Engine management light-16XE into Nova

[Dan Stanley]

Hi. Ive recently put a X16XE into my nova saloon. Ive junked alot of the emissions recirculating crap and have shortened/made the loom. The engine runs sweet but the engine management light is on. The only sensors Ive left out are the tank vent valve and some other sensor that had vacuum pipes on it. Ive tried flashing up the fault codes but it wont give them to me with the engine running. Any ideas? Perhaps Ive wired up the engine mamgement light wrong, or am using the wrong diagnostics wire? I know this is a difficult thing to solve due to all the wiring Ive changed!
:confused:

[craig green]

You cant just leave sensors off, if you have deleted the parts they are used with, you still need to plug them in & hide them.

[peester]

as craig said fault lights are breaks in a circuit so u need to complete the cut off looms. Or rid altogether.

[Dan Stanley]

I measured the resistance across them when they were off the car, then soldered in resistors of the same impedance. Hopefully that would have fooled the ecu into thinking they were still plugged in but just not giving any readings. Any ideas why I cant get the fault codes to flash up? When the ignitions on but the engine not running it gives me code 12 (which just means the diagnostic check has started) and then code 30 something which was a crank sensor no signal code. I assumed this was just because the engine wasnt running. WIth the engine running and the diag plug bridged it just flashes constant

[muzzy]

Crank sensor fault code will show when engine is not running. There is obviously something, somewhere that is not plugged in that it is noticing or there is a wiring fault at a plug.

[Dan Stanley]

Right, Ive been flicking through a corsa B Haynes manual and have identified the two sensors that i left out. One is the tank vent valve, which is just a motor so should be fine with the resistor i wired in. The other is a secondary air switchover valve. This I imagine needs to feed the ecu with a proper signal, so wont work if I leave it disconnected/bypassed. This must be why the engine mangement light is on.
Does antone know where the two vacuum pipes on it go? Its not shown in the Haynes manual.
Cheers guys.

[Benn]

Vent valve needs to be plugged in.

[Dan Stanley]

Its not plugged in, but a resistor of the same impedance as the vent valve motor is soldered across the wires. The ecu should still think its there as theres a circuit and a resistance. Well thats the theory anyway!!lol

[Dan Stanley]

Ive soldered a reisitor across the wires for the tank vent valve, its got the same impedance as t he resistor. Since the vent valve is just a motor this should be fine. The ecu sees a resistance and a completed circuit. Well thats the theory anyway!!

[craig green]

Yeah thats the theory but maybe the ECU still doesnt like it.
I personally have no idea of the secondary air intakes as my 2 16XE's were non ecotec models.

[phazer]

Certain sensors feedback to the ECU. The EGR on the Astra 4 for example is a stepper motor, the position is fed back (I guess via resistance changes) so the ECU knows exactly where it is. Replace it with a resistor and the ECU complains as it issues a move signal and gets no corresponding change in resistance etc

Simple, but a pain if you want to remove the useless crap!

[Dan Stanley]

never thought of it like that, it might well be a 'stepper' motor. However it only has two wires on the plug, so I can only assume it sends +12v down one wire to get the motor in one position and then reverses the polarity and sends +12v down the other wire to get the motor to turn the other way. This is all guess work though! Im an electrician by trade and have built a few engine looms, but Im still learning as I go along!

[Dan Stanley]

i think trying to reinstate the vent valve and the secondary air valve has to be the next step. I dont kno what they connect to though, any ideas guys? they each have two outlets for vacuum hoses on them.
The 16XE is a good everyday engine for the nova, but its not as fun as the 20XE!

[Dan Stanley]

Just to upate you guys, Ive sorted it all out now. No more eng man light on and my saloon now flies!! Bring on Track and Road's rollers!