Hi All:
Posted this on General Mech. and received no response.
So here I go.
e34 m50 top end rebuild
I have been rebuilding top end of engine due to overheat and blown
head gasket. I got it all put back together and it fires up then dies
in two seconds unless I pump the accelerator like a madman. I bought
a code reader from Peake Research and the following two codes come up:
1A control unit supply
29 air mass sensor
What the heck is Control unit supply?
Any help would be greatly appreciated.

Thanks,

Tally

id imagine it was the 12v supply to the ecu? low v battery perhaps?

Just bought a new battery.

still assuming a bad 12v supply measure the voltage at the ecu and check for good earths from the ecu?
thats what the code suggests to me, ifd have the tendancy to investigate that first.

I'll try it. Thanks.

Sounds like something is unplugged or a wire got damaged during the rebuild - check the harness, especially the MAF. These sound like an electronic problem.

Thanks I'll try and report back.