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Oil pressure light behaviour


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I like to share a little observation with you. It might look familiar and I am interested in your experience.

I used to ride pre-injection Guzzi's like the Cali 2 and LM2 and 3. They have always a very clear oil-pressure-light behavior. Switch-ON(the master-key or ignition-key)--> Oil pressure light is ON. Start engine --> Oil light turns OFF. Engine running --> Oil pressure light OFF. Turn OFF ignition --> 3-6 sec delay and Oil pressure light turns ON.

With my V11 2002 it is like this. So, it satisfies my expectation.

With my V11 '99 it is different. The oil pressure light stays of after the engine stalls(Ignition OFF) and the oil pressure light is sometimes ON when Ignition is ON and engine is not running. But not always. It feels to me like the switch has some hysteresis or something or the oil pressure remains above 0,5 bar near the switch. I use 10w60 oil, the viscosity is a little higher, could this have an effect.

Then we have the V11 LeMans '02 of a friend. I have not seen that light ON for ages, so that will probably be a defect light. We grounded the wire to the oil-pressure sensor and that didn't switch the light ON. Now in the 25 years that I am riding Guzzis, this light has never been the cause (there can always be a first time) .

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36 minutes ago, motortouring said:

I like to share a little observation with you. It might look familiar and I am interested in your experience.

I used to ride pre-injection Guzzi's like the Cali 2 and LM2 and 3. They have always a very clear oil-pressure-light behavior. Switch-ON(the master-key or ignition-key)--> Oil pressure light is ON. Start engine --> Oil light turns OFF. Engine running --> Oil pressure light OFF. Turn OFF ignition --> 3-6 sec delay and Oil pressure light turns ON.

With my V11 2002 it is like this. So, it satisfies my expectation.

With my V11 '99 it is different. The oil pressure light stays of after the engine stalls(Ignition OFF) and the oil pressure light is sometimes ON when Ignition is ON and engine is not running. But not always. It feels to me like the switch has some hysteresis or something or the oil pressure remains above 0,5 bar near the switch. I use 10w60 oil, the viscosity is a little higher, could this have an effect.

Then we have the V11 LeMans '02 of a friend. I have not seen that light ON for ages, so that will probably be a defect light. We grounded the wire to the oil-pressure sensor and that didn't switch the light ON. Now in the 25 years that I am riding Guzzis, this light has never been the cause (there can always be a first time) .

Your description doesn't make sense for the 02 v11. You turn the ignition switch OFF and after a 3-6 second delay the LOP light comes ON? It comes on with the ignition switch OFF?

Here's how it works or is supposed to work. Turn ignition ON, LOP light ON. Start engine, LOP light goes OFF. Mine goes OFF during cranking. Turn ignition OFF,LOP light goes off with engine shutdown along with everything else. Any variation on that and you have an issue.

Phil 

 

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I don't own a V11 but have a Sport 1100 an LM 1000 & a HiCam engined bikes, so on V11 specifics I'm somewhat lacking, but AFAIK there is little difference between the V11 and Sport on the lubrication side.

You obviously are well aware of the pressure behaviour on the bikes and I'm sure you also know that the oil pressure switches don't have the best reliability reputation.

On your friends V11 it's almost certainly the bulb that's defective.

I've never switched the bike off with the kill switch and then kept an eye on the pressure warning, so can't say for sure, if there would be a slight delay or not, but I can't recall seeing it happen.

I've never ran a 2 v/v bike on 10/60, but the additional viscosity might also increase the pressure decay time.

I also don't understand the statement about the oil pressure being out after the bike stalls (ignition OFF), the light will be out if the igntion swtich if OFF as there is no voltage to it, pressure or not it will not illuminate.

If the light doesn't illuminate when the ignition is on and the engine has not been run the pressure switch is defective or starting to fail.

What I'd do is either replace the switch, remove the exisitng switch and test it, or install a temporary gauge into the pressure switch location to separate the true pressure behaviour in the system from the instrumentation. If installing a gauge I believe the crankcase thread for the switch is an M12x1.5 thread

Here is a crank test on a HiCam (4v/v) bike with cold 15W/50 oil, it doesn't have any relevance except you can see there is a short period when the engine stops rotating and the pressure decays to approx 7psi. That's on cold oil though, I'd expect it to be much quicker on a hot engine

 

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54 minutes ago, Lucky Phil said:

Your description doesn't make sense for the 02 v11. You turn the ignition switch OFF and after a 3-6 second delay the LOP light comes ON? It comes on with the ignition switch OFF?

