Building a diypnp, Standalone harness wiring Options

[HardHead93]

Glad you were able to get the unit working!

Here is what I did for AC idle up.
I disconnected all AC1, ACT, ATS connections. With nothing hooked up to the ecu, the ac compressor would come on just fine.
Next, I looked at the vehicle wiring diagram to determine the wire that ground switches the ac compressor relay in the passengers side fuse box.
I cut that wire and ran the ground signal into the Flex pin. Then I connected the PA0 output to control the ac relay.

I believe the in order to use the PA0 output, you have to run it into the in port of relay1,relay2 or relay3 of the DIYPNP circuit board. Just double check this in the assembly documentation.

Does the car stall at idle or deceleration?

I am a little confused with this statement. Is the wire to cut the one that goes to the MGC pin on the AC amplifier or the one that goes to the AC magnetic clutch? Then when I cut the ground wire going to the AC relay in the fuse box under the hood. I connect the ground side of the cut wire to the flex pin on the DIYPNP. Then I connect the relay side of the cut wire to the PAO using one of the relays on the DIYPNP board. Set the PAO to output and the flex to input in TunerStudio under the AC idle up settings. Is that correct? Do I need to run the flex connection through one of the board relays?

This post has been edited by HardHead93: Aug 30, 2016 - 10:07 PM

[lagos]

Here is the basic idea:

1. Don't connect any of the AC related functions that exist on the OEM ECU to Megasquirt and verify that the AC works just fine without them (with the exception of the idle up functionality).

2. Find the wire that sends the ground switching control signal to the AC relay located in the engine bay on the passengers side of the car. You want to cut this wire and have Megasquirt intercept this signal.

3. Once you have the wire cut, connect the signal side of the wire directly to the Flex input. No need to run this through any MS relays.

4. Connect the PA0 pin to Relay1 IN on Megasquirt, and connect Relay1 OUT directly to the AC relay in the fuse box.


In this configuration Megasquirt will see that the factory ac amp wants to turn on the AC and will delay this signal by a few seconds so that it can idle the engine up first to create a smooth transition. I will take a look at my wiring book and let you know the color of the wire that goes to the AC relay.

This post has been edited by lagos: Aug 31, 2016 - 11:03 AM

[HardHead93]

Here is the basic idea:

1. Don't connect any of the AC related functions that exist on the OEM ECU to Megasquirt and verify that the AC works just fine without them (with the exception of the idle up functionality).

2. Find the wire that sends the ground switching control signal to the AC relay located in the engine bay on the passengers side of the car. You want to cut this wire and have Megasquirt intercept this signal.

3. Once you have the wire cut, connect the signal side of the wire directly to the Flex input. No need to run this through any MS relays.

4. Connect the PA0 pin to Relay1 IN on Megasquirt, and connect Relay1 OUT directly to the AC relay in the fuse box.


In this configuration Megasquirt will see that the factory ac amp wants to turn on the AC and will delay this signal by a few seconds so that it can idle the engine up first to create a smooth transition. I will take a look at my wiring book and let you know the color of the wire that goes to the AC relay.

Is this the wire that needs to be cut? I have it circled in red. It looks like it goes to the MGC pin on the AC amplifier.

[HardHead93]

I did some researching and figured out how to get the idle up to working by using the AC1 pinout on the ECU! I did the following.
1. Connected the PAO to the RELAY1 IN on the Megasquirt and the RELAY1 OUT to the engine ground.
2. Connected the FLEX on the Megasquirt to the AC1 pinout.
3. In Tunerstudio in the Air Conditioning Idle Up screen I set the output to PAO, the input to FLEX, and the Idle-Up Input polarity to Low.
That was it, every time I turn on the AC within a few seconds the DIYPNP recognizes the AC compressor is on and idles up the engine. I was going to tap into the AC Relay like Lagos said but that would defeat the purpose of me chosing the Megasquirt. My goal is to cut into the factory wiring as little as possible to avoid causing some damage I could not repair. So far the only wire I had to cut for the Megaquirt was the intake air temp sensor harness to add a GM sensor. I figured if the stock ECU can idle up with the AC1 input then so can the Megasquirt. Lagos, thanks for all the help in figuring out this ECU. I would not have been able to track this problem down without your help.

Another problem I am recognizing is that the DIYPNP is very limited on additional features remaining if you go with the sequential injection mod. If I want to use a boost controller, I am out of ports for that function. The PAO, PT6, and PT7 are the only ports that can use a boost controller. When you go sequential injection, PT6 and PT7 taken to control the injectors and if you attempt to use them Tunerstudio will give you a config error. With me using the PAO for the AC idle up, I have nothing left to run a boost controller unless I switch back to batch fire injection and reclaim the PT6 and PT7 ports for use. Are there any other options?

