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1994 BMW 318i (Turbo) Direct FI wiring help
Posted: Sun Jan 11, 2015 12:08 am
by supramike
I finished installing a turbo kit on a 94 318i 4cylinder. Shawn Church was tuning it however he told me that we had issues with the MAF fuel injector voltage maxing out to 5v. If I understand correctly the input voltage is scaled to have the fuel injectors open more. He recommended me to wire the fuel injectors directly which I will do once I completely figure out the correct way.
The factory ecu has two triggers for two injectors each. Is that sequential?
I added the two pins to the diagram 3 and 32 which trigger the injectors. Is this the correct method of wiring it? I was also curious as to what pullup is on the diagram. Is it an internal resistor that I just have to join wires 10 and 8 together?
Thanks,
Michael
Re: 1994 BMW 318i (Turbo) Direct FI wiring help
Posted: Thu Jan 15, 2015 3:13 am
by ktsirigotakis
Why you dont fun FIT mode simulate maf as n/a not turbo with stock injectors make a nice ride to grab the voltage from maf and convert it to map after that remove maf wire up injectors on power 1 & 2 and tune it!!!
Read manual det3 for the maf simulation and after det3 fit to wire it and tune it.
The way that are you trying to do your job wont work!!!
Re: 1994 BMW 318i (Turbo) Direct FI wiring help
Posted: Thu Jan 15, 2015 9:14 am
by supramike
Thanks for replying. I made a diagram following the FIT diagram. The injectors are wired in group mode, Should I use power 1 & 2 for two injectors each?
I drew out the pinouts of the individual sensors individually. Did I draw the diagram correctly? Thanks in advance

Re: 1994 BMW 318i (Turbo) Direct FI wiring help
Posted: Fri Jan 16, 2015 12:51 am
by ktsirigotakis
80% correct inj 1-4 connect to power out 1 and inj 2-3 to power out 2. My opinion dont conect the iat!!! I you want you have to open your maf and remove it or you can find the same iat that you can trill a hole to your intake and put it there!!!
I have done it in the past and it dosent look nice! Before you cut the injectors somulate your maf it would be easier. Do you want to see my file from my s13 to have a clue
Re: 1994 BMW 318i (Turbo) Direct FI wiring help
Posted: Tue Jan 27, 2015 3:50 am
by supramike
Thank you so much for helping me out.
We decided that we will keep the MAF connected. I followed the diagram as you told me. I was just wondering if I could use the built in MAP sensor on the det3 instead of adding an external map sensor to the system. It seems easier that way since I have to use one less wire for the system. We would like to keep the factory MAF.
What I noticed with the factory ECU injector connections is that ECU Pin 3 wires Injectors 2 & 4. ECU Pin 32 connects Injectors 1 & 3. According to what you told me it should be wires 2 & 3 as a pair and 1 & 4 for the other pair using DET3 PWR out for each pair of injectors. That is correct right? I was just curious about the difference in factory ecu wiring versus wiring with the DET3 FIT.
For the crankshaft sensor it was wired before without doing Direct Injector Control. Crank sensor wire (67 to ecu before) connects directly to DET3 Pin 9 for Ignition IN. I cut the cut the wire like before so that it goes Crank sensor to PIN 9 IN for DET3. Then DET3 connects to ECU Pin 67 to modify the crank signal. So Crank signal to DET3 then crank signal to Factory ECU.
The difference this time is only with FIT it shows that I should Connect the other Crank Angle sensor Wire (BLK) to DET Pin 4 for Bip Ign Out Inv. I did not cut this wire according to the FIT diagram. However, In the diagram, it shows that the other wire (BLK) on the crank angle sensor is connected to ground. Is that correct?
Thanks again!