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No fast idle at start up

R

Ratty109

In Second Gear
Hello everyone, new to the forum and after a bit of advice.
I have a Range Rover 3.5 EFI flapper transplanted into a SIIa, it's been sat for a while due to lack of funds and always used to fire up and run fine.
Since getting it running again recently i've found that on start up from cold it overfuels badly and fast idle doesn't kick in.
Any ideas on likely things to look at?

Thanks in advance.
 
I've moved this thread here to the Series section, you might get a better response. Plenty Series owners with V8's.

Can't help you myself though, sorry. Diesel I understand, 2.25s I get... But V8's? They sound fantastic, but that's the limit of my knowledge. :)
 
Over fueling sounds like the thermo time switch is dodgy (or the injector). Cold start enrichment on them comes from a 9th 'injector' straight on the plenum housing (top middle opposite the throttle body). If the switch goes wrong it can simply cause them to overfuel constantly. Or maybe that injector is stuck open? The thermo time switch is, from memory (not what it used to be!) the brown topped one on the left side (right as you look at it from the front though) of the manifold, near the front, near the corner of the plenum (right next to it is the temp sender for the ECU IIRC)

Fast idle is performed by a bimetal strip turning a disc in an air bypass device, 12v is supplied to it and eventually it closes off. However, over time, these can clog up and stay stuck shut/open or anywhere inbetween. This sits on the front corner of the manifold and will have 2 large bore hoses going into it, one to near the throttle body and the other into the plenum/manifold area.

The old flapper systems are fairly 'analogue' even though they have an ECU etc, so are prone to simple mechanical or basic electrical issues.

Try unplugging the thermotime switch and give the bypass device a good clean inside with some carb cleaner etc (also check its getting a voltage to it, or that a wire is even connected!)

Hope this helps!
 
Thanks for the reply, just disconnected the 9th injector and fast idle kicked in straight from turn over (Should have thought of doing that first!) So now I just need to narrow down what is causing the problem, injector, extra air valve or thermotime switch, i'll break out the multimeter at the weekend and let you know how I get on.
Many thanks, sometimes you need another brain to pick when you start doubting your own!
 
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