K8 GSXR K line data/signal drop to Aim Evo 4 logger

[Benno88]

Gday all, just putting out a dew feelers to see if anyone else has any knowledge of this issue, we are currently trying to fault find but just encase someone else has knowledge we dont it might be something simple, and better to ask..

Simply put we are loosing signal/data from the k line to the Evo 4 logger when the engine is started. (intermittent fault )

when the engine is off and the ignition is on we have a perfect signal and are receiving data and have a constant 7 volts from the k line.

however when the engine is started at a random point the data is lost. (the voltage drops to 0) we have tried a pull up resister in line and when the data drops we spike to 12 volts.

once the data is gone it dosnt come back until the engine is switched off.

We have checked connections as best we can, we have also replaced the GSXR ecu, we are going to try another K line to another Evo 4 logger next but are waiting to head up to the track for that.

So basically seeing if anyone else has had this problem or has some amazing suggestions? my next thought would be that maybe a sensor feeding the k line is tripping ? i would assume its not the TPS as the car runs fine, but maybe another???

Cheers Guys

[Pi_guy]

I would put a cut off switch in for the data system.
Which I hope would tell me that the issue is caused by start issue or is present when engine is running.
The issue I had was no communication with unit while running and using the online monitoring program. It seemed to have been cured with other wiring repairs.
But in saying that had communication issues with data logger and the GCU when we were on the road dyno last week. My two cents on that it was the interference from the dyno, did not even think of that there.

[David Ferguson]

The K-Line spec requires a ~500 ohm pull-up resistor between the K-Line and the 12V from the same 12V supply as the Evo4. Some of the early Evo4 K-Line adapter cables (2014 and earlier) had a 1k pullup resistor in the cable instead of a 500 ohm, so you could add a 1k resistor in parallel to achieve the 500 ohm required by the spec.

When you mention added a resistor in line with the K-Line, I hope you really mean you added an additional pull-up resistor.

I would make sure you have good grounding of the ECU, Evo4 to make sure the K-Line communications works properly.

You might try re-routing the K-Line wiring to avoid interferece (particularly from coils or generator wiring.

Since your problem is at staring time - I would pay attention to the engine grounding, and starter wiring (the starter current path)-- perhaps you are having too much of a voltage drop while the engine cranks.

If you are going to add a switch, I would switch the power to the Evo4, causing it to drop then re-start the K-Line communications during the power cycle.

[Benno88]

Hi guys thanks for the replies.
We googled the problem and Aim recommended installing a pull up resistor, to which we installed one, then when checking the wiring we noted that we already had one hidden in the wiring so we effectively put two in parallel. unfortunately that had no effect.

thanks for the info re the coils i will check the wiring is moved and well away. its a strange problem as it has only just reared its head. after months of being fine since we installed the new engine.

The drop out point is hard to place, though it is not on initial startup, it can idle fine in the pits for up to 5 minutes and then it will just loose signal, other times it only takes a few seconds. I will recheck the grounding to see if that is the issue.

i also like the idea about a switch to cycle the EVO 4, it will make fault finding that much easier not having to restart the engine all the time.

cheers guys and keep the ideas flowing, its really appreciated.

[Pi_guy]

Check grounds.
Check battery and connections. I used to swear by a load tester and will work in a lot of applications like checking master switches, battery quick check. But in this day and age where battery chemistry has advanced it is often best to have a specialized tester to confirm all is well there to remove that from the loop.

[ghickman]

I first reported this problem to AIM in Italy clear back in 2013. I've been through all the possible fixes. I don't know a single person with an Evo 4 that has successfully used the K line.

Chris Harrison (who I consider to be one of the best AIM guys) has looked at the problem and no joy.

The pull up resistors are a waste of time, they simply won't correct the data from dropping out.

I've long since ditched the K Line. It would be nice to have it frees up a few channels and you can see Throttle Position, etc.

The ZX10R has a CAN BUS works awesome. Suzuki K Line protocol not so much.

[Benno88]

I first reported this problem to AIM in Italy clear back in 2013. I've been through all the possible fixes. I don't know a single person with an Evo 4 that has successfully used the K line.

Chris Harrison (who I consider to be one of the best AIM guys) has looked at the problem and no joy.

The pull up resistors are a waste of time, they simply won't correct the data from dropping out.

I've long since ditched the K Line. It would be nice to have it frees up a few channels and you can see Throttle Position, etc.

The ZX10R has a CAN BUS works awesome. Suzuki K Line protocol not so much.

Thanks for your input Ghickman. it is just strange because we have had the k line working perfectly for over 2 years with this car, and we also have 9 other cars over here running GSXR k8 motors all without this error. Did Chris give you any pointers to look at?

Cheers

[ghickman]

Thanks for your input Ghickman. it is just strange because we have had the k line working perfectly for over 2 years with this car, and we also have 9 other cars over here running GSXR k8 motors all without this error. Did Chris give you any pointers to look at?

Cheers

I had the same thing happen. We ran something like 5 races then all the sudden quit working. It would sometimes work then blank out.

We looked at the signal with an oscilloscope and it was very unstable.

Someone told me they built a variable pull up resistor that they could tune and claimed it worked.

[Brian.Novak]

As an interesting aside, I have had 0 problems getting K-Line data off of a GSXR600 but had trouble on my F1000.

[AEA_Team_Lotus]

I run the EVO 4 off of the K-line on my Radical SR3 and my Stohr F-1000 with no problems at all. I utilize the bike kit V02563140 and a harnesses (and engines) that Richard At Rilltech built me.