Couple of R51 behavior questions... is this normal?

[k9sar]

Still getting the feel for my new-to-me 05 pathy and have a couple of items that seem odd but may be normal. Any other R51 owners, please chime in with your observations.

 

1. When I start the truck in cold weather using the key only (no gas pedal), the engine revs up and holds at a fast idle for several seconds then drops down to what I would consider to be a normal idle. When I start it the same way after driving for awhile, it does not do that. Is this a 'feature'?

 

2. Watching my oil pressure indicator, it seems to fluctuate quite a bit with engine speed. During normal driving, the needle is midway in the normal range but, when I stop, the needle drops to almost out of normal. It also jumps up and down when I rev the engine. I don't recall my other vehicles doing that. Does the oil pressure fluctuate that much?

 

I have short videos of each of these if needed. Would have to upload off my phone which I don't have with me right now.

 

 

[Citron]

I don't have a r51, but from other vehicles, I would say this is normal. My Titan will stay at high idle for a few minutes on cold start.

 

The oil pressure is normal. The oil pump is engine driven, so it changes based on RPM. As far as not seeing it on other vehicles, not all vehicles give true readings on the gauge. A F150 I had the oil pressure gauge was either in normal or not, kind of a pass fail. If pressure was above a certain psi, it read normal. The sending unit was a pressure switch.

[k9sar]

I don't have a r51, but from other vehicles, I would say this is normal. My Titan will stay at high idle for a few minutes on cold start.

 

The oil pressure is normal. The oil pump is engine driven, so it changes based on RPM. As far as not seeing it on other vehicles, not all vehicles give true readings on the gauge. A F150 I had the oil pressure gauge was either in normal or not, kind of a pass fail. If pressure was above a certain psi, it read normal. The sending unit was a pressure switch.

 

For the idle issue, I would understand if it were a high idle to warm the engine when cold but this is only a few seconds (no more than 10). Maybe it is to get the oil pressure up. dunno. Definitely different than any vehicle I have owned.

 

For the oil pressure... I don't recall ever seeing it fluctuate that dramatically. Never goes low enough to be 'bad' but the range seems to be much more than I am used to. Again, could just be the nature of the sensor.

 

Neither issue has me worried that there is a problem. Still learning the truck.

[adamzan]

My parents have a 2012 Xterra with the 4.0 and it does the same thing. Revs to about 1500 or more then settles down. So dumb because that is probably terrible for the motor when it is -30 outside.