i had many issues wit my beamer but most were minor.. last night the wiring harness decided to go up in smoke..some owner in the distant past had an alarm installed which was not working, with piggyback connecters.. the wires on my headlights were tapped to make them flash i suppose, but it started fusing behind my headlight switch and melted up into the main umbilical..i've just removed the insturment cluster, heater controls, and all switches, waiting to pull dash but dont have a $#@% 9mm socket..looks like mine will soon have custom race inspired dash..i have miles of wire, and as painless doesnt seem to know this car exists , it looks like i got a project ahead of me..i'll probably be back with questions on wiring the brain seperate from chassis electrical and minimalizing the wiring to essentials..yeehaw...........peace

The so called "brain" is simpler than a calculator and not actually required to make it run. The wiring is easy, I would go back with stock stuff, but custom is not too hard either.

whoa, whoa whoa whoa!!!!!! you don't need the ecu to drive the car!!!!! are you screwing with me because i'm new or something?!?!? you guys keep putting up this information in these threads like you are testing to see if i read everything.

you really need to go more in depth on this bit of information

You dont need the ecu to run a CIS car. Go ahead, unplug yours while the cars running. Might idle a little shitty, but it will run. CIS is mechanical, all the ECU does is factor the O2 signal in

77-79 cars don't have one and people say they run. It's not an ECU, its not a brain, it's a simple calculator that adjusts the mixture based on o2 sensor input.

Sorry to hear of the trouble. Their was an E21 up in Memphis at the pull a apart yard on Mitchel for the last few weeks. I agree about getting another harness, rather than making one. I could go by and see if it's still there if you want. Then you could make a trip up here and get what you need. I got some stuff off that car also, but not wireing. Let me know, it'll be a tin can soon. David

77-79 cars don't have one and people say they run. It's not an ECU, its not a brain, it's a simple calculator that adjusts the mixture based on o2 sensor input.

While what you say is true, I'm not 100% sure you can just unplug the so called "ecu" and run. I think there are a few functions that are dependant on the ecu at least being plugged in to the engine wiring harness. I'd have to refresh my memory and study a wiring diagram to be sure. Or does the ecu control the frequency valve and nothing but the frequency valve based on signals fromt the 02, WOT switch, and temp sensor?

I know for sure you can run with the 02 sensor unplugged and the ECU will just send a 50% duty cycle to the frequency valve (the valve the ecu uses to try to control fuel mixture). With the ecu unplugged the frequency valve will just shut off. The car will still run but it could have an effect on control pressure with could cause some drivability issues unless the system is adjusted to run without it.

Yes, you're absolutly right, it would run like crap until you adjusted it to run without the frequency valve. I don' know offhand exactly what you'd have to do , but the early cars get away with it. The ecu has no other functions. Please note that I don't reccomend removing this system, making it work is too simple to give up the better fuel mileage and emmisions it provides.

yeah, the car will run fine with the 02 sensor unplugged, but with the valve itself disabled you're in a whole different ball game. You might be able to get away with just adjusting the mixture, otherwise you're stuck adjusting your control pressure to compensate.

This is all very interesting. When I bought my car both the O2 sensor and the frequency valve were disconnected and the car was running well. I still replaced the O2 sensor and connected the frequency valve, and it still runs well. That might explain why the spark plugs I replaced were so fouled up. They had a lot of light-grey colored ash-like build up.

so what do you guys think of gutting out all the wiring and throwing it in the fire. i'd leave leads going to lights and thats it..throwing out the inconvenient fuse panel, replacing the alternator with chevy, use a fuse panel out of anything newer, and just rewire back from it..i heard of someone else on here using a chevy alternator, and how weak the beamer one is..then i could relocate the battery to the trunk and run those cables new..i plan on running subs, and being that i'm into obnoxius bass, i'd be laying out wire for it anyway..i almost wouldnt mind trying a smooth fiberglass dash and console with no bulky blower a\c upright radio stuff..throw some speaker pods of like finish around for "accent".. i also wonder about scrapping the feul injection, "feul distribution, o2 ecu overcomplicated efficency device and running a carb or two.. my performance wouldn't suffer just the efficiancy right?...probably need feul preasure regulator to run carbs with feul pump from injection??? i mean, couldn't i pull every thing down to the head, pop on some ebay , dremil ported and polished intake manifolds, bolt up a carb or two, jet it , set timing , and be done?...allright.. yeah, i get off work with a million ideas swimming around and babble on the internet ...i'm cool...basically my knowlage of german feul delivery is that it is frustrating.. i guess my overall plan doesnt pay much homage to the german engineering but hey i'm an american..and if i can power my subs with chevy electrical , why not...any way thats probably enough for now...haha ......peace ...........bumping around mississippi in a beamer with chevy parts and a glasspack..that"s funny huh..yeehaw

i think you would have to get a carb fuel pump as they run around 6 or 8 pounds while these fuel injected pumps run around 75 or 100psi

how about an electric feul pump meant for a chevy.....

that is whati was thinking of when i do my carb swap. easy and cheap to get