ok, guys, forgive me if this gets long-winded.
i've been having and intermittent start problem for a while. the car would start, run a bit, then shut off, then have trouble restarting. i could sometimes go months without this happening, but it reappeared lately, and has gradually gotten worse and worse. i've replaced plugs, plug wires, cap, rotor, coil, multiple relays, and crank sensors.
a while ago i noticed that if i did some wire jiggling of the harness that connects to the DME, i was i able to get it cranked. but eventually it got so bad to the point that it wouldn't start at all.
had it towed to my mechanic, and he was baffled, but he told me today that he replaced the DME with a unit out of a 5er (not sure if it was the right number DME), and it cranked but it's not running properly. he said something about only getting spark on 3 cylinders at a time, and the coil's not getting the right signal or something like that.
anyone have any ideas as to what's going on? could my original computer be dead, and the one he put in be the wrong one? also, what would happen if you had a Miller MAF with an original BMW chip, how would the car run then?
and does anyone have an 059 DME laying around?
thanks for any help i can get.
Did he or you check the reference sensors that run from the bell housing??
81 Euro undergoing total nut and bolt restoration
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Maybe keep it simple....My similar situation, which went on for 2 years, turned out to be crappy connections at the OBC Relay box hiding under the left dash. Found, fixed and happiness for 2 years.
Small box in a rack left of the steering column w/ 1 or 2 other boxes and it has 2 3or4 wire plugs connecting to it and 1 of them provides power to the main relay coil.
You should only get spark in One cylinder at a time. Are you sure that he didn't say that the injectors were only firing on three cylinders at a time? I believe that our cars (Motronic 1.0) fire all of the injectors at once and that the later cars (Motronic 1.1 and above) fire them in batches of three. What year 5er is the temp DME from?
yeah, i'm positive he said the spark was only firing 3 at a time...and he also said the injectors were working normally. i'm not sure what year 5er he got the DME from, or its number.
Maybe I'm misunderstanding what you or your mechanic mean by that but it's impossible for the distributor to supply spark to three plugs simultaneously...that would be an ignition timing disaster of the first order.i'm positive he said the spark was only firing 3 at a time
Everything points to something wrong with the DME.
Motronic 1.0 adaptive (which is what you are supposed to have in your car...the 059 ) fires the injectors three at a time. The rev delimiter works by depriving one 3 bank of injectors of power until the RPM comes back down to a safe level.
I know very little about the Miller set up but I did just check their website and note that their MAF is sold with 'software' (see link) whatever that means so I think that running it with the stock 059 chip might be the source of your trouble. By all accounts they are very pleasant folks to deal with so I suggest you give them a call and ask.
I also think you really need to have a look at least at the casing of the replacement DME and verify that it is in fact an 059. It's very easy to get at and only involves dropping the glove box to have a look.
http://millerperformancecars.com/ima...ION%20LIST.pdf
yeah, i didn't mean 3 firing simultaneously, i just mean running on 3 cylinders...sorry if that wasn't clear, i should've written down what he was saying because now i'm doubting my understanding of what he was saying. but what i do know for sure is he said it was running on 3 cylinders and that it was spark-related.
the Miller MAF does indeed come with a chip, that's why i asked in my original post if anyone knew how a MAf'd car would run with the oem chip. i mentioned the whole MAF/chip thing to my mechanic and he dismissed it, but i'm still suspect...he may not be familiar with the unit at all. i did think about contacting Miller and asking them, but forgot to, so thanks for the reminder.
and as i mentioned earlier, i'm not sure what model DME he put in there, he just said he grabbed one out of a 5er that was up there to test it out...i didn't think to ask until i was off the phone. but i'll definitely call monday and try to find out.
so i'm thinking you're right in that it's the DME, so now i'm just curious if anyone has ever run their car with the wrong DME, and how it behaved.
and what would happen when a MAF'd car has an oem chip.
i'll just put those queries out there 'til monday when i can call Miller and the shop.
Last edited by XTimServoX; 12-17-2011 at 11:29 PM.
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