E30 Zone

Have recently developed an issue with my MS setup. Long story short, my carefully mapped setup has gone very lean (esp on load). its basically undrivable unless the VE tabke is really scaled up (like by 20%). anyway just went out to play with it and changed the squirts from alternate to simultaneous and it started running fine again on the original map, absolutely spot on. relief. but change it back to alternate and it goes very lean. whats going on, what have i done wrong?! I've screwed around with a few things in the engine bay this last few days and wonder if i've screwed something, although everything looks in order. Want to hook up a fuel pressure gauge and make sure nothing strange is going on, i've checked the fuel lines etc and everything looks ok as far as i can tell, did reroute the return line the other day but nothing dramatic. Any suggestions? i'm not going to cry into my pint if i have to leave it firing all the injectors simultaneously, but i reckon i'm missing something here, as its been running alternately fine for several months, and now runs terribly.
cheers
tim

Not had that issue Tim, infact never touched the aim/alt injection settings ever.

any datalogs to share?

you'd be amazed at how some small sensor readings can change a map's output, my Gbaro went to 140% for no reason at all and cured itself overnight...I had a smoke machine that day Sensor grounds, if they are not shared caused some weird readings on mine back in the day, caused all kinds of weird running probs.

HTH, Mark.

Stim time to check the outputs

but 100% with Fozz, check those grounds, and see what the realtime display has for voltage with engine not running, sounds odd ? believe me a flat battery cost me 3 days troubleshooting recently Tim

agreed, datalog 2 minutes and forward please

thanks for the ideas fellas, will get some datalogs sorted tomorrow, that'd be great to have them checked over. i'll also check the grounds etc over, reckon that's a good call! i don't have a stim to check the outputs though sadly.
interesting about the battery idea, voltage is often quite low when the engine's not fired up, and MS pops up the warning about flashing with low voltage, although it hasn't done this for quite some time.

Check your injectors' wiring:
Could it be that all of your injectors are wired to one bank?
Or maybe bank 1 and bank2 are shorted to each other?

Avner.

ok, think i'm getting a bit closer with this. had a look at it today, and simultaneous staging is not working correctly either, it just behaved a bit differently. I think fozzy and ant you guys are spot on with suggestion of ground problem, am 99% certain that's it. on stg 1 of ignition, where coolant and inlet temp used to read 102 deg. C until stg 2 (sensors shared with motronic), now one or t'other is reading around 70 degrees C on stg1. Although the sensors show roughly sensible readings when the car is running, the air inlet temp seems too high, so i reckon something is going on. Question is what? Will get onto checking the grounds. the things i've done before it stopped working correctly was add the fast idle valve to one of the outputs (JS3 i think), and possibly change injectors - cant remember exactly when i did the latter. Any clues? I've tried running with the fast idle vlave disconnected, still runs crap.
Thanks again,
tim

ok, fixed now! not sure exactly what was wrong with it, everything seemed fine as it was, but having looked at all wiring etc the inlet temp and coolant temp are reading lower than they were and everything's working fine again. cheers for the help guys

gotta be a ground or voltage correction issue Tim, the voltage correction is my main suspect.

Got all this to go through again at the weekend when I add my V3 and wasted spark.

God damn I hate wiring but hopefully it'll work first time.

Tim, I've rewired all of my sensors to a single ground now, including the WB and ECU itself. The only one thats not is the CLT as it's never played up and reads fine.

I'm also about to get a proper IAT sensor reading as my original one was 20c out all the time, another Bimmerchump fuck up! ( Yes if you read this Jim you're a twat! and be glad I live in the UK or I'd stick the sensor right up for ******* ****! )

blimey, sounds like you'll have a fun wknd then fozzy. got another smaller problem with mine since I've got it running again sadly (other than the fact that the mapping isn't feeling spot on atm). The Output 2, which I've wired to a TIP121 then direct to a veedub fast idle valve, is set to switch on at 50ish degrees C, but after a while decides to switch itself on and off every few seconds. Think I may have to use a relay off the darlington maybe, is a bit odd really. any ideas?

won a multipoint LPG kit today on ebay, so that will keep me busy, am considering whether to run it off the second injector channel on MS or to use the piggyback ECU it comes with.
tim