3-Series (E21, E30)Chat relating to the BMW 3-Series from 1975-1983 and 1984-1991 line. Specific models: BMW 315, BMW 316, BMW 318, BMW 318i, BMW 320/4, BMW 320i, BMW 320/6, BMW 323i, BMW 320i. E30 Family models include: BMW 325e, BMW 325i, BMW 325is, BMW 325ix.
My 85 318i is having some air flow meter (AFM) issues. With clean spark plugs I can start the car and it sluggishly gets to idle with misfiring. If I disconnect the AFM from the boot connecting it to the throttle body, I can start the car and it will immediately idle at 3000 rpm's If I put my hand into the AFM and move the flap, I can get it to idle under 2000 rpm and all cylinders are firing. I have replaced the ignition coil and wires, the distributor cap and rotor button and have replaced the AFM three times, each one does not give the correct resistance readings according to my haynes manual but I can open the door until it works. What is going on? Can I be just that unlucky in ordering this part or is it not the AFM at all? I have tested many things and all things are a go. I keep finding myseldf back at the AFM. Anyone?... anyone?
I opened the AFM and adjusted the spring tension until it was opening correctly and allowing the car to idle at roughly 2000 rpm. This is high but it sounds better at this rpm. I am still baffled as intake leaks would cause it to run lean not rich. I guess I should say that the original problem occured in Key West over two years ago. I was getting ready to drive back to Wisconsin, when my friend suggested z-max oil and fuel additives. I added them according to their requirements and the next day while driving home from work, the car died. Opened the hood to find black oil coated spark plugs. We towed it home and went to work. i remember at that time that we could get it to run if someone played with the AFM while the person pressed on the gas. I left the car there and went on a 3 month road trip with my girlfriend (recently x-girlfriend) after which we moved to Chattanooga. There I changed the head gasket (I took in the head to have the valve seals put in and the compression checked, all OK) and emptied all the fluids and replaced them. I ordered a new AFM and I got the car to drive around the block, there was still a little white smoke (oil?) and it was misfiring. We towed it to Boone, NC and now here I am. see first post.
So I started her up this morning and she runs better. Pulled the plugs and #4 looks like it might be getting oil. Head gasket seal? #3 is fine, #2 has excess gas on it and #1 was just dirty. I'm going to get new 4+ bosch plugs (this is what is in there now) and try again. I have not tested the fuel pressure yet nor have I taken the injectors out to look at them. Do I need to reseal my head gasket to get rid of the oil in #4 cylinder? or can I just try tightening it down? Will I crush the gasket if it is too tight? Anyone... anyone?
Got some white smoke so I went and bought some head gasket sealer stuff, very thixotropic. Flushed the system, put it in with water and ran the car. Voila no more white smoke. Instead, I started getting black smoke and eventually my catalytic converter started glowing red hot. I stopped the car and let it cool. Changed the oil and flushed the coolant system. I didn't see any white smoke and I hope the fuel pressure regulator I ordered for tomorrow will fix my running rich problem which may have just ruined my cat. Till then...
Car is alive but still running rich. By adjusting the AFM, I can get it to run without smoke but at an idle of 2000-3000 rpms. I still blame the fuel injector cleaner for this problem. Could it have caused an internal leak in the fuel injectors? If so, would replacing the o-rings fix such a problem or do the o-rings only keep the gas and air seperate? Would I see a leak if it were the o-rings? Also, I had the fuel rail disconnected today and went to pull out fuel rail and injectors. I removed the retaining clips from the tops of each injector but they would not come out easily. Am I supposed to have to pull on them with some force or do they come right out? I will try again tomorrow, but I hoped someone could shed some light on this before I brake something expensive.
The o-rings only job is to keep the injector in the intake manifold/fuel rail tightly so that they don't leak fuel. If you had bad o-rings, you'd be smelling fuel at start-ups (of course, you prolly smell fuel anyway because your running rich). I belive they just pop out of the intake manifold. I dunno if they come off the fuel rail the same way... but I would imagine they do (once the clips are removed).
Have you checked the wires going to the AFM? I'm not sure how you test these... I'll look around and see if I can find something.
Where'd you order the AFM from and how much was it?
i purchased the AFMs at bavarian auto sports and advanced auto. Both had funny resistance readings according to my haynes manual. I pulled the injectors, changed the o-rings on two of them and put them back in. one of them is not clicking now but that can wait. My problem is mainly that the car stumbles(misses) to a start and then idles at 3000 rpms. I am cleaning the ICV tonight and will put it back in the morning. I changed the o2 sensor today with no change. Hopefully its the ICV and hopefully I can get the injector to work tomorrow too.
I think it's often a good idea to look into the things that happened just before the car began having trouble. You seem to think that the fuel additive may have influenced this issue, and while that usually should not have caused this type of a problem, it seems an odd coincidence. I wonder if you don't have injectors that are stuck partially open for some reason. Are you getting any type of check engine light(s) coming on? Bad airflow meter would typically cause them to come on. It is just so unlikely that you have gotten 3 defective sensors. And the head has been off, so mechanically, we should be able to rule out the engine (as it relates to combustion). Perhaps you do have a headgsket issue, causing a vacuum leak, which could contribute to all sorts of rich running conditions and fouled plugs. The intake must have been off during head removal, is that all sealed properly? Pour or spray a little water over all areas that have seals/gaskets between them while the engine is cold and running, look for bubbles.
I don't know if this would be of any help or not, but I happen to know of a very good running 1991 318I that was wrecked recently, parts would be very reasonable. I have no idea what differences there are between the 85 and the 91, but you could have the entire engine and all of it's accesories for a few hundered bucks, I'll bet that meter costs that much alone! It's in the St. Louis area.
Today I tested the injectors and found an open wire on one that was not working. I took out the fuel rail again and swapped injectors from a different cylinder. The injector was bad. I purchased a new injector and some crimp connectors for the wire. Installed it all and am still having the same problems.
1) Idle that stumbles up to 3000 rpm
2) running rich
3) not enough power (tried going up a small nearby hill)
I don't car about the high idle for now. It is the running rich and lack of power that I am worried about. Tomorrow I am going to drain the coolant/water and run a batch of head gasket sealer through. I did this last week but I did not quite do it right, so I'll do it again. I will check for bubbles on gaskets of intake tomorrow and hopefully find something to cure my power troubles. Funny thing was that even after I replaced the injector, and tested the wire it still seems like that injector is failing somehow. Cylinders 3 and 4 seem to be working good. When I take out the ignition wire on either of these cylinders, the idle drops like it should. I can not really tell much difference on cylinders 1 and 2, especially 1 (the new injector). Even with only 2 cylinders, the car idles at 3000 rpms. Crazy!!! If the injectors are stuck, would a different brand of cleaner help unstick them? Tomorrow I think I will remove the fuel rail and put a jar under each injector and try to start her and see what happens. I am pretty sure the idle is the result of the idle air stabalizer which I can't afford at the moment. It drives OK when not in idle, bucks a little occasionally (I am still trying to work out the timing without a timing light. Could the timing cause the injector craziness? Could the car be timed incorrectly and still have two to three cylinders firing correctly? stay tuned for another day of tinkering and despair.
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.