.com this outfit is from texas and I pay $190 free shipping)).
Anyway, some ideas, I hope I does not confused you.

[reconn]

I'll have to check with company I ordered the injectors from to double check that they're correct. How would I check fuel pressure to verify it's correct? There's no check engine light, or any warning lights, that have come on and it doesn't rev or stick like Droopy9 was suggesting. I have also replaced the cat with in the last month and ran with it before rebuild. I appreciate the assistance and I hope we can get this figured out.

[reconn]

Well, I've called Bosch and verified that the injectors were correct. I did a little messing around with some stuff and found that the engine purrs perfect and doesn't blow any smoke when I disconnect my mass air flow sensor. I'm assuming this means it's bad, but this is also bad news since they run $560.00 from the stealership and I can't seem to find anyone else who carries them. Does anyone know of a cheaper place to purchase one, or even a way to just bypass the sensor all together. I would drive the car with it disconnected, but the engine isn't as responsive when reved with out it. Any ideas?

[Pirate_copy]

Hey mate, Welcome to the fest :)

Get onto some of the sponsors to see what they can do. Also look into getting a second hand one.

Just one other thing to look at is the intake boot, is it in good condition with no damage or cracks?

Pull your codes too, just to check all the other sensors are ok

Ps, congratulations on the re-build. Mightily impressed!!!

[jasonf860]

Sounds to me that your MAF is bad indeed. Bad in the way of it's reading an excessive amount of air coming in causing the rich condition. Hmm, maybe adding a CAI would help!

[hawk2100n]

Well, I've called Bosch and verified that the injectors were correct. I did a little messing around with some stuff and found that the engine purrs perfect and doesn't blow any smoke when I disconnect my mass air flow sensor. I'm assuming this means it's bad, but this is also bad news since they run $560.00 from the stealership and I can't seem to find anyone else who carries them. Does anyone know of a cheaper place to purchase one, or even a way to just bypass the sensor all together. I would drive the car with it disconnected, but the engine isn't as responsive when reved with out it. Any ideas?

Pelican parts
318i MAF $182.75 reman (http://www.pelicanparts.com/bmw/catalog/shopcart/BE36/POR_BE36_FULint_pg2.htm#item7)

A pretty good price with free shipping.

[reconn]

Thanks for the line through Pelican parts, deffinently a better price. I believe my fuel pressure regulator needs to be replaced also, so I went ahead and ordered one, figured it wouldn't hurt. Been wanting to upgrade to CAI since I already did the rebuild with port and polish, any recommendations? Anyone have a homemade design they've come across and would recommend? Just dropped a few of dollars on the rebuild and trying to save a couple bucks if you know what I meen.

[mofski]

hey dude don't be so sure it's your afm as i did think aswell till i read your post, my car has exact same problem, i just finished puttin a reco'd head on it, and when i start it with the afm connected it runs like ****, but when i discconet the afm, it runs alot better, i'm starting to think my cam gears may be off, tho i just bought a afm thats comming in 2 days :(

[mofski]

well after putting on my new air flow meter my car runs like a million bux, so i can happly say it was definatly that, found it funny how both our cars had the same problem after removing the head.

[reconn]

Well, sure enough, a new AFM went in and it runs like new. Actually I think it runs better due to the port and polish. Thanks to all who helped.