Author Topic: Temperature light flickering (Read 59156 times)

Inge K. · « **Reply #75 on:** February 23, 2015, 05:49:56 PM »

When looking back on the picture of the relay box it seems like you have a pre -94 model,
then what I did say about the relays in post #73 isn't valid.

And the FI relay must be present for the function even when the current comes in through the back door.
And then as you say the FI relay is in the front left corner, ....is the output marked 87/87 or 87/87b ?

About testing the relay you can just disconnect the signal connector at the starter relay so the engine don't
turn.....but on the other hand it could be that it need to be turning before the relay gets a signal.
If you try, just do some short pushes on the starter button....don't keep it pushed for longer periods.

About the relay connectors: 86 coil signal, 85 coil ground, 30 input contact, 87 output contact.

SeanK75 · « **Reply #76 on:** February 23, 2015, 09:12:41 PM »

I'll take a better pic of the relay box. I did remove a couple relays to wrestle the fuses out of the box so it may not look right in that picture. I tried the starter and the fuel pump is getting power on starter without the jumper. Jetonic cpu is still unplugged though. Not sure if that matters.

Inge K. · « **Reply #77 on:** February 23, 2015, 09:21:51 PM »

A new picture isn't necessary, could see that the horn and LSR relay was of the older type.
If the fuel pump now gets power, I wonder why the PO have placed the jumper there in the first place.

SeanK75 · « **Reply #78 on:** February 23, 2015, 09:39:59 PM »

I'm not sure. Although I should mention that when I had it in the shop last summer my mechanic pulled one of the fuses (6 or 7 I can't recall) and the bike started up with no fan. We thought we had solved the problem for the time being as I was heading on a trip the next day. Half hour into the trip the bike cut out and I pulled over and popped the missing fuse back in and everything worked again. My guess would be that the fuel pump was getting intermittent power and that was the bandaid solution. Do you think it's a short or a computer related problem?

Inge K. · « **Reply #79 on:** February 23, 2015, 09:49:47 PM »

I have no idea what the problem is, too few clues, only way to find out is to start measuring when the
problem is present.

But I would guess what I have suspected earlier that you have a intermittent ground connection at the
FI relay coil in the ignition ECU.

What you can do is to connect a temporary wire at the relay 85 terminal, the other end you just lay in
the tool tray under the seat (unless you have a low seat model).
Next time the bike stops you ground the wire, if it then starts.....you need a new/used ignition ECU.

Inge K. · « **Reply #80 on:** February 23, 2015, 10:10:52 PM »

Do you have the last seven digits of your VIN number easily accessible, then we can find out how old it really is.

SeanK75 · « **Reply #81 on:** February 23, 2015, 11:19:29 PM »

Vin number is: WB1056207R0255367

I've emailed the PO to see if he know about it. He was the second owner so who knows.

Inge K. · « **Reply #82 on:** February 23, 2015, 11:30:04 PM »

Then it's produced in May -94....so it is a -94.
You did write K75S in the first post, so I did guess that was correct...............
the layout on the electrics was changed on different times on different models.

Inge K. · « **Reply #83 on:** February 23, 2015, 11:49:44 PM »

Text have been added to post #79.

SeanK75 · « **Reply #84 on:** February 24, 2015, 12:11:43 AM »

What exactly does that do?

Inge K. · « **Reply #85 on:** February 24, 2015, 12:17:34 AM »

If the ground connection at the FI relay coil is lost the fuel pump stops and FI system shuts down.

This is also described in post #53....and I suspect that the jumper between fuse 6 & 7 was placed
there to mask the the intermittent ground connection at the relay coil.

SeanK75 · « **Reply #86 on:** February 24, 2015, 12:23:37 AM »

Ok I'll take a look on Wednesday when I'm working on it again. I'll keep you posted.

SeanK75 · « **Reply #87 on:** February 24, 2015, 12:54:13 PM »

So just to clarify, do you suspect it's the FI relay or the ecu? Or it will be one of those things if the fuel pump fails again and the ground wire from 85 works. Could the ground wire from 85 be a solution or would it send power to the fuel pump again with the ignition again?

SeanK75 · « **Reply #88 on:** February 24, 2015, 02:36:51 PM »

So I got the story from his mechanic when I called around with the Vin#. The bike had been sitting for a number of years and it wouldnt start so they tried to jumpstart the bike and they think it may have messed up the fuel computer. Jumping the fuses was a much cheaper alternative. I've replaced the relays just to be safe and I'll probably be looking for a new cpu. Does this add up to you? I don't want to use a wait and see approach and get left stranded on a trip. Is there any way to test an fuel cpu?

