MK2 kjet abf Smoking

[rubjonny]

the idle switch gets 12v from the ignition, and when the throttle is off the stop it creates a circuit to the white wire, sending 12v to the vacuum switch.  Then when the vacuum switch 'sees' the correct vacuum condition it closes and sends 12v to pin 15a on the starter motor which is also where the 5th inj is plugged in (hence why this pin has 2 wires to it)  therefore sending 12v to the 5th injector.  This then earths thru the coolant sensor on the side of the block

The temp sensor on the side of the head switches at 30degreees C, so it will always fire when stone cold, though the heater inside it will soon shut it off if its warm out and residual heat after sutting off the engien will keep it off for a while.  That being said it doesnt get cold enough that often for the engine to actually need it to fire in order to start

[Conker]

the idle switch gets 12v from the ignition, and when the throttle is off the stop it creates a circuit to the white wire, sending 12v to the vacuum switch.  Then when the vacuum switch 'sees' the correct vacuum condition it closes and sends 12v to pin 15a on the starter motor which is also where the 5th inj is plugged in (hence why this pin has 2 wires to it)  therefore sending 12v to the 5th injector.  This then earths thru the coolant sensor on the side of the block

The temp sensor on the side of the head switches at 30degreees C, so it will always fire when stone cold, though the heater inside it will soon shut it off if its warm out and residual heat after sutting off the engien will keep it off for a while.  That being said it doesnt get cold enough that often for the engine to actually need it to fire in order to start

Apologies, can I briefly divert the topic...

Jonny, what would happen if the electrical connector on the starter motor wasn't connected - i.e. I the connector that leads to the 5th injector. Does this meant the 5th injector would never-ever "fire"??

[rubjonny]

this would stop it firing when you start the car when cold, but it wouldn't disable the cold fuel load enrichment from the vaccum switch

[Conker]

this would stop it firing when you start the car when cold, but it wouldn't disable the cold fuel load enrichment from the vaccum switch

Ta!

[Diluxe]

the idle switch gets 12v from the ignition, and when the throttle is off the stop it creates a circuit to the white wire, sending 12v to the vacuum switch.  Then when the vacuum switch 'sees' the correct vacuum condition it closes and sends 12v to pin 15a on the starter motor which is also where the 5th inj is plugged in (hence why this pin has 2 wires to it)  therefore sending 12v to the 5th injector.  This then earths thru the coolant sensor on the side of the block

The temp sensor on the side of the head switches at 30degreees C, so it will always fire when stone cold, though the heater inside it will soon shut it off if its warm out and residual heat after sutting off the engien will keep it off for a while.  That being said it doesnt get cold enough that often for the engine to actually need it to fire in order to start

cheers that helps alot , so I should be able to see 12V at the flying saucer like thing, if i take the leaver of the switch?, also what is this pin15a on the starter motor, i'm pretty sure my starter motor only has 2 wires going to it, and one piggy backing from the alternator on itys way to the battery, so i'm not sure if my 5th injector is powered up.............

[rubjonny]

yeah you should get 12v at the white wire on the saucer with the throttle open, 15a is the 2nd spade terminal on the starter motor, which generally only k-jet motors have.  If you only have 1 spade on the starter then you dont have a 16v starter motor, though all this means is you wont get any fuel spray from the 5th injector when turning it over on the starter stone cold.  I had my 5th injector unplugged for ages and it didnt seem to make any difference, I dont think it gets cold ienough in the UK for the 5th injector to be needed really.

[Diluxe]

its for enriching the fuel mixture a tad when cold, when you put a load on the engine off idle. i.e. floor it to pull away, it makes the 5th inj chuck a bit more fuel in.

does it only add extra fuel when your floor it from cold or all the time?

[Conker]

its for enriching the fuel mixture a tad when cold, when you put a load on the engine off idle. i.e. floor it to pull away, it makes the 5th inj chuck a bit more fuel in.

does it only add extra fuel when your floor it from cold or all the time?

The K-Jet page says as its controlled by the thermotime switch, then yes, only when cold:


15.1.11 The Cold Start Injector
To aid the starting of the engine an additional injector is located into the inlet manifold, this sprays fuel into the engine at systems pressure when the engine temperature is cold and the starter motor is activated. The length of time that this additional injector sprays is determined by the engine's temperature, seen by the thermo time switch.
The thermo time switch provides the earth path for the cold start injector via a heated bi-metalic strip, this heater is activated by a voltage from the starter motor. As the strip heats, over a period of approximately 8 to 10 seconds (when cranking only), the legs on the bi-metalic strip separate and the earth path is lost.
A warm engine will perhaps only require 2 seconds before the circuit is broken and a hot engine will already show open circuit. This simple circuit is to avoid the engine being flooded when cranking and the additional enrichment only given when essential, see illustration below.

[rubjonny]

I'm not so sure?  I bench tested 3 of these things, and from what I could see the earth path was only interupted when voltage was applied to the heater pin.  I had em all in boiling water for ages to no effect, but as soon as I rigged up the heater pole to a battery the earth path was lost.
If they are supposed to work like that then that would suggest when cranking for a few seconds the earth path is lost, but at all times when you boot it some fuel enrichment is supplied.

However I might have a load of bust ones though, I need to do some on-car testing I think

[Conker]

Have you tested it yet?




How about now?




Now?



Come'on Mr RJ!!!   Really want to know the answer to this as mine is currently unplugged and could be loosing me a few BHP!!