Setting Bosch idle

[306Puggy]

I cut off the cold start cable from my wax stat, I'm wondering if this is causing the following problem. When the engine is cold the idle is too low and the engine shakes on the mounts and shakes its tits off, when the engine warms up the idle is too high like 1300rpm. I am adjusting the minimum throttle stop to set the idle speed at the moment, I have removed the hot idle and cold idle screws from the back of the pump to simplify things so that I am only adjusting one thing at a time. I have read this thread: http://306oc.co.uk/forum/thread-2883.htm...transition
Which seems to suggest going by Ruan's post that I shouldn't be having a fluctuating idle since I have snipped the cold start cable. According to Ruan the idle should be fixed but my pump seems to have a mind of it's own once it's warmed up. Unless it's a symptom of the fuel pump warming up and therefore warming the veg up and making it easier to pump?

[cwspellowe]

Sounds like normal veg behaviour to me, mine always does it.

When cold on veg it sits about 800rpm and clattery then jumps up to 1000rpm and smooth, as soon as I go back to diesel it behaves again. Wouldn't worry tbh.

[darrenjlobb]

The reason it jumps is because when its cold the glow plug relay is on, which pulls raping amps and drops it 2-300 rpm, the more you adjust the max fuel / take the gov out of spec, the bigger the jump will get as it looses the ability to self regulate...

[cwspellowe]

The reason it jumps is because when its cold the glow plug relay is on, which pulls raping amps and drops it 2-300 rpm, the more you adjust the max fuel / take the gov out of spec, the bigger the jump will get as it looses the ability to self regulate...

ORLY? Hmm. Why does mine only do it on veg?

[darrenjlobb]

Because the veg further amplifies the governors effect to stabilize the idle, hence you see it more, im surprised it don't do it at all on diesel... Most stockish pumps when screwed right out do it like mad because there so far out of calibration.

[cwspellowe]

So what you're saying is I need m0ar fuel?

[Luhoer]

So what you're saying is I need m0ar fuel?

it's always time for more fuel

[306Puggy]

Aaaaah, veg. That makes sense that it is more prounounced on veg then. I haven't run derv for ages! Almost forgotten what it's like TBH!