Here's how it works or is supposed to work. Turn ignition ON, LOP light ON. Start engine, LOP light goes OFF. Mine goes OFF during cranking. Turn ignition OFF,LOP light goes off with engine shutdown along with everything else. Any variation on that and you have an issue.

Phil 

 

Phil, this is indeed not well explained. I switch OFF with the RUN/STOP button, because I like to check the delay in the OIL Pressure Light. That is where the delay is coming from.

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2 hours ago, motortouring said:

Phil, this is indeed not well explained. I switch OFF with the RUN/STOP button, because I like to check the delay in the OIL Pressure Light. That is where the delay is coming from.

OK, but the question is why would you do that? The time it takes to illuminate is of no empirical value. I don't know of anyone that monitors such things so answers might be hard to come by.

Phil 

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I doubt this adds to your initial post, but I'll share it just the same.

I have a 2010 V7. For years, I never saw the oil pressure light. Then once while riding at over 100mph, I heard a bang, white smoke bellowed our of the left tailpipe. I pulled over, then towed it home. After inspection I couldn't find anything wrong, so I started it and it ran fine, and has for well over another 10,000 miles. The bike currently has 23k on the clock.

However, since that time, the oil pressure light comes on sometimes if I sustain speed on the freeway. So when I ride 20 freeway miles to work, holding the throttle steady for minutes on end at roughly 80mph, the light will sometimes come on for a few moments, then back off. I checked and checked, and could not solve the issue, including swapping the engine case breather check valve. I've finally ignored it and continue to ride with no problems.

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5 hours ago, Lucky Phil said:

OK, but the question is why would you do that? The time it takes to illuminate is of no empirical value. I don't know of anyone that monitors such things so answers might be hard to come by.

Phil 

Well, to me it shows some constant time that I like to relate to the slope of pressure drop when the engine is turned off. I started doing this when I had a pressure problem with a LM3. That light went off the instant the killswitch was off.

It turned to have a bad adjusted pressure valve and worn crankshaft bearings.  

I guess a sort of a tick.

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But on the topic. Could a oil pressure sensor have some sort of temporary failure? Something like a clothed opening that works like a membrane?

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I have not checked this. I think that might be located in the tank, on the pump/filter assembly from what I just researched.

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5 hours ago, motortouring said:

Well, to me it shows some constant time that I like to relate to the slope of pressure drop when the engine is turned off. I started doing this when I had a pressure problem with a LM3. That light went off the instant the killswitch was off.

It turned to have a bad adjusted pressure valve and worn crankshaft bearings.  

I guess a sort of a tick.

For general information to anyone reading this thread in the future this methodology is flawed and it's best to stick with the historically tried and tested oil pressure observations for troubleshooting. This LOP light on after the kill switch timing thing has way too many variables to be a troubleshooting tool. If the engine runs fine and has no unusual noises and the LOP stays off at idle in hot weather in traffic and the used oil has no concerning contamination then all is fine with the oil system. What do you do on a weekend trip or touring trip when you use this observation technique? Stop for fuel and for one of a dozen different reasons the LOP light illuminates without or with a reduced delay compared to usual observations? Pull up and start troubleshooting and have the engine apart? What would be an acceptable amount of delay? 1 second? 3 seconds? Sometimes people can go looking for issues and worries. Fitting an OPG every 30 or 40,000klms for an oil system evaluation would be reasonable but only for the oil pressure obsessed. 

It's the same as permanently fitted LOP gauges, a waste of time and added failure points and complexity. All you get is additional things to worry about and questions to observations you don't have the knowledge to understand. There's a good reason motorcycles in particular don't come standard with LOP gauges and only a light. It's just too cruel for the OCD riders out there. Even modern cars with LOP gauges dont use actual direct reading gauges anymore they use an indication derived and calculated from the ecu for the display and rely on a LOP switch and light for indication and warnings. If they used direct reading gauges that indicated the actual oil pressure the dealerships would be overflowing with owners with oil pressure issues. It's not just about the engineering but human psychology as well.  

Phil

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16 minutes ago, Lucky Phil said:

It's the same as permanently fitted LOP gauges, a waste of time and added failure points and complexity. All you get is additional things to worry about and questions to observations you don't have the knowledge to understand. There's a good reason motorcycles in particular don't come standard with LOP gauges and only a light. It's just too cruel for the OCD riders out there. Even modern cars with LOP gauges dont use actual direct reading gauges anymore they use an indication derived and calculated from the ecu for the display and rely on a LOP switch and light for indication and warnings. If they used actual direct reading gauges that indicated the actual oil pressure the dealerships would be overflowing with owners with oil pressure issues. It's not just about the engineering but human psychology as well.  

