Gen 1 - CHEC + High Temp

[DDT]

Hi All,

I am having quite the adventure getting my '99 back on the road.

A little history. I have had it a long time (1999). I used to ride it but then due to work / family it just sat in the garage.

About 6 or 7 years ago (maybe 8 or 9?) the fuel tank lines developed a leak and the fuel (of course in the middle of the night) was running all over garage floor. I qucily unhooked tank and drained it. There it sat for the last many years. Mileage is under 8000.

I decided to get the old girl running due to changes in life. Well, first new fuel lines. Great. Then the petcock and fuel sender gaskets leaked. The bike wouldn't start because of gummed up injectors. So long story short.. everything in the fuel injection is new (o-rings, pump, filters, professionally cleaned/flowed injectors).

Finally she started and runs. It is snowing so she hasnt been a test drive.

But she has a very strange problem.

The temp gauge goes down after ignition on, but then goes back up to "H" (i know sitting in a 30 something degree garage it is not "H"). The chec light is on. I cannot put it into dealer mode by jumping the connector. I cannot get the temp gauge being near max and chec on. But even with these conditions it starts and seems to run well.

And yes the run switch is in run (the engine is running with these errors). So these are not preventing from starting / running.

I have jumped side stand switch. No change.

I have ordered some variable resistors to send known resistance into ECU.

Voltage to ECT is right at 5V (so right in middle of 4.5 to 5.5V)

ECT resistance seems a little off. Showing 1.8kOhm when it is "cold" but dont know exact temp as engine was on some but it is by no means hot or or really warm. May test again tomorrow with a known [cold] temp. But 1.8kohm is not in the 0.142kohm range for 110C that it seems it would be showing "H".

I am completely baffled. Any ideas how to trouble shoot the temp gauge on H plus chec?

 

[SSGT_B]

Unplug the back of the gauges, plug them back in. See if your problem goes away

 

[Mr Brown]

Chec is normal for key on, not started iirc. Does the temp gauge go to the normal place once it's running?
If you can't put it in dealer mode by jumping the plug you're not doing it right, that's how it has to be done.
Again iirc you have to pull the clutch in or bypass the clutch safety switch even if it's in neutral, it's a Suzuki quirk.

 

[DDT]

Unplug the back of the gauges, plug them back in. See if your problem goes away

Will try this. Makes sense as the ECU seems to be getting correct signals because the engine is running and seems to run fine.

Most of the instrument cluster works (tach, fuel gauge, neutral light) but it could be that the signal for the temp gauge is not working. I will try with resistors to see if the values change (waiting in resistors to come in).

In the mean time, I will take more apart and try plug/unplug. It is worth a try.

 

[DDT]

Chec is normal for key on, not started iirc. Does the temp gauge go to the normal place once it's running?
If you can't put it in dealer mode by jumping the plug you're not doing it right, that's how it has to be done.
Again iirc you have to pull the clutch in or bypass the clutch safety switch even if it's in neutral, it's a Suzuki quirk.

Nope. CHEC stays on and temp at H when running.

I think from what I can tell if CHEC stays on, that is the first error code and cant go into dealer mode.

Trying to figure out why it wont go into dealer mode with CHEC on.

But bike runs. It is not an issue with the kill switch / side stand switch.

 

[Mr Brown]

Have you burped the cooling system?

 

[DDT]

Have you burped the cooling system?

Yes. new coolant also.

But ECT, when starting from cold (mid 30s F), should show cold even if there was an air pocket. ECT sensor was measured at 1.8kOhm so that does not match “H” on gauge

 

[Mr Brown]

So you're thinking it's a fault in the gauge itself? If the CHEC is a function of the needle being at the H end of the sweep, then a faulty gauge would make sense.

 

[DDT]

So you're thinking it's a fault in the gauge itself? If the CHEC is a function of the needle being at the H end of the sweep, then a faulty gauge would make sense.

Until I get resistors for troubleshooting, that is what I am thinking.

I don’t live in a high humidity area, bike while out of service sat in garage the entire time (dry) so electronics normally don’t just go bad.

but the factory manual suggests “replace cluster” if id there is voltage to ECT and resistors don’t show correct temp.

The hard part is finding a 220mph speedo that looks new...

 

[SSGT_B]

Did you try unplugging it and plugging back in? I’ve had that issue before and this fixed mine. The only time I had a similar issue was because I had a flash tool plugged in and tried to ride the bike

 

[DDT]

Did you try unplugging it and plugging back in? I’ve had that issue before and this fixed mine. The only time I had a similar issue was because I had a flash tool plugged in and tried to ride the bike

That is first plan this week. Just have to take more apart to do that and haven’t had time yet.

Good news is snowing and snow on ground so I have some time...

 

[DDT]

Did you try unplugging it and plugging back in? I’ve had that issue before and this fixed mine. The only time I had a similar issue was because I had a flash tool plugged in and tried to ride the bike

Tried that. Didnt help.

Also unplg/plug ECU.

Didnt help

Removed PC. Didnt help.

But luck seems on my side. Today Ebay HAD a 220mph speed off same year that was in nice condition. Hopefully it works when it arrives. For the price, I couldnt let it go knowing it could be a bad instrument cluster.

At worst, I have a back 220mph speedo.

I will keep troubleshooting.

But bike so far seems to run nicely.

 

[DDT]

Mystery Solved.
Got a new (used) instrument cluster. Did not help.
So (probably should have done this earlier) I decided to go check continuity between the pins in the ECU and gauge cluster.
Unplugged harness.
Three wires were broken (Black/green, pink, yellow/red).
The power commander that has been installed 20ish years put stress on the wires and the wires sheered.
Some heat shrink tubing & solder and the wires were once again connected.
I didnt think to take picture before stripping the insulation back to solder, but the wires in the photo were the broken wires.


Both instrument panels work!!

It seems pink is gear position
black/green is dashboard
yellow/red is injector #1.

The bike was running with broken wires, but I suspect it will run a lot better with yellow/red connected and the injector working properly..

I just wanted to give an update so people in future know to also start looking at wiring if they see problems on gauge panel.

 

[Berlin Germany]

yes the two harness ends are very short - they were stingy at every millimeter - so stupid

btw. - all wire colors (´02-´07) are described here in post #1 in a separate table.

 

[Red05]

Glad you found it and thanks for posting the results