HarleyTechTalk

Bike doesn't start

Quote from: hrdtail78 on August 06, 2022, 05:11:34 AM

Quote from: rigidthumper on August 06, 2022, 04:43:29 AMIAC Warmup steps adds a little air to the IAC base position to maintain steady idle during warmup.
Logging from start to full temp would show what the steps and AFR are doing during this time, and give an indicator if it's getting too much air (lean sneeze/die) or too little air (rich stumble/die), and at what temp & IAC position that occurs.

How do you log start up with vision?  I set it up to log at key on, but once the bike starter button is hit.  It limits 12 volts and the unit is restarting while it should be logging.

Turn your key to ON'
Allow your power vision to power up fully.
Set your data logging up on Gauges.
Connect a USB power supply or Laptop or what ever you have, to your PV.
Start engine and record data.

^^ I'll try that SJ." It would only need to log a few seconds during start and idle. Thanks.

Quote from: Jim Bronson on August 08, 2022, 08:02:51 AM^^ I'll try that SJ." It would only need to log a few seconds during start and idle. Thanks.

Quote from: Jim Bronson on August 08, 2022, 08:02:51 AM^^ I'll try that SJ." It would only need to log a few seconds during start and idle. Thanks.

Record it anywhere from 20 seconds to 2 minutes. More data the better for me!!

The bike shuts off after a few seconds, so it wouldn't be recording anything except maybe temps.

Quote from: Jim Bronson on August 09, 2022, 08:56:45 AMThe bike shuts off after a few seconds, so it wouldn't be recording anything except maybe temps.

VEs??

I think it is more of an idle issue rather than a cranking problem. Everything is normal during cranking and initial idle, but it shuts down after idling for a few seconds. It does this only when hot, so the problem is that something happens to cut off fuel shortly after starting and running when hot but not when cold. It doesn't stumble; it shuts down cleanly like I turned off the switch. I guess I'll need to think it through and keep reading, since DJ is no help at all. All inputs are welcome.

Here's a log file I captured today during shutdown. I made some notes to the right of the data.

You cannot view this attachment.

I'm not able to use the data in your log as its set to pro/YX mode rather than simple .csv however looking at the tune you posted the VE tables appears to be extremely lean in much of the idle region. For example at 0%  1000 RPM you the VE values are 53/58, but at 2% 1125 RPM the values are 84/89, this is about a 60% increase which is not normal within such a small area. If I had to speculate I would say the bike starts & runs ok when cold as it has enough warmup enrichment and then goes into closed loop, when shut of and restarted it does not have the same enrichment as when the motor is cold so it struggles.
I would start with blending all of the VE cells in that big hole you can see in the 5/2/0%, try starting with 85's with some smoothing and see how that works.   

Sounds like a plan. I'll get it done and post the results. Thanks Jamie.

It didn't fix the problem. It doesn't run as long as it did previously before shutting down. It shuts down almost immediately after starting and running (maybe two seconds). Also, when coming to a stop, the idle sometimes drops below 800, so I have to add throttle. Sigh....

Logically if you increase the 1000 rpm ve in both tables by 10-15% and make the 750 rpm the same as the 1000 rpm values, it should stay running. Big question here is why did it autotune to those low values at idle? It's running condition points to low idle ve .Once off the warmup table which adds fuel, it struggles going too lean when the table times out.
Ron

Since this problem only happens on a warm engine.  Have you tried to shut off warm up enrichment?  Might even try loading your original tune and see if problem disappears. Could be a bad cal in the first place.  Find another starter and copy all info and try that one.

I have seen bikes idle with way too rich and way too lean.  Might not be the smoothest but they don't die.

Maybe I'll try adjusting the low RPM VE setting in the Quick Tune screen. Can't hurt I guess.

Is it target tune by chance?
Also
Just up your VEs throughout the idle areas on both cylinders, perhaps 10% at a time.
Nothing to lose.

Quote from: Jim Bronson on August 26, 2022, 11:28:54 AMMaybe I'll try adjusting the low RPM VE setting in the Quick Tune screen. Can't hurt I guess.

Im a little late to the party, so maybe you fixed it, not sure but I had this problem with my twin cam 13 Street Bob 96" Andrews 48H cam. It auto tuned itself into a no start hot condition. If I cracked the throttle it would start fine. And it took a minute before it would maintain a stable idle. Only hot. Everything else was fine. Long story short it was the VE tables at idle were too low. Putting either the stock tune or the FM tune in fixed it. But auto tuning the FM tune, it would go back to not starting hot. So Change the auto tune to not change VE's below whatever MAP reading your getting at idle. For me it was 40. If I remember right it wanted to bring the VE's down to mid 50's I put them at upper 60's and blended the tables and the problem went away.