Oil light on again:

[tmcafe]

Riding today around town as I was approaching a traffic light I suddenly noticed the oil light came on. I stopped the engine right there and pushed the bike into a parking lot. Temp gauge showed 120 C A (today was in the mid-hi 90s here).

 

Later in the evening I went back to the bike and dropped the sump. Sure enough all appeared kosher, filter rock solid screwed in, nothing in oil nor mesh filter, pipes okay. WTF? I had similar stuff happen last summer. Anyway, I started the engine and the red light lasted just one sec after starting. Rode bike home no oil light anymore.

 

The only pattern I see is that the light has only come on while the engine was hot. Pump is pretty much ruled out as far as experts say. All I can think of is bad pressure sensor, though I don t know what it has to do with oil/engine higher temp. Theres been at least one more topic here about the light coming on when the engine was hot.

 

Any suggestions appreciated.

[pete roper]

Throw a switch at it beacause they're dirt cheap and dead easy. Stick a pressure gauge on it and check the presure when hot. If it's low disassemble and clean the OPRV and check its crack pressure. If it's still low after all that it has to be the pump really.

 

Pete

[antonio carroccio]

Get to check the oil carter and the filter too. This has to be fixed very hard.

I don't know in the USA but here in Europe the oil filter costs around 10,- Euro. Not that much thus.

You can change it for a better pression.

I could not understand if Pete says to you to check also the pressure valve.

[pasotibbs]

Riding today around town as I was approaching a traffic light I suddenly noticed the oil light came on. I stopped the engine right there and pushed the bike into a parking lot. Temp gauge showed 120 C A (today was in the mid-hi 90s here).

 

Later in the evening I went back to the bike and dropped the sump. Sure enough all appeared kosher, filter rock solid screwed in, nothing in oil nor mesh filter, pipes okay. WTF? I had similar stuff happen last summer. Anyway, I started the engine and the red light lasted just one sec after starting. Rode bike home no oil light anymore.

 

The only pattern I see is that the light has only come on while the engine was hot. Pump is pretty much ruled out as far as experts say. All I can think of is bad pressure sensor, though I don t know what it has to do with oil/engine higher temp. Theres been at least one more topic here about the light coming on when the engine was hot.

 

Any suggestions appreciated.

If you've ridden in heavy rain the oil pressure sensor probably has water in it (my V11,Paso, mates 850 Lemans and another mates 900SS have all done this) swap it out as Pete suggests.

[Admin Jaap]

If you've ridden in heavy rain the oil pressure sensor probably has water in it (my V11,Paso, mates 850 Lemans and another mates 900SS have all done this) swap it out as Pete suggests.

 

The tube connector to the sensor could be wet too. I found out in heavy rain coming back from the GMG 2006. After cleaning/drying it no more problems. Didn't need to exchange the sensor.

[GuzziMoto]

The relationship to engine temp could be that as the engine gets hotter the oil pressure goes down. The oil pressure may only hit the point where the sensor falsely turns on the oil light when the motor is really hot. the rest of the time the pressure is above that point. The sensor may be working but not correctly. I would replace it. I like the gauge idea.

[pete roper]

The relationship to engine temp could be that as the engine gets hotter the oil pressure goes down. The oil pressure may only hit the point where the sensor falsely turns on the oil light when the motor is really hot. the rest of the time the pressure is above that point. The sensor may be working but not correctly. I would replace it. I like the gauge idea.

 

Problem is the switch operates at about 2psi! If its working properly and oil pressure is getting that low there are major engine problems.

 

Pete

[luhbo]

Riding today around town as I was approaching a traffic light I suddenly noticed the oil light came on....snip... Temp gauge showed 120 C A (today was in the mid-hi 90s here). ...

 

Under conditions as you've described them above mine shows the same symptoms. 120°C oil temperature is hot. My engine tends to idle very low at such temperatures, your's probably does the same.

I like to ignore the oil light under these conditions either or eventually hold the idle rpm a bit higher, especially while approaching a stop. Next time grab together all the balls you have and rise the rpm a bit, 1500 will do already. I'm sure the light will go off.

 

Hubert

[Guest ratchethack]

Riding today around town as I was approaching a traffic light I suddenly noticed the oil light came on. I stopped the engine right there and pushed the bike into a parking lot. Temp gauge showed 120 C A (today was in the mid-hi 90s here).

TMC, congrat's on not continuing to ride with the light on! It's always amazing to me the number of catastrophic engine failure stories that start with, "But I was only XX miles from home, and only rode it X miles with the light on. . ."

 

You didn't indicate if blipping the throttle/raising the idle RPM would cause the light to go out, nor at what RPM idle is set. I assume you tried this, and idle is ~1200 RPM? At full operating temp, my oil press light will "just start" to glow much lower than this.

 

Riding with a goup one day, I observed the same scenario as yours on a friend's 2000 Guzzi Sport as we started up, preparing to hit the road from a parking lot. Blipping the throttle didn't make it go out. My first thought was bad oil pressure sensor, but he also did the wise thing. He didn't ride it, went for a trailer, and towed it to a local Guzzi shop, where it was discovered that the pressure relief valve had stuck open. Clearing the bore of the PRV cured it, and no prob since.

