Author Topic: Temperature light flickering (Read 59193 times)

Inge K. · « **Reply #50 on:** February 22, 2015, 07:22:09 PM »

That shouldn't make any difference.

Inge K. · « **Reply #51 on:** February 22, 2015, 07:31:05 PM »

Scott did have the idea that maybe a override switch could have been installed by a PO.
Does the fan run with the relay disconnected?

SeanK75 · « **Reply #52 on:** February 22, 2015, 07:33:30 PM »

It only runs with the relay on. I also think the fuel pump comes on at the same time. Before I start it.

Inge K. · « **Reply #53 on:** February 22, 2015, 07:36:36 PM »

Quote from: SeanK75 on February 22, 2015, 07:33:30 PM

I also think the fuel pump comes on at the same time. Before I start it.

That also isn't normal, the fuel pump should start to run when the starter button is pressed.
Does the wiring under the tank looks modified?

The fuel pump is powered from the FI relay which is managed by the ignition ECU which grounds
the relay coil.
It happens that this function in the ignition ECU goes haywire, instead of buying a new ignition ECU
owners/backyard workshop permanently grounds the relay coil...and the pump runs as long the
ignition is switched on......then it's a safety function that doesn't work anymore.

SeanK75 · « **Reply #54 on:** February 22, 2015, 07:47:30 PM »

15 on the relay is getting constant power on ignition. The relay is supposed to do the switching but I'm getting power from A2 from the relay when it's plugged in so is the relay bad maybe? Any way to test?

SeanK75 · « **Reply #55 on:** February 22, 2015, 07:54:46 PM »

I tested it by pulling the fan lead out of the relay harness and sticking my power tester in its place with the ignition on. Seems like the fan is getting a signal directly from the relay.

Inge K. · « **Reply #56 on:** February 22, 2015, 08:04:05 PM »

That you have power on 15 when the ignition is switched on is normal. But the relay shouldn't close the
contacts so you get power out on A2.

So far in the testing I would also say that the problem must be internal in the relay, but you did mention
earlier in the thread that you have tested with swapping with a known good one...and fan did still run :dunno

SeanK75 · « **Reply #57 on:** February 22, 2015, 08:22:28 PM »

I'm getting constant power, from the green and white wires going to my fuel pump, on ignition as well.

Inge K. · « **Reply #58 on:** February 22, 2015, 08:33:35 PM »

Try to remove fuse #6, and check if you still have power in the connector.

SeanK75 · « **Reply #59 on:** February 22, 2015, 08:34:56 PM »

I also noticed this on the fuses. There's a loop connecting fuses 6 and 7 together which seems strange to me because one fuse is 7.5 and the other is 15. Is this normal? Seems to me this is why the 7.5 fuse keeps blowing. Also of note, when I remove the loop I get no power to fan or green fuel pump wire. Thoughts?

Inge K. · « **Reply #60 on:** February 22, 2015, 08:42:49 PM »

That is non factory, and can explain some of the problems...........I must study the wiring diagrams.

SeanK75 · « **Reply #61 on:** February 22, 2015, 08:47:10 PM »

Finally! It really makes a lot of sense. I'm just worried that the previous owner did that to fix another problem. I didn't see that on the wiring diagram. I'll have to Put it all back together and see how it works. Any idea why that would prevent it from starting? Or what kind of damage having those two fuse circuit joined would do?

Inge K. · « **Reply #62 on:** February 22, 2015, 09:00:08 PM »

That is the reason to your fuel pump does run as long the ignition is switched on, it could have been done
for the same reason as described in post #53.

The same circuit also supplies the the electronic parts in the fan relay with Power, which should only be
powered when the engine is running......but I guess the difference would only be that the fan now runs as
long the engine is running.

Scott_ · « **Reply #63 on:** February 22, 2015, 09:04:42 PM »

Inge, as I haven't had my hands on a K75 I'm a little confused with this one. According to my schematics and by the terminals you all are discussing the fan controller is a 6pin relay with some internal electronics.(I've got no reference for the relay electronic internals other than the fan contacts).
If this is so, could the electronics within the relay be bad.

Inge K. · « **Reply #64 on:** February 22, 2015, 09:11:37 PM »

As said in post #56 I would have guessed a problem internal in the relay, if it haven't earlier been
swapped with a known good one....and same problem.

