Hello everyone! Hope everyone had a good weekend! Over the last month, my Jag takes around ~3 seconds or so to startup. I'm wondering if it's because of the cold mornings, or something else? Is it normal to have this happen as well or does something have to be fixed. It's not too much of an annoyance to me, however, if it's leading to a major problem, i'd like to fix that asap. Thanks everyone, have a good week!

- Pilotman

 

Hi Pilotman11,

Lots of possibilities, but the first question is: have you scanned the system for any stored Diagnostic Trouble Codes (DTCs)? On some models DTCs can be stored without triggering a Check Engine Light (CEL / MIL / SES).

The second question is, how long has it been since your car had a good tuneup? Plugs, air filter, fuel filter, drivebelt condition and tension check, MAF cleaning, fuel injector cleaning, cleaning of all engine bay electrical connectors with zero-residue electrical contact cleaner spray, cleaning of ground points and battery power connections, etc.? In my experience slow starting is often the result of multiple minor issues.

A couple of other possibilities come to mind:

If the battery voltage sags when you first turn the key, the ECM may not trigger the ignition to fire until the voltage rises to a sufficent level. You can test the voltage while cranking if you have a fast-reacting voltmeter.

When the fuel pressure regulator and/or fuel check valve lose their ability to hold pressure in the fuel rail, the fuel pump must work long enough to repressurize the rail before the injectors can reliably atomize the fuel. You can test for a problem with the FPR and/or check valve with a simple procedure. In the morning, before you start the car for the first time of the day, turn the key to Position II (Ignition ON) but do not start the engine. Listen for the fuel pump to run briefly to prime the system. Turn the key off, then repeat the same procedure. After two or three of these, start the engine and see if it starts faster. If it does, suspect the FPR and/or check valve. Unfortunately, it's not easy to isolate one problem or the other, so the easiest thing to do is to replace the FPR and see if things improve. If the problem isn't resolved, you can add a new check valve in the fuel line (the original check valve is in the fuel tank).

A failing Camshaft Position Sensor (CMP) or Crankshaft Position Sensor (CKPS), or loose or corroded electrical connector can contribute to longer start times.

A failing Engine Coolant Temperature Sensor (ECTS) can cause longer start times if its signal is not informing the Engine Control Module (ECM) that the engine is cold and requires cold-start fuel enrichment.

An intake air leak or vacuum hose leak can undermine cold-start fuel enrichment, leading to longer start times.

Have you had any indication that the ignition switch is having issues? There are also some relays that can contribute to slower starting if they become lazy with age (ignition positive relays, ignition coil relay, etc.).

I'm sure others will have some suggestions. Please keep us informed.

Cheers,

Don

 

Of all the above excellent suggestions the fuel check valve would seem to be high on the list of problems matching your description.

 

My daughter in San Leandro says it has been colder in the upper Bay Area now than in February. Don's points are all on the mark; but start with checking the temp sensor (ECTS).