Inge K. · « **Reply #89 on:** February 24, 2015, 05:47:34 PM »

It have been the ignition ECU (behind the headstock) which is the suspected part.
The jumper between fuse 6 & 7 have only masked the problem.
By using the temporary wire to ground the FI relay when the problem occurs, was to verify the real problem.

When you turn on the ignition the FI relay (which powers the fuel pump +++) coil gets gets power but it isn't
grounded.
When you push the starter button the ignition ECU gets a signal and grounds the FI relay coil and the fuel
pump starts.....and continue to run as long as the ignition ECU receives signal from the hall sensor that the
engine is turning.
Time to time the ignition ECU's goes haywire and this grounding function for the FI relay coil becoming intermittent.

By connecting the jumper between the fuses the fuel pump +++ still would receive power even when the
FI relay didn't function, but it would be to much load for the one fuse after some time.
By temporary grounding the relay coil when the problem occurs, you would verify that this is the problem.

SeanK75 · « **Reply #90 on:** February 24, 2015, 08:17:40 PM »

Ok! Put everything back together and tried to start it and still no luck. The fuel pump is getting power on startup. The fan runs only for a second or two after I let off the starter, but NOT while I'm trying to start it. I even tried hooking up 85 to ground and it worked as you said And The fan also comes on with it Hooked up like that, but the fan is on with the ignition Turned on, not after. So it must be getting fuel. what's next? Could it be the ignition system?

SeanK75 · « **Reply #91 on:** February 24, 2015, 08:37:40 PM »

Ok I pulled a plug and it was bone dry and getting spark. I disconnected the fan and tried to listen for the fuel pump. I can't say I heard it. I wonder if it's not working. It's been replaced about 10000k ago and I did the filter last summer. It looks clean and bike hasn't been sitting too long since it was replaced.

Inge K. · « **Reply #92 on:** February 24, 2015, 08:44:42 PM »

If you just touch the starter button you should hear the fuel pump running ~1,5 sec after you have released the button.

SeanK75 · « **Reply #93 on:** February 24, 2015, 08:48:53 PM »

Does it matter if the fan is plugged in? I unplugged it to hear better. I also removed this full line to see if the if there was any fuel gking to the injectors and it was bone dry. No pressure, no fuel.

Inge K. · « **Reply #94 on:** February 24, 2015, 08:52:51 PM »

The fan you don't need since the engine don't run anyway.
I would guess that the pump haven't been running, and if it does the next step would be to disconnect the filter.

SeanK75 · « **Reply #95 on:** February 24, 2015, 08:55:05 PM »

Yeah its getting power and I see my tester light on for about 1.5 seconds after I hit the button. Definitely not hearing the fuel pump. I have to laugh. It seems I am battling this war on two fronts. Tomorrow I'll take the tank assembly apart and see what's happening there. Looks like I could be in the market for an ECU AND a fuel pump. Talk about a tough week! :dunno

Inge K. · « **Reply #96 on:** February 24, 2015, 09:02:53 PM »

Much gunk inside the tank? Is the prefilter under the pump OK? if the answer is yes and no, you can try to
reverse the pump for a short period ...10-15 sec.

Where did you measure for power to the pump?

SeanK75 · « **Reply #97 on:** February 24, 2015, 09:28:33 PM »

Tank is clean. Pre filter was changed within 5000 k, less than 6 months ago. I'm gking to pull it all apart and see if the lines or filter are plugged and if the pump spins. Also check the power to the pump inside the tank as well.

I'm testing the green wire at the harness before it goes into the tank.

Any reason to believe these two issues could be related? Would that fuse setup put any extra wear on the parts inside the tank? Like I said, the filter was clogged and replaced not less than 6 months ago.

Inge K. · « **Reply #98 on:** February 24, 2015, 09:46:09 PM »

Easiest and most reliable metod I think would be to remove the pump and test it outside of the tank.
But if you run it dry, do it only for a few seconds to test..............

I don't think these issues is related.

SeanK75 · « **Reply #99 on:** February 24, 2015, 10:02:33 PM »

Ok I'll access the fuel tank issues tomorrow.

To put my mind at ease with the ECU, theres no way the Jetronic CPU directly interacts with the pump, correct? So it must be a faulty ECU? I will confirm by grounding 85 as you advised When/if the pump cuts out.

My mechanic says the ECU's rarely go bad, but he's seen a few Jetronic CPU's go bad. I just want to try and eliminate the possibility that it's the CPU.

Also, it sounded like the PO trying to jump start the bike caused some damage related to the fuel pump circuit which caused him to resort to jumping the fuse. So it's likely that it's the ECU that's messed up, not the Jet CPU. In your opinion does that sound about right?

Thanks Inge.

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Author Topic: Temperature light flickering (Read 59156 times)