MAF issues 1991 e34

[jippijak]

i have a 1991 525ia it has 41600 miles on the clock(actual). it started to run really shitty and didnt idle rite so i tohought it needed plugs, so i replaced the plugs with some bosch plat.+4 and in the process i replaced the plug connectors (boot on the coil pack). because they were measuring to be 1.k to 1.4 k. it ran better but still shitty, so i got the diag codes using the stomp test, the code it gives is 1215 which means a faulty maf. so i went to the scrap yard and got another one and its the same. according to the clintons book and i think the bently book u are suppose to measure on the connector at pins 2 and 4, when its unplugged, to see if there is a 12 volt source flowing. i did and there is a +/-13 volt source with the engine on. is this rite? then i measure the air mass between 5 and 6 and get 3-4 ohms as the book states. but when i measure pins 1 and 5 the resistance is at 14 k ohms, when the book states it should be 16 ohms or so. and it is the same for both the one i have and the one i bought from the scrap yard. are they both bad? how can i tell if i have a bad maf? if i go and driive with it unplugged, its a little better with both maf's. are the resistances stated in the book right or are they off?
thanks in advance
Jippi
1991 525iA M50 all stock

[Kalevera]

Do a search before posting. We talk about platinum plugs in E34 engines all the time and how they DON'T help things out.

There are a couple of things you need to do:

1) Pull the DME, remove the cover and see if any of the final stage resistors are burnt. Usually, the DME will actually smell burnt when this has occured. Running a leaking coil pack can blow one or more of them out, and you'll have a misfire no matter what you do.

2) Reset adaptations (do a search on the "Shogun Reset") after changing a component.

3) Get rid of the shitty plugs. Bosch F7LDCR (or the PRs are okay) dual electrode silvers or the BMW NGK plugs ONLY. And the dealer WILL give you the wrong plugs for the car, so specify NGK BKR6EK if that's how you buy parts.

4) Are you certain that the replacement MAF is the same? M50 ('91/'92 MY cars) have a different unit than the later M50TU cars.



best, whit

2)

[jippijak]

the cars at 41 k what would cause the dme to be bad? the parts store dont carry the plugs that u list and the dealer dosnt either sone special order that would cost the same as the +4's the only reason i got the +4's is because one of my friends switched to +4's in his 325i m50 and they were pretty good, besides i have then on my other cars and they r fine, is there something with the 5-ser m50 motor that it doesnt work with? btw i already searched this board top to bottom and came up with nill. that was my first step. would it be a good idea to bring it to the dealer for a diag?

how do you check the coils on an m50 motor? what is this whole debate about platinum plugs and bmw's? since i had my 91 525ia withan m50 motor there were platinum plugs in there. i got the car in 93 with 12k now it has 41k. it worked fine the last 2 winters i had it out but when winter hit this year it started to idle bad. so i decided to tune it up, i have always used bosch plat plugs on all my cars including my 88 528e, and the various other ones. i did the stomp test and got an 1215 code saying there is a bad maf. how s it likely t have a bad dme when the car has 41k, age? well the whole point of this is, how do you test coil packs and what is this big debate about platinum plugs?

btw: the car was in for service about 6 months ago with 21k and they replaced the ICV (idle control valve) and the O2 sensor. costs me $700 at the time. parts were cheap labor was expensive, only reason i took it thhere was that i had no time to deal with it.

[jippijak]

really out of options i tried everything, i even put in stock bmw plugs. no difference. tried 4 MAF's from the scrap yard and everyone i put in is worse then the one before. the car sometimes runs better with no maf plugged in.

ne other ideas?

thanks in advance
Jippi 1991 525iA M50