Hey guys finally broke down and got a megasquirt and wow I was blown away how well my car ran even on the base tune. However after 300 miles something went terribly wrong. I set out on a road trip and about 80 miles in, injectors 1 and 3 were stuck wide open. I reloaded the base tune and nothing. A buddy at the shop i hang out at said it might be a injector driver. Diyautotune has been helpful, but has anyone else had a bad pnp? Were they willing to fix the mistake? Anyways I also checked my entire harness for shorts and it runs ok on the stock ecu. Just a little disappointed for 820 dollars... I guess it could happen
with anything. Also on a side note diyautotune needs a phone number haha!

 

We had a supplier change transistors on us without warning to ones that had a slightly different package size. These could contact the case and short out. As soon as we found out about the problem, we came up with a way to fix it, but a couple slipped out before we realized what's going on. Sounds like you got one from that batch. We can get these repaired and turned around in a few days; it's an easy fix. Sorry for the inconvenience.

 

No problem I appreciate the fast response. I'll test it out of the casing, and keep you guys updated. I've been working with Stephen a little bit on the issue. Can't wait to get off work and be able to drive the miata again!

 

Hey just following up I took it out of the case and set it on a antistatic mat. Injectors still stuck. Where should I go from here?
Thanks!
Chase

 

Hey Matt, are you guys closed for the holidays? Ive sent 3 emails with no response. Hoping to get back on the road soon. Thanks!

 

I also had not heard anything from Matt since Monday. I got a response today after leaving a voicemail yesterday. I guess one of the techs was on the road all week and the other was dealing with some urgent issues.

 

Pretty much - most of our techs were at PRI. Things are back to normal now.

 

Just wanted to say that Matt and his team were very helpful and got everything cleared up, even shipped it two day air to CA. Thanks guys!

 

Hacksaw worked for me

 

That was about what the fix was, until we could get a new board spin out.



You can see the new design uses an internal heat sink (at left) designed for the new packaging.

 

curious about this hacksaw fix...

 

Sorry, should have been more descriptive ....

So basically I came across a situation where the MSPNP worked great when not in the enclosure, but as soon as I buttoned it up the car would behave very strangely. This includes rough idle, rich AFR, poor starting, and operational changes with connections/disconnections of the USB cable. I discovered that we were getting battery voltage into the case, which was creating various shorting paths (through the USB cable for example). This is measurable by using a DMM between any of the connector shells to the GND reference. You will see a non-zero voltage.

The cause is a TO package mounted to the connector panel (presumably for heat dissipation) shorting the TAB connection to the enclosure close to the screw from the connector panel into the extrusion. I simply used a hack-saw to cut the tab back (on a diagonal) such that the tab no longer made contact with the enclosure when closed. The hacksaw fix damaged the insulation pad under the TO package, so I used electrical tape to provide electrical insulation.

It should be noted that I doubt this unit was DOA. It was given to me by a miata buddy who has gone Hydra. I am pretty sure he picked it up pre-owned, so I have to think somebody used it before, with good results.

So if your car starts running super rich, and showing operational changes with USB connect/disconnect events, I would look here first. I do not have a picture handy, but if I were to describe the location; it is on the baro sensor side, MS connector panel (not the car side), last TO package in the bank of 4.