dizzy advance

[Aragorn]

i wanna have a play with advancing the timing on the spi so i need to know which way to turn the distributor to advance timing

nova manual has dissaperaed into the blue yonder and the corsa one says "see dealer" which is a pile of wank

[getlost29]

i did say about this

the nova haynes manuel says no ajustment and the auto data books in uni said the same thing.

when u set the dizzy up inichaly u need to make sure the arrow on ur dizzy points towards the rotor arm when its at tdc on cylinder 1 (or when the timing mark on the cam shaft is in refrence to the cover)

the only way to try and see if it will do it is to use a strobe light and turn the dizzy to see what happens

but as i said the timing is controld by the ecu, and may not work

[Adam]

i did say about this

the nova haynes manuel says no ajustment and the auto data books in uni said the same thing.

when u set the dizzy up inichaly u need to make sure the arrow on ur dizzy points towards the rotor arm when its at tdc on cylinder 1 (or when the timing mark on the cam shaft is in refrence to the cover)

the only way to try and see if it will do it is to use a strobe light and turn the dizzy to see what happens

but as i said the timing is controld by the ecu, and may not work
Yeah it does say that
but you can physically move the dizzy position.
The ecu only controls advance etc for different engine rpms, which would normally be done using the vacuum advance on carb engines.
I think anyway, i may be talking c**p :lol:

Aragorn-Won't it just be the same way to advance as on carb engines and dizzys?
I'll have a quick look throught mk3 astra haynes, see if theres ought in there about spi timing.

[burgo]

looking at the dizzy from the passenger side of the car you turn it clock-wise

[j1400]

the SPi ign is controlled by the ecu as said, so evenif you adjust the dizz you can't gain any advance, unless you move it so much the spark can't jump properly :?

[Aragorn]

the point is this - the ecu expects the dizzy to be set at 10degrees BTDC at idle, it fires using the hall sensor in the dizzy and an advance map programmed into it

if u get the dizzy to 15degrees BTDC its totally unaware of that, will assume its still set to 10degrees and will run with advanced timing

the same ignition system is used on nova gte's and ive heard of a few folk having advance creep on those due to overadvanced ignition timing simply because it IS adjustable when it really shouldnt be

same with the idle control valve setup on the spi systems - apparently its controlled by the ecu, the truth is however the ECU can only increase idle speed from its default setting, under normal conditions the icv is completely closed and the throttle plate is held slightly open by a stub on the linkage, when i fitted the 1800 throttle body to the 1200 this meant too much throttle was ocurring at idle and that meant the idle wouldnt drop below 1000 and the ecu would flag a fault code, brust off the tamperproof cap and turn the torx screw and its now idling perfectly

and thanks for the help, it IS clockwise so i'll have a play tomorrow

[burgo]

lol aragorn you do realise even after explaining they will still say
but its still ecu controlled . i understand ya though so gd luck with it hope it works

[getlost29]

i do kind of understande what ur saying

but u need to use a strobe light to do it porperly, or if u want to be old skool use a gunsons cooler tune to see what the flame looks like.

by the way, u said u did an assignment on somthing u did, what u doin in uni collage

[Stuart]

had this problem with dans car before fitting 1.4 ignition to it.

i think they managed to get 1degree or so of advance extra even with the dizzy rotated all the way round to its stops. So the ECU does control it regardless of what you "claim" is the base setting.

[Aragorn]

that just seems impossible stu?

the only reference point the ecu has is the hall sensor on the dizzy, and your moving the hall sensor with the dizzy? where can the ecu find the old reference point from?

surely dans GTE setup wouldve been heavily retarding the timing anyway becuase half the engines sensors had been removed? the afm etc was removed just leaving the ignition stuff so the ecu is just gonna use a very conservative map?

im assuming that with a timing strobe i'll be able to see the advance? ie i set the strobe to say 10degrees and when pointed at the crank pulley the marks will appear stationary when the timing is there, setting the strobe to 12 and slowly moving the dizzy should advance the timing round to 12 and marks should become stationary again?

[getlost29]

thats not how u use a strobe light

conect the strobe light up and point it at the timing marks, when engine is runing ull see the the marks line up. then when u turn the dizzy, ull see the marker on the pull move back or forth with rfrence to the stationary marker on the cover

[S_Gault]

the only way to do it right is use a proper timing light with digital advance-

set it to 32deg at 5000rpm.

Steven

[Stuart]

is that for "all" engines?

as thats bit of a rash thing to state on a forum full of very naieve kids.
eg the engine may well det at that much advance etc.

as with mapping its very individual to the engine and conditions at hand.
Flippantly stating "use x at this rpm" is a tad blinkerd dont you think?

[S_Gault]

not really thats why i said 32, and not the 36 that they run std.

its more blinkerd setting an unknown dizzy at 12deg and having no idea what the full advance is.

[Aragorn]

lol now im confused, ive never seen or used a timing strobe before so ive no idea what settings or functions are available on it

and if the car runs 36 as std why are u telling me to set it to 32? surely thats retarding the timing back from std settings? or did u mean that u usually run 36 on your race engines and that 32 would be alright for this setup?