From a point at sea, to the circles of your mind, this is David:
What are ALL the symptoms of a cold start injector failure/problem ?
I'm guessing that "difficulty starting when cold" is a given, but
what sort of driveability issues would I see, if any ? At what
ambient and/or engine temps should it make a difference ?
The answer may vary, depending upon the type of fuel system you have
(the age of the vehicle is no guide - it varied from territory to
territory).
On a system with K-Jetronic fuel injection (if you are UK based this
is you, but maybe other places as well) the cold start injector only
operates when the starter motor is cranking, and even then only for a
limited time. So if it is failing to open, difficult starting during
cranking is the only symptom; after that the engine should behave as
normal.
If the cold start injector is sticking open, then you will have all
the symptoms (to a varying degree) of a rich mixture - lumpy,
'hunting' idle even when warmed up; black, pungent smoke from the
exhaust under accelleration; heavy fuel consumption; sooty spark
plugs; failure of emissions tests - high HC.
On K-Jet there are a couple of other things to be aware of:
1) Auxiliary Air Valve. This allows more air past the throttle valve
for a few minutes during warm-up, similar to a fast idle device (note
- propely adjusted, the cold idle will not be a fast idle - it should
maintain the idle at about the normal speed). If this fails, you will
either have very low idle speed when cold, often leading to stalling
and the need to keep revving the engine, or too high idle speed when
warm. Above idle speed, drivability will be unaffected.
2) Warm Up Regulator. This enriches the mixture during the warm up
period. Because of the way it works, it normally fails to its enriched
position, so cold starting and warm-up wouldn't be a problem, but the
engine would be running rich when warm. In the unlikely occurrence of
it failing in its 'warmed up' state, then cold starting may be harder,
and until the engine is warm, idle would be weak and unresponsive to
the throttle, there would be a lack of power, stalling common.
--
Stewart Hargrave
A lot faster than public transport
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