1st Gen Haltech ECU Discussion

I've been wanting to setup an electrical load switch idle up function. When I try to run my ARB dual, it stalls the motor cause it's too much of a draw

 

You should already be able to do that; I had generic idle ups available from the beginning. There's also an "electrical load" idle up but I'm not sure how to enable it.

 

Yea I'm referring to the electrical load idle up. Wasn't sure how that was triggered and if I needed to add some sort of wired input for that.
The first thing that comes to mind for an "electrical load" idle up condition would be looking for a voltage drop in a certain range to trigger an added idle RPM offset. Guess I could setup a generic for that kind of condition, but don't know how effective that would be. Gonna need to test that

Edit: so looks like I would wire in the same switch to my ARB to that generic sensor 1 on the ECU so that it offsets the idle at the same time the compressor is turned on.

 

Ah, think this is what triggers it
https://support.haltech.com/portal/en/kb/articles/electrical-load-switch

I'd probably just tap my air compressor switch output into a generic since as far as I'm aware our trucks don't have a load sense output.

I also don't think there's a way of scaling idle up to a load draw even if we did have such a sensor (analog voltage output rising with current draw), so either way should work the same. You just don't also have the RPM-up target with the generic.

 

Gotcha. So could theoretically tie that into the voltage sense circuit on our alts? Don't know if that circuit is analog or SPI or if that would even work.

And yea that's what I think I'll do. Didn't think of the generics for idle up.

 

I don't think that would work directly since I don't think you can do analog sense above 5V. Tbh I've never looked into the alternator circuit so I'm not sure how the regulator functions exactly.

What you could do if you're adamant about sensing entire system draw instead of just a static on/off of a single large draw is get a current shunt and controller. You'd wire it between your battery post and main power wire and read the voltage drop over it, and amplify it to max out at 5V, at say, 100A. https://learnarduinonow.com/2015/05/11/reading-current-shunt-with-arduino.html
Then you'd have a linear voltage output proportional to the current draw and can set a trigger based on a certain amperage draw. You could then set conditionals for various, discrete levels of Idle Up too if wanted (since again, there's no proportional idle up as far as I'm aware), but generic conditionals are scarce on the HT so use them wisely.

 

The easiest way to trigger the ECU for just that load would be to have the compressor positive activate the control side of a relay that completes a circuit from the ECU to ground. Then the ECU can just look for that pin to be grounded to idle up. You could hook lots of stuff to it that way @betterbuckleup

 

Do those compressors have an internal shut off/regulation? I might be oversimplifying if so.

 

Yeah, they turn off on their own at regulated pressure, like 120psi

 

Ah gotcha, I was just assuming he had a switch that directly controlled the load and could tap off that.

In that case, ya, I think a relay would be the simplest. Though it would probably need to be a beefy one since the switching side (coil) has to support the full load of the compressor (I don't even know where to look for that). In that case the current shunt might prove to be the most practical solution after all

 

Now that I think of it you could just use the compressor relay itself to trigger the new (electrical load) relay right?

 

If you can access it and it's got electrical pins that are de-energized and then energized, ya that would be perfect. If it's purely mechanical, might be SOL.

 

Tech tidbit from Haltech since we were both interested in it.

 

good idea with the controller and current shunt. Although don't really think I need a system sensing function.

Now that I thinking though, the winch is another high draw item that I would need the idle to compensate for. Even more so than the compressor since it's capable of pulling a lot more amperage. So maybe possible to tie both of those outputs into one with diodes?

My compressor has two dedicated positive bat wires to supply it, and then an 18?ga or so wiring harness that goes into the cab for the switch and locker control. So I was thinking I'd just tap off of the positive output of the switch for the ECU switching signal.

not really sure where the relay for the compressor is. I assume inside of it somewhere since it's not in the diagram but listed as a PN

 

What is your idle set to that the compressor can make it stall so easily? I turned every load on my truck on with it idling the other day and it barely even dipped. The stock 5vz electrical load compensation is only about 100 RPM plus or minus 20

 

If you can dedicate yourself to only using the in-cab switch, you just tap the power from the switch into the Haltech. x2 if you need one for the winch also. The complication is only arising because the compressor can apparently be always switched on, and self-regulate within that ON state. If you de-smart it, problem solved.

Or you can try increasing the I part of the PID idle control for negative RPM error

 

Well honestly I've been having idle issues for quite some time now. That and cold start behavior. But I don't wanna go into too much detail about the different things it does in different situations for the sake of clarity. I can't quite seem to iron it out no matter what I try. Gabe was having a lot of trouble with it too.
I have it set for 850 when warmed up, but it idles at around 1k. I have to bring the base output down way too low to get it to hit the target, and then it doesn't consistently come back to the target after some revs. Just overall not consistent behavior.
I've been told it could be because of my IAC and deleted EGR, but the coolant lines to the tb are good and the IAC functions as it should

 

This might be a calling for me to do my Idle tuning write-up

I have mine running better than factory now.

 

What does your min output table look like?

 

This looks extremely under defined. @treyus30 or myself could probably help you straighten this out. It doesn't appear that it's been tuned at all other than trying to put in some RPM goals, but that alone won't make it function. I don't think you have load based stall issues, I think you have a really poorly configured (not configured at all) idle control section. It doesn't have any reactivity to vacuum so it can't really self adjust.