Haltech Control of the A442f (1 Viewer)

[moremazda]

So I've been struggling with an engine rpm flare on hot start. It is related to IAC function. The IAC shows that on start the engine state is in "Decel Mode", my guess is that the IAC is full open since without a time based rev limit it runs straight to 3k rpm. And that's basically the only issue that I have. So if y'all have any ideas, the tech help at Haltech USA said call Austrailia.

The transmission functionality is just fine. The haltech base map is only 5%-10% rich and the LTFT are coming in nicely. Starts with the base coolant corrections, and cranking maps. Tonight I'll leave out side and see how starts when gets into the 20's.

Since the timing solenoid is the primary reason I started this it worth mentioning what I found today. That is running the A442 timing solenoid with the A342 default settings for the A342 accumulator solenoid (which is PWM duty cycle of 50% at 5% throttle tapering out to 0% duty at ~40%) takes the rough edge off of the shift turning more into the stock shift characteristic. I'm not sure if that is actually how the stock solenoid runs, or if there is a true timing aspect and it simply opens during the shift. Not knowing I disabled it until I learn how it's actually supposed to work. The shifts without feel more firm but that is totally subjective measure of function with out knowing how these were designed. Anyway, you could probably do what several people here already mentioned (and do), at not use it at all.

 

[ThreeEyedBandit]

Can you see in the software the IAC being commanded to step open? It should be in the last position otherwise. I'm also guessing there isn't a setting to disable iac moves in decel mode?

Don't forget there is a vacuum operated dash pot that opens the throttle when no vacuum is applied. Opens the throttle when engine is off, and fairly quickly closes the blade once the engine is alive. Mine had a similar start flair(2500rpm) when it was mis adjusted.

With a modern ecu I would disable it.

 

[moremazda]

I do want to post a summary of the parts used. My rig is a '94 and I made everything completely plug and play.......other than having to trim the back of the glove box to clear the ECU header plug, no other modification where made to the rig. There are three parts to un-plug and three stock parts to put back in order to return the rig to stock; the transmission ECU, the engine ECU, and air flow meter.

I 3D printed a TCU box to hold the solid state relays (Hella P/N 931774031) the header pin and the Haltech PRNDL converter.
I 3D printed a box to hold the ECU header and provide strain relief to the soldered pins. I used a haltech basic harness to graft to the ECU header
I 3d printed an AFM delete pipe to hold the Haltech supplied GM air temp sensor......and delete the AFM
I bought the seven pin plug linked in this thread to build a connector that uses the AFM plug as a fuel pump relay pass through and connect the air temp sensor to the Haltech.
I used the dual channel CAN Wideband controller from Hlatech.

I'll probably get the 2" Haltech CAN gauge........once the turbo goes in. But that will be a little bit further down the road.

Also there is a big difference in the drivability of the rig now, like night and day for those weirdos that pay too much attention to how the cars work. It is clearly quicker at full throttle and still runs in the low 12's for AFR. I plan to map knock threshold against 87 and 93 and figure out what timing it really wants. I also have fuel milage data for the 3500 miles that I've gotten on it before this and plan to use it as my daily to capture the effect on milage of adding the Haltech.

 

[moremazda]

Can you see in the software the IAC being commanded to step open? It should be in the last position otherwise. I'm also guessing there isn't a setting to disable iac moves in decel mode?

Don't forget there is a vacuum operated dash pot that opens the throttle when no vacuum is applied. Opens the throttle when engine is off, and fairly quickly closes the blade once the engine is alive. Mine had a similar start flair(2500rpm) when it was mis adjusted.

With a modern ecu I would disable it.

I did not know that. I'll go look for it now.

 

[moremazda]

I did not know that. I'll go look for it now.

nope that's not it.

This seems like the IAC running to full stroke at cranking, and then the ECU going into a decal cut state that disables IAC control and then it just sits there. While it's happening I can put in a different value for the IAC step count and it kicks the ecu out of the decal state everything starts to work. this it only on starts.

 

[ThreeEyedBandit]

That makes sense, how long does it hang at the higher RPM?

 

[moremazda]

That makes sense, how long does it hang at the higher RPM?

Sometimes it won't come off of it until I do something.

But I have found a thing. Haltech has the number of IAC steps in the base map ( and their 1fz setup page) set to 240. Well it looks like the IAC logic puts the IAC at that full position during cranking. It doesn't care too much about the max percentage number in the IAC settings.

