TLDR
Cold start issue resolved -
Hello!
I'm relatively new here, mostly a lurker, but having some issues and could use some guidance/help. I've searched for answers/guidance over the past couple days but have not been able to find conclusive info.
Bike details
I installed the MWR PUK last weekend, a couple days before the Rexxer arrived and took the bike for a spin - definitely seemed to be running hotter, but did not have any cold start issues. After the MWR install, my throttle cable was slightly misaligned and there was 0 slack in the throttle and roughly a 2mm gap at the throttle body - meaning it was slightly open.
As soon as the Rexxer arrived I sent off the ECU data for tuning and received a map. I uploaded the map reset the TPS, DTC, and Adaptive settings and started the bike / took it for a spin. It had a little bit of a hesitation to start, but I was not starting from a cold engine. Also, the CEL came back on for O2 sensors. I reset the codes and TPS again, took it for a spin, and the CEL did not come back - seemed successful. That being said, this was all on a "hot" engine. I ended up fixing the cable slack issue yesterday and reset the TPS, and last night I took it for a spin - everything seemed fine.
However, from a cold start I seem to be having issues - this morning after sitting for over 12 hours, I tried cranking the engine multiple times and could even smell raw fuel coming out of the exhaust. I even tried turning the ignition on/off multiple times in case the fuel system was not pressurizing. With no luck firing up, I reset the ECU back to the stock map, it fired right up - I let it run for a couple minutes to warm up. I flashed the ECU again w/ the tuned map, and the bike started - I assume because the engine was now hot.
I've been in touch with David from Rexxer, from whom I purchased the unit, but it's unclear what the issue could be. He mentioned the tune does not touch the bottom end/startup process and that after the flash the ECU needs to learn how to fire up, and that I should let it continuously crank until it fires. I'll give it another try in the morning, but certainly do not want to burn out my starter.
Something seems off. So, I'm also going to chase down the fuel and tank vacuum lines again, but I'm stumped because the bike seems to fire w/ the stock map and not the tuned map. Unfortunately, there's no way to diagnose the issue through the Rexxer unit as it doesn't let you capture OBD data.
The only other thing I can think of, is that when I initially flashed the ECU, the TB/throttle cable was not completely at 0, and maybe it learned w/ bad data. So I'm hoping since I reflashed the ECU to/from stock today, that tomorrow morning it will fire up after learning from a new baseline. Fingers crossed.
Has anyone faced this type of problem, any other thoughts?
Cold start issue resolved -
- Cold start issue started immediately after loading the Custom map, and would not happen on the Original map- never had a problem until the map was loaded
- On the Custom map, the bike would not fire even after holding the ignition down continuously and I could smell fuel from the exhaust, indicating the fuel injection system was working properly
- The problem was caused by a corrupted map file - the map itself was good but the file generated by Rexxer (dealer side) was corrupted
- Rexxer US was responsive through the two week ordeal and we resolved the issue together, having to regenerate the map three times
- The bike feels incredible w/ the tune, improving throttle response, and giving a meatier mid range from 4-6k - on the stock map, this is a very "dead" zone
- Disabling the O2 sensors is a common request in custom maps - I had requested this in my Rexxer tune, but the CEL continued to throw after clearing
- In the Rexxer instructions, they say to disconnect the O2s because if you leave them connected, the ECU sees them and will continue to use them
- This is not the case with the 2019+ Desert Sleds where the ECU and map is totally different than the base Scrambler family
- You have to keep the O2s connected, otherwise the ECU detects a drop in resistance in the circuit and will continue to throw a CEL (codes P0130 and P0150); the O2s are disabled in the map itself
- Thank you to Liam Venter at Fast Bike Gear in NZ (NZ's Rexxer Rep) for this information and @NevM for the intro!
Hello!
I'm relatively new here, mostly a lurker, but having some issues and could use some guidance/help. I've searched for answers/guidance over the past couple days but have not been able to find conclusive info.
Bike details
- 2019 Desert Sled
- Comp Werkes Exhaust
- MWR PowerUp Kit
- O2s Disconnected
- EVAP Canister Removed
- Rexxer EVO User ECU Map
I installed the MWR PUK last weekend, a couple days before the Rexxer arrived and took the bike for a spin - definitely seemed to be running hotter, but did not have any cold start issues. After the MWR install, my throttle cable was slightly misaligned and there was 0 slack in the throttle and roughly a 2mm gap at the throttle body - meaning it was slightly open.
As soon as the Rexxer arrived I sent off the ECU data for tuning and received a map. I uploaded the map reset the TPS, DTC, and Adaptive settings and started the bike / took it for a spin. It had a little bit of a hesitation to start, but I was not starting from a cold engine. Also, the CEL came back on for O2 sensors. I reset the codes and TPS again, took it for a spin, and the CEL did not come back - seemed successful. That being said, this was all on a "hot" engine. I ended up fixing the cable slack issue yesterday and reset the TPS, and last night I took it for a spin - everything seemed fine.
However, from a cold start I seem to be having issues - this morning after sitting for over 12 hours, I tried cranking the engine multiple times and could even smell raw fuel coming out of the exhaust. I even tried turning the ignition on/off multiple times in case the fuel system was not pressurizing. With no luck firing up, I reset the ECU back to the stock map, it fired right up - I let it run for a couple minutes to warm up. I flashed the ECU again w/ the tuned map, and the bike started - I assume because the engine was now hot.
I've been in touch with David from Rexxer, from whom I purchased the unit, but it's unclear what the issue could be. He mentioned the tune does not touch the bottom end/startup process and that after the flash the ECU needs to learn how to fire up, and that I should let it continuously crank until it fires. I'll give it another try in the morning, but certainly do not want to burn out my starter.
Something seems off. So, I'm also going to chase down the fuel and tank vacuum lines again, but I'm stumped because the bike seems to fire w/ the stock map and not the tuned map. Unfortunately, there's no way to diagnose the issue through the Rexxer unit as it doesn't let you capture OBD data.
The only other thing I can think of, is that when I initially flashed the ECU, the TB/throttle cable was not completely at 0, and maybe it learned w/ bad data. So I'm hoping since I reflashed the ECU to/from stock today, that tomorrow morning it will fire up after learning from a new baseline. Fingers crossed.
Has anyone faced this type of problem, any other thoughts?
