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Getting LH2.4 to learn with an automatic

OVERDRIVE

OVERDRIVE

Well-known member
Joined
Jul 31, 2017
Location
Brooklyn, Neu York
I'm trying to get some chips to learn fuel trims down low (1800-2100rpms) under load with an automatic. Of course I'm only able to do this from a stop for a brief moment. B230F/AW70. Shaved head, V cam, pretty normal stuff.

1: Can I disconnect the kickdown cable and do a lot of WOT pulls from say 40 to 60mph? Is there a concern about a WOT shift while the transmission is seeing zero throttle input?

2: I am not sure how lean I am but it's definitely causing detonation and pulling a lot of timing at heavy loads down low. Is this interrupting how the LH is learning?

3: I've put 450 miles since resetting the ECU trying to get it to learn, would it learn faster if I reset it then immediately went and did this experiment?
 
OVERDRIVE said:
1: Can I disconnect the kickdown cable and do a lot of WOT pulls from say 40 to 60mph? Is there a concern about a WOT shift while the transmission is seeing zero throttle input?
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The trans doesn't see throttle input from my knowledge, its all mechanical. Nothing should be hurt at all. The kickdown cable is for just that, kicking down.
 
RE 2, 3:
There are only two global long term fuel trims. One is used at idle and the other at part throttle & WOT. There aren't any load/rpm dependent trims there or any map it creates. This is why I don't like the term "learning" in regards to LH2.4, it makes it seem less primitive than it really is.
 
Pietercc said:
The trans doesn't see throttle input from my knowledge, its all mechanical. Nothing should be hurt at all. The kickdown cable is for just that, kicking down.
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It affects the shift points based on throttle. The more throttle, the more pressure is fed to counteract the governor to make it shift at a higher rpm. It also affects line pressure. It also kicks down.
 
esmth said:
RE 2, 3:
There are only two global long term fuel trims. One is used at idle and the other at part throttle & WOT. There aren't any load/rpm dependent trims there or any map it creates. This is why I don't like the term "learning" in regards to LH2.4, it makes it seem less primitive than it really is.
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This.

If it's so lean it's knocking at low rpm, it's not because it hasn't learned, you've either got an issue with your mechanical fuel delivery or your fuel map is out of whack. The trim is for minor correction.
 
244tiCanuck said:
This.

If it's so lean it's knocking at low rpm, it's not because it hasn't learned, you've either got an issue with your mechanical fuel delivery or your fuel map is out of whack. The trim is for minor correction.
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This is kinda what I've been thinking but didn't want to hear. The car runs totally fine on 87 and the stock 933/140 bins. My injectors are cleaned and flow tested, o2 is new, fuel pressure checked, I'm running out of mechanical stuff to rule out.
esmth said:
RE 2, 3:
There are only two global long term fuel trims. One is used at idle and the other at part throttle & WOT. There aren't any load/rpm dependent trims there or any map it creates. This is why I don't like the term "learning" in regards to LH2.4, it makes it seem less primitive than it really is.
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So you're saying that WOT corrections (and part throttle too) aren't specific to anywhere in the map, it just makes a blanket correction across the board? Do the NA LH modules even use the WOT circuit of the TPS? I already checked that mine was engaging with the pedal to the floor.
 
Is it better with 93 octane? Even in stock form these engines seem to like premium no lower than 91.
Edit: Your issue made me think of the 240 turbos with the turbo Intercooler Boost System. They used a relay to keep boost at 8.5psi till over 3700 rpm because of low rpm high load knock sensitivity. Seems there is a rpm zone where they are sensitive.
 
OVERDRIVE said:
So you're saying that WOT corrections (and part throttle too) aren't specific to anywhere in the map, it just makes a blanket correction across the board? Do the NA LH modules even use the WOT circuit of the TPS? I already checked that mine was engaging with the pedal to the floor.
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Yea, it pretty much is a single global correction. What I like to call the part-throttle LTFT (as opposed to the idle LTFT) is also applied at WOT/open loop. And about the WOT circuit, after a quick lookie into the common NA bins, it triggers a RPM based map that is added to the fueling target but only when both a load threshold and RPM threshold are exceeded and the wot switch is grounded. (so it can't do anything to fueling below 3k rpm on a stock bin)
 
If you’re interested in the finer points of tuning it sounds like you’re a perfect candidate for megasquirt. All the internal combustion variables your heart desires.

Seriously.

Pick up a microsquirt, wire it in and start some control over the tuning process.

You’d need a 5v tps, wide band O2, a laptop, tunerstudio and megalogviewer….

What’s stopping you?
 
740atl said:
What’s stopping you?
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I value that I understand LH2.4, and that I have the spares I need to keep it running happy. This is my only running car right now and dependability and refinement is important, I have a local friend with an MS 16V car and it rips but it doesn't feel polished. I want to keep factory fail safes like knock control, and sensor failure modes. Next step is to buy an emulator and tweak the tune myself.
 
Are these EGR LH/EZK modules? Are you mixing and matching them? My '91 CA EGR car would run fine with the correct modules in it but rattle like a mofo if I switched to a -951 LH.
 
shoestring said:
Are these EGR LH/EZK modules? Are you mixing and matching them? My '91 CA EGR car would run fine with the correct modules in it but rattle like a mofo if I switched to a -951 LH.
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My car is originally an EGR car, EGR is still there and running the EGR LH/EZK stock ecu's. My chipped EZK is a 207 with the EGR enabled. There are no changes to the LH tune for the EGR in my car. The LH tune is in a 954 which shouldn't matter, it did the same thing when in a 933.
 
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