***UPDATE: My problem has been resolved. Please see last post for details.***

Hello everyone. My bike seems to have developed a problem and I'm not sure where to start looking for why it's happening. The problem used to be a minor one, it would only happen when I came to a stop at a light and the idle would start to die, it almost sounded like it was only running on one cylinder. The thing was it was so random, it was almost impossible to recreate if I wanted to. Now recently the problem started happening more often but still quite rare up until tonight. As I was coming to work tonight, the bike would start to slow down and it even died twice. And this time it didn't matter if I was stopped or moving, as long as the throttle was at the home position. As long as I kept some throttle going the bike stayed alive.
Also after I restarted the bike, the engine light started to flash and continued to do so until I turned the bike off. If I was home I would check the manual to see what that means but unfortunately I am not. I checked the diagnostic codes and got these:
- U1300: ECM Serial Data Low, Serial Data Low, Serial Data Low Instruments, Serial Data Low TSM/TSSM
- B1004: Fuel Level Sending Unit Low Instruments
- B1005: Fuel Level Sending Unit High/Open Instruments

Any and all help would be greatly appreciated.
Thanks
-Theo

 

Ok so I've been thinking about this and I think I might have a plan of attack. First I'm going to switch back to the stock ECM to see if it might be a problem with the thundermax. If that doesn't work, I'm going to take a look at the throttle body and see if there is crud built up on the butterfly and clean it. If that doesn't work then, I'll try changing the TPS, but I don't think that's it. Maybe it's the IAC. Or maybe it's the alternator or regulator, but I feel that would be more of a consistent problem rather than an intermittent one. But I'm still confused about the code U1300 - "ECM Serial Data Low". I have no idea what that means. Maybe whatever is causing that code to appear is my problem and not the other stuff I mentioned. Any ideas? Thanks.
-Theo

 

I'd even check intake seals for leaks just for the heck of it.

 

1) Fuel leak at fuel rail and fuel tube sealing point????
2) Did you recently adjust your ECU program?
3) Is your motor running hot?
4) adjust your VE table F/R at 0% throttle position and 1000 rpms up by 5 milliseconds. If that fixes the problem. you may have a feul leak that is so slight, that you may barely smell it.

 

Check your leads comming off your coil pack -I had the same problem there was a bad crimp on the connector I put a new connector on mine it ran like new/ this will cause your computer ecu/ecm to go nuts

 

Ok so I just got back home from work and the bike worked perfectly. This is really annoying me. I almost wished it was a steady problem.

I'll do that but the more and more I think of it, I'm pretty sure it has something to do with the IAC. Either it's gummed up or malfunctioning. Tomorrow I'm going to get some carb cleaner to clean it out. Although I could be completely wrong.

1. What's the fuel rail. Are you talking about the high pressure hose that goes from the tank to the injectors. Or...?
2. No. I changed the base map a couple of months ago but this problem happened with the old map as well.
3. It's hard to tell in this cold weather. Today when the motor quit on me, I was stuck in some bad stop and go and the oil temp got up to 232 degrees, with an ambient temperature somewhere in the 40's. Is that too hot?
4. What is the VE table? I'm looking all through the thundermax software and can't find what you are talking about.

Sorry for my ignorance, I mean well.

Thanks for the help so far. Appreciate it.
-Theo

 

Are you talking about the wires that go to the plugs or the wires that supply it with power. I'll check out both. Thanks.
-Theo

 

It could be the coil leads that streetrider was talking about. Also, look at retarding your timing at idle. Do you have a stock cam in your bike? Maybe look at your crank shaft postion sensor connection too. It's located right next to your oil filter on the left side (primary side) of the engine.

232 degrees is normal.

The VE table is where you adjust your injector pulses to give each cylinder enough fuel to run the motor. They are not set at the same values though. There may be general settings in the T-Max software for different throttle positions or MAP percentages. I'm only familliar with TTS Mastertune and SERT software.

Your throttle position sensor may be arguing with your MAP sensor too and not be giving you an engine code. If that's the case your engine may be getting too much fuel when it goes back down to idle.

Also, maybe lean out your deceleration table, in the engine temperatures range that you are having problems at. Do you smell fuel when the motor quits?

Another thing is that your idle might be set too low.
Sorry for throwing all this stuff at you. It's hard to take in. I've had to look at this stuff before..

 

Yeah I'm going to check all of that stuff. I'm also going to check the wires that go to the fuel injectors. By checking, I mean I'm going to let the bike idle and I'm going to jiggle all of the wires that go into all of these sensors and connectors. How does that sound?

How many degrees should I retard the timing? 1 or 2 degrees, or is that something I just have to test for myself? Currently it's at 8 degrees.

The cam I have in the bike is a SE203

Okay now I know what you are talking about the VE tables. In thundermax it's called the "Fuelflow tables" and they are adjusted in degrees. I'll try that as well.

The thing is it doesn't happen at a specific engine temperature. It's happened when I started the bike stone cold and let it idle to warm up. So I don't know if I can adjust for that. Also this is the first time the bike has died on me and I was in thick traffic so I have no idea if I smelt fuel or not.

I have the idle set at 960. The stock thundermax setting was 976 so I didn't think I was harming anything lowering it 16 rpms, but I'll raise back up to say 1000.

Thanks for taking the time to help me, I really appreciate it. It seems like I have a lot of trouble shooting ahead of me.
Thanks
-Theo

 

Before you tear into it too much. Repost this with Tmax stalling problem in the thread title so the guys here who know Tmax can see it and maybe give you the answer.