NO START

[4806]

HI ALL,
I GOT A 325I AUTO WITH A UPGRADE NUMBER 173 ECU. AFTER I REMOVE MY HEAD FOR POLISH AND FITTED IT BACK AND TIMING ADJUST IN PLACE, THE CAR WON'T START. GOT SPARK FROM THE COIL AND PLUG. GOT FUEL TO THE FUEL RAIL ONLY. INJECTOR IS NOT SPRAYING FUEL. REMOVE INJECTORS AND TEST IT AND ALL WORKING IN GOOD CONDITION. PUT IT BACK STILL THE SAME NO FUEL SPRAYING FROM IT. BUT I SPRAY FUEL DIRECT IN THE INTAKE IT FIRE UP. REPLACE A NEW CPS STILL THE SAME NOT FIRE UP. CHECK THE RESISTANCE ON THE ECU PIN 47, 48 ONLY GET 65+-. WILL THE ECU FAULT? OR GOT OTHER THING? PLS HELP ALL.

[martauto]

Welcome to the zone mate and I`m sure folk will be along soon to give you some help.

Mart.

[arrisbmw]

what was the resistance on original cps. iirc should be 540 ohm . but that does not prove its working.
but as you got fuel to the rail , appears the fuel pump is running , can you hear it hume , its under the back seat under a black cover , easy to get at
( it only runs when engine cranking ) it's no pre prime like modern cars .
my diagnoses is fuel pressure issue . are you sure all fuel lines are secure and no leaks anywhere.
to test the fuel pressure you need to T in with a gauge . should be 3 bar at idle.
another likely suspect is the FPR FUEL PRESSURE REGULATOR . black mushroom shaped metal thing attached to the fuel rail.
plenty youtube examples how to test the fuel pressure

[4806]

what was the resistance on original cps. iirc should be 540 ohm . but that does not prove its working.
but as you got fuel to the rail , appears the fuel pump is running , can you hear it hume , its under the back seat under a black cover , easy to get at
( it only runs when engine cranking ) it's no pre prime like modern cars .
my diagnoses is fuel pressure issue . are you sure all fuel lines are secure and no leaks anywhere.
to test the fuel pressure you need to T in with a gauge . should be 3 bar at idle.
another likely suspect is the FPR FUEL PRESSURE REGULATOR . black mushroom shaped metal thing attached to the fuel rail.
plenty youtube examples how to test the fuel pressure

Hi, bro.
the original cps reading around 520 ohm+-5% and is seen better days so i replaced it. both of the fuel pump is running strong. and i use a adjuster fuel regulator and is on 3.5 psi. i did use the original FPR but still the same not fire up. swap ECU with my friend 325i and same not fire up.
when i cranked the engine there got tiny amount of fuel dripping down. recheck all fuel line and no leak and correct fitted.
the car has been driving for years with no problem until i pull out the head to polish it. and it not start with strong spark on the MSD coil and plug.

[paultv]

If you have fuel pressure, sparks but non working injectors - I might suspect the injector wiring connector under the inlet manifold - is it correctly re fitted ?? as I guess you had to disconnect it
when you removed the head for skimming.

Paul

[4806]

If you have fuel pressure, sparks but non working injectors - I might suspect the injector wiring connector under the inlet manifold - is it correctly re fitted ?? as I guess you had to disconnect it
when you removed the head for skimming.

Paul

yes, Paul. i did disconnect the connector and re fitted. tomorrow will remove the inlet manifold and re check all the connector once again. finger cross i can get it fire up.

[arrisbmw]

have you tried removing the fuel rail with injectors still connected . cranking the engine . disconnect king lead on dizzy first.
and see if the injectors are spraying and clicking. if not
stop the cranking . the fuel pressure should hold . remove an injector electric plug then connect twelve volts across the injector
if it sprays , you know you have an electrical problem , no voltage getting to the injectors, your have to chase the wiring back.

the red and white wire to the injector is the + power side comes from the dme ( main relay ) the dme is activated by the ecu once it sees the crank turning,

brown and white wire to the injector is the - Ground side which is switched by the ecu, pins 16 /17 in two banks 1,3,6 or 2,4,6 .

hope that helps abit

[4806]

have you tried removing the fuel rail with injectors still connected . cranking the engine . disconnect king lead on dizzy first.
and see if the injectors are spraying and clicking. if not
stop the cranking . the fuel pressure should hold . remove an injector electric plug then connect twelve volts across the injector
if it sprays , you know you have an electrical problem , no voltage getting to the injectors, your have to chase the wiring back.

the red and white wire to the injector is the + power side comes from the dme ( main relay ) the dme is activated by the ecu once it sees the crank turning,

brown and white wire to the injector is the - Ground side which is switched by the ecu, pins 16 /17 in two banks 1,3,6 or 2,4,6 .

hope that helps abit

How I know the ECU is sending signals to the injectors from pin 16,17?