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Offline BartZ

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Re: Z900 ECU Flash
Reply #90 on: January 16, 2021, 11:44:35 PM
*Originally Posted by 2 Wheel DynoWorks [+]
Do you still have your O2 sensor connected?

In my case I initially had O2 sensor plugged after flash, but was told to disconnect it in case it causes issues even though it was disabled which I did eventually. Its hard for me to pinpoint the exact cause of the hot start issue, because I ve changed the headers, removed EVAP, installed block off plates and flashed ECU all on the same day. I am hoping its the caps on throttle bodies from EVAP removal that didn't seal fully and it gets some extra air in. If you have any other suggestions that would be appreciated. Since I ve done all the work myself apart from the flash, I want to make sure I exclude all possible mechanical issues before I get the bike checked for flash related issues.

*Originally Posted by Z900GERM [+]
Say when I stop to get gas in between canyons. When I try to start the bike back up it sputters and falls on itself for a couple seconds and then starts.

In my case it sort of starts for split second, but switches off like there is no fuel?, it does that 3-4 times before it eventually starts, weird thing is that it starts first time when cold, the hot idle RPM seem to be in spec as well.
Last Edit: January 16, 2021, 11:50:42 PM by BartZ

Offline 2 Wheel DynoWorks

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Re: Z900 ECU Flash
Reply #91 on: January 17, 2021, 12:43:39 AM
*Originally Posted by BartZ [+]
In my case I initially had O2 sensor plugged after flash, but was told to disconnect it in case it causes issues even though it was disabled which I did eventually. Its hard for me to pinpoint the exact cause of the hot start issue, because I ve changed the headers, removed EVAP, installed block off plates and flashed ECU all on the same day. I am hoping its the caps on throttle bodies from EVAP removal that didn't seal fully and it gets some extra air in. If you have any other suggestions that would be appreciated. Since I ve done all the work myself apart from the flash, I want to make sure I exclude all possible mechanical issues before I get the bike checked for flash related issues.

In my case it sort of starts for split second, but switches off like there is no fuel?, it does that 3-4 times before it eventually starts, weird thing is that it starts first time when cold, the hot idle RPM seem to be in spec as well.

If the EVAP system was removed, the ports on the throttle bodies are also the very first thing we would check as well!

-2WDW

Offline KawaJagz

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Re: Z900 ECU Flash
Reply #92 on: January 17, 2021, 10:11:39 AM
BARTZ, have you tried giving it a bit of throttle when hot starting?
I have the standard tune on mine but it has always been a bit of a bitch to hot start after a refuel for example, it starts but dies right away, but if I give it a little throttle and a couple of small revs as it fires up, it then idles away normally again.
I used to be indecisive, but now I'm not so sure!

Offline BartZ

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Re: Z900 ECU Flash
Reply #93 on: January 17, 2021, 01:06:05 PM
*Originally Posted by KawaJagz [+]
BARTZ, have you tried giving it a bit of throttle when hot starting?
I have the standard tune on mine but it has always been a bit of a bitch to hot start after a refuel for example, it starts but dies right away, but if I give it a little throttle and a couple of small revs as it fires up, it then idles away normally again.

No, I never had to do it in the past so didn't want to start doing it now, there must be a reason why it struggles to start. I spoke with the guys who done the flash for me and they said it will be something small and will get it sorted, but before I go there and give them more work I want to check the basics and make sure I didn't mess something up. Did you disable your EVAP and PAIR?

Offline MZ900

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Re: Z900 ECU Flash
Reply #94 on: January 17, 2021, 01:36:40 PM
i have a small story abt EVAP.

so far i see most of the tuner uses a Woolich software, so for 2017-2019 bikes it offers:
Features available for Kawasaki Z900 2017-2019
IAP Fuel Maps
TPS Fuel Maps
Ignition Timing Maps
Ignition Dwell Map/s
Secondary Throttle Plate (STP) Opening Maps
Adjust RPM Limiter
Adjust Fan Temperature
Quickshifter - (Requires Race Tools)
Launch Control - (Requires Race Tools)
Pit Lane Limiter - (Requires Race Tools)
Race Shift Pattern Sensor Configuration - (Requires Race Tools)
Disable Stock O2 Sensor
Disable Deceleration Fuel Cut
Disable PAIR Valve / AIS
Engine Data - View Live Engine Data
Woolich Racing AutoTune - (Requires Applicable LogBox + Zeitronix Package)
Diagnostics: Read and Clear Fault Codes - (Requires Applicable V3 Interface)


No word abt EVAP.  But when we were tunin my bike i was behind the tuner to see what he doing in laptop, i saw on app options and he also ticked the box Disable EVAP.... and we unplugged evap connector
ok, dyno runs done, bike ecu flashed... suddenly on a dyno we got Check engine light..... tuner tried to read the code, reader showed no errors.... he suggests to run on the street for some kms, as it can be possible due bikes front wheel stands still.... errmmm ok, i did - nothing.
after several tries he gave up and called to kawasaki dealer friend to arrange me to come and check with their oem data reader.... i went to kawa service (lucky it was in same town, 15min drive), mechanic came with the data reader and first started to make visual inspection, he found evap connector unplugged - first thing he plugged it back, with words : you fccoking raaacers, doing shite to ur bikes then cry  :745:  then he he connected his computer, started the bike and voila, error gone, check engine gone. He said - dont do sh#t to your bike anymore, also ne didnt know i was just from ecu flash. he thought it was me - trying to fool evap system.
since that, evap in place, bike starts and runs fine.  dunno why woolich software interface shows that option available, while they dont even list it on the web site.

just my 5ct
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Re: Z900 ECU Flash
Reply #95 on: January 17, 2021, 01:52:33 PM
Without having all detailed info, I will add...

You need to check your IAT sensor. If that is out of spec, it will explain this issue. But it does sound really lean when that condition exists. If not sensor, its an easy fix in the tune as focus will be around a narrow 30-50kpa. Also not knowing if they changed idle timing (from 10-degrees).

Here is something you can try, when hot and before start, open the gas cap, close it then quickly try starting. I would also connect a volt meter and measure before/during/after start attempt.