Lifan Xpect EFI Stalling

mototech77 · 08-21-2021, 08:41 PM

My Lifan Xpect EFI tends to stall when cold,and occasionally when taking off from a light. This is happening just as I start to roll the throttle, before the clutch is engaged (not a newb rider stall). Seems mostly like the calibrated mixture is lean while it is in open loop, though this would not explain the occasional stalls when it is up to operating temperature. I have done a few things already, but would like to know if anyone knows a resolution for this.

Only has 900 miles
NGK plug checked and gapped
Valve lash adjusted
Ignition coil ground cleaned and tightened
Connectors checked and reseated
O2 sensor inspected for buildup and connection checked and reseated
No CEL

Boatguy · 08-21-2021, 08:56 PM

I think that’s just the nature of the machine. It’s pretty lean running. It shouldn’t stall when it’s warm, but it does sometimes. All I do is just control the idle speed a little bit with the throttle. It rarely does this. At least mine doesn’t.

weiser23 · 08-21-2021, 09:26 PM

I had a stalling problem with hawk deluxe my friend suggested raising the idle and it took care of the problem

mototech77 · 08-21-2021, 10:33 PM

Thank you both for the responses. I will see if bumping the idle screw up some may help.

mototech77 · 08-21-2021, 10:50 PM

Though I am skeptical of this, I must say that I am tempted to try for the ability to rich up the mixture a little. If I do decide to take the $250 risk at some point, it will probably not be until I am out of warranty.

https://www.magnumtuning.com/en/deta...200-dual-sport

Figured I would throw this out there in case anyone wanted to take a chance on it themselves.

old_airhead · 08-22-2021, 08:37 AM

Wow! Their website shows a chart that indicates your Lifan engine makes 100 hp. Definitely worth 250 bucks. I think I'll wait for someone else to check this out.

mototech77 · 08-22-2021, 02:09 PM

Quote:

Originally Posted by old_airhead

Wow! Their website shows a chart that indicates your Lifan engine makes 100 hp. Definitely worth 250 bucks. I think I'll wait for someone else to check this out.

Ha ha!

I don't blame you there.

Yes, 100HP would be an insane claim for these bikes. That's a generic image, just like the one they have showing the IAT sensor on the automotive engine. Their actual advertised claim is 15% which would be a jump from 14HP to ~16HP (though I'm sure they hope someone will see those numbers and jump to buy the chip). Since all this "performance chip" really does is alter the signals going from the IAT and O2 sensors to the ECU to enrich the air/fuel ratio, I'm not even sure it would even give the extra 2HP. I will admit that for what this device does, $250 is a bit ridiculous. It is really probably worth about $20, but I hope to to find a way to get the bike to run just a little richer, especially during warmup. I enjoy tinkering and finding ways to make these bikes better. For me, I think half the fun of owning one of these non-refined Chinese bikes is the tinkering aspect. I will keep looking to see if I can find a similar way to reach my goal without getting sapped for $250, but if it will do what I need it to effectively, it might be worth it for me. Will have to wait until my bike is out of warranty, though. I would like to install a wide-band O2 sensor and gauge to get a better idea of what is really going on before and after.

JFOlivier · 08-22-2021, 03:55 PM

I have only about 900 miles on my x-pect and also have this problem with stalling when cold, but it is much better when warmed up and has also improved with the mileage going up. To be fair that 100 hp chart you are refering to clearly says below "Generic dyno chart for a 100HP asperated gas engine". Sill $250 for the hardware is a little pricey. I am pretty sure that somebody will soon come up with ways to tweak the ECU for better performance as there are already threads going on about the same thing on the Zongshen Riders.

mototech77 · 08-22-2021, 05:17 PM

Quote:

Originally Posted by JFOlivier

I have only about 900 miles on my x-pect and also have this problem with stalling when cold, but it is much better when warmed up and has also improved with the mileage going up. To be fair that 100 hp chart you are refering to clearly says below "Generic dyno chart for a 100HP asperated gas engine". Sill $250 for the hardware is a little pricey. I am pretty sure that somebody will soon come up with ways to tweak the ECU for better performance as there are already threads going on about the same thing on the Zongshen Riders.

