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Old 12-17-2016, 08:11 AM   #1
SLEEPYDUB
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HELP: Bought a Megasquirt ECU off a member and having trouble

I recently bought a Megasquirt unit off of a member, that bought if off if another member, and was supposedly a good working unit that was pulled out of a running car.

I went to plug the ecu in, and as soon as I turned the key to load the base map, the 02 sensor wiring became very hot and started smoking.

No connection with the ecu through the laptop. Board does not have an LED light.

Taking the board apart, I can see jumper wires ran to different points and there were a few screws that were loose and rattling around. The board says V1.5B and the adapter is B55 DIYPNP V1.2.






I checked the power at the harness and it seems to be supplying power to pin 18, but on this board pin 18 isn't even soldered to anything. Pin 37 goes to 12v, then from 12v to main relay out, then main relay in to pin 27.

I am so lost. I don't know what I need to do or where to go from here.

Was I sold a bad unit? Should I just request a refund? Because this is not how it was described to me and now I'm stuck with a bunch of parts I may not be able to use.

Help a guy out?
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Old 12-17-2016, 06:04 PM   #2
Golfer_705
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Hey hate to give bad news but you may want to contact the seller, based on your pictures I'm noticing a few issues. It appears that was not a functioning DIYPNP when you bought it. Do not put power the MS until you have fixed it to prevent further damages! You are going to need a soldering iron, de-soldering braid or solder sucker, new solder and some new wire.

The whole build can be referenced here: https://www.diyautotune.com/support/...-1992-bmw-325/

First off the 55pin harness adapter to the adapter board appears to have been soldered on upside down and isn't bolted to the board, all of your pin out #'s are going to be reversed left to right ie pin 1 on the adapter board is actually pin 19 on yours. You could probably work with the pinouts being reversed but i doubt its worth the future headaches.

If you flip the harness adapter and adapter board around how they were intended to be installed there are still a few issues. Once the harness adapter to adapter board connections are corrected you will also need to flip the adapter board over and redo the wiring between the adapter board and main board to fit in the case. Everything I'm going to reference will be the main board to adapter board and assume you have flipped the harness adapter around properly.

-S1 should be going to pin1, you have no wire present. This is your ign coil trigger.
-IAC Open should be going to pin 4, you have no wire
-IAC Close should go to pin 22, you have nothing
-Inj 1 should go to pin 17, you have nothing
-Input 1 IN should go to ground, you have nothing
-Ground should go to Pin 26, you have nothing
-TPS sig should be run to ground on the main board with a 1k ohm resistor inline, your runs to pin 15? on the adapter board, cant totally tell from the picture


I would strongly recommend double checking all your connections with the DIYAutotune link provided.

I'm NOT sure if the mainboard itself was assembled correctly because all of your pictures are from the back side of the board. The biggest errors I see is the harness adapter to adapter board being soldered on upside down and the missing or incorrect pinouts I mentioned. The Main board to adapter board connections that are to the correct # will only be correct once the harness adapter to adapter board are fixed.

Hope this helps clarify whats going on and why your having issues. If you attempt to fix the DIYPNP and need any help just ask!
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Old 12-18-2016, 05:18 AM   #3
varg
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What a mess. The builder didn't do us any favors using a bunch of wires that are the same color for everything, and it looks like low quality work. It definitely won't even start the car as it is configured, and with the wiring so screwed up, there may be damage to the MS.

Here's what looks like it's connected in the right place:
-12v Supply (pin 37)
-Fuel pump relay trigger (pin 3)
-IAT (pin 44)
-CLT (pin 45)
-O2 input (pin 28)
-Grounds (pin 14, 2, 24)
-Tach (pin 6)
-O2 ground (pin 10)
-AFM ground, used for IAT (pin 26)

Problems:
-Connector is soldered to the wrong side of the board, so the pins are not what they say they are.
-Injectors. INJ2 is hooked up to 16 (1,3,5) but pin 17 is not connected to anything (2,4,6). Maybe 16 and 17 are bridged but I can't see it? You would run batch fire anyway so if 16 and 17 are bridged this is OK.
-Crank sensor is hooked up to the right place (Pins 47, 48) but pin 47 has a resistor bodged in, this is unnecessary.
-TPS is hooked up to pin 15 and has a resistor on it. Pin 15 is for the CEL.
-Relay 2 appears to be hooked up from the start input of the key (27) to the trigger for the main relay (36) This won't work unless you ground what is, in stock form, the +12V supply to the main relay's coil.
-Pin 19, a ground, is unused. This may or may not cause probems, but I always connect all stock ground pins to the MS ground plane.
-No ignition coil trigger wire (1)

There is no wiring for IAC control even though the 3 wire IAC transistors are installed, but the IAC is not necessary for the car to run. I hope the damage to your harness is not too extensive, it's a big task to strip the harness and replace burned wires. I don't know about getting your money back, that's between you and the seller, but with the damage caused by this and the possibility of damage to the MS you may want to have a qualified person have a go at this. It's not impossible for you to do but it's not a beginner friendly task.
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Last edited by varg; 12-18-2016 at 05:33 AM.
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Old 12-18-2016, 10:58 AM   #4
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All DIYPNP's come with a roll of orange wire to join the main and adapter board, wasn't the builders fault the wires are all the same colour.

