Mileage with efi marginal increase. Don’t get it to save fuel. Its about drivability mostly hot restarts and actually having the car run in Reno elevation at 100 degrees.
I Finally Did It.....EFI
- Thread starter threewood
- Start date
Here is a pull today. WOT, RPMs climbing slowly and you can see the afr start to break up with the spikes. Fuel flow and duty cycle continue to climb out of sight.
andyf
Well-Known Member
Change your CL comp limit to 100 from 50 and see if the fuel flow can keep up. Right now you are running the engine lean because you have a limit set. The Sniper can't add fuel due to the limit you have set. You've hand cuffed your Sniper and if you keep going WOT like that you'll damage the engine.
That_Tall_Dude
Well-Known Member
Huh, somebody said misfires will show lean...
Those spikes are lean... so misfires?
Or no?
Those spikes are lean... so misfires?
Or no?
Wietse
Well-Known Member
I am just getting into this EFI stuff and are reading up as i can, but from what i understand the CL (Closed Loop) mode will not be active during WOT right?
The extreme AFR spikes at the moment the throttle is opened and closed are understandable as there is an extreme change in conditions.
The AFR readings during the period of WOT also show spikes, think that is something that needs to be sorted out?
The extreme AFR spikes at the moment the throttle is opened and closed are understandable as there is an extreme change in conditions.
The AFR readings during the period of WOT also show spikes, think that is something that needs to be sorted out?
Wietse
Well-Known Member
I guess you are correct that those spikes during WOT might be misfires.
If you would pull an average line of the AFR during the WOT period it just gets a little leaner as rpm increases.
Too bad there is no AFR scale on the chart to see where it is at, although it says an average of 13.6 in the right top makes me think it runs on the lean side, but that will be included to 2 big spikes which are not really applicable when looking at just WOT.
I changed the parameters prior but maybe it didn't save. Educate me a bit on this. I thought the CL Comp % was the amount of fuel being added to the base or subtracted (shown with a minus) from it. So I thought the 50% number was showing that 50% more fuel was being added to keep near the target afr?
If you look at the chart, the intersection of the white horizontal and vertical lines shows exactly what the sensors are seeing at that moment. 13.7afr is what is shown for THAT point. But you can see that the longer at wot (as shown by the tps plateau at 93% open) the more afr fails to maintain. And duty cycle goes way up along with fuel flow. I'm not sure the fuel flow shown is correct.
The fact that the duty cycle goes way above 100% makes me think it is trying to deliver fuel it needs to keep up.
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Wietse
Well-Known Member
From what i understand is that when in closed loop (CL), which is setup to run the engine as efficient as possible due to reacting on the feedback of the A/F sensor to maintain a predetermined AFR, is not applicable at all under WOT conditions.
The AFR reading should be completely ignored under WOT conditions and the ECU only uses the map values as programmed.
I think the CL Comp % is just a limiter of the fuel feed that is available under Closed Loop conditions.
So when closed loop is activated the ECU can only use 50% of the max. fuel flow.
Ok. When I went into advanced tuning on the handheld the values for CL Comp can go way above 100% but I set them up for 100%
andyf
Well-Known Member
Did you upload the file to the ECU after you made the changes? You have to turn the key on, find the file on the SD card, up load to the ECU, and then cycle the ignition. It it easier to keep track of things if you change the name of the file each time. That way you can verify if you uploaded it. If the name is always the same then you can't really tell which file is which.
You are correct that the 50% number is showing that the program is adding 50% more fuel than is in the base table. You are hitting the guardrail for some reason. I don't know why but the easy thing to do for a beginner is to just move the guardrail over. I'm pretty sure you have a fuel delivery issue. Could be the pump, could be something else. One easy thing to do is to look into the Sniper while the engine is running to confirm that all four injectors are firing. If you have one injector that isn't firing then that could explain what you are seeing.
andyf
Well-Known Member
CL should be working at WOT. If it isn't then there is another issue. It is easy to tell if CL is on or not since the data log captures that. I always look at that first before I do anything else since you need to know if the system is working or not. If the system is working then you change the parameters, if the system isn't working then you figure out how to get it working.
Wietse
Well-Known Member
I was reading this:
https://hooshmand.net/open-loop-clo...n a nutshell, closed loop,revs are, and so on.
Thats why i figured during WOT the ecu does not look at the O2 sensor, but instead just goes by the fuel map, then again the target ARF can be set for WOT conditions so in that case it means the ecu will use the O2 sensor feedback indeed.
https://hooshmand.net/open-loop-clo...n a nutshell, closed loop,revs are, and so on.
Thats why i figured during WOT the ecu does not look at the O2 sensor, but instead just goes by the fuel map, then again the target ARF can be set for WOT conditions so in that case it means the ecu will use the O2 sensor feedback indeed.
No, i did it on the hand held panel. Clicked save but never cycled the key off. Is this suppose to be done on a computer? I'm not certain how to get the sniper software from the handheld to my computer. Do I save the file onto to SD card?
Also, I'll probably wait until I have the new pump in to test it out more. I checked all the lines and they are in good shape.
andyf
Well-Known Member
That article is a bunch of confusing gobble gook. If you want to understand how a Sniper works read the Sniper instruction book: https://documents.holley.com/techlibrary_199r11031r-1.pdf
andyf
Well-Known Member
Tuning changes are difficult to make on the hand held, especially for a beginner. You'll learn a lot faster if you down load the tune file from the Sniper to the SD card and then pop the SD card into your desktop computer. This is assuming you have something that runs windows 10 on it. If you a Mac then you're kind of screwed.
Thanks! I watched a video about copying it to the SD card and also about doing the same for firmware updates. I'll give it a shot tonight.
Verified all 4 injectors are firing. Looked at the learn table and you can see how much fuel the Sniper was trying to add at wot. My new pump should be here Tuesday so I will clear the learn table and start over with the new Walbro 450 installed.
That_Tall_Dude
Well-Known Member
Very cool!
Same questions.
If the engine is misfiring it will show a false lean read in the 02 sensor right, and the sniper will try to try to go rich in response right?
That’s what’s the learn table is showing here correct?
That the O2 is showing leaner (cause not determined) at high rpm than the baseline and the efi is trying to compensate
Do we know the spikes aren’t misfires?
Not saying that are, am just wondering if they could be misfires...
Seems like inadequate pressure would do that too, but I don’t really know..
Also we don’t know the fuel pressure at the efi when this is occurring correct?
If it were a false lean condition, then the EFI would make overly rich correct?
And if it fuel starvation it would be overly lean, correct?
Wouldn’t those different scenarios show up on the plugs efi gurus?
A misfire will show as lean because of the extra unburnt O2. The spikes could be misfires, yes. Until I get a pressure gauge on it, I won't know for sure. Because the spikes start after wot and not immediately I still believe it is fuel availability dropping. I dealt with pressure loss with a mechanical pump before and the car acts the same... strong on the throttle and then leaning out after a few seconds wot. I had pulled the plugs a week prior to the Sniper install and the plugs were a bit on the lean side. Gray/tan, no soot.
And I would think with a misfire the rpms would break up as well.
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