Motronic 745i Information... wiring diagrams, pinouts, etc

[Hit Man X]

Just posting all of these up, I am sure most of you 745i guys have never seen this stuff before. I uploaded these in the highest quality they would, some of these initial scans were not super high resolution. Sorry. Save it in the event something occurs.

I do have full pinouts for the 4HP22, ECU, and Knock Box too. Once I can figure out how to upload a damned PDF I will post it. Or email me and I will send that stuff to you to upload.

Also have some BIN files for the -013 computer and Knock Box. I think I have a stock four chip, a boost delete four chip, and a stock one chip. If you want those, drop me a note.

[Cjarvis]

Good info, Thanks!

[yert315]

What exactly is the "boost delete 4 chip"?

[Hit Man X]

What exactly is the "boost delete 4 chip"?

Some -013 Motronics had four ECU chips... others had two, seldom had single. Basically hardware revisions. I do not know what is most common, I would guess the two chip as I have a few of those laying about.

[CMG]

IIRC the 1 and 2 chip the eprom can be swapped out simply but the 4 chip requires solder

[yert315]

Understood on the amount of chips various ecu's run. Curious on what the boost delete means.

[Hit Man X]

Yes two and one chip units are socketed.

The chip is to remove the 0.7bar overboost cut so you can run high boost.

[sius072]

connector A in ur diagram does the main relay and pin11 and pin 1 of the dme can u explain more about those 2 pins

[sius072]

basically i want to find out if pin 1 and pin 11 can a no start condition

[Hit Man X]

Well, Pin 1 triggers the ignition coil. Best I recall, Pin 11 is for the silly fuel rate input below the tachometer.

Did you ever do both tests for the sensors on the bellhousing? There is a resistance test AND an cranking ACV test (reference should do about 0.4ACV and speed about 4.0ACV). I had a pair test fine with the resistance, but had a dead speed sensor.

Clean ALL of your grounds. The 013 main grounds and power are at the battery terminals.

[sius072]

yes i tested the bell housing sensors while cranking the car but still cant get a ground signal to the fuel relay

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ill clean the grounds again cause the battery terminals are old and rusted

[Hit Man X]

Can you post your results from the tests of the bellhousing sensors? Have you tried another multimeter? Missing or chewed up teeth on the flexplate can cause all sorts of running issues.

If the terminals are in that poor of shape, you should consider making or buying new OE replacement cables. This will cause all sorts of odd issues, been there before with my old Ljet and crappy battery cables. Also, I always upgrade that main bus wire into the fuse box, from the positive side of the battery to 8awg. It is undersized for the load.

What happens if you spray 'Starting Fluid' into the intake manifold and then try to start the car? What if you jump pins 30 and 87 at fuel pump relay socket?



PM me, I will send you my email address. I will attach the factory 3.4L M106 troubleshooting manual. Once your car runs on its own, you need to send us a video of it driving around please. Also, are you close to Mt Gay? I really enjoy that rum, when I am in that mood.

[sius072]

ok i havent try the starting fluid i'll try that. I did jump the fuel pump but it did not start, but i thought it would have so ill check the fuel lines to see how the fuel flows.
Question: Can i try a 735i dme for testing purposes.
My email address is sius071@gmail.com.

[sius072]

some further info: when i got the car the previous owner had the fuel pump grounded to the battery negative so i suspect that there was a no start issue with the fuel pump not getting a ground signal.

[Hit Man X]

I swear I have heard someone using a 735i ECU to see if the harness was good and engine was good.

[sius072]

just wondering if the 735 dme will work. I'll also check the fuel flow to see if fuel is flow through the return line.

[sius072]

it will eliminate any doubts about if the rail is being pressurized

[sius072]

intank fuel pump was seizes so i replaced with a 255 lph pump then hose bursed from the pressure it had a bulge. so now when i crank it wants to fire but does not continue to run. Also i notice that if i jump the fuel pump there is fuel spouting from somewhere under the intake manifold but it stops after a while.

[Hit Man X]

Damn man, stop trying to make it run NOW. Replace anything rubber under the hood (and in the rear dealing with fuel supply and return), then proceed.

[sius072]

ok

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well i'll also wait until the speed sensor come

[sius072]

i did notice that when i reverse the 2 sensors, crank and speed that it wont fire so ive concluded that the speed is bad. so with a new speed sensor and crank sensor along with ur manual i should be able to get some joy

[Jay535is]

Did you swap the sensors in the bellhousing, and connect to the appropriate wires?
Or did you just swap the connectors?

[sius072]

at first i swaped the connectors then i swaped the sensors. I noticed that i got good spark and the car would attempt to start but wont run then when i reverse the sensors no spark so ive concluded that the speed sensor is bad.

[sius072]

new speed and reference sensors installed still no joy not a good feeling im wonderin what else can it be

[sius072]

speed sensor measuring 3.2 volts AC an reference measuring .4 VAC