There is and should be a 1k ohm resistor installed between the TPS sig and ground on the main board, it just shouldn't be run to pin 15 on the adapter board. The 1k ohm resistor for TPS sig should only be removed if variable TPS is installed like from an m50 or an m20 automatic 6 wire TPS. The resistor prevents the TPS signal from gradually rising.

The 10k ohm resistor inline with the crank position sensor (VR) is needed for the DIYPNP, there will be sync loss issues without it. Alternatively the variable resistor included for the cam position sensor (that the m20 doesn't have) can be installed into the proto area with the VR wire hooked inline to allow for adjustments for the CPS. I tried a couple different CPS on my car, made tooth logs and found the resistance needed to vary from 7k-11k ohm depending on the sensor itself.

Even though the injectors are firing in batch mode wouldnt it make more sense to just add the INJ 1 wire anyways instead of jumping pins 16&17 together on the adapter board. DIYautotune makes it very simple to convert to semi-sequential if the initial build is done properly to begin with. Jumping pins 16&17 will just make for extra work in the future if he decides to upgrade his type of injection.
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Old 12-18-2016, 03:13 PM   #5
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Quote:
Originally Posted by Golfer_705 View Post
All DIYPNP's come with a roll of orange wire to join the main and adapter board, wasn't the builders fault the wires are all the same colour.
I always build from kits, so I haven't seen this. Disappointing. That's not the kind of thing I'd expect from DIYautotune. Poor form. Even in the case of including only one color, at least alternating colors is a good thing, wire is cheap.

Quote:
Originally Posted by Golfer_705 View Post
There is and should be a 1k ohm resistor installed between the TPS sig and ground on the main board, it just shouldn't be run to pin 15 on the adapter board. The 1k ohm resistor for TPS sig should only be removed if variable TPS is installed like from an m50 or an m20 automatic 6 wire TPS. The resistor prevents the TPS signal from gradually rising.
No point in using the stock TPS IMO. Why upgrade to standalone and keep antiquated limitations of the stock system when upgrading to a variable TPS is so easy? Late '80s LH-jetronic used a variable TPS, it's a useful thing to have.

Quote:
Originally Posted by Golfer_705 View Post
The 10k ohm resistor inline with the crank position sensor (VR) is needed for the DIYPNP, there will be sync loss issues without it.
Interesting. I haven't encountered any issues with VR sync loss without additional resistors on these cars, the normal MS potentiometer has always been enough. Does the DIYPNP change the basic layout of the stock MS VR conditioner circuit? Seems like a bodge for the design of the circuit to require an additional resistor on top of the regular pot. There should at least be a jumper which can be removed to add an additional resistor to the board.

Quote:
Originally Posted by Golfer_705 View Post
Even though the injectors are firing in batch mode wouldnt it make more sense to just add the INJ 1 wire anyways instead of jumping pins 16&17 together on the adapter board.
They're functionally the same thing as long as the driver can handle the current, so it doesn't really matter. The whole thing needs to be redone in any case, so you may as well run the extra wire and use both drivers.

Quote:
Originally Posted by Golfer_705 View Post
DIYautotune makes it very simple to convert to semi-sequential if the initial build is done properly to begin with. Jumping pins 16&17 will just make for extra work in the future if he decides to upgrade his type of injection.
True, but at the same time this upgrade is of debatable benefit for the work required. Adding a cam position sensor, wiring it and changing the tune isn't a trivial task for the uninitiated. It's probably possible to use the stock inductive pickup on the spark plug wire, I haven't tried it.
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Last edited by varg; 12-18-2016 at 03:20 PM.
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Old 12-18-2016, 10:44 PM   #6
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Hey Varg, I wasn't trying to be critical of your write up Just wanted to make sure we were giving the same info to SLEEPYDUB to make his life as easy as possible for his first DIYPNP experience

Your absolutely right that DIYautotune should provide a couple other wire colors to make tracing them easier. Would be great if they included about 2 feet more wire anyways to work with the mods the DIYPNP is easily capable of running.

The DIYPNP is microsquirt(ms) based not MegaSquirt(MS). M2025/27 TPS is a WOT and Closed Throttle switch that can not be used by microsqurit. Because of this the ms need to be able to ignore factory TPS signal. It does this by grounding the mainboards TPS with a 1K Ohm resister. Couldn't agree more that a variable TPS is the best option but until then that's how the TPS needs to be wired.