 

PRV jams tend to be "permanent" until freed up, but have occasionally been known to be intermittent. Just a thought. Good luck.

[Tom M]

Using good oil makes a difference here too. You are using a full synthetic 20w-50, right?

 

I had a car that started showing it's oil light at idle on hot days, but oil pressure was more than adequate everywhere above idle. After much mechanical mucking about didn't fix it I switched from 10w-30 dino to 15w-40 full synthetic and I never saw the oil light again.

[Greg Field]

TMC, congrat's on not continuing to ride with the light on! It's always amazing to me the number of catastrophic engine failure stories that start with, "But I was only XX miles from home, and only rode it X miles with the light on. . ." <_>

 

You didn't indicate if blipping the throttle/raising the idle RPM would cause the light to go out, nor at what RPM idle is set. I assume you tried this, and idle is ~1200 RPM? At full operating temp, my oil press light will "just start" to glow much lower than this.

 

Riding with a goup one day, I observed the same scenario as yours on a friend's 2000 Guzzi Sport as we started up, preparing to hit the road from a parking lot. Blipping the throttle didn't make it go out. My first thought was bad oil pressure sensor, but he also did the wise thing. He didn't ride it, went for a trailer, and towed it to a local Guzzi shop, where it was discovered that the pressure relief valve had stuck open. Clearing the bore of the PRV cured it, and no prob since.

 

PRV jams tend to be "permanent" until freed up, but have occasionally been known to be intermittent. Just a thought. Good luck.

 

 

Ratch: I have this nifty mechanical gauge that can be plugged in place of the sender for short- to mid-term use. In the interest of science, would you be willing to plug it in and just see what your fully-hot pressure is at your 1200-rpm idle and just a bit lower? It's be easier to install while cold, and you could zip-tie itin place and then see what your cold pressures are, too.

 

TM: You are, of course, free to use it, too.

[Guest ratchethack]

Ratch: I have this nifty mechanical gauge that can be plugged in place of the sender for short- to mid-term use. In the interest of science, would you be willing to plug it in and just see what your fully-hot pressure is at your 1200-rpm idle and just a bit lower? It's be easier to install while cold, and you could zip-tie itin place and then see what your cold pressures are, too.

 

TM: You are, of course, free to use it, too.

I'd be willing enough to give it a shot, Greg. I b'lieve I've got a proper gauge and all the correct fittings to plumb in my own for "experimental" reads. To be honest, though I've done this with many auto's for many decades, I haven't been all that motivated to do it with the Guzzi, since (with notable exceptions) I've tried to stick with the KISS principle WRT hanging stuff on the Sport, and I've been pretty confident in the OE setup.

 

IIRC, John Mickowski (and maybe others?) did the equivalent of this with his own nifty kit, and reported on it in some detail here a few years back?

 

If I happen to get the time lined up with the appearance of the elusive ROUND TUIT this weekend -- hey, it COULD HAPPEN! -- I'll give 'er a go, and will advise.

 

EDIT: FWIW -- Here's John M's mighty nifty setup:

 

http://www.motratech.com/Motratech/MGPG10.html

[Greg Field]

OK, if you have the stuff, I'd be interested in hearing what your pressures are. I have a permanent gauge on my bike, too, with an electronic sender. The device I was talking about lending out is a guage hooked up to an adapter that I use to check pressure on rebuilt engines.

[tmcafe]

Thanks everybody for the helpful comments.

 

One more Q: does removing the oil pressure sensor (even just to check/clean the connecting tube) involve removing the tank? It looks like it takes a 21 mm wrench which I happen to have, but I'd be so happy if I didn't have to remove the tank again. Also if the sensor is easy to remove I'd be glad to check the pressure with the gauge from Greg. I may install a pressure gauge anyway as that idiot light is too little too late.

 

So far bike has been running great. Yesterday I put about 200 mi on it. Oil temp was around 90 C, but I was shocked to see earlier in the day 120 C after only a couple miles around town from cold! Yes it was hot ouside but still... Oil is Mobil 1 racing 10w 40, will replace with Elf 10w 50 full syn SG which I got a while ago.

[Guest ratchethack]

One more Q: does removing the oil pressure sensor (even just to check/clean the connecting tube) involve removing the tank? It looks like it takes a 21 mm wrench which I happen to have, but I'd be so happy if I didn't have to remove the tank again. Also if the sensor is easy to remove I'd be glad to check the pressure with the gauge from Greg. I may install a pressure gauge anyway as that idiot light is too little too late.

TMC, it looks like you've correctly ID'd the OP sensor. It's 21 mm. No need to remove the tank. Unplug the sensor wire and spin it off. Once you have the sensor out, you can BRIEFLY check for oil pressure by taking out the spark plugs and spinning the motor with no compression. Unless you have a rag over the hole, with normal operation of the oil pump and PRV, you'll have a small geyser. At that point, a small (but significant!) celebration may be appropriate.