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Old 11-28-2017, 04:22 PM   #1
Sjeng
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Default LH2.4: How does the "tq" signal correlate to load?

Hello,

My name is Frank and I own a '97 940.

I want to learn more about LH2.4 tuning and even though I have read lots about 2.4, I haven't found an answer yet to the following.

As I understand "load" is calculated using AMM voltage, RPM and the injector constants.
LH2.4 sends a "tq" signal to the EZK which is directly correlated to the calculated load.

Is the tq signal to the EZK scaled using the load axis in LH2.4?
Meaning: If the max load in the scale is 128 this corresponds to 100% tq signal send to the EZK.
Or is there a different relation?

Also, what exactly does the "tq signal to EZK adjuster" value do?

The reason I am asking this is because changing to larger AMM/Injectors (without software changes) skews the tq signal send to the EZK and I would like to know how to compensate for that.

I appreciate your help!

Kind regards,
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Old 11-28-2017, 06:39 PM   #2
lummert
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There are write ups on certain pins of the LH 2.4 ECM retarding or advancing the ignition timing. Apparently its the pins of the EZ116K that require grounding.

http://forums.turbobricks.com/showthread.php?t=75838
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Last edited by lummert; 11-28-2017 at 07:16 PM..
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Old 11-28-2017, 09:23 PM   #3
bobxyz
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I don't know the details, but can give you a hand-waving answer to some of your questions.

Early this summer, I looked at using a EZK-116 box as a knock detector for a MicroSquirt install. I dug into it far enough to figure out that re-creating the Tq/Load signal needed by EZK box was non-trivial. The Tq/Load signal is PWM encoded. The pulse width, after some scaling, directly selects the row in the EZK ignition table. As lummert mentioned, fixed adv/ret adjustments are available by jumpering 4 pins. These adjustments are directly added/subtracted to/from the table values.

You've probably seen these:
http://www.ipdown.net/jetronic.info/...q%20and%20Load
http://ipdown.net/wiki/index.php/EZK

I have more notes somewhere, but my memory is that the Tq/Load value is essentially fuel per squirt.
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Old 11-28-2017, 11:10 PM   #4
brian smith
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50% load signal, even if that "load" is higher with your higher throughput engine, should still probably call for a similar change to ignition timing that 50% calls for on a stock set of AFM/injectors. You probably would prefer to burn a new ignition timing map for your needs and let the "call for advance" run as it may. Perhaps if you find that your installation never hits on the cells near the lowest load, you would then benefit from a change. Basically, the full-load ignition timing map is probably the one that you are most concerned with getting right for your collection of components, given that you are increasing AFM size and injector flow, so that the lower-load areas of the ignition map are probably more minor refinements. You can convince yourself of this by pulling the load signal terminal out of your EZK connector and driving the car. This sends the EZK into the full-load timing map for the safety of the engine. Fuel economy may take a hit, but drivability is fine and possibly improved. Sorry if this is well-understood and I'm misunderstanding the question.
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Old 11-28-2017, 11:54 PM   #5
turbotankshane
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In any of the custom lh2.4/ez116k mapping I've done I only ever needed to move the ezk tq signal adjuster once, IIRC the stock value for an 8v turbo bin was 20 and the value from a bin from an ecu originally calibrated for a 3" AMM was 22. The one time I had to change the value from 20 to 22 (on a car where the customer had installed a 3" AMM) it helped very slightly with engine speed slowing to idle without stalling, but I'm still not convinced that was the issue.

Basically, you shouldn't need to change that value. Compensate for the larger AMM by copying the values in the main 1x256 AMM signal lookup table and the AMM signal multiplication factors table, and adjust for your injectors with injector constants 1 and 4.
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Old 11-29-2017, 12:28 AM   #6
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turbotankshane - I think you're saying that the LH2.4 ECU needs to be reprogrammed for the larger AMM and Injectors. Once this is done, the ECU will send the correct Tq/Load signal to the EZK, correct? (At least all ECUs have easily swapped chips, unlike most EZKs.)

If the OP runs a bigger AMM and bigger injectors without reprogramming the ECU, what will happen? I think a bigger AMM by itself would result in too small of a Tq/Load value (ECU thinks there is less flow than actual). Bigger injectors by themselves would result in too big of a Tq/Load value (ECU thinks there is less fuel than actual). What do you think?
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Old 11-29-2017, 08:54 AM   #7
Sjeng
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Thank you very much for your replies.

I will burn a chip with the 012AMM linearization tables/constants and start from there.

Also I completely forgot about the jumbers adding/substracting timing. Anyone using this for switching between different fuel quality?
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Old 11-29-2017, 10:40 AM   #8
turbotankshane
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Quote:
Originally Posted by bobxyz View Post
turbotankshane - I think you're saying that the LH2.4 ECU needs to be reprogrammed for the larger AMM and Injectors. Once this is done, the ECU will send the correct Tq/Load signal to the EZK, correct? (At least all ECUs have easily swapped chips, unlike most EZKs.)

If the OP runs a bigger AMM and bigger injectors without reprogramming the ECU, what will happen? I think a bigger AMM by itself would result in too small of a Tq/Load value (ECU thinks there is less flow than actual). Bigger injectors by themselves would result in too big of a Tq/Load value (ECU thinks there is less fuel than actual). What do you think?
Personally, I would agree with you, not everyone thinks so.



Quote:
Originally Posted by Sjeng View Post
Thank you very much for your replies.

I will burn a chip with the 012AMM linearization tables/constants and start from there.

Also I completely forgot about the jumbers adding/substracting timing. Anyone using this for switching between different fuel quality?
I ran a dual-fuel setup for about two years, but I used a pair of moates two timers.

http://www.moates.net/font-size-12timerfont-p-80.html

One in the lh2.4 ecu, one in the ezk, then burn a 27sf512 chip with a stacked bin so you can ground the switch and access the other map. I had it set up for 91 normally, then with the switch grounded it was on the e85 tune.
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