This post has been edited by HardHead93: Sep 2, 2016 - 6:25 PM

[lagos]

Just to clear up the original question, yes that is the same wire that I intercepted for the ac relay. When I did my modification, I used some nice insulated bullet connectors so that I could easily reconnect the factory wiring if needed.
http://www.ebay.com/itm/100-Premium-Fully-...FMAAOxyTjNShyND

So you're getting an input signal from AC1, but your output is simply going to ground? This will idle the engine up since MS has an input that tells it the AC wants to turn on, but it doesn't sound like it will allow MS to delay the AC compressor from turning on. What you want is for MS to get a signal that requests the AC to come on, idle the engine up and then turn the AC compressor on after about 700ms. This will create a smooth transition as the AC cycles on and off. Right now it sounds like your idle up and compressor are turning on at the same exact time.

You are 100% right that the DIYPNP is a bit limited on outputs, especially when using sequential injection. You can however use WLED and ALED if they are not being used for anything important. On my setup I have ALED setup to simply turn on the CEL light when the key in ON but engine is not running. I could use that output for boost control if I wanted to.

[HardHead93]

Just to clear up the original question, yes that is the same wire that I intercepted for the ac relay. When I did my modification, I used some nice insulated bullet connectors so that I could easily reconnect the factory wiring if needed.
http://www.ebay.com/itm/100-Premium-Fully-...FMAAOxyTjNShyND

So you're getting an input signal from AC1, but your output is simply going to ground? This will idle the engine up since MS has an input that tells it the AC wants to turn on, but it doesn't sound like it will allow MS to delay the AC compressor from turning on. What you want is for MS to get a signal that requests the AC to come on, idle the engine up and then turn the AC compressor on after about 700ms. This will create a smooth transition as the AC cycles on and off. Right now it sounds like your idle up and compressor are turning on at the same exact time.

You are 100% right that the DIYPNP is a bit limited on outputs, especially when using sequential injection. You can however use WLED and ALED if they are not being used for anything important. On my setup I have ALED setup to simply turn on the CEL light when the key in ON but engine is not running. I could use that output for boost control if I wanted to.

I thought the WLED and ALED pins could only be used for on/off type of functions. If that is the case can I use them for the AC idle up and save the PAO for boost control? Will I need to run the WLED or ALED through a relay circuit? In the drawing from my previous post, I circled part of it, was that the correct AC relay wire you tapped into? Again, thanks so much for the help! I am not sure how I would have gotten this DIYPNP to work without your advice.

[lagos]

I'm not 100% sure if they could be used for PWM control, but you could use them for the AC like you said and use PA0 for boost. I don't think they need the relay circuit and can drive an automotive relay directly. Just make sure they supply a ground signal. You can command them to turn on in the Test I/O menu of Tuner Studio to ensure correct functionality.


Yes that is the correct wire the the AC relay.

This post has been edited by lagos: Sep 5, 2016 - 11:48 PM

[HardHead93]

This thread is going to change gears and deal with my 3sgte swap on the same vehicle. Now that I have fixed all the issues I had with the car and the 3sgte 4th gen swap it is now time to work on getting my standalone ECU installed. Luckily I kept my DIYPNP 76pin from my 5sfte build. The problem is that it is a 76 pin which is different from the 4th gen 3sgte. DIYAUTOTUNE sells a 122 pin kit that converts it to the proper pin out. I installed the new pin out mod and soldered the wiring to it.



Now I am ready to drop it in the car.

Please see the following thread if you want to see how I did my build:
http://www.6gc.net/forums/index.php?showtopic=96700

This post has been edited by HardHead93: Jul 27, 2017 - 11:45 AM

[HardHead93]

After messing with the DIYPNP for the 4th gen 3sgte I found it was going to be a downgrade using it. Since the motor is sequential injection and COP ignition, I was using all my outputs just to work those basic features. I was going to lose all my idle up capabilities and would not have anything left for any expansion down the road. The DIYPNP is great for a batch injection and distributor setup of the 5s but as the motor becomes more complex the ECU loses the ability for the extra fun stuff.

After talking with the people at DIYAUTOTUNE, I decided to pull the trigger on a MS3pro EVO. This will give me all the basic functions I need plus the ability to add extra sensors, performance mods, and safety features. I plan to start with their base 3sgte tune and go from there. The final goal will be to get it running well with the Auto Tuning features. That should yield me a safe tune. Then I will take it to a tuner to get the fine ignition timing tuning done. The great thing is since I will be building this as a plug and play unit I will have the ability to go back to the stock ECU if I want to move the ms3 to another vehicle.

My car put down 238 horsepower and 233 torque on the dyno at 15 psi. That is with aftermarket camshafts and a stock ECU. With my stage 1 BC camshafts and a good tune I am going to shoot for 280 horsepower.

I will be starting a new thread to document this work because this is no longer dealing with the DIYPNP ECU.

This post has been edited by HardHead93: Sep 3, 2017 - 3:17 PM