Firstfives.org

Hi there, this is my first discussion posting on this forum so here goes. Last year our BMW specialist in Calgary diagnosed our 530i with three misfiring injectors. I have a pretty good idea of the work it would take to replace them however I have not done work to this degree on the engine. I ordered three injectors from Bavauto along with intake gaskets and new plugs. Any help answering these questions would be very well appreciated.

First of all wondering how you would distinguish a misfiring injector from a normal firing. I presume looking at the spark plugs would be a start??

Second, what needs to be removed on the intake manifold to get at the fuel rail and the process of removing the fuel rail.

Third, removing and replacing the injectors from the rails. Also any cleaning I should do of the fuel rail and the other properly firing injectors.

thanks for the help

Somehow I'm skeptical of the diagnosis. One, sure. Three but not six? Seems odd. Regardless, you'll probably have to pull much of the intake, the "C" runners with the plenum. Then you can get to the fuel rail, such as it is. At the ripe old age of 37 now you will want to replace every bit of fuel line in the engine compartment you see, from the bits and pieces of the fuel rail to the supply to the return to the cold start valve. Getting it off the non replaced injectors will be a pain too. But I'm jumping ahead too far. After you get most of the intake off, pull the injectors leaving them connected. Get some paper cups to put under each one and after removing the coil wire entirely, rotate the distributor rotor with the ignition on repeatedly. You should be able to get the injectors to fire. Do it a few times and see if one or more has any more or less fuel in it than the rest. Be very careful of course, you will have fuel loose and don't want spark going anywhere it shouldn't and lighting it off. You may have to rotate the engine slightly to get this to work, but there is definitely a point where rotating the distributor rotor back and forth thru the centrifugal advance will fire the injectors. You will also need new seals, large and small when you replace the injectors. If original the old paper insulators by the bolts are nice but not a necessity.

Aren't the 6 injectors controlled in 2 pairs of 3? Maybe the issue is electrical.

Thanks mike, that seems like a good test to do for selecting the misfiring ones. Just to be sure, I remove all the injectors keeping them connected, then do I just turn the engine over with the ignition to fire the injectors?? Also where would you suggest picking up fuel line to be used on the rail and injector connections?

Thanks, and yeah I am not too sure about the diagnosis either, although the specialist was very good.

Did you consider having them professionally cleaned with a service such as www.witchhunter.com instead of buying new ones?

Autohaus AZ has the fuel lines you will need.

maxmadill76530i wrote:Thanks mike, that seems like a good test to do for selecting the misfiring ones. Just to be sure, I remove all the injectors keeping them connected, then do I just turn the engine over with the ignition to fire the injectors?? Also where would you suggest picking up fuel line to be used on the rail and injector connections?

Thanks, and yeah I am not too sure about the diagnosis either, although the specialist was very good.

Correct, remove them from the intake manifold, but leave all the fuel lines connected. With the ignition on, rotate the distributor rotor back and forth, it should move enough to fire the injectors without actually cranking the engine. Make sure spark is safely disable with gas around.

AutohausAZ on the fuel line. Often you have to play around with years and models to find it, but high pressure 8MM fuel line is 8MM high pressure fuel line if it's an E12, E24 or E36. But for some reason they only list it for a few models. But 8MM, not 7MM.

http://www.autohausaz.com/search/produc ... 3311469781

Thanks for the replies guys. I will definitely order some 8mm line from autohauz. I will be doing the install in two to three weeks when I have time to go get my Bav auto order in Montana. Just wondering what spark plug you would use?? Also I have learned about engine flush, like the stuff you add in with oil to clean your engine. Would this stuff do anygood to my engine or would it even damage it??

No need for an engine flush, you're probably better off without it. On plugs the biggest thing is do not get platinums. Bosch coppers, Bosch silvers or NGK are good. Just no plats, they like to foul.

alrighty sounds good guys, I checked out the proffesional injector cleaning service although I would rather do it myself to save some money and time. Wondering what you guys would do just to clean up the three injectors that I do not replace??

I always hook up the injectors with my six shortened clear tennis ball cans, open the air flow meter door with a big screwdriver (so the fuel pump runs), get the wife to crank the engine, and look at the cone of gas coming out of each injector with a powerful flashlight. Then I check the amount of fuel in each can. Haven't found a bad injector yet. If you have to take an injector connector off of its injector, I use a dental pick to take off the steel spring clip. They DO NOT pop off on their own. They'll break. Repair kits from AutohausAZ are $8 each. Remember to keep the brown ground wire in the area connected or none of 'em will fire.

hey guys, after three days in the engine I have everything back together and she is working awesome. Sounds like she did back in the day. Kinda wish I had gotten 6 new injectors but the three that were still working were still pretty powerful. There were only 3 left at BAv auto on clearance for $30 each. Thanks for all of the help, I really appreciate it and I definitely wouldn't have been able to do it without the tips and feedback.