NO RPM!!! engine will not start

brogdan

hello
i have BIG problem. my engine will not start.
i checked my car with op-com and i have no errors, but i found that when cranking the engine i can't read any RPM in measuring blocks!
i changed the cranksensor with a new one. i checked the wireings from the sensor to the ECU. everything is right. but still can't read RPM!
i tested on my fathers Astra G and on his car i can read RPM when cranking(without letting the engine to start).
what could it be?? notsure.gif

francav

possible coil pack fault.

sophos9

Explain the problem

Does the engine turn over?
Do you have fuel pressure?
Is there any strange noises?
Are all the multiplugs attached?

brogdan

the engine turns, have fuel pressure, no strange noises, just can't read any RPM with OP_COM while cranking . all plugs attached.
can't be coil pack because if ECU can't read any RPM it will not give spark😉

francav

try PM vocky or ATOM X

sophos9

If you insist on RPM - what are voltages to crank sensor? Test to ensure no loom damage. Also, have you tested 'new' crank sensor, because its new dont mean its working

brogdan

voltages? i measured the loom it has 700 ohms, and when cranking i can measure _1V on the sensor(sensor disconected). i have conected the sensor to an osciloscope and i can see a beep(sin waveform) while cranking.
2 sensors...both bad? i talked to vauxhall service and they told me it could be the ECU..but i have no errors on ECU. could it be that this input to the ecu to pe dead..?
thanks

sophos9

When I get home I'll lookup nominal values on ECU, loom and component. If crank sensor had failed you would get error code, ECU would shut off fuel pump as part of the defense but you say you have fuel pressure?

brogdan

what exactly do you mean by fuel pressure? and how can i test that? i can smell gass when cranking.
please help me on this..i have my car at a local shop for over than 3 weeks and they don't know what is wrong with it...they say it's the ECU..but i don't want to buy another ecu until i'm 100% that's the problem.
thank you for your time and please let me know ASAP

sophos9

If too high resistance in the loom, ECU would not receive pulses from crank sensor and would assume crank sensor fault and shut down the relevant circuits - no fuel pressure

sophos9

You can either do the lazy check on the fuel pressure valve - this is on one of the fuel pipes that go into the fuel rail. Remove the 'tyre cap' and press the centre. If the fuel system is pressurised then you will get a spray of fuel (please take necessary precautions).

Proper way is to get a multimeter on the fuel pump and measure activation when cranking. No RPM signal would either be crank sensor (would report code), bad wiring between ECU and crank sensor or ECU issues.

Aside, do you have any immobiliser codes?

brogdan

i understand that, but the loom resistance is 700ohms for this sensor(standard data ) and 700 it has. that is why i don't understand why the ECU does not indicate any RPM...i tested on my fathers Astra G diesel, and while cranking i can read from ECU the 150-200RPM given by the starter motor.
this i should also read from my ECU...but i don't. if the ECU does not receive this info, it will block the rest of the ignition circuits, because it does not know when and in what order to give the sparks.

brogdan

when i turn the key i can hear the fuel pump activating...so fuel pump si working..i have fuel pressure.
i checked the wires between the sensor and ECU with a multimeter and they are ok! i measured directly to te pins that go into the ECU, and there i have 700ohms.
next..there's the ECU..and i don't know how to test that 😃

brogdan

immobiliser is ok..it sees the key..if it were the immo i would get a wrong key error, tested that too

sophos9

But friend, all your reliance is on a comparison with an Astra G Diesel vs. your z22se. Personally I would be testing mechanical function and logical deduction and not pinning my hopes on the OP-COM (I bought one and got a fair few bogus results with it and its buggy software)

Test the function of the crank sensor (see what happens to voltage when you pass some ferrous metal in front of it - volts should increase. You said you have fuel pressure which would indicate your fuel pump is pressurising on crank, it can only do this if ECU allows. Please test.

Do you mean the crank sensor is 700ohms or the loom between crank sensor connection and the correct ECU pin is 700ohm?

brogdan

the crank sensor is 700ohms..not the wireing from the ecu to sensor...sorry i understanded wrong😃
if i pass a piece of mettal infront of it it shows me some volts.

sophos9

Edit ignore some of the above - just the read your additional posts after replying - so ECU to crank wiring has continuity removing doubt, you are confident that crank sensor is performing in specification (please test voltages change with ferrous metal and test resistance of the sensor - by memory should be between 400 and 700ohm) however ECU is not receiving RPM pick up could determine that ECU is losing the plot

I don't know the answers to this
#1 - does the opcom software read RPM for z22se, another member could confirm?

sophos9

brogdan said:
if i pass a piece of mettal infront of it it shows me some volts.

Sensor is in parameters (by my memory will double check when home). Voltage goes from x to y - please fill in the x and y

brogdan

with sensor disconected from ecu the voltage is 0 and while cranking it gets to 1V

sophos9

Remove crank sensor from block - ignition on, pass ferrous metal over sensor - what voltage?