Low Oil Pressure at Hot Idle

[HotRodMojo]

Hey guys, I did a search for low oil pressure issues in the forums but it didn't come up with much at all. I was having a low idle issue that was resolved by the ECU re-learning the idle with and without the AC on. While I was having this issue, I noticed the oil light coming on when the RPMs would drop to around 500 RPM. I attributed this to the low idle. I was both right and wrong. When I was sitting in the car letting it idle for about 15 minutes to re-learn, the oil light never came on. I took it for a spin around the neighborhood for a while. The temp goes up some when only going 30 MPH and I read that is typical. So when I got back home and pulled in the garage, the temp was around 230F and I was idling around 1K, ready to shut everything down, and I noticed the oil light flickering some. Has anyone had this issue or may know what could be the cause assuming the oil level is good? Maybe oil pump going bad or pick-up screen? Or maybe the idle just needs about 100-200 more RPM would take care of it? What do you all think?

'97 GTS Venom 650R

 

[DrumrBoy]

What weight oil are you using in the summer?

 

[HotRodMojo]

I have not changed the oil yet. I just got the car 2 weeks ago from Illinois. I do not hear any valve noises. The engine has 30K on it. I can't imagine that the engine would be worn so early would it? I heard Viper engines in Gen 1 & 2 were almost bullet proof. I hope it is just a needed oil change or something simple.

 

[AZTVR]

Hey guys, I did a search for low oil pressure issues in the forums but it didn't come up with much at all. I was having a low idle issue that was resolved by the ECU re-learning the idle with and without the AC on. While I was having this issue, I noticed the oil light coming on when the RPMs would drop to around 500 RPM. I attributed this to the low idle. I was both right and wrong. When I was sitting in the car letting it idle for about 15 minutes to re-learn, the oil light never came on. I took it for a spin around the neighborhood for a while. The temp goes up some when only going 30 MPH and I read that is typical. So when I got back home and pulled in the garage, the temp was around 230F and I was idling around 1K, ready to shut everything down, and I noticed the oil light flickering some. Has anyone had this issue or may know what could be the cause assuming the oil level is good? Maybe oil pump going bad or pick-up screen? Or maybe the idle just needs about 100-200 more RPM would take care of it? What do you all think?

Well, first thing that I would do is find out what the oil pressure actually is. The service manual says that light should come on when the oil pressure is below 8 psi. I wouldn't be running the engine if that is what is happening. If the pressure is considerably higher than 8psi, then replace the switch.

edit: Manual says: "Check oil pressure using gauge at oil pressure switch location. Oil pressure should be 68.9 kPa ( 10 psi.) at idle or 310 to 517 kPa (45 to 75 psi.) at 3000 RPM. CAUTION : If oil pressure is 0 at idle, Do Not Run engine at 3000 RPM ."

My oil pressure gauge on my 2002 read above 40 psi at idle (approx 600-700RPM) with engine warmed up.

 

[HotRodMojo]

Great news. Once the engine cooled and wife was around to help pull the 4 pin hood, it just turned out to be a quart low. Goes to show never trust anything you hear such as " we checked it all out good". My bad for not pulling the hood day 1 though. Shame shame. I couldn't help but to jump in and road test it right off the transporter. The Venom 650R is extremely strong. The sound wakes up the neighborhood. It's nothing short of a street legal racecar. The original owner got 10.7 quarter mile. Wife determined she should not eat right before a ride and to get some sports bras.

 

[AZTVR]

Great news. Once the engine cooled and wife was around to help pull the 4 pin hood, it just turned out to be a quart low.

I can't think of how that would affect whether the oil light would come on or not at idle. (Unless you mean that it was 1 quart lower than the lower mark which would have made it 3 quarts low? - I think ?)

 

[HotRodMojo]

It did the trick. It was in the middle. I kept a close look at the gauge and it never went below about 38psi. The light never came on either. The engine ran a bit cooler also. I did a lot of neighborhood driving to get it hot. Most of the time it idled around 45Psi. I found out they ran 10w40 or 15w40 at the oil change up north. I heard in Houston area it's best to run 0w40. Either way I feel a lot better the light stays out.

 

[AZTVR]

It did the trick. It was in the middle. I kept a close look at the gauge and it never went below about 38psi. The light never came on either. The engine ran a bit cooler also. I did a lot of neighborhood driving to get it hot. Most of the time it idled around 45Psi. I found out they ran 10w40 or 15w40 at the oil change up north. I heard in Houston area it's best to run 0w40. Either way I feel a lot better the light stays out.

It sounds to me like the oil light switch is defective? Did you see what the oil pressure gauge read when the oil light came on? I believe that the oil pick up on a Gen 2 is from a passageway at the bottom of the oil pan. If you were stopped at idle and on a level surface, then you would have had to be extremely low in oil to get below 8psi oil pressure that turns on the light, i.e., almost sucking air from the bottom of the pan.. At least to my understanding.

 

[HotRodMojo]

The switch will be the first thing I check if it does it again. I trust the analog gauge more than light switches. I didn't notice the gauge sadly when the light was flickering. I was in the process of shutting down.

 

[Nsane1]

Agreed, I would watch this closely. 1 quart low will not cause a low oil pressure light. And yes, the idiot lights are just that, the analogs are the key, if your oil pressure gauge is EVER way to the left (except when going from off to on and back off), please turn it off.

It does sound like a intermittent switch, as 30k miles is low for these engines, also doesn't sound like oil pump... But just keep an eye out.

 

[mrbob]

i had the same problem on my gen 1 , oil light on at idle . got sacred and took off the right side valve cover and started the car to see if i had any oil flow . i had good pressure it shot oil to the top of my garage . then i put a new sending unit on and the light has not come back on at idle.

 

[Nsane1]

LOL, I think hitting the ceiling is a good indicator of flow, I wish I can say I haven't done that myself