How does the G60 ignition system work exactly?

[Riley 0]

Can anyone describe exactly what happens in what order to get a spark at the plugs? from start to finish...im talking...current passes from this to this via this kinda thing :lol:

 

In really easy to understand terms please if possible.

Cheers,Neil.

[flusted 0]

something like the hall sender tells the coil to spark as it reads 4 slots in the dizzy shaft, spark goes through rotor arm to the relavent plug lead?

[Riley 0]

Cheers m8...

 

Now,what could cause that spark to bounce back and forth? (going off the mark on the crank pully/or flywheel)

 

Imagine you are setting ignition timing,holding rpm at 2k or 2.5k...and the mark is jumping backwards/forwards...not stable,what could be the cause?

 

Neil.

[Yandards 0]

Cheers m8...

 

Now,what could cause that spark to bounce back and forth? (going off the mark on the crank pully/or flywheel)

 

Imagine you are setting ignition timing,holding rpm at 2k or 2.5k...and the mark is jumping backwards/forwards...not stable,what could be the cause?

 

Neil.

 

If you are moving the dizzy in its housing then that will, otherwise various inputs can advance and retard the timing on a G60 engine (this is an electronic advance/retard as oppossed to earlier cars using a vacuum system).

 

At 2.5k the timing advance/retard should be fairly stable but the following can influence fueling and as such engine speed and advance/retard.

 

A speed signal comes from the hall sender into the Digi ECU, this also takes a load signal from the pressure sensor incorporated into the ECU (black 1m long vacuum hose from the TB) these two pieces of info are used to identify where on the basic ECU map the engine is (RPM and engine load = fuel required) This is then adjusted by other sensor inputs; these are coolant temp, exhaust gas composition (lambda probe) and inlet air temp via the CO potentiometer. What you end up with is a signal sent to the injectors based on the default ECU map modified by the inputs from the sensors to give you an injector opening time.

 

However, there are only really three of these that are going to cause you a real problem. The pressure sensor will detect a fault and switch to a safe map in the ECU so that would be stable. The CO pot is designed to vary the engine speed by +!0% or 10% at part throttle settings, the intake air temp sensor (CO Pot and intake air temp sensor are within the same sender) works on a range that starts at 25% longer injection time at -24 C up to 0% longer at 100 C. The lambda monitors exhaust gas flow and adjusts the engine mix to maintain 14:1 air to fuel (again at part throttle)

 

I would probably look at the lambda first but, it may be you have a vacuum leak on your inlet or exhaust manifold causing the fluctutating RPM.

[Riley 0]

Superb,thanks for that m8 8)

 

The actual rpm is steady as you like...but yet the timing marks jump about...Just cant understand it :(

 

May be a stupid question...But could a tired fuel pump somehow cause it?

If its tired and the rpm+load asks for x amount of fuel...and then the fuel isn't delivered in the correct amount,the lambda would pick that up right? And maybe ask for more fuel?

 

Sorry,just trying to get my head around it...

Ps:If anyone has a pic of how the coil should be wired up,that would be handy...which wires on which side.

 

Neil.

[flusted 0]

all the blacks are lives and the red/black and green wires are earth i think

[g60bv 0]

is your timimg light a good one.? could the senor for it be getting a source of number2.?

sounds silly. sorry.

[potatonet 0]

riley you have to unplug the blue sensor, rev past 3k 3 times and then time your car @ 2500 rpms. if you just do it w/o undoing the bts the timing will be all over the place.