Hello there! I have a 1986 325 eta with the 2.7 engine. I recently did a motor swap using a junkyard motor from a 1987 528e. My car has the Motronic 1.0 green label system with the 35 pin ecu.
I am to the point where I am trying to start this motor for the first time! However it is not firing. The motor cranks over just fine, and I have spark, and fuel to the rail. I unhooked a the wires that go to injectors 1 & 2 and used a test light bulb while a person was cranking the motor to see if I had pulsing. Well it is pulsing, BUT it's extremely weak and you have to look closely at the filament of the bulb to even see anything. I used this same test light on the cold start injector connection on the passenger side of the intake and it lit up bright.
So, I proceeded to disconnect the main ecu thinking that was my culprit. While I had it disconnected, I did some tests with a multimeter. My conclusions are that pin #35 of the harness that plugs into the computer, which should be injector ground, is not working. When I ground out the multimeter to pin 35 and plug the other end into pins 14 or 15 (which are for the injectors) I get nothing. However when I change my ground to pin #17 (which is another ground used by the computer but not for the injectors), I get 12 volts.
I used this for reference http://www.rtsauto.com/ecu-pinout-an...cal-tests-e30/
So essentially what I am asking is what grounds out pin #35?! So hopefully I can find a disconnected ground somewhere and hook it back up.
PS I also tested for power on the injector side by using a good known ground (pin 17 on ecu harness) and I have 12 volts on both ports of the injector receptacle with the ignition on.
THANK YOU to anyone that can make sense of this !!!! Sorry for such a long drawn out post lol
I am to the point where I am trying to start this motor for the first time! However it is not firing. The motor cranks over just fine, and I have spark, and fuel to the rail. I unhooked a the wires that go to injectors 1 & 2 and used a test light bulb while a person was cranking the motor to see if I had pulsing. Well it is pulsing, BUT it's extremely weak and you have to look closely at the filament of the bulb to even see anything. I used this same test light on the cold start injector connection on the passenger side of the intake and it lit up bright.
So, I proceeded to disconnect the main ecu thinking that was my culprit. While I had it disconnected, I did some tests with a multimeter. My conclusions are that pin #35 of the harness that plugs into the computer, which should be injector ground, is not working. When I ground out the multimeter to pin 35 and plug the other end into pins 14 or 15 (which are for the injectors) I get nothing. However when I change my ground to pin #17 (which is another ground used by the computer but not for the injectors), I get 12 volts.
I used this for reference http://www.rtsauto.com/ecu-pinout-an...cal-tests-e30/
So essentially what I am asking is what grounds out pin #35?! So hopefully I can find a disconnected ground somewhere and hook it back up.
PS I also tested for power on the injector side by using a good known ground (pin 17 on ecu harness) and I have 12 volts on both ports of the injector receptacle with the ignition on.
THANK YOU to anyone that can make sense of this !!!! Sorry for such a long drawn out post lol
Comment