Continuing - So what did you do to your bike today...?

[grog]

Well done with payout Hooli. Expensive bike so fix it/ paint it right. Is Harley the most popular bike there, sure are lots around here.Reckon thered be lots of used mufflers for sale, none have them fitted.

[Hooli]

I doubt they are the most popular here, that'd be sports bikes I think although adventure stuff seems to be replacing them now.

I'll speak to the paint guy as remembering what he charged Moonie for a hugger I doubt it'd cost too much to get done properly. Once it's home though, no rush especially at this time of year.

[Eric GSX1400K3]

Finally think I've sorted my C28 error. Replaced the STP sensor with a new one.  I also went through and checked all other sensors and they all checked out ok.  Finally checked the TB balance and they were all within 5mm Hg of each other, so very happy with that.  Went for a ride with the bride on the back, cruising through some 40kph zones along the beach front.  No more low speed snatchiness at part throttle, just nice and smooth.  I could cruise along in 5th gear at 50kph and it would just pick up, as before it would almost stall out.

As per the manual, the sensors I checked:
CMP: removed and cleaned it, some minor oil sludge, otherwise ok
CKP: 172 ohms recorded, acceptance range is 134 to 202 ohms
IAP: 4.99V, acceptance range 4.5 to 5.5V
TP: 4.9V R-B and 5.05V R-E wires.  Acceptance range 4.5 to 5.5V
Resistance of TP : 1120 ohm at fully closed, 4230 ohm at fully open. Acceptance range 1100 to 4300 ohm. Adjusted to 1100ohm
EOT:4.78V, acceptance range 4.5 to 5.5V. Resistance measured 6.16kOhm. the manual states the maximum value should be 61.3kOhm, I think that might be a typo.
IAT: 4.72V, acceptance range is 4.5 to 5.5V. Resistance measured 2.139kOhm, the manual says it should be about 2.6kOhm at 20deg C and lower at higher temperatures, it was around 25-26deg Celsius when I measured,so to me this is ok.
AP: 3.869V R-G and 4.76V GY to B/BR wires. Manual says 3.4 to 4.0V at R-G for the elevation range of 0 to 610m. I live at about 10AMSL so again I think this  a valid value.
TO: 61.9kOhm from B to BW wires, manual says range is 60 to 64kOhm.
STVA: 5.9 ohm measured, acceptance range is 4.8 to 7.2 ohm closed
STP: 5.0V read at the sensor plug.  Resistance measured at 760ohm, which I thought was too low.  Manual says 800ohm, this was the one I replaced, so I adjusted it to read 801 ohm with ST held closed through the air box.  Checked between 1-2 and 3-4, and no measured difference, which is great.  Wide open I measured 2880 ohm.

After this I checked the TB balance and found this to be as per above.  Went for a ride as I said and bike is just perfect, no FI codes.

Will take it for a longer run tomorrow and see how it behaves.
Happy Days.

[Andre]

Nice report

Copy/paste into a file on my puter for future use (hope not).

[Hooli]

Finally think I've sorted my C28 error. Replaced the STP sensor with a new one.

For my curiosity, would you mind checking the old one compared to the manual & then do the same sweep test but using the power not sensor wire. On my failed one, I got the same variable resistance displayed between power & earth as I was successfully seeing between sensor & earth. When obviously power & earth should remain static.

That's the fault I found described on the US GSXR forums that allowed me to finally fix mine. I'd assume ours will often fail the same as it's exactly the same design of sensor. It seems as the resistance track wears under the wiper inside the sensor, it shorts the two paths together resulting in the wrong signals to the ECU.

[Eric GSX1400K3]

Finally think I've sorted my C28 error. Replaced the STP sensor with a new one.

For my curiosity, would you mind checking the old one compared to the manual & then do the same sweep test but using the power not sensor wire. On my failed one, I got the same variable resistance displayed between power & earth as I was successfully seeing between sensor & earth. When obviously power & earth should remain static.

No worries mate, as requested, I tested the old STP sensor tonight.

