I have a 2006 LR3 that has recently had some issues starting. I've had it for two years and no problems and then a couple of weeks ago, started having issues. When I start it in the morning or after it sits for several hours, there are no problems - it fires right up. If I drive it and let it sit for 30 or so minutes, when I try to start it, it will crank but won't start (check engine light comes on). For instance, the RPMs will shoot up to about 1500 and immediately fall. It will start if I give it a little gas and will run perfectly fine after starting. It just won't fire up. Anyone had a similar issue?

 

How many miles on your vehicle? I don't recall many similar issues, but almost sounds like a fuel pressure problem - perhaps fuel pump? Wouldn't explain why it's fine when cold though, so eh..


Actually I'm thinking out loud here, buuuut...
The only obvious engine temp related scenario I can think of off-hand is if the vehicle is warm enough that it's starting in closed-loop and referencing MAF / o2 sensor data. I don't actually know if the ECU will immediately do this or if there's still an initial open-loop time period even if it's warm.

If it can indeed go straight into closed-loop, that may be why it's only giving issues when warm. It starts fine when cold - since it's open-loop and referencing stored fuel and ignition tables and ignoring all the real-time data/sensors. By the time it changes over the engine is already warm / running and you have a lot more "wiggle room" for errors.

You can probably pull real-time data and see something a little strange or near-limits. I'd check MAF and pre-cat o2's first. Could also be one of the many temp sensors feeding funky data to computer. I've seen those fail and give insane values like -/+ 150 degrees which can cause really wacky AFR issues also (same if a harness is damaged or disconnected).

Have you been keeping the throttle body clean? I haven't heard of it causing anything this dramatic, but it's possible (considering how nasty it can make the idle in some cases).

Of course most closed-loop sensor issues will almost always cause a check engine light.

 

Thank you for the response. It has 104,000 miles. The only things I have tried to date are cleaning the MAF sensor and cleaning the throttle body - neither helped the issue. It's definitely strange it only happens when warm. Like I said, it fires right up in the morning and again after work but if I drive it in between, it's not starting. I was hoping someone else has had a similar issue before taking it to get looked at. Thanks again.

 

Any clue if the crankshaft position sensor would cause this? I noticed a few other threads with a similar problem and this was one of the items mentioned.

 

That shouldn't be influenced by heat at all - from what I've read on most engines, once it's gone you're screwed.

I'd try to hook up a scanner that's capable of displaying real-time data and check the temp sensors and other things.. I still think once it's in closed loop/warm and using internal sensor data, something is throwing it off to the point where it's screwing up AFR, spark advance, etc etc.. and messing with your starting capability.

 

When you try and start it warm, do you notice any strong fuel smell, as in it could be flooding out?

 

I've never noticed a strong fuel smell. Typically, when it won't start after the first try, on the second try, I'll give it a little gas and it fires right up and runs with no problems.

 

Update: Had the codes pulled and they came back with:

-P0108 (Manifold Absolute Pressure/Barometric Pressure Circuit High Voltage)
-P0069 (MAP/bARO Correlation)
-P0406 (Exhaust Gas Recirculation Sensor A Circuit High)

Would a bad EGR valve cause these problems? Looks like the MAP sensor is part of the EGR valve on the V6. Is that correct?

 

Those sound like diesel codes lol, that's really strange - all of them actually.

 

There is a map sensor on the back of the intake, according to Google.