So I played with two settings moving the decel rpm higher and that didn't do anything. And I played with the number of steps in the IAC configuration. So far a step count of 120 keeps the rpm low enough to not get into the decel cut trigger and still give the controller enough authority to actually control the idle. The min allowed position needs to go to zero for this steps setting (or at least that is where I have it right now) or it will just bottom out on that min setting and not reduce the idle further.......so far it is working pretty well.

I did a 177 miles this morning on the free way at 70-75mph and got 11.7mpg, I was secretly hoping for at least a little bit of an improvement right out of the box, but I have to remember that it is basically a rolling brick

 

[Speedytech7]

@moremazda Are you using a factory gauge cluster in your 80?

 

[moremazda]

@moremazda Are you using a factory gauge cluster in your 80?

Yup, bone stock other than the things to make the haltech plug in.

 

[obe12]

That makes sense, how long does it hang at the higher RPM?

Did you find the reason for Hi RPM after restart? I noticed My 94 Haltech 2500 installation, If I shut down and immediately restart no Hi PRM, but if I wait after shut down and my 2 inch Haltech 4-1 gauge goes dark and then at restart the rpm races up for a few seconds and settles down.

Now if I turn the Key to ON after sitting 1 min or longer and allow the Fuel pump to prime and shut off / also my tach sweeps up and down too, then start the engine its Normal RPM with No Engine RPM flare up.

I can reproduce this symptom every time now. Now that I learn the timing of it.

 

[ThreeEyedBandit]

Did you find the reason for Hi RPM after restart? I noticed My 94 Haltech 2500 installation, If I shut down and immediately restart no Hi PRM, but if I wait after shut down and my 2 inch Haltech 4-1 gauge goes dark and then at restart the rpm races up for a few seconds and settles down.

Now if I turn the Key to ON after sitting 1 min or longer and allow the Fuel pump to prime and shut off / also my tach sweeps up and down too, then start the engine its Normal RPM with No Engine RPM flare up.

I can reproduce this symptom every time now. Now that I learn the timing of it.

I don't know, I don't have a Haltech running a 1FZ. I would guess that it's homing the IAC, and the couple seconds that it takes to prime is long enough.

Try shutting it off, then go out and listen with a stethoscope/rod/extension to the iac when someone else turns the ignition back on(no cranking or starting). You might hear the iac moving for a second or two then stop.

 

[obe12]

I don't know, I don't have a Haltech running a 1FZ. I would guess that it's homing the IAC, and the couple seconds that it takes to prime is long enough.

Try shutting it off, then go out and listen with a stethoscope/rod/extension to the iac when someone else turns the ignition back on(no cranking or starting). You might hear the iac moving for a second or two then stop.

Well we might be hi jacking the thread after I saw the idle issue.

Learned today after Calling Haltech about this transmission Timing solenoid control. Haltech tech said the Timing solenoid
Can be configured… the question asked was What’s its function and how it is controlled, Off /On or PWM modulated and when. I will now connect a scope and monitor this control to the timing solenoid, engine braking , hard throttle shift ect. With this info Haltech can provision this.

While on the phone with the tech, we talked about increased idle speed after restarting. This tech zero in in this issue, now we discuss IAC stepper motor. After shutdown and some time elapses the ECU powers down, you can witness this via Haltech Software… then after drop out restart it… the Haltech recalibrates its IAC from either full closed or full open to finds is position. If your is like mine full open after you start it take this tile to extend the stepper to normal idle.

If you shut down and restart immediately it doesn’t seek recalibration.

The tech through live connection, uploaded a timing map. To retart the timing for like 5.5 seconds if ilde is above xyz and engine run time is under this parameter.

This addition keep my idle after restart “after drop out” to 11-1200 rpm and settled down.

Doesn’t rev 2500 rpm and then come down.

This is a work around but works…

Next, this is save shut down IAC position.

The tech thinks depending on how it powered could make a difference if save IAC position.

Tex

 

[ThreeEyedBandit]

My(94) timing solenoid is either on or off, no pwm. I'll check some documentation to see otherwise, but I believe this is accurate.

 

[obe12]

My(94) timing solenoid is either on or off, no pwm. I'll check some documentation to see otherwise, but I believe this is accurate.

Nice to know, the next is when under what conditions.

1 peice of the puzzle… solved

 

[ThreeEyedBandit]

It's on a little before the shift then off after the shift completes, but only under light throttle. I'm sure the timing is mapped slightly different based on throttle position and rpm.
II
've driven with it connected and disconnected and as I've said in the past, wouldn't waste my time with it. My old diesel swapped 80 is still running around, almost 10 years later amd has never had it hooked up.

