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 ?
From a point at sea, to the circles of your mind, this is David:
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.MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.