Just installed a DIYPNP in my 96, still otherwise stock in terms of engine.

I cranked it up and it ran pretty poorly, but I had yet to set anything up so that wasn't totally unexpected. I shut it down to calibrate the throttle position sensor and a host of other things.

I turn the key back to on and heard some relays clicking behind the steering wheel. I turned the key to off so as not to kill the battery while I did other stuff. I came back and turned the key to on and got the offline message. I tried cranking and predictably the car won't run.

I'm getting power to the ECU as I'm running my LC2 off of it and it's LED is on green, solid a few seconds after turning the key on.

I pulled the Megasquirt and brought it inside, hooked it up to my computer directly using the AC adapter and it works totally fine. Same cable and all. Any ideas?

 

Did you remove the STsig fuse?

 

I was under the impression that only applied to 1.6 cars.

 

Yeah I just double checked, the install directions make no mention of pulling a fuse for 1.8L cars.

 

Oh, the first time I cranked it I had left the maf unplugged. After that I had it plugged it. I just remembered that if its in any way relevant. I plan to do the gm iat mod to delete the maf but figured I would get it running first instead of waiting on the iat.

 

Going to mess with it more, does anyone know if I can use the AC adapter while the ecu is in the car to troubleshoot a power issue?

 

Correct. 1.8s use a proper ECU controlled fuel pump relay circuit.

Don't!!!!! If there's any improperly grounded wiring in your garage, or you plug the adapter in wrong, you end up transferring any ground offset between the car and the AC adapter though the ECU.

If you think you have a power issue, measure the voltage between any 12 volt point and the ground points on the DIYPNP with the key on and engine off. If you have 12 volts, move on to other things. If you get no voltage, check your jumpers and the car's wiring.

 

Gotcha, thanks. Do you mean check the ground pins on the connector at the wire or take the case off and check the ground points on the board?

I don't feel like it's a power issue as it's an unmodified stock harness and it ran fine with the stock ECU, but I can't think of anything else that would be causing this issue.

 

Just for funsies, I grounded the TEN connector at the diagnostic port underhood. Instantly I had connectivity! I tried cranking the car but it wouldn't start, i think fueling isn't set correctly. No matter though, I turned the key off, heard clicking from the steering column again, and now I'm back to no connectivity.

I feel like this has to be a pretty simple fix, so maybe someone can point me in the right direction.

 

Do you have an alarm system that might be disabling the car?

 

Not that I know of and it certainly didn't on the factory ECU. Good idea though, I'll check for it. I cleaned the grounds under my brake booster and that seems to have helped a little bit, it now works about 50% of the time. I think I've narrowed it down to a ground problem. Is there any reason I can't just run a ground to the negative battery terminal to rule that out?

Also, when it does connect, it still doesn't run. I haven't really had a chance to set anything up yet, fuel looks way off though, any idea why? This is the base map from the website, unless I've done something terribly wrong.

 

That's odd, now it's back to not recognizing it at all. This is decidedly not "Plug and Play", lol.

 

Your battery has a full charge, right? Looking for ~12.5VDC at rest and ~10.5VDC when you crank.

 

Check the power on the main circuit board inside the DIYPNP.

 

Off-topic: Your avatar is giving me seizures.

 

Yeah, I've kept a battery charger on it while trying to diagnose it, was showing 12.7 on the charger.

 

I'll check that when I get a chance later this week, thanks.

 

Feels good man.

 

Finally some progress. I checked for power at the plug, and I have it. I checked for power on the board and I'm good to go. I plugged in just the 4 plug of the connector and it works fine. Plug in the 1 connector and it works fine. Plug in the 3 and no connectivity. This is the connector that my wideband is wired in to, 3C. Is this not correct? I mean, I'm obviously thinking it's the WBO2 wiring since that's the part that I changed. Is there somewhere else I should be putting the WBO2 input?

Edit - By works fine, I mean it powers on and communicates, I haven't tried cranking the car yet.

 

Because I've read the entirety of the internet about this I started trying basically everything I've ever heard to nail down the problem. Unplugging the TPS makes it work normally. I haven't tried calibrating the TPS because I can't get the son of a bitch to connect with the TPS plugged in. Any ideas? Aside from that it seems to be working now, though I have still yet to attempt to crank it. Gonna go try and figure out how to calibrate the TPS if at all possible.