m52 don't want start

[Mr Mpower]

Hi, i've made a complete m52 swap in my early 318i, is obd2 and ews delete.
the engine turns nice and is near to start sometimes in fact sometimes start with "jump start" or "easy start" spray fluid,revs a lot and dies in a second.
i have all the sensors plugged and i have fuel.

my pinout

C101 square ……………x20 round………………
1 blue…………………………………25 blue……………………alternator
4 brown/violet………………12 brown/violet……temp gauge
6 green/yellow………………15 black/green………..starter
7 green/violet……………………13 green/violet………fuel pump
8 black/yellow…………….18 black/yellow……….cranck
9 black……………………………20 black……………………rpm tach?
10 green…………………………...21 green………………….dmw power
16 brown/green...............23 browm/green……oil pressure
17 white/blue...................19 white/green....service interval reset


any idea?

thanks!

[Mr Mpower]

a bit of searching make me think c101 pin6 to x20 pin 15 is wrong..i think is x20 pin 22.
but maybe taht isn't enought to start..

edit. the wiring seems to be ok, because i dont have pin 22 in engine harness..

i have this wires in my early chassis.

1 blue Alternator
4 brown/violet Coolant Temp gauge
6 green/yellow Power supply with ignition turned on. fuse protected
7 green/violet Fuel Pump
8 black/yellow Ignition start position?
9 black ??
10 green power supply with ignition turned on. no fuse protection
16 brown/green Oil pressure
17 white/blueService Indicator reset

and this wires in my engine harness

Blue Alternator
White/Black OBC Fuel
Green/Violet Fuel pump
Green Ignition, run position
Brown/green Oil pressure
Black/white speed signal
Black/green Starter?
Black Engine Speed signal input
Black/yellow ignition start position?
Brown/violet Coolant temp gauge
White/Green..Service indicator reset

[RobertK]

Double check your fuel lines and be sure they are not backwards. You might have fuel but not proper fuel pressure.

Also, if this engine has sat for some time check to be sure some of your injectors aren't stuck. I've seen this happen too many times.

[Mr Mpower]

Double check your fuel lines and be sure they are not backwards. You might have fuel but not proper fuel pressure.

Also, if this engine has sat for some time check to be sure some of your injectors aren't stuck. I've seen this happen too many times.

i have m50 injection rail and is easy, the supply is in the front and the return is in the back of the motor near the fuel pressure.
i can see the fuel through the lines and is correct
the fuel pressure is enough for sure, the fuel pump is a k jetronic fuel pump and makes a lot of pressure, more than enough.

How can i test my injectors?

[Mr Mpower]

ok, now i now "pin 6 c101 to pin pin 22 x20" only works to american cars, in europe cars we don't need to plug pin 6 c101 to nothing..and pin 15 to x20 i don't need it to, i hear i can plug to pin 18 x20

[Mr Mpower]

I check spark and fuel , wich other thing i need to check?

[Rdreas]

Are you sure you have proper fuel pressure? to much is not a good thing and can cause your engine to not fire

[Mr Mpower]

Are you sure you have proper fuel pressure? to much is not a good thing and can cause your engine to not fire

my fuel pump is a k jetronic system fuel pump and can make too pressure i think, but the fuel pressure regularor it's for that reason, true?

[Rdreas]

Its what the reasoning I found when I had the issue was. It wasn't my reasoning but they said if there was to much pressure it could skip over the injectors. Don't know how true it is but added a fpr and vroom. BUT originally my m50 rail didn't have a regulator.

[Mr Mpower]

i have the stock fpr, i can see it, i've read it can handle 7 bar, thats enought for the most pumps..maybe i need a pressure gauge to check if it's working well

[Rdreas]

Prolly not a pressure issue. Got fuel lines switched?

[Mr Mpower]

i don't think so, i can see the fuel in the lines and the supply line have a lot pressure.

[Mr Mpower]

maybe i know wich is the problem



when im doing the wiring..i cut the thin green wire and keep only the thick on the pin 21 of x20 connector engine side
opinions?

[RobertK]

Pretty sure that thin green wire is your issue. IIRC that is the 12v+ supply to your ECU.

Best practice is not to cut wires unless you completely trace them and confirm what they are going to.

[Mr Mpower]

ok, for the first time in three weeks im with the car.
all the time i've think that thin wire is cut, but NO..is correct spliced with the thick.
the cranck position shows 640 ohms, seems ok.
all the injectors spray while cranking, not at the same time.
next step, pliers in the return line.