When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Ignition/Tuner/ECM/Fuel InjectionNeed advice on ignition issues? Questions about a tuner? Have questions about a EFI calibration or Fuel Injection? Tips on Engine Diagnostics, how to get codes, and what they mean. Find your answers here.
rahall
"I plan on making a couple of data runs for the purpose of checking the timing. My theory is that I will check areas where there are excessive anti-knock adjustments being made. I was planning on reducing the timing table in those areas. Does this make since?"
How are you finding your knock? By ear or by the log files. I found by using a o2 data log the knock was quite evident by watching the retard fast traces for the front and rear cylinders. I tried to increase my fuel to improve the problem with no great success. I ended up with my 4.89 gm/sec maxed out at 20 ms and 100% duty cycle and still knocking. I started reducing timing in the problem spots and seemed to make it worse. This is why I have the heads off again to remove any sharp edges that could be hot spots.
Yes, the Vtune process needs the ECM to stay in closed loop to complete.
That said, you can choose with the closed loop bias tables the "real" AFR value that the ECM will consider as 14.6:1
I might be wrong but when you set the CLB value to 750mV for ex, the ECM will go in closed loop for this voltage, thinking it's 14.6:1 and try to stay at it...
the ECM doesn't really know the AFR, all it knows is the value in mV that the sensors send to it... and we choose for it which voltage means 14.6:1
How are you finding your knock? By ear or by the log files. I found by using a o2 data log the knock was quite evident by watching the retard fast traces for the front and rear
That's what I did too
but for me, decrease the spark advance in the area the knocking was detected, seems to have cure it
of course, my cams are OEM and your's aren't, that could be a reason
That's what I did too
but for me, decrease the spark advance in the area the knocking was detected, seems to have cure it
of course, my cams are OEM and your's aren't, that could be a reason
Are you using the data master log viewing tool or another program to view the log files?
I'm still in the 'TTST 100' class so to speak. I have done a couple of short V-tune runs, and the bike runs very well with one exception: popping on decel.
I found this in the manual: "The VE table will affect the mixture during the entire decel event. To eliminate the popping, increase the VE setting in the first column (1 percent throttle) between 1750 and 3500 RPM by 5 to 10 percent. Some experimentation here will find the sweet spot that eliminates the popping."
I did one 5% with no effect, then another 5%... But it has been snowing and temperatures in the single digits since so I have not had a chance to try out the second adjustment.
Can't wait to take it for another run to see how it works. If it doesn't, I'll be back here asking questions.
I do have a question about AFR. I set the Closed Loop Bias Tables to 778 in order to get an AFR of 14.45. I'd like to go a little richer... like 14.2 eventually, so the CLBT would be set to 803 according to the O2 calculator. Am I missing something here? Streetdjack says in a recent post that 796=14.2:1. In Doc's V-Tune outline I got from someone, it says 680=14.5:1. But when I calculate it 680=14.63:1!
Are you using the data master log viewing tool or another program to view the log files?
that's what I do ... I don't have anything else to use than the datamaster...
to Rahall : I'm exactly like you, no knocking problem but I hate to see anti-knock system activity in the data....
so I made some mods in the spark advance tables and it seems to cure it...
to Yso : I also had some popping on decell and had to increase the VE 10 units front and rear between 1500 and 4000 rpm in the 0 and 2 % colums to cure it... now it's nearly totaly gone (nearly ...)
The manual states not to go in CLB value more than 798mV (about 14.2 AFR) in the Tuning comments and information... that's where I'll stop
I don't think it's a problem of difference between maps, just too little difference between 803 and 798 mV ....
Doc was a little out when estimating 680mV to 14.5:1...
I have been using the megalogviewer for a year or so. I started with it when I was using the DTT ecm and trying to understand cause and effect. It will allow you to look at 12 lines of data of your choice and zoom in on specific points It can be used to look at tts data also. You can see the knock on the green trace on bottom of the graph. You also can see many of the other paramiters that I was looking at the time the knock was occurring. Keep in mind I was not able to hear this but the ion sense was picking it up.
One thing users need to know is the HD system first then understanding knock will be much easier. The system is not there to tune the spark yet to stop the engine from knocking. What this means is it will do what it can too stop knock as quick as it can event if that means more spark is removed than necessary. Remember this is a safety device, so safety first then performance. The system reports what it see's, so you need to remember this is after it has already happened. So when you look for knock retard on a datamaster recording locate the first spot it happens and understand that it really happened just before that. This means you will need to look back a few frames of data to see where the engine was operating at to find the spot to apply a correction.
Slideshow: Jason Momoa's latest restoration project blends 1920s Harley-Davidsons with modern electric technology, creating some of the most unusual hybrid motorcycles ever built.
Harley-Davidson Fat Boy Becomes a Dark, Decepticon-Inspired Custom
Slideshow: Killer Custom's latest build relies on styling changes rather than performance upgrades, giving the cruiser an entirely different personality.
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Slideshow: The bar-and-shield logo shows up on far more than motorcycles, some of the company's most unexpected products have nothing to do with riding.
Slideshow: From the troubled AMF years to modern misfires, these bikes earned reputations for reliability issues, questionable engineering, or disappointing performance.
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Slideshow: The Swiss custom shop has taken a Harley Softail and stretched it into something so long and low that it looks closer to a rolling sculpture than a conventional motorcycle.