Starting - no crank - battery is fine. Jaguar tested coils and starter motor - all ok. spark plugs new. Seems to be effected by cold or damp weather.

1. Cold weather: Cold temperatures can affect the performance of the engine and make it harder to start.
2. Battery issue: A weak or failing battery can cause the engine to take longer to start.
3. Starter issue: If the starter is worn or damaged, it may struggle to crank the engine, especially in cold weather.
4. Ignition system problem: If there's an issue with the ignition system, such as a faulty spark plug or ignition coil, it can cause the engine to crank for a long time before starting.
5. Viper DS4+ installation issue: The Viper DS4+ remote start system may not have been installed correctly, or it may have a defect that's causing the issue.

If you are talking about actual CRANKING (with the starter turning the engine over) then I would check all of the electrical connectors on the battery cables to make sure they're clean. If they are clean and tight you could get a load test done on the battery at pretty much any auto parts store or repair garage.

IF you are talking about the actual STARTING of the engine (though it turns over good with the starter) and it ONLY happens when it's damp out, then it could very well be ignition related.

If it's been awhile or you don't know when the last full tune up was done (distributor rotor, cap, spark plug wires and spark plugs) that would be a good place to begin.

Now, if the plug wires themselves don't look the greatest you could simply try to spray the wires and distributor cap with WD40.

This will help to dissipate any moisture that may be causing the poor starting condition. (The "WD" in WD40 actually stands for water dispersion)

IF this helps, then it's time to do a full tune up.

Hope this helps.

Have you had a battery test done? Sounds like a weak battery or dirty and loose battery connections. The cold weather doesn't help because it makes your engine oil thicker.

If it is happening more frequently in cold or damp weather it could be a spark issue. Wet or damp weather can effect spark plug wires if there is even minor damage to them (usually occurs durring rain). The other things that come to mind are the fuel pump and lastly the fuel line check ball that is in the fuel tank. If it is leaking then all the fuel in the line will drain back into the tank over night (pressure lost in the fuel line) and this will cause repeated, extended cranking when you first start the car in the morning or after the car has sat for several hours.

You can get the error codes from the ecu. Many auto parts stores will loan a meter to do it.
Also test the glow plugs using the vehicles system. Do them individually.

I am assuming this a cold weather only issue ?? Turn your key to on before cranking it over for about 5 sec to let the glow plug heat up a moment. Not allowing the glow plug to warm will wear out your starter.

perhaps you need a new cap and roter a new spark plug wire set. they don;t like moisture. also check to see if you have any broken or leaking vacuum hoses. the worse case senerio would be that your head gasket is leaking--at cold temps a little antifreeze will enter until everything warms up and it seals shut due to metal expanding. but since you say it's cold weather only--this probably wou;dn't be the case. good luck.

I would change all of it. Spark plug wires will leak under the high voltage w/o any outward signs. Unlikly fuel pump . Not effected by damp weather. If after all that and it still doesn't work, change the coil.

Q1. Engine will not start or is hard to start (Cranks OK) A1 -Ignition lock switch faulty -Ignition coil faulty -Power transistor faulty -Spark plugs faulty -Ignition wiring disconnected or broken -Spark plugs faulty Q2, Engine will not crank A2. Battery discharged Battery cables loose, corroded or worn out Transaxle range switch faulty (Vehicle with automatic transaxle only) Fusible link blown Starter motor faulty Ignition switch faulty Ignition lock switch faulty REMEDY Charge or replace battery Repair or replace cables Adjust or replace switch Replace fusible link Repair starter motor Replace ignition switch Replace ignition lock switch