Tuning throttle tip-in enrichment, LH2.4

Hello there! I figured I'd make a separate thread than post in the long thread because this way you can actually find a thread just for what you're researching...

In the General Leif we're running 850T injectors with a 960 MAF, 933 ECU and injector constants of Injector Constant 1 at 104 and Injector Constant 4 at 3400. The fuel map is decent at full throttle and the top load cells, but the lower load and midrange stuff has not been dialed in on the dyno(or street). I haven't driven the car with the current tune in it yet, but even before it was going lean on tip in at lower rpm and will do a lean backfire if you don't ease into it. This is especially noticeable when cold and I haven't warmed it up fully to double check that it's an issue when warm. I might be able to alleviate it with a little more warm-up enrichment, as I have that leaned out a bit.

That being said, I know there are some accel. enrichment tables but am curious what would have the greatest affect on the initial lean mixture you get when you stomp the gas.

There's a value that's been adjusted on some of my tuned bins from other people that I want to say is an injector latency thing, but I don't think I see that table in TunerPro unless it's the pulsewidth modifier under the Start and Warmup folder. Maybe it is that... It looks like that when you raise the values there, it lessens the amount of fuel injected when trying to start the car, such that if you are needing to give it throttle because it's too rich, you could raise these numbers to lean it out and maybe not need to give it throttle?

Thanks in advance!

And yes, I know this is best fixed by having something other than LH2.4 that only has an on/off switch for the throttle position sensor...

I'd like to learn more about the coarse and fine "rpm vs load" maps as well as whether the WOT enrichment works. It says not enabled in my bin, but people claim it works. I have a bin I'm experimenting a bit with that I'm trying the WOT enrichment above 3k-ish.

Lh & ezk

Hi Kyle

The LH has several adjustments for fuel enrich/enleanment depending upon wether you increase or decrease throttle, usually stock settings are fine so most people haven't fiddled too much with it and due to that they are mostly unchartered.

regarding the start regime I suspect your injector change has upset the constant governing fuelling before the engine is considered started. (start fuel injector constant)
I would have tried lowering this before anything else.

YS
JB

klr142 said:

Hello there! I figured I'd make a separate thread than post in the long thread because this way you can actually find a thread just for what you're researching...

In the General Leif we're running 850T injectors with a 960 MAF, 933 ECU and injector constants of Injector Constant 1 at 104 and Injector Constant 4 at 3400. The fuel map is decent at full throttle and the top load cells, but the lower load and midrange stuff has not been dialed in on the dyno(or street). I haven't driven the car with the current tune in it yet, but even before it was going lean on tip in at lower rpm and will do a lean backfire if you don't ease into it. This is especially noticeable when cold and I haven't warmed it up fully to double check that it's an issue when warm. I might be able to alleviate it with a little more warm-up enrichment, as I have that leaned out a bit.

That being said, I know there are some accel. enrichment tables but am curious what would have the greatest affect on the initial lean mixture you get when you stomp the gas.

There's a value that's been adjusted on some of my tuned bins from other people that I want to say is an injector latency thing, but I don't think I see that table in TunerPro unless it's the pulsewidth modifier under the Start and Warmup folder. Maybe it is that... It looks like that when you raise the values there, it lessens the amount of fuel injected when trying to start the car, such that if you are needing to give it throttle because it's too rich, you could raise these numbers to lean it out and maybe not need to give it throttle?

Thanks in advance!

And yes, I know this is best fixed by having something other than LH2.4 that only has an on/off switch for the throttle position sensor...

Click to expand...

mrjaybeeze said:

regarding the start regime I suspect your injector change has upset the constant governing fuelling before the engine is considered started. (start fuel injector constant)
I would have tried lowering this before anything else.

YS
JB

Click to expand...

Hey JB!
Thanks for chiming in. Are you talking about the 1x9 cranking main pulsewidth modifier?

The car starts fine, it?s just a little lean on tip in.

More feedback after messing with the tune this evening before our race tomorrow:

My idle was super lean in general(17-18:1 or so, so giving that a lot more fuel helped a lot(now around 15:1), and giving it back to stock warmup enrichment numbers seemed to help as well(I had lowered almost all of them around 10 points). My map looks really weird though, and we apparently have some serious restriction in airflow or something at high rpm as you can see how much fuel I had to take out to keep the AFRs near 13:1 up top.

