engine light on and off

joepua · July 03, 2009, 03:38:54 PM

Hey guys, looking for some help on this issue...

I decided to take my '04 GS500F out for a spin on some tougher twisties today and was avging about 7-9k RPM through them. I usually ride between 4-6k RPM.
Anyways,

Half way through, my engine light comes on, but it doesnt stay on, it comes on and off randomly. I check the engine oil, it is a little low, I top it off temporary, but the engine light still goes on and off. I had no choice but to ride it home, after about 30 min, it stays off. My buddy says it might be a faulty oil pressure sensor, or wiring coming loose.

Can anyone help me out with this? I'd like to troubleshoot this, but I dont know where to start. Maybe I should check the pressure sensor? Im not sure where that is on the '04.

Bridger · July 03, 2009, 06:22:34 PM

It's not a pressure sensor. It's a pressure switch. When ur oil pressure drops below a certain amount it switches the circuit closed and the light comes on. I would see if it is expensive to replace the switch and see what happens when you do if it's fairly cheap. If the switch isnt faulty then ur screwed and will need a rebuild. A loose/bad connection is probably an unlikely cause IMHO. Oil pressure "idiot lights" don't come on until oil pressure is super low, although I'm not sure of the exact value on a GS. In my experience, once the light comes on your motor is toast. I would not ride your bike at all until you either buy and test a new switch unit OR take the bike to a mechanic and have him test the oil pressure. Best of luck to you and hopefully it's just a bad switch!

joepua · July 03, 2009, 09:00:16 PM

If it was an oil pressure issue, than wouldn't of my motor of been toast within a few minutes of riding? It took me an hour and half after the light started going on and off to get home.

Is #28 on this diagram the pressure switch?

http://www.bikebandit.com/showschematic/m6061sch503046

jeremy_nash · July 03, 2009, 09:31:41 PM

that would be it, on a related note, I used to have the same problem, I could unhook the wire from the switch, and it would stay lit, so obviously the switch wasn't my problem, you may want to check that.

bill14224 · July 03, 2009, 09:48:59 PM

A bad connection would stop the light from coming on. Since it is coming on, your connections are good. Since you didn't blow the engine up after all that riding, it's a safe bet your oil pump is working. I would guess you either need a new oil pressure switch or you're using the wrong oil. I've heard of this happening to people who use too thin oil looking for more power, only to not have enough oil pressure at times.

If you pay attention to the sound of the engine you can hear low oil pressure and it will make you reach for the key or kill switch quickly. The top end will get noisy like it's very low on oil. Worn bearings can cause low oil pressure, but a 2004?

joepua · July 03, 2009, 10:32:50 PM

Ya, the bikes only got 8300km on it.

The reason I am having hard time pin pointing the problem is because the engine doesn't sound any different than before.
I used Motul 5100 semi-synthetic, pretty standard engine oil for bikes?

I am not sure what you mean by "top end will get noisy", if I am around the 7-9k RPM range, the engine is screaming @ me, but I only do that on stretches of twisties, isnt that normal?

It looks like #28 is bolted in on the ride side of the engine, I am not sure if it is useful for me to take that out, or what I am going to see when I unscrew it.

I am currently in the process of doing an oil change.

joepua · July 03, 2009, 10:58:21 PM

Quote from: jeremy_nash on July 03, 2009, 09:31:41 PM
that would be it, on a related note, I used to have the same problem, I could unhook the wire from the switch, and it would stay lit, so obviously the switch wasn't my problem, you may want to check that.

So in the end was it a oil pressure problem?

joepua · July 04, 2009, 06:23:54 AM

Helppppppp is there anything I can do now that the oil is all out..

Chanse · July 04, 2009, 11:05:42 AM

partially plugged oil journals? build up in oil passages?

joepua · July 04, 2009, 12:40:25 PM

I won't be able to check those without taking the engine apart right?

Is there any point on unscrewing the pressure switch and having a look?

simoniz · July 04, 2009, 08:17:12 PM

Could be a build up of gunk and stuff in the pressure switch on the engine itself - while the oil is drained, take it out and clean it. That should fix it. I had a Yamaha FZR1000 that kept doing that, and it was a bad switch.

sledge · July 05, 2009, 08:49:31 AM

There will a bubble of air trapped in the gallery behind the switch. Remove the switch, let it bleed oil for a few secs then refit the switch and see what happens.

joepua · July 05, 2009, 09:12:40 AM

So unscrew #28 on the diagram and clean it out?

http://www.bikebandit.com/showschematic/m6061sch503046

There isn't anything wrong riding at 7-9rpm is there? it's not for long stretches...

mister · July 05, 2009, 07:42:15 PM

Call a local Suzuki dealership and ask them what kind of oil they use on GS500s when they replace the oil. Then get yourself some of that.

Guy I work with does all his own work. Noticed that on longer riders at prolonged higher speeds - not shorter commuting rides - he started getting what he described as a tappet noise. He dreaded needing major work. Chatted with a mechanic who asked what oil he used. When he told him Synthetic the mech told him to NOT use synthetic cause it was getting too thin at the higher temperature of the prolonged highspeed rides. He replaced with a semi-synth to test and the problem vanished - or was at least hidden. Don't know if he changed to a different thickness of oil or any of those issues, but it's something to consider.

Michael

natedawg120 · July 06, 2009, 05:36:31 AM

the book recommends 20w40 If i am not mistaken for the GS. I used full synthetic for the 10+k i had my GS with no problems at all. No noise other than the occasional tap tap from the cam play. I would do as people are saying and remove and clean crap off the switch or just replace it if it doesn't cost that much.

Dr.Sparkie · July 06, 2009, 09:33:48 AM

You'll know if your oil pressure was dropping out while cruising if your old oil is full of metallic sparkles.
If not, presume it's the switch and get a new one.

Porkchop · July 06, 2009, 10:53:04 AM

Quotethe book recommends 20w40 If i am not mistaken for the GS.

My book says 10w40. I'm sure 20w40 will work too.

-Porkchop

natedawg120 · July 06, 2009, 12:32:05 PM

Quote from: Porkchop on July 06, 2009, 10:53:04 AM
Quotethe book recommends 20w40 If i am not mistaken for the GS.

My book says 10w40. I'm sure 20w40 will work too.

-Porkchop

Actually i believe you are right. Cause i didn't have to buy but 2 quarts of synthetic for my last GSXR oil change cause i had an extra couple laying around and 10w40 is what my GSXR takes. So +1 for PC.

JB848 · July 07, 2009, 10:03:52 AM

Did we ever resolve what is wrong with his bike? I am curious to what the fix was. I've always wanted to use synthetic oil but reading things here it is a NO NO and I would assume that the OIL cleaning additives would also be classified as NO NO's?

joepua · July 09, 2009, 05:20:11 PM

My impression is that it was a combination of hot engine (reving high for a period of time) and plus the engine oil said it was at the low mark.

I may be wrong, but I've since changed the oil (I use Motul 5100)... The light has not come on. From what I hear around, if it was indeed my oil pressure, than my motor would have broken already on my 1hr ride back.

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engine light on and off