Phil

This is precisely why the automotive industry moved to "steady state" coolant temperature gauges (if any coolant temp gauge at all!). Ever notice that your car's coolant temp gauge points right at the middle, or slightly below, within a mile from start-up? And never varies, even in brutally hot ambient temps stuck in traffic?

This is because owners would present their vehicle for service because "the needle is all over the place!" Now the "needle" stays "steady state" over a very broad range of (normal) operating temperatures.

Actual coolant temperature (and perhaps oil pressure?) is like sausage. The less we know about the details, the better we sleep at night . . . :sun:

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1 hour ago, docc said:

This is precisely why the automotive industry moved to "steady state" coolant temperature gauges (if any coolant temp gauge at all!). Ever notice that your car's coolant temp gauge points right at the middle, or slightly below, within a mile from start-up? And never varies, even in brutally hot ambient temps stuck in traffic?

This is because owners would present their vehicle for service because "the needle is all over the place!" Now the "needle" stays "steady state" over a very broad range of (normal) operating temperatures.

Actual coolant temperature (and perhaps oil pressure?) is like sausage. The less we know about the details, the better we sleep at night . . . :sun:

Back in the 80's docc I had a new GPZ900 Kawasaki. They used to run quite high engine temps, a little higher than what most people were used to. So the complaints came as did the traffic to the dealership mechanics. Kawasaki's response? They fitted a resistor to the gauge to bring the reading down a little. Complaints ceased.

Phil  

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17 hours ago, motortouring said:

With my V11 '99 it is different. The oil pressure light stays of after the engine stalls(Ignition OFF) and the oil pressure light is sometimes ON when Ignition is ON and engine is not running. But not always. It feels to me like the switch has some hysteresis or something or the oil pressure remains above 0,5 bar near the switch. I use 10w60 oil, the viscosity is a little higher, could this have an effect.

@motortouring, while I find my 2000 Sport retains oil pressure (light stays off) briefly after shut down (with the Run Switch off / Ignition on), I don't actually monitor the time or consider the information actionable.

Yet, when the Ignition is switched on (regardless of the Run Switch position), the LOP light (and the "Battery" light on the early V11) should be lit. If they are not, or "not always" this would lead me to investigate the circuitry involved: yes, the pressure sender and its connection, but also Relay #2 and its connections. On the early V11 wiring, this function also relies upon current through the weak NC contact of Relay#1.

The relay contacts are especially suspect when more than one function fails simultaneously (no LOP light along with no Battery Light).

There is the "Wiggle Test" (I'm not making this up! :nerd:) to consider. With the seat off (for access) and the light(s) do not come on as expected: "wiggle"/jostle/wrangle/bump/tap Relay #2 , Relay#1, Fuse #5, and the connection to the LOP sender. Observe for change in illumination and from what was "wiggled."

P.S. - I recall the early V11 (likely the later V11, as well) connected the wire to the LOP sender with a barely shielded "bullet" connector. This is located in the air/weather/spray stream on the left side, top of the engine case ahead of the left cylinder base. Strongly recommended to clean, crimp, and seal (Vaseline®?) this connection.

I went a step further and sourced the rubber boot fitted to the "EV" models ( GU12717600 ) . . .

DSCN1080.JPG

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7 hours ago, docc said:

Actual coolant temperature (and perhaps oil pressure?) is like sausage. The less we know about the details, the better we sleep at night . . . :sun:

When I was a kid growing up in a small town, I remember my parents spinning stories among friends and neighbors about that one butcher and how it should be avoided to buy sausages from him. It was said that his sausages were filled, among other things, with wood chips scraped from the chopping block... and anybody that’s been in an old butcher shop has seen that massive worn out chopping block and how much wood is missing from this thing.. (the psychology factor..) I don’t know how much of that stemmed from local lore or misguided bias toward that particular butcher shop but it sure made a lasting impression on little me. I try not to think about it when I’m at the grill with a stack of wieners.. Grill’ em until crisp and enjoy with your favorite topping and please, please put away that pocky digital temperature thingy you just wielded out of your pocket.

Intermezzo finito, I’ll go back to my corner now.. :whistle:

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