Yes, you are right about the chart. It would be nice to find an all-around solution. I have found some Honda 6-pin to OBD2 adapters that appear to fit the diagnostic port on these. I am looking into the pin outs to see how they match. Only 3 of the 6 pins are wired on the bike. It looks like power and ground would need to be wired in. Not sure of the other missing wire yet. Even if I get the wiring worked out, I don’t know if my software would be able to read the ECU. I’ll keep looking.

JFOlivier · 08-22-2021, 05:41 PM

Moto, take a look at this thread: "high idle TPS" Guy there called Lukas has put out quite a bit of info on working with the ECU and its interfaces. I have seen some other posts all about modifying the ECU's so if you checked out more of Lukas's posts you may find them.
I guess a great deal may have to do with the o2 sensor, but there is a lot to learn about this system.

mototech77 · 08-22-2021, 06:35 PM

Will do. Thanks!

Boatguy · 08-22-2021, 09:30 PM

I should clarify... if mine gets a little stally, I use the throttle to give it some rpms and it smooths out and idles just fine for hours after that.

old_airhead · 08-23-2021, 10:05 AM

Is the Lifan EFI system the same as the Hawk DLX? I have about 1100 miles on the DLX and it still runs like absolute crap when cold. It takes at least 5 miles, sometimes up to 10 miles, to warm up. When it's hot it runs OK, a bit of popping and the idle 'hunts' a bit. It used to stall out once in awhile at idle, but that stopped after a few hundred miles. I have a BMW in the garage that used to stall out when coming to a stop and I tried all kinds of stuff to fix that (the dealer couldn't find anything wrong). I even tried a device that plugged in between the intake air sensor and the ECU - that didn't seem to do anything. I finally just increased the idle speed about 200 rpm and never had another stall.

mototech77 · 08-27-2021, 09:31 PM

Not sure if they use the same EFI system, but these bikes do interchange some parts. Remembering an old issue with my brother’s Honda Superhawk years ago, there was a TSB for off-idle stumble caused by misalignment of the throttle position sensor. It looks like the TPS on my Lifan may have an elongated mounting screw hole, so it makes me wonder. I have not been able to locate what the idle resistance values are to calibrate this yet, though.

mototech77 · 08-27-2021, 09:41 PM

I also did more research on the ECU diagnostic port. Looks like there are not missing wires like I thought. It appears now that there is power, ground and K-line data. I ordered a Honda 6-pin to OBD2 adapter cable. When it arrives, I’m going to verify the pin-out, then attempt to interface with my ELM adapter. Worth a try at least.

08-21-2021, 08:41 PM	#1
mototech77 Join Date: May 2021 Location: Central Florida Posts: 80	Lifan Xpect EFI Stalling My Lifan Xpect EFI tends to stall when cold,and occasionally when taking off from a light. This is happening just as I start to roll the throttle, before the clutch is engaged (not a newb rider stall). Seems mostly like the calibrated mixture is lean while it is in open loop, though this would not explain the occasional stalls when it is up to operating temperature. I have done a few things already, but would like to know if anyone knows a resolution for this. Only has 900 miles NGK plug checked and gapped Valve lash adjusted Ignition coil ground cleaned and tightened Connectors checked and reseated O2 sensor inspected for buildup and connection checked and reseated No CEL
	0

08-21-2021, 08:56 PM	#2
Boatguy Join Date: Feb 2021 Location: Northeast Posts: 934	I think that’s just the nature of the machine. It’s pretty lean running. It shouldn’t stall when it’s warm, but it does sometimes. All I do is just control the idle speed a little bit with the throttle. It rarely does this. At least mine doesn’t. __________________ 2020 Lifan x-pect
	0

08-21-2021, 10:50 PM	#5
mototech77 Join Date: May 2021 Location: Central Florida Posts: 80	“Tuner” Though I am skeptical of this, I must say that I am tempted to try for the ability to rich up the mixture a little. If I do decide to take the $250 risk at some point, it will probably not be until I am out of warranty. https://www.magnumtuning.com/en/deta...200-dual-sport Figured I would throw this out there in case anyone wanted to take a chance on it themselves.
	0