Keep updating this though, info is always good.

One other thing I have not seen is anyone posting up their tune file, I have been working on one for a 1fz/a750 and would be nice to have a starting point for others.

 

[obe12]

I ordered the PNDL2 interface box to interpret gear position as well as OD off / On . Boomslang is making me a fly lead harness to plug directly into the trans ECU connector harness to keep from cutting wires. Have this Haltech PNDL2 box in inline to Haltech. Now I be able to allow Haltech to control my A442F which now it’s parallel connected oem engine trans ECUs currently. Moving towards full standalone.

Having Haltech parallel creates unique settings for as IAT , Coolant, TPS, sensors. Haltech has its own IAT configured but shares TPS and Coolant. Wouldn’t take much to complete full standalone at that point once transmission is moved over.

Once I get the A442 running with Haltech I post a file.

The bigger plan in the works : transfers my A343 to behind my 1FZ with Haltech and then 2UZ VVTI Superchage along with a750 , heeders 3 inch full exhaust in my 100. I think I found a Donar and working a part out deal.

That’s a possibility.


Tex

 

[jimbote]

Yeah, the stock tcu works fine standalone. Iirc it just needs temp and tps analog signals.

Can you provide more details? Pin 6 for tps? Pin 13 for temp? Thanks!

 

[obe12]

Ok, an update my low mileage 07 donor truck fell through. I am proceeding with the Haltech to control the 442F transmission. The custom harness is due today via UPS. Now looking Haltech tech article it shows two wire connection to the lockup solenoid and the 442 uses 1 wire, power to and the solenoid is grounded to operate, the same as the timing solenoid along with S1 and S2 shift solenoids. Tech article claims two outputs from the 2500 can power the Shift Solenoids directly with Elite 2500 B25-26 terminals DBW 2 amp max. Now the lock up solenoid how have you all wired it? DPO pull to ground a relay to power the Lock up Solenoid perhaps?

The PRNDL box, the quick install manual shows Method 1, or Method 2 which option did you follow and did you have calibrate the software to learn the gear positions? with OD button off/On? It appears without and Haltech Display and OEM harness wiring Method 1 to follow am I correct?

About to undertake this in a few days and any advice before hand would be great.

Tex

 

[obe12]

Just an update on the Haltech 2500 elite controlling the A442F transmission. Boomslang harness was ordered and received. The Haltech PRNDL2 converter was ordered and received. Now the fun part. The question is start scratch on Universal Trans control or modify the yota A340E choosable one. I had an issue getting the PRNDL2 converter to signal 2nd and Low. I kinda mistakenly wired Method 2 by Haltech and hoped I could do the internal resistor short to enable pull to Hi. But opening the unit via Haltech instructions no such pins exists inside to short. Therfore I had to de pin Park and Reverse from it. Once I did that it started signaling the correct logic to Haltech.

Did not help I was in muscle relaxers for a pulled neck muscle and had clouded thinking. !

Now test drive not changing a thing just to see. Using a340E selection and default settings, I have 1-2 shift just not 2-3 on a short test drive. Now I look into that. I was looking 1 time ans thought I saw MAF for engine load, I am MAP. I Perfer MAP over TPS since I am boosted with Supercharger. I see if I can build a chart to shift under MAP/TPS for engine load/ RPM and Speed.

More work… to go.

So far preliminary this is where I am at.

Tex

 

[pgmatt]

Just an update on the Haltech 2500 elite controlling the A442F transmission. Boomslang harness was ordered and received. The Haltech PRNDL2 converter was ordered and received. Now the fun part. The question is start scratch on Universal Trans control or modify the yota A340E choosable one. I had an issue getting the PRNDL2 converter to signal 2nd and Low. I kinda mistakenly wired Method 2 by Haltech and hoped I could do the internal resistor short to enable pull to Hi. But opening the unit via Haltech instructions no such pins exists inside to short. Therfore I had to de pin Park and Reverse from it. Once I did that it started signaling the correct logic to Haltech.

Did not help I was in muscle relaxers for a pulled neck muscle and had clouded thinking. !

Now test drive not changing a thing just to see. Using a340E selection and default settings, I have 1-2 shift just not 2-3 on a short test drive. Now I look into that. I was looking 1 time ans thought I saw MAF for engine load, I am MAP. I Perfer MAP over TPS since I am boosted with Supercharger. I see if I can build a chart to shift under MAP/TPS for engine load/ RPM and Speed.

More work… to go.

So far preliminary this is where I am at.

Tex

Please keep the updates coming this kinda information and testing is invaluable.