MS3 not syncing and not reading TPS correctly

[curry.style]

Hey guys new user here. Built my MS3 and thinking now that was a mistake on my part. My MS3X isn't getting an RPM sync at all. It's also reading 488 to 490 on the TPS circuit even with no TPS connected. Is my board internally faulted? I can't get my JimStim to connect to my MegaSquirt to power it up to bench test it but it does power up when connected to the car. Can anyone help me out here?

*There is no MSQ or datalog because I can't get that far with it.

[billr]

You can certainly provide the MSQ you are trying to use or load, no matter what the condition of the MS unit; no excuses there. Likewise, if it will power-up in the car, then you should be able to provide further info; either an MSL (blank as it may seem to you), or error messages that pop up when TS tries to connect.

It seems odd it will power up in the car, but not with the stim. Usually it is the other way around, because problems in the external wiring (the car) can happen that aren't possible with a stim. What are you using to power the stim, and have you done all the voltage measurements specified in the build assemblies?

Posting good pictures of both sides of the mainboard may help sort this out; pictures of the stim too, if you built that.

Let's defer the "floating" TPS reading for now, that can have many causes and may get resolved when the basic powering-up issue is gone.

[curry.style]

Thanks for taking the time to respond. I'll get all that together and uploaded tonight. Just didn't seem relative to the issue to me to load the MSQ I'm trying to use. In hindsight I definitely should have loaded a log of it cranking. I should also note that when building the board it powered up fine with the stim but now it doesn't. I'm using a plug in wall adapter for the stim. I did notice that when flipping the stim off the injector LEDs on the stim briefly and dimly flickered while connected to the MS3 but not when disconnected. I'm wondering now if the stim got jostled around in the garage at some point.

Also there are no errors when connecting. It connects in the car fine, but gets nothing hooked to the stim.

[billr]

That "nothing with the stim" is a huge clue. Be sure to measure V ref again when it is on the stim. If that is low, remove the daughterboard and repeat the voltage checks on the 40-pin socket.

[DaveEFI]

Thanks for taking the time to respond. I'll get all that together and uploaded tonight. Just didn't seem relative to the issue to me to load the MSQ I'm trying to use. In hindsight I definitely should have loaded a log of it cranking. I should also note that when building the board it powered up fine with the stim but now it doesn't. I'm using a plug in wall adapter for the stim. I did notice that when flipping the stim off the injector LEDs on the stim briefly and dimly flickered while connected to the MS3 but not when disconnected. I'm wondering now if the stim got jostled around in the garage at some point.

Also there are no errors when connecting. It connects in the car fine, but gets nothing hooked to the stim.

What power rating does your plug in PS have? Marked in either amps or watts? Some are simply too small to power an MS3 and Stim.

[curry.style]

That "nothing with the stim" is a huge clue. Be sure to measure V ref again when it is on the stim. If that is low, remove the daughterboard and repeat the voltage checks on the 40-pin socket.

Wouldn't it not power up with the vehicle as well of something were wrong with the MS3 unit? Not trying to instigate anything. I just don't understand the logic behind this.

[curry.style]

What power rating does your plug in PS have? Marked in either amps or watts? Some are simply too small to power an MS3 and Stim.

It looks like the output is 12v 5 amp. I would hope the one I bought is adequate since I bought it, the stim, and the MS3 all from DIY Autotune all at the same time. I did mention in my second post in this thread that the MegaSquirt did power up with the stim during the board build.

[billr]

That "nothing with the stim" is a huge clue. Be sure to measure V ref again when it is on the stim. If that is low, remove the daughterboard and repeat the voltage checks on the 40-pin socket.

Wouldn't it not power up with the vehicle as well of something were wrong with the MS3 unit? Not trying to instigate anything. I just don't understand the logic behind this.

If the MS is drawing an abnormally large load, the car system may be able to maintain the "raw 12V" power and the AC wall adapter cannot. Also, did you build the JimStim? Maybe we are needing to troubleshoot it too.

[curry.style]

So after chatting with someone on a Facebook group I took another look at the stim and found some questionable solder joints. Freshened them up and was able to get the MS powered up and synced on the laptop again. From looking at the sensor inputs there and the MS3 schematics I'm fairly certain the ground circuit for the MAT, TPS, and CLT is faulted on the board. Most likely a drop of solder in the wrong place. Thanks for the input guys!

[DaveEFI]

What power rating does your plug in PS have? Marked in either amps or watts? Some are simply too small to power an MS3 and Stim.

It looks like the output is 12v 5 amp. I would hope the one I bought is adequate since I bought it, the stim, and the MS3 all from DIY Autotune all at the same time. I did mention in my second post in this thread that the MegaSquirt did power up with the stim during the board build.

Doubt a wall wart will be 12v 5 amp. That would be more like a laptop power supply. But if it came from DIY Autotune, should be ok.

[curry.style]

I ended up finding a transistor installed backwards. This is why you shouldn't build sensitive electronics late at night...