08-22-2021, 09:30 PM	#12
Boatguy Join Date: Feb 2021 Location: Northeast Posts: 934	I should clarify... if mine gets a little stally, I use the throttle to give it some rpms and it smooths out and idles just fine for hours after that. __________________ 2020 Lifan x-pect
	0

08-21-2021, 09:26 PM	#3
weiser23 Join Date: Jan 2011 Location: mechanicsburg pa Posts: 170	I had a stalling problem with hawk deluxe my friend suggested raising the idle and it took care of the problem
	0

08-21-2021, 10:33 PM	#4
mototech77 Join Date: May 2021 Location: Central Florida Posts: 80	Thank you both for the responses. I will see if bumping the idle screw up some may help.
	0

08-22-2021, 08:37 AM	#6
old_airhead Join Date: Nov 2020 Location: Bloomington, IN Posts: 56	Wow! Their website shows a chart that indicates your Lifan engine makes 100 hp. Definitely worth 250 bucks. I think I'll wait for someone else to check this out.
	0

08-22-2021, 03:55 PM	#8
JFOlivier Join Date: Nov 2020 Location: Northern Neck of Virginia. Posts: 165	I have only about 900 miles on my x-pect and also have this problem with stalling when cold, but it is much better when warmed up and has also improved with the mileage going up. To be fair that 100 hp chart you are refering to clearly says below "Generic dyno chart for a 100HP asperated gas engine". Sill $250 for the hardware is a little pricey. I am pretty sure that somebody will soon come up with ways to tweak the ECU for better performance as there are already threads going on about the same thing on the Zongshen Riders.
	0

08-22-2021, 05:41 PM	#10
JFOlivier Join Date: Nov 2020 Location: Northern Neck of Virginia. Posts: 165	Moto, take a look at this thread: "high idle TPS" Guy there called Lukas has put out quite a bit of info on working with the ECU and its interfaces. I have seen some other posts all about modifying the ECU's so if you checked out more of Lukas's posts you may find them. I guess a great deal may have to do with the o2 sensor, but there is a lot to learn about this system.
	0

08-22-2021, 06:35 PM	#11
mototech77 Join Date: May 2021 Location: Central Florida Posts: 80	Will do. Thanks!
	0

08-23-2021, 10:05 AM	#13
old_airhead Join Date: Nov 2020 Location: Bloomington, IN Posts: 56	Is the Lifan EFI system the same as the Hawk DLX? I have about 1100 miles on the DLX and it still runs like absolute crap when cold. It takes at least 5 miles, sometimes up to 10 miles, to warm up. When it's hot it runs OK, a bit of popping and the idle 'hunts' a bit. It used to stall out once in awhile at idle, but that stopped after a few hundred miles. I have a BMW in the garage that used to stall out when coming to a stop and I tried all kinds of stuff to fix that (the dealer couldn't find anything wrong). I even tried a device that plugged in between the intake air sensor and the ECU - that didn't seem to do anything. I finally just increased the idle speed about 200 rpm and never had another stall.
	0

08-27-2021, 09:31 PM	#14
mototech77 Join Date: May 2021 Location: Central Florida Posts: 80	Not sure if they use the same EFI system, but these bikes do interchange some parts. Remembering an old issue with my brother’s Honda Superhawk years ago, there was a TSB for off-idle stumble caused by misalignment of the throttle position sensor. It looks like the TPS on my Lifan may have an elongated mounting screw hole, so it makes me wonder. I have not been able to locate what the idle resistance values are to calibrate this yet, though.
	0

08-27-2021, 09:41 PM	#15
mototech77 Join Date: May 2021 Location: Central Florida Posts: 80	I also did more research on the ECU diagnostic port. Looks like there are not missing wires like I thought. It appears now that there is power, ground and K-line data. I ordered a Honda 6-pin to OBD2 adapter cable. When it arrives, I’m going to verify the pin-out, then attempt to interface with my ELM adapter. Worth a try at least.
	0