Injector scaling and latecy for different injectors.
Quote:
Originally Posted by l2r99gst
On average, your crusing injector pulsewidths will be double your idle injector pulsewidths. So, any changes that you make in the injector deadtime will affect idle twice as much as it will affect cruising. But, yes, it will affect both if they are both in the same V range that you are adjusting for.
DSMLink used a global fuel setting slider and then an injector deadtime value to tune the injectors. Their global slider was basically the injector scaling value in the ECU and their deadtime was basically what we get to adjust in the voltage latency tables.
But, with the years of experience with DSMLink and seeing others dial in injectors, the above holds true.
Basically, what we did with DSMLink is as follows:
1. Choose a global setting (ECUFlash injector scaling number)
2. Log trims at idle and cruise
3. If trims are roughly the same, but positive, then you need to increase your global fueling, or in terms of ECUFlash, you need to lower your injector scaling number.
4. If both trims are roughly the same, but negative, then you need to descrease your global fueling, or in terms of ECUFlash, you need to raise your injector scaling number.
5. If idle trim is more positive than cruise trim, then you need to increase the dead time, or in terms of ECUFlash, you need to increase the latency value.
6. If the idle trim is less positive than the cruise trim, you need to decrease the deadtime, or in terms of ECUFlash, you need to decrease the latency value.
Note: After #5 or #6, you may need to readjust #1 accordingly.
Note 2: #5 and #6 implicitly answer ludikraut's questions about affecting idle and cruise trims. Basically, let's say that the IPW is 1ms at idle and 2ms at cruise. If you adjust the deadtime to add 100us (.1 ms), then you are affecting the idle fueling 10% and the cruise fueling 5%.
Eric
Originally Posted by l2r99gst
On average, your crusing injector pulsewidths will be double your idle injector pulsewidths. So, any changes that you make in the injector deadtime will affect idle twice as much as it will affect cruising. But, yes, it will affect both if they are both in the same V range that you are adjusting for.
DSMLink used a global fuel setting slider and then an injector deadtime value to tune the injectors. Their global slider was basically the injector scaling value in the ECU and their deadtime was basically what we get to adjust in the voltage latency tables.
But, with the years of experience with DSMLink and seeing others dial in injectors, the above holds true.
Basically, what we did with DSMLink is as follows:
1. Choose a global setting (ECUFlash injector scaling number)
2. Log trims at idle and cruise
3. If trims are roughly the same, but positive, then you need to increase your global fueling, or in terms of ECUFlash, you need to lower your injector scaling number.
4. If both trims are roughly the same, but negative, then you need to descrease your global fueling, or in terms of ECUFlash, you need to raise your injector scaling number.
5. If idle trim is more positive than cruise trim, then you need to increase the dead time, or in terms of ECUFlash, you need to increase the latency value.
6. If the idle trim is less positive than the cruise trim, you need to decrease the deadtime, or in terms of ECUFlash, you need to decrease the latency value.
Note: After #5 or #6, you may need to readjust #1 accordingly.
Note 2: #5 and #6 implicitly answer ludikraut's questions about affecting idle and cruise trims. Basically, let's say that the IPW is 1ms at idle and 2ms at cruise. If you adjust the deadtime to add 100us (.1 ms), then you are affecting the idle fueling 10% and the cruise fueling 5%.
Eric
My car is now throwing P0300's now.. It's running like poop. Could this be related to having the injectors scaling really out of wack?
The scaling now is set to 1044 I believe... Was at 9XX and was still getting negative fuel trims..
These FIC 1050's seem to spray a TON of fuel. I remember looking at the flow chats that came with the injectors, they were rated at 1072, 1068, 1068 and 1072 cc/min. So, based on that, what kind of scalings should I be looking at? These FIC's are a little harder to get to work right than my old PTE680's..
My car is now throwing P0300's now.. It's running like poop. Could this be related to having the injectors scaling really out of wack?
The scaling now is set to 1044 I believe... Was at 9XX and was still getting negative fuel trims..
These FIC 1050's seem to spray a TON of fuel. I remember looking at the flow chats that came with the injectors, they were rated at 1072, 1068, 1068 and 1072 cc/min. So, based on that, what kind of scalings should I be looking at? These FIC's are a little harder to get to work right than my old PTE680's..
My car is now throwing P0300's now.. It's running like poop. Could this be related to having the injectors scaling really out of wack?
The scaling now is set to 1044 I believe... Was at 9XX and was still getting negative fuel trims..
These FIC 1050's seem to spray a TON of fuel. I remember looking at the flow chats that came with the injectors, they were rated at 1072, 1068, 1068 and 1072 cc/min. So, based on that, what kind of scalings should I be looking at? These FIC's are a little harder to get to work right than my old PTE680's..
I tuned the injectors of a set of RC 1000 and kept going up to 914 from 812 and the trims stayed negative. Then I decreased the latency by 0.1 ms in the 11-14 V area and the trims when down from -11 to almost 0.
With big injectors the trick is in changing the latencies and not the scaling.
I have a question about fuel trims. I installed RC 1000 cc injectors and used the following scaling/latency:
The above gave me a +4 trims. After that I reduced the latency to 835. That gave me a -3 trim for both lo and hi.
So which is better for fuel economy a fuel trim of +4 or a fuel trim of -3. I think it is -3, but I want to check with you guys.
The above gave me a +4 trims. After that I reduced the latency to 835. That gave me a -3 trim for both lo and hi.
So which is better for fuel economy a fuel trim of +4 or a fuel trim of -3. I think it is -3, but I want to check with you guys.
I have a question about fuel trims. I installed RC 1000 cc injectors and used the following scaling/latency:
The above gave me a +4 trims. After that I reduced the latency to 835. That gave me a -3 trim for both lo and hi.
So which is better for fuel economy a fuel trim of +4 or a fuel trim of -3. I think it is -3, but I want to check with you guys.
The above gave me a +4 trims. After that I reduced the latency to 835. That gave me a -3 trim for both lo and hi.
So which is better for fuel economy a fuel trim of +4 or a fuel trim of -3. I think it is -3, but I want to check with you guys.
Different trims are just going to change the transitional AFRs from closed to open loop a bit.
Eric
Which would you prefer to see on your car, -3 trims or +3 trims assuming fuel economy is unaffected? If -3, then why? If +3, then why?
There are other reasons, too, that may effect your decision, like what gas you use and whether they add 10% ethanol during different seasons of the year, etc. There are really too many variables to say which is better. I would be happy with either, since you have enough room for adjustment either way to compensate for any variables that may change the trims in either direction.
Eric
I am gonna have to reassess these settings...over time they have gone a little to far out trim for my liking. Evo 8's Trims never seem to reset unlike the Evo IX where it resets everytime you flash.
Hmmm....Well, no more P0300's now. I noticed exactly what you guys said, the latency adjustment make big impacts, more so than the overall scaling.
This seems a little off the wall my settings now:
Scaling: 1083
9.38 1.344
11.72 1.152
14.06 0.840
16.41 0.360
The car as it was after driving to work this morning:
Fuel Trim Low - -0.84
Fuel Trim Mid - -2.xx
It seems with changing the 14.06 and 11.72 volts, I am chasing a ghost. Any changes to latencies now take the fuel trims farther away from where they are currently.
Any thoughts on the 1083 scaling though? Sounds really high to me. FYI, they are FIC 1050's, and the flow sheet that came with them said they flowed min 1068 cc/min with a max of 1072 cc/min. These things probably flow more like 1100's from other brands. So, does that scaling make sense? At least the fuel trims are in check now..