Scott_ · « **Reply #65 on:** February 22, 2015, 09:14:16 PM »

Quote from: Inge K. on February 22, 2015, 09:11:37 PM

As said in post #56 I would have guessed a problem internal in the relay, if it haven't earlier been
swapped with a known good one....and same problem.

Ok that explains it, I missed that he swapped it with a known good one.

SeanK75 · « **Reply #66 on:** February 22, 2015, 09:23:45 PM »

A picture is being painted. I think you're on to something with the wire being a band aid fix. I'm going to put it back together and try with a different relay. I'd rather buy a new ecu or relay than spend 7 hours chasing a phantom short! Thanks again for your help guys I wouldn't be at this point without your help! I won't get to it for a while as I had to sacrifice a rad hose to remove it. I'll be waiting for parts and troubleshooting again in a week or two. I'll keep you guys posted.

Thanks again,

Sean

Inge K. · « **Reply #67 on:** February 22, 2015, 09:28:30 PM »

Good Luck :2thumbup: .

SeanK75 · « **Reply #68 on:** February 22, 2015, 09:36:35 PM »

Any idea on price of a new ecu and/or relay?

Scott_ · « **Reply #69 on:** February 22, 2015, 10:01:23 PM »

With the jumper removed and everything back in place, does it start?
Fuel pump running with the starter button?
Headlight drop out with the starter button?

I'm guessing something else is bad somewhere else they wouldn't have put that jumper in.

A relay will be much cheaper than an ECU, but I'm guessing that a bike breaker would be your most economical place to look. Not sure that an ECU would be available from BMW.
There is always flea-bay as well, equally as risky as a breaker in not getting a bad one.

SeanK75 · « **Reply #70 on:** February 22, 2015, 11:05:55 PM »

Didn't have time to put the radiator back together and put the fuel tank on. When I removed the jumper the fan power didn't go on with the ignition and green wire didn't show power to the fuel pump anymore so that should solve both of those mysteries. I'm hoping my local shop still has the other K75 kicking around so I can swap some parts out, relays, ecu etc. and see what the issue(s) are. I might try and go out there on Saturday next weekend. I'll let you guys know how it goes. Can't thank you guys enough for the help. I bought the bike a couple years ago and was constantly switching blown fuses and worrying about my bike on trips. I ride with 4 other friends and the last trip we did my clutch boot and fuel filter went at different times! It's nice to finally be close to having a solution on this, I feel like my bike will be finally be reliable soon and I wont have to be the guy who always breaks down anymore :clap:
Luckily I've always been able to fix it and make it home!

Inge K. · « **Reply #71 on:** February 22, 2015, 11:19:57 PM »

Congrats! :riding: ..but as earlier mentioned, I would guess that the fan will run as long the engine is running.

It's also this jumper that have caused the blowing fuses so that is also history.
I would guess the jumper is placed there because of a nonfunctional FI relay, but this can be investigated
when it's possible to touch the starter button........BTW, is the FI relay present in the relay box?

SeanK75 · « **Reply #72 on:** February 23, 2015, 12:16:43 AM »

I'll take a look for the FI relay. It looked pretty packed in there, didn't notice anything missing. I'll let you know when I take a look. Good point about checking the starter switch. I wish I would have checked before I left. Bike is in a friend's garage. Any idea what the green and white wires are for going into the fuel tank? I think green Is for the pump but not sure about white.

Inge K. · « **Reply #73 on:** February 23, 2015, 12:30:33 AM »

About the fuel tank connector, green is power to the fuel pump, white is signal for the low level warning lamp,
yellow is for the gauge (if fitted) and the brown is ground.

About the FI relay, in the front right corner of the relay box you have four relays if you have ABS brakes.
The front left of these four is the FI relay, if you don't have ABS the rear left socket is empty.

SeanK75 · « **Reply #74 on:** February 23, 2015, 09:28:26 AM »

With the tank and rad off I won't be able to start it, but I'd like to test the starter button to see if that green wire gets power when The starter is pushed. Is it safe to try that? Is there a safe way to try that as is?

Also, I think there's a small square black relay in the front left of the relay compartment. Do you have a diagram for the connectors?

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Author Topic: Temperature light flickering (Read 59193 times)