Miata DIYPNP works on power adapter, not in car.

[Mikel]

Well, that's as concise as I could make the thread title.

I installed a DIYPNP in my 96 Miata with stock engine today. MS2 Extra release 3.3.1. Prior to install I connected it to power adapter and flashed the base tune. All went well. I did the physical part of the install (Wiring in the wideband, running vacuum line, etc) and plugged the ECU in. I cranked it up, and it ran, but pretty poorly. I had yet to set TPS or anything so this wasn't a total surprise. I turned the engine off and then switched the key back over to "Key on, engine off". I heard some clicks, like a relay, that sounded like they were coming from the steering column. I turned the key to off, worried that whatever relay was cycling would kill the battery while I was attending to other things.

I put the airbox back on, cleaned up the harness routing for the wideband, etc, then came back to properly set up my ECU.

I turned the key to on, and got an "Offline" message in TunerStudio. Try to crank the car and it cranks but won't run, just like there's no ecu connected. I checked all my connections. I'm powering my LC-2 wideband off the power and ground from the factory harness going to the ECU, and the controller is working, so it's definitely getting power. After cycling the key a few times I think I heard some relays again, and it connected, but before I could do anything it went offline again, never to come back. I figured I had screwed something up and shorted the ECU. I brought it inside, connected it to power, and hooked it up to the same computer using the same cable. Tunerstudio finds it immediately and everything seems to be fine. I can write new maps to it, etc.

Any ideas here? I would LOVE to attach a datalog but I'm gonna need to get it reliably online first, lol.

[hybrid]

If you are sure you have 12v to the unit because your wideband is working, maybe check your grounds?

[Matt Cramer]

Check the voltage on the main board from 12V to ground with the DIYPNP in the car and the key on.

[Mikel]

I got the connection issue fixed by unplugging the TPS. Not sure why that worked, it looks to be setup correctly for the stock manual trans 1.8L TPS. I'll do some more investigation. I got the car to crank and run but it's super rich to the point that it won't idle now. Attached is a log.

[jsmcortina]

Sounds like the TPS must be miswired causing a short between TPSVREF(5V) and ground.

James

[Mikel]

Sounds like the TPS must be miswired causing a short between TPSVREF(5V) and ground.

James

It's wired (what I believe to be) correctly inside the ECU. TPS is ran to 3F. I have another TPS on an automatic parts car, I guess I'll give that a shot before I start looking for a short in the harness.

[Mikel]

Swapped the TPS with the parts one, same result. I'm going to check to see if the TPS is functioning normally with a multimeter, then see if the signal being sent is clean to the ECU plug.

Assuming both of those are fine and the issue is with the jumper wiring inside my ECU, can anyone give me a crash course in what to test for? I bought my ECU assembled, secondhand. I'm now kinda wishing I had just bought a kit and built it myself.

[Mikel]

Ok, I'm officially lost. I pulled the ECU and as far as I can tell it's wired correctly. TPS on the main board is jumped to 3F. It's a 96 with the variable TPS. I've tried two different TPS sensors to make sure the sensor is not the issue. I turned the key on with the TPS disconnected and then connected the TPS in an effort to calibrate it. The sensor data makes no sense, barely any spread and the WOT value is lower than the zero throttle value.



I've spent days googling around and I've found mountains of stuff about the 90-93 TPS and retrofitting but nothing about this. Any ideas as to what I need to do to make it work?

[Matt Cramer]

What pins do you have VREF wired to on the adapter board?

Is this a 1.6 or 1.8 car?