Car cranking, but not starting(Now with spark!)

[solo318]

Jumper the main relay and check pin 37 at the DME for battery voltage.

[ST1G]

Jumper the main relay and check pin 37 at the DME for battery voltage.

Replay was not plugged in all the way. With it plugged in fully get 11.88v at 37 with 36 grounded. I am still get 11.88v with out 36 grounded though. The relay does switch when I ground 36z

[spdracrm3]

here's a pdf schematic of a motronic 1.3 with all the pins identified ,might help identify additional pins

[ST1G]

Car cranking, but not starting

here's a pdf schematic of a motronic 1.3 with all the pins identified ,might help identify additional pins

Is this an attachment? My phone shows it as a broken photo.

Edit: got it going in my chrome browser. I'm going to need an electrical engineer on that one....


Good thing my dad's one. Time to make a house visit.

[spdracrm3]

pinnout for 4cyl

this is the pinout i have and mentioned for the 4cly ,like what would be nice to find for yours

[spdracrm3]

Is this an attachment? My phone shows it as a broken photo.

Edit: got it going in my chrome browser. I'm going to need an electrical engineer on that one....


Good thing my dad's one. Time to make a house visit.

well just look at the tabs on the side that identify the pins by number ,as to what each pin is .dont need to know what the electronics do internally

[itskingsteelo]

aint this some shit, for the past few days my car hasnt been wanting to start, i log on to r3v and bam!! i come across this thread.

[ST1G]

here's a pdf schematic of a motronic 1.3 with all the pins identified ,might help identify additional pins

I guess I'm confused. I follow pin 37 for example (Because I don't seem to get the right voltage) and it takes me to different controller banks. Are these banks inside the ECU? I just don't know quite how to read it.

[spdracrm3]

i just posted that as a reference to identify pins that arent listed on other pinouts/diagrams. if you look at pin 37 on that diagram it shows the pin as "programming voltage" as is pin 39 but if you look at a FI diagram for 90 325i as posted it shows pin 37 as a voltage feed direct from main relay (pin 36 being the control of the main relay) so if your not seeing 12v on pin 37 there is a problem somewhere in that circuits Red/Blu wire .(notice a Red/Yly wire branches off to the ABS if thats shorted or has an issue it could bring voltage down ,might be worth disconnecting to see if voltage comes back to 12v)

i would trust an ETM over that ECU diagram ,like i said i posted it for reference only ,just trying to find as much info as possible ,knowledge is power....

[ST1G]

i just posted that as a reference to identify pins that arent listed on other pinouts/diagrams. if you look at pin 37 on that diagram it shows the pin as "programming voltage" as is pin 39 but if you look at a FI diagram for 90 325i as posted it shows pin 37 as a voltage feed direct from main relay (pin 36 being the control of the main relay) so if your not seeing 12v on pin 37 there is a problem somewhere in that circuits Red/Blu wire .(notice a Red/Yly wire branches off to the ABS if thats shorted or has an issue it could bring voltage down ,might be worth disconnecting to see if voltage comes back to 12v)

i would trust an ETM over that ECU diagram ,like i said i posted it for reference only ,just trying to find as much info as possible ,knowledge is power....

Interesting, I thought it was schematic of where the 37 was getting power, or going.

So there should be direct power from the relay to pin 37 on the ECU. That is really what I was looking for. I was curious what else was the loop, whether a connector or splice. I wasn't sure which schematic in the Bentley would have it.

I also didn't know what wire came off the main relay that powered pin 87, so that answers that too.

Good point on the ABS wire, I'll check that out to see where that is going.

Side note, did a little testing at lunch, for kicks I jumped the relay.

With the main relay jumped (86 & 30) I am still getting 1v at 37 with 36 grounded. The same result as with the relay in place with 36 grounded. This is the same result I had been having

I also get the same result of 12v at 36 and 37 with the relay in and ignition on.

However, I am getting 0v at pin 36 with the relay jumped and ignition on.

I get 0v at 36 & 37 with the ignition off and the relay jumped.

[spdracrm3]

reading back thru the last few pages of testing and results ,something is not right as you should not have voltage present on pin 37 if main relay is not engaged ,and looking at the diagrams the only possible source i can find would be thru the ABS control unit (unless the ECU is bad ,it can only be the other source as all devices on that circuit are grounded thru the ECU , which you have already swapped), what reading do you get on pin 37 to ground with the ECU disconnected? if there is voltage present it has to be the ABS or a short to voltage in the wiring , disconnnect the ABS controller and again test pin 37 for voltage?

[ST1G]

reading back thru the last few pages of testing and results ,something is not right as you should not have voltage present on pin 37 if main relay is not engaged ,and looking at the diagrams the only possible source i can find would be thru the ABS control unit (unless the ECU is bad ,it can only be the other source as all devices on that circuit are grounded thru the ECU , which you have already swapped), what reading do you get on pin 37 to ground with the ECU disconnected? if there is voltage present it has to be the ABS or a short to voltage in the wiring , disconnnect the ABS controller and again test pin 37 for voltage?

I've got a spare 153 ECU. But like I said a few pages back. I have used this ECU in a friends car and it ran well. He even had a stroker set up. So, two 173 ECUs and the 153 in this car all have the same result of no spark.

I will test with the ABS as soon as I'm home from work.

I have been worried about voltage on pin 37 without the relay engaged, I knew that wasn't right.

what reading do you get on pin 37 to ground with the ECU disconnected?

All my tests were done without the ECU connected as I can't test the pins with it connected.

so,
Pin 37 voltage is as follows with the relay in:

With ignition on, and 36 NOT grounded 12v.
With ignition on, and 36 grounded to pin 2, 37 has 1v

[spdracrm3]

"All my tests were done without the ECU connected as I can't test the pins with it connected."

you can take the small screw out of the back of 55pin ECU connector and remove the cover to be able to backprobe with the ECU connected (also alllows you to check/confirm wire colors at each pin)

[ST1G]

"All my tests were done without the ECU connected as I can't test the pins with it connected."

you can take the small screw out of the back of 55pin ECU connector and remove the cover to be able to backprobe with the ECU connected (also alllows you to check/confirm wire colors at each pin)

I did not know that. That's good to know. I will do that after I check for ABS stuff.

[ST1G]

Okay, here is my understanding.


Power off pin 86 of main relay goes to pin 38 (Red/blue) at ecu and ABS (Yellow/Red) goes to connector C101 first, then to the unit, then to the ignition. So I can just disconnect the ABS unit as a whole? Should I check voltage at C101 Red/Yellow?

[IMG][/IMG]