Results as per below;

BL-BK wires: 4.87kOhm steady throughout full range of sensor sweep, I.e no change in resistance when moving the sensor 'wheel'
BL-Y wires: 0.436 to 4.88kOhm
Y-BK wires: 0.387 to 4.83kOhm

Letting the sensor ring go, base reading seems to be 500ohm, there a mm or two of movement to hard zero, so holding it there gave me the 436ohm reading.  Same at top of the sweep, 4.88kohm with holding it at the end of the sweep.

Not sure which is earth, but assuming it's the BK wire, and Y is the signal return, it makes sense that only one of these, not both should return a variable resistance reading, so with BL-BK also reading a resistance this is not correct and indicates a failed stp sensor to me.

I also noticed that on both BL-Y and Y-BK sweeps, the resistance signal drops out around the 3.9 to 4.2kOhm range, then re-appears from 4.2 to 4.88kOhm. I took a video and then some screen shots of these points when reviewing frame by frame.

Also some photos of measurements of each.

Hope this helps.






Rode about 120km today, mainly freeway, no FI red light, engine runs sweet and pulls like a freight train clean through the revs, and no low speed snatchiness at all. Pretty happy with that.

[Hooli]

Thanks for that, it reminds me of what I saw testing mine.

Sounds like your drop out between the Y-BL wires was the cause of your C28 code then, I believe that's near fully closed so as the bike started to open the STP valves then the reading dropped out & the ECU threw a code as it didn't know what the STVA was doing. I think that's how mine failed originally too, as I had a problem for years where I could trigger a code by holding just the right revs/throttle & accelerate slowly. Makes sense to me the STVA was moving the sensor onto it's 'dodgy range'. That's the same way I've had two TPS fail too & they are the same design of sensor.

I believe from what I've read your steady resistance between BL-BK is actually correct. I've never opened a sensor to confirm it, but what I've seen says they use a second track on the resistive foil for the power > earth connection rather than a normal wire. Then as the wiper sweeps over the range of the sensor, the resistance seen is actually the combination of the power track & sensor track at that point of sweep. One advantage of that is it doubles the length of the resistive track feeding the ECU at any point so changes are bigger & easier to measure for the ECU.

Think we've got geeky enough to bore everyone else yet?

[KiwiCol]

@Eric GSX1400K3, exact same multimeter as I have.   

[Eric GSX1400K3]

Definitely got my nerd fix for the year.

Makes sense, I also think the steady resistance is ok, as is the range on one of the sweeps, at least it's as per the manual.  The issue is the variable resistance on both BL-Y and Y-BK. If just checking the range from open to closed on the Secondary Throttle, the sensor would pass inspection.

I need to check if the manual asks you to check for variable resistance across the other wire pair,if not,then it's hard to spot a dodgy STP.

I was getting the C28 code at random, usually at highway speeds after a time. Perhaps this was at the 3.9-4.3kohm gap, as I thought closed was the lower resistance and open the higher value, but I could be wrong.

[Hooli]

The manual doesn't tell you to check the resistance between power and earth when sweeping the sensor. It's only after finding the gsxr forum I thought to test that and prove mine sensor was faulty.

I could be wrong about which end of the sensor's travel is high resistance. I was at work when I wrote my reply after all

[Eric GSX1400K3]

All good mate, bottom line is we've determined a faulty STP sensor

[grog]

Well done you pair👍👍👍If i have those troubles ill just replace sensors, TPS and STPS.

[Eric GSX1400K3]

I enjoyed this trouble shooting. I was going to pull the throttle bodies off and open up the STVA and or replace the STVA sensor, as this is what the C28 code indicates, when it's actually the STP

[Hooli]

That's the thing, there isn't a STVA sensor. The ECU gets no feedback from it so relies on the STP to know the STVA has done what it's told to do.

Pretty much if you turn the ignition on & the STVA does a sweep of it's travel & a 'shudder' as it lines up with the fast idle position then it's working.

[Hooli]

If you remember I put the part number for the pivot bolts to fit DL-1000 handguards on another thread, I've finally got around to investigating prices. They are £44 per bolt in the UK!

A bit more shopping & I've got a complete set of handguards & fitting accessories (bolts, bar ends with slots etc) for £40 from those lovely copyright ignoring blokes in China - https://www.ebay.co.uk/itm/184336940352

Looks like I'll have a spare set of fake DL-1000 handguards laying around then. Guess I could ebay them to get my £22 back but I'll probably shove them under the bench & forget about them.