I have a stock P75 ecu that I've socketed and chipped myself. Before the socket the ECU ran my JDM b20b perfect and had no issues. Now anytime I load a basemap into the ecu it kicks the car into limp mode. I was wondering if I did anything wrong?

Heres everything I did:

- soldered in 28 pin socket

- soldered C51 & C52 Capacitors

- soldered 74hc373 chip

- jumped j1

- soldered datalogging port into CN2

- replaced C14 capacitor

- Cut j12 for datalogging

Am I missing something? All the solder points are clean and are not touching any other points. I'm using crome and a stock P75 basemap. I also am removing the checksum routine before burning the chip. I've attached some pictures.

 

I like to put a jumper @ J1 so that if I ever run into any hardware issues I can pull the jumper and check the ECU in it's stock trim.


by GhostAccord, on Flickr

After a quick look at your pictures, it looks as though you may have a few pins with cold solder joints. Anywhere that you see black around the pin/leg of a socket it will require a bit more heat and or solder to form a complete solder joint. If that doesn't work, try cutting J1 and see if it works as a stock ECU.

Will the car start and run? can you get any codes from the check engine light?

 

Thanks for the reply! I'm going to add more heat to those points today. It would run but it is was in limp mode. I cut the J1 jumper and removed the chip and the car is back to normal and running fine. I'm assuming some solder points aren't fully making a connection? I've double checked and none of the solder points are touching, so that's a plus. I'm new to this, so thank you for helping!

 

No problem, you have to start somewhere. I practiced on an old burnt out ECU that I picked up from the junk yard for free. De-soldered and re-soldered every component off the board. Trick is to get your iron at just the right temperature, removing the gel coat from the areas that you are going to be working on helps as well. I use carb/throttle body cleaner and a soft bristle tooth brush to get the gel coat off.

 

So, I fixed the issues you marked for me and I'm still getting limp mode. But if I remove J1 jumper its back to normal. As before, no joints are jumping each other and the board is fine. I did notice however, that when the J1 jumper is disconnected my car will run perfectly until I get into high RPMs and then it'll kick me into limp mode until I shut the car back off. Would it be recommended to swap to a different ECU? or is that something that'll happen after an ECU is chipped?

 

Does the check engine light stay on? If it does you could try reading the codes that it is throwing

 

It's been on since I did the swap. I'll look into the codes tomorrow sometime and let you know whats up