High load up top, low load on the bottom, idle cells in bold, rpm x1000 on the top:

6.72___ 5.65___ 4.96___ 3.90___ 2.76___ 2.32___ 1.41___ 0.72 0.51
110 113 121 156 149 137 147 145 142 122 121 118 116 109 109 109
110 113 121 156 149 137 147 145 142 122 121 118 116 109 109 109
110 113 122 146 142 132 140 139 135 120 118 115 113 109 109 109
110 111 120 138 134 127 130 128 124 113 112 109 107 109 109 109
110 111 118 134 130 121 117 115 111 106 106 104 103 109 109 109
108 110 117 129 125 116 111 110 103 102 102 101 100 109 109 109
106 108 114 123 116 111 108 105 098 098 098 098 098 109 109 109
104 106 112 116 112 107 102 095 091 091 091 091 094 109 109 109
097 098 099 102 100 098 092 092 088 090 089 089 090 109 109 109
091 092 093 093 089 086 082 082 082 082 082 083 087 109 109 109
091 092 092 090 086 082 077 076 076 077 077 080 085 112 112 112
090 090 090 084 082 076 074 072 072 075 076 078 082 112 112 112
090 090 088 083 079 074 073 072 072 072 076 076 082 112 112 112
090 089 087 080 077 074 073 072 072 072 073 076 082 112 112 112
090 088 087 080 077 074 072 071 071 071 074 076 082 112 112 112
091 091 090 084 079 078 077 076 076 076 078 079 085 112 112 112

Another weird bit is WOT at really low rpm(under 2000 or maybe 1500rpm), it goes very rich even though the number aren't going up. Ooooh, I think I just figured it out. It's because the fuel pressure goes up with the reduction in manifold vacuum!

Last thing that I'm curious about, is how do you get the car to be not so lean when it returns to idle? It isn't as bad now that I've added fuel at idle, but it still drops back to 17:1 or leaner and takes a moment to recover. This may go away with turning off the decel fuel cut, but I like that fuel saving feature. Maybe I'll dig into it some more.

Have you made any progress with the lean idle? I am experiencing this with slightly smaller than stock injectors. Increasing constant #4 makes the load axis cell move too low and off the map.

Hi



Could you try to explain a little more detailed what you are experiencing ?


YS
Jaybee

Sorry haha!
It seems as though when the idle switch is engaged, the computer is trying to lean out the mixture. This is my map right now to correct for it. It happens with both lambda on and off.


For reference I am using a 946 (NA b230fd emissions) computer and bin which is the same exact code-wise as the 954/962 bins so i'm using your xdf for it. I have EV14 4 hole, single spray cone injectors from a mid/late 2000's ford 4.6L which flow at about 170cc at 2.5 bar. Stock, unchanged bin with these injectors is way too lean to drive, it barely runs.

When i increase constant #4 to like 4200, it sort of helps the situation, but it causes the load axis on the main map to hit the bottom row even at not-fully-wot throttle angles, where with the stock constant of 3889, WOT pulls the cells in the 3rd or 2nd cell from the bottom as it should. I was playing around with constant 1 values from 100-180 ish but that was not behaving correctly, i forget how on the top of my head. It and the other known constants are at stock.

Also, not sure if this is related, but at really low loads the computer seems to have a tough time doing the lambda 'sway' thing for the catalyst. it almost seems like its in open loop at idle, but it correctly hangs out at ~1.0 lambda.

I will get a video maybe this weekend to show what is going on better than I can explain.

Hi


Interesting stuff


The #4 constant seems to be a sort of load range denominator and not connected to actual injector size.
Meaning that for max power with NA engines it should be set at 3889 for atmospheric at WOT, while on Turbo engines it will decrease as boost levels rise at WOT.


The #1 constant sets the actual injector size and this is a very sensitive constant, just a few numbers up/down have a very noticeable effect.


It is also worth remembering that the behaviour in the main fuel map map will reflect in your ignition timing. If it not entering the top row or are there too early the timing will be off in a similar manner.


YS
Jaybee

Thank you much for your input. I tried again the other night with small changes to constant #1 and it did adjust total fuel delivered but it seems idle is still too lean compared to cruise/wot in the same ratio.

I was also trying to trace the use of each lesser documented map and maybe trying to find one that was only accessed at idle/low loads where it goes lean, but I didn't find one that seemed to behaved as i thought it should.

I have a new catalyst for my car to try to get it to pass Massachusetts inspection, and I really want to get this and the lambda sway thing to work properly to give it a long life. If I can't figure it out, I have 250cc @ 3bar injector which should flow about ~208cc at 2.5 bar which might make the computer happy with less tweaking. I'll try fiddling with it some more before swapping injectors. Would be nice to figure it out.

Hey guys!

Very interesting, @mrjaybeeze "The #4 constant seems to be a sort of load range denominator and not connected to actual injector size.
Meaning that for max power with NA engines it should be set at 3889 for atmospheric at WOT, while on Turbo engines it will decrease as boost levels rise at WOT."
That explaines a lot for me, i am running 315cc Injectors on an NA set the value to 2350, and never saw Open Loop under load. Thank you!