The reason for the VR 10K Ohm resistor is again because the DIYPNP is microsquirt based so it does not have the MS potentiometer you mention. Microsquirt uses the 10K ohm resistor as its conditioner, that is also why I had suggested to use one of the spare variable resistors for the cam in the proto area to allow for adjustment. This would allow virtually any sensor to be use and be able to calibrated properly.

As for the injection microsquirt only allows the DIYPNP to run Batch and 2ch semi-seq if you re-pair the injector wires. With an inexpensive adapter board you can add 3ch semi seq, for 3ch semi seq inj you just need to pair the injectors like you did for waste spark and your all set with no need for a cam sensor. We are unable to have Sequential injection because of the limits of the microsquirt. We are able to build sequential ignition drivers however that would need the cam position sensor you mentioned.
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Old 12-19-2016, 02:55 PM   #7
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Does this look better?

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Old 12-19-2016, 03:57 PM   #8
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That's a start!

Quote:
Originally Posted by Golfer_705 View Post
lots of well-informed text
I'm aware it's microsquirt based, a little surprised that there are so many of what I think are design oversights in the DIYPNP kit for the E30. From the omission of colored wire to the super-easy mod of adding pot to the kit for the VR conditioner and a simple jumper based mod for the (easy and necessary IMO) conversion to a variable TPS. When I read over the DIYPNP description and have tuned them a couple of times in the past, I assumed that what I would've do to make the a PNP kit from MS hardware is what was done.

My apologies for any misinformation.
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Old 01-04-2017, 01:05 PM   #9
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Quote:
Originally Posted by varg View Post

My apologies for any misinformation.
No need to apologize Varg! I found it interesting to re-think the differences between the DIYPNP and MS2.

My understanding was that the V1.5 mainboard for the DIYPNP series was designed to work with the entire DIYPNP line up (not gen2). Only the circuits we assemble onto the mainboard and the adapter board really make it m20 specific. That said, it would probably be pretty simple for DIYAutotune to make an m30 and m10 variant by swapping the adapter board.

Nice build thread Varg, I was curious to see when it was going to turn m20 powered! Looks like we have similar taste in rims, I'm running the XXR 530's as well.
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Old 01-05-2017, 02:20 AM   #10
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Quote:
Originally Posted by SLEEPYDUB View Post
Does this look better?
Great work tidying up the boards SLEEPYDUB, looks much better!

Now that there is a top view of the board I see there is a resistor installed between WLED and the 5V pull up in the lower right corner of the main board, this resistor needs to be removed unless your installing logic level coils. I also noticed you already have the high current Ignition jumpers soldered for spark 2&3 (next to pins 12-14 of the db15 adapter), these need to be de-soldered so TS will let you select a single ignition coil.

You should be all set to start soldering the main to adapter board jumpers after pulling the WLED 5V resistor. It will probably make your life a lot easier if you remove the MicroSquirt module when you go to solder the mainboard outputs (4 screws and it unclips from the 2 stand offs, be gentle). You should have room between the underside of the boards and the case to run all your wires and keep everything looking clean. Just follow the DIYAutotune link for the pin-out running your jumpers or follow the notes Varg and I left for you earlier in the thread.

The high current jumpers for spark 2&3(WLED) wont be needed until you go to a dummy coil wastespark ignition system. If you decide to set it up you will need to run 2 more wires for spark S2&S3 triggers and new coils (can be done through the db15 connector, I used 2 pins per spark trigger to reduce the amount of current going through each pin). Until then make sure you select that your using a single ign coil (stock) in your settings. If you decide to go wastespark using logic level coils the resistor for the WLED 5V pullup will need to be re-installed.

The other thing I saw was that you have the variable resistor for the Cam Position Sensor circuit installed (grey box with a screw next to R39). It is not needed for the m20. Right now the rest of the resistors to build the circuit are not installed. That is the resistor I had suggested moving into proto area to allow for adjustments of the Crank Position Sensor circuit. I installed mine along the long stand off for the ms module parallel to proto area writing, the pins in the proto area are linked vertically, you can see the trace. VR in+ on the main board would run up to the proto area then back down to pin 47 on the adapter board instead of having a resistor soldered in line. There are 3 pins on the variable resistor, 1 pair will the resistance will increase when the screw is tuned clockwise, the other pair the resistance will drop, test with a meter to see what pair will work for you. DIYAutotune now recommends an 18k ohm resistor so i would use that as your starting resistance till you do a tooth log, im at 7k ohm now. You do not have to move the cam sensor resistor to the proto area for the crank position sensor circuit, it was just something I found handy.

Looking forward to seeing the end result!

Last edited by Golfer_705; 01-05-2017 at 09:41 PM.
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