1992 E30 won't start after changing OBC !! HELP !!

[built2grind]

Hi guys, my name is ANDYand I'm obviously new here cause I had no where else to turn, and you guys are probably the most knowledgeable out there. Im sure this problem has been discussed time and time again but I've had no luck searching nor figuring it out. I'll give a little recap of what happened. I tried to reset my oil service light the other day by jumping pin 7 and pin 19 on my E30. Everyone says pin 7 is the reset and 19 is just a ground. I don't have a pin 19 in my cap for some reason so rather than try to jump the wrong pins, I grounded pin 7 to the cars ground itself for about 12 seconds. Probably REALLY Stupid on my part!! I went through the sequence everyone talks about and it didn't reset. This is where my memory fails me. I can't remember if I started the car after that. Now, just after that the real problems occurred. I decided to change my 13 button OBC with a better example of a used one with a functioning screen, and try to get the factory anti-theft radio to work. I punched a few buttons on the radio, may have hit the CODE button on the OBC and may have inserted a number sequence, highly unlikely though since it requires the key to be in position 1 enter code, turn key to position 0 then back to 1, reconfirm code and car is now disabled/ enabled. I grabbed my new/used OBC, inserted my chip from my original unit and plugged it in. WHAM!! car won't start now. Starter turns but more than likely its disabled the spark or fuel possibly with the OBC code. I have an original dealer installed HOFCO II alarm and I'm sure maybe its involved?? Im curious if I fried a relay or something possibly by trying to reset my oil service lights.

First, Does anyone know if you can even change the OBC in these cars?? my car is 1992 E30 325i convertible.The replacement OBC is exactly the same but says it was manufactured in December of 1985. Just curious.

Second, has anyone mastered retrieving the "code" that disables the car when activated, and if not how do you fix it? Get a new cars computer? The car can't be rendered useless now??

Third, Is it possible to just completely remove this old HOFCO II alarm since its tied into the ignition also? Im sure I fired something or entered a code.

PLEASE HELP ME !!! I'm at a loss and not very good with auto wiring. I live near SAN JOSE, California if anyone knows somebody. Im prepared for the abuse, I totally deserve it. Thanks for all your future help and comments.

[ELVA164]

Hi Andy,

Try disconnecting the battery for at least 30 minutes, then trying to start the car. That should be enough time to wipe the memory in the OBC. And welcome!

-Mike

[royAdler]

You can most definitely swap the OBC. Very common to do.

[built2grind]

Thanks for the kind words and information. I'll keep plugging along until i figure this out, ANDY

[richardodn]

The CODE function is something you choose when enabling the CODE function. Is the new OBC displaying CODE?

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There should be no problem using any OBC. Just be sure to swap the coding plug in the back from your old to the new.

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Owner's manual pages for OBC.

[built2grind]

Thanks guys for the help so far. So I surgically removed the alarm system and the car still doesn't start. I located the fuel pump relay, checked it, confirmed voltage but when I crank the car over I'm not getting any voltage on pin 85. I should be seeing battery voltage, right? I jumpered pins 30 and 87 and I get the whining sound of the pump working but car still doesn't start. All this is leading me to believe that the fuel pump is working fine but the car isn't sending the voltage to the fuel pump relay making it work. I haven't checked for spark yet.

I did change the OBC and used my original coding plug in the back, screen lights up well with the word CODE. All this is confirming my worst nightmares of the actual computer that runs the fuel system, ignition, start procedure is locked with some random CODE that I may have inserted without knowing! Can the computer be changed in my car with another one if there is a lock code inserted, and will my car start again? Im starting to get frustrated, but don't want to give up and take it to the shop/ dealer.

Anyone have any suggestions now, should I confirm spark or no spark, to narrow it down to the cars computer?

Thanks in advance, ANDY

[dohcdoh]

Confirm spark. If no spark, check your cps. The ecu needs to see timing data from the cps to turn the fuel pump on.

[ELVA164]

Did you let the car sit with the battery disconnected yet?

[built2grind]

For all that are wondering, I did leave the car sit for 24 hours with the battery disconnected, it didn't work. : ( I'll confirm spark or no spark next. I'll keep everyone up to date just in case anyone experiences the same problem.

[built2grind]

Ok guys, I finally got the BMW running, not correctly but running. I checked everything again, and again, spark, fuel, battery, key, the whole thing. What I found out was the OBC relay under the dash wasn't sending the signal to the computer to start the car. I must have entered a LOCKOUT code by mistake and disabled the vehicle. I was reluctant to do this but there is a GREEN wire and a GREEN/ RED wire at the relay that I read in other posts that, if I jumpered them together by actually just splicing them together the car should run. Well, IT WORKED! My mechanic did advise me to start looking for another OBC relay to put the car back to factory original condition. But hey, it works right now why change it! Thanks for all the help and support and I hope this post helps others that have experienced the same problem with their OBC being LOCKED OUT.

[ELVA164]

Weird, wonder if something in that OBC got messed up somehow.