[escape82]

Hi guys!

I have a problem on Astra G Z18XE, ECU is Siemens.
From day to other wont start.

Stored code: P1600 replace or reprogram ECU, clearable, until some start attempts not come back.
After swap all spark plugs and the ignition coil for OEM GM, all the same.
Sparks are ok, fuel pressure ok.
After replace the ECU for second hand, all the same.

After DTC clear in few attempts once the main relay clicks 5 times for 1 sec then stay on.
At the 5x1s the mil light and immo light flash together, after that mil stay on, immo goes off.
In immo I see, that transponder reconised.
ECU see, that engine running, 180-200 rpm noted during cranking.
In this 5x1s I have injection, engine jumps for a second, after that no injection pulse grounds, the +12V constantly on on all injectors.

Injectors are checked, no shortcut on them or their wiring.

Any advise appreciated!

[hahn181]

just to be clear:
have you checked that there is an spark while cranking?

you could also lift the injectorbar to see if they fire gasoline while cranking.

Have you ruled out mechanical faults? like ripped of belts etc?
Does it have enough compression?

and just to point to the most annoing fault -> are all fuses ok?

Is there just P1600 nothing else? Even with changed ecu? sounds strange

[escape82]

Yes, sparks on all plugs are ok. Petrol pressure ok, also the pump running during crank. Compression wont checked, wasnt at focus. Yes, belt visually checked, as cover removed for cmp sensor check. Fuses looks ok, +12 there on injectors as well, and yes, even with replaced ecu, the only one code is P1600, after 8-10 start attemps stored, until that nothing.
Going to crazy already…

[vectrac20tsri]

Could there be a short damaged old ecu and new ECU?

How many wires on injector? If there is 3 then 1 will be a trigger wire, if you can test or hook up scope to check.

Normally if ecu trying to fire injector then it has all requirements to start, if you go back to basics engine only need air, fuel, spark and compression to run.

If all have you checked timing?

But with that fault code all seems to point to ecu fault.

[escape82]

I have 2 wires injectors, no switched ground there.
What I found now, i had some shortage on the cmp sensor wires, now those separated, 5v and ground ok, signal given to the ecu, but no injection at all. Air and spark looks well of course.

[hahn181]

looked at the schematic right now. all four injectors are getting their 12v from connection 87 (redblue) cable of your fuelpump relay. (switched 30) and is supposed toreach the injectors with brown/black cable. are you getting 12v readings there ?

the other injector pins gets switched directly from the ecu.

if no 12V on inj, check if you have power on 30 and 87 on fp relay.

also give all relays an good smash/knock to rule out some issues with stuck parts etc.

cmp sensor should have these normal conditions

pin 1 & 2 (ge/vi & br/ge, plug connected to harness) put in led which should flash during cranking.

pin 2&3 (br/ge & sw/ws) should show 5v on ignition on

injectors should have:

pin 1 and ground (br/black) should show 12V
pin 1 and 2 with attached led should flash while cranking.

[escape82]

Yes, the 12v after ignition there on b-r wires.
During cranking, the ground osnt coming, by this reason I tought for ecu fault so changed.
All else are looks ok.

[volodea]

Does the ecu case have a good ground to cars' chassis or battery minus?
Is the coil pack new?

[escape82]

Yes, the ground got one more extra wire, the coil pack changed, there no difference unfortunately

[volodea]

Sounds common. Usually, this comes in when bad coilpack puts ecu in protection and that time, you have no comm with ecu. Start by disconnecting all engine sensors, one by one (not the crankshaft), and see if it starts ok. Seems to be some short there, when ecu is powered, even the 12v or 5v branches gets in short.