The All New, New "What have you done to your Bay today" thread.

Haven't had a chance to test it as peeing with rain, but I think we may have been deceiving ourselves about the initial priming pulse.

Slipping on my anorak and glasses held together with insulating tape, I've looked at the circuits for the VW, KAE and Porsche relays, which are all pretty similar. There's no provision in them for triggering an initial pulse. They're just designed to keep the pump relay energised for as long as the engine's running, driven by ignition pulses, which is their purpose in life. Engine stops, and the pump stops.

If you did get an initial prime with the Accuspark, I can only think it's something to do with the state of the coil line when the ignition supply's turned on that causes the relay to trigger once. As before, the 123 won't provide any current to the coil if it knows the engine isn't turning (to stop the coil overheating when just the ignition's on).

Does it really matter? As you said, just turning the engine over will get the pump going, which should quickly fill the system up, even cranking on the starter. Hope so.

 

Back to the separate push button for a primer?

 

If it's needed. I'm hoping it won't be with an electric pump.

Don't forget to add a hot-start relay to your wiring, BTW

 

Wasn't planning on it as all the wires are new and I've erred on the side of caution for wire thicknesses. One day when the wires get tired I might .

 

The 321 906 059 C relay is definitely intended to run the pump as soon as the ignition is on to pressurise the fuel rail. And with the Accuspark I could hear the pump running for a second or so before cranking. I don’t know how it worked but it did.

Have you seen this? http://www.cabby-info.com/Files/Relays_Kjetronic.pdf Note the rev limiter, I didn’t know the relay had that, not that I’m ever going to get close to 7500 revs.

Not really but the prime function was nice, for some reason I liked hearing the pump run as soon as I turned on the ignition – and my fuel injected V8 MGB does it, albeit with an entirely different relay.

 

Putting the hot-start relay in will save your ignition switch contacts being nibbled. Worth doing, IMHO. If you stick an extra connector on it in the engine room, you can just plug a pushbutton in to crank the engine from the rear (matron).

 

Well, nothing I can see in the circuit I found that would perform that function. Also no rev limiting gubbins.

 

Ok ok, you win. Have you got a back of a fag packet diagram?

 

I'll find one when I get back from the boozer

Seriously, well worth having. When you let go of the switch from "start", your ignition switch contacts get a hell of a belt from the field collapsing in the solenoid.

 

Is the circuitry the same in this generic relay as the VW one?

 

Which one?

 

3.300.300 - generic
vs
321 906 059 C - VW

 

It must be electronic wizardry, I know it worked. If you look at the MK1 Golf forums there are plenty of threads about the relay – it should prime before cranking.

 

Can anyone recommend some good reading to learn about relays? Yes I need to get a life.
For instance the mini loom that came with my 3 VDO Audi gauges had this relay in the light bulb circuit to illuminate the gauges. What does it do and do I need it?

 

Just to confuse you...it’s not a relay It’s a slave dimmer for the extra gauge lights.

 

3.300.100 is equivalent to 321 906 059C. The 3.300.300 pin layout is different but I don’t know if there are any functionality differences.

 

So do need it if I want to dim all the dash lights together or can I leave it out as I've daisy chained all the dash bulbs in my diagram?

 

I left it out, fitted LEDs and by-passed the dimmer.

 

So I'll try connecting the grey/red wire from the end of the dash lights to the small terminal on the light switch, if the dimmer doesn't work (and it might not as I've not had a chance to check the switch) I'll just connect it to the terminal with the grey sidelight wire. Plan sorted

 

Not really. It was presumably just to prevent you burning the dimmer rheostat out on your old Golf or Corrado. Just connect the gauge lighting to the top of one of the sidelight fuses, which'll go live when the lights are switched on.