I've been having trouble with getting my S4 TII swap running right and I'm running out of things to check.
- S4 n/a with a JDM S4 TII engine swap
- N333 ECU with RTek 1.8 (bought secondhand)
- Greddy 720cc injectors (secondhand, seller claimed they were cleaned and flow tested previously. I've confirmed that they're not clogged but I'll have to take them into a shop to have the flow verified)

The reason I question the ECU is that when the car starts, it jumps up to about 2000rpm and stays there for a few seconds (usually dies right after) even though the Rtek is supposed to eliminate AWS. I do still have the thermowax in place as well as the BAC, could these be the reason for the high starting RPM?

Are there any tests I can do with a multimeter to see if everything on the ECU board is working correctly?

 

I swapped in a stock N333 ECU and the car seemed to start much easier and wanted to actually rev instead of dying when I gave it throttle (I couldn't run it too long because it's late and the car has an open downpipe).

I'm really hoping that problem with the other ECU is not related to the RTek chip and I can just move it over to the currently stock ECU. Otherwise I'd have to put my stock injectors back in and figure out how to not run too much boost. I currently have a 3" aluminum pipe and a cone filter for the intake and I know that would result in too much boost for the stock ECU, even with the larger wastegate of the S5 turbo that I have installed.

 

I took a look at the board of my Rtek-modified ECU and desoldered the socket and another one of the factory chips for practice. The area around the IC604 chip that's meant to be left out with the Rtek install has some traces ripped out, it must have been a self-install. I wonder if the poor functioning had anything to do with this:






The one I did myself is directly above IC604, I think it came out okay. I'll practice some more on the other chips before I try to move the Rtek to my other ECU.

 

Unless the ECU was hit by lightning/static or there was physical damage, the chip itself is unlikely to be bad. It is much more likely to have harness or sensor issues, particularly since you are using a USDM ECU with a JDM engine and a ???? (hopefully not NA) harness.

You can check the chip itself by making sure the check light blinks out codes. That's how we used to test before and after an install.. Any issues with the install and the program on the chip wouldn't load into the processor. The processor will not clock out codes unless that whole process worked.

That board looks really rough, definitely a really bad self install. I can't say for sure if that is an issue, but if I had to guess I would say it definitely isn't helping. The test above would tell you if it was an issue.

 

Oh, it's n/a, alright. Even better, I chopped it up to splice on the immaculate connectors from the cut harness that came on my JDM engine , which must have been pretty low mileage. I'm fairly confident that I've got everything right, though.

It starts much easier after I swapped in my stock N333 ECU and will actually rev instead of just dying upon any throttle application, so I'm going to try putting the Rtek chip into that ECU, hopefully better than whoever did it before. Unfortunately I have already unsoldered the Rtek from the questionable ECU so I can't perform that test at the moment.

Thank you for the input.

 

Huh, I opened up the "stock(?)" N333 ECU and these two chips are socketed and look quite different from the stock chips I've seen.

 

someone just took the stickers off. But as it's socketed, it's also possible someone reprogrammed them,
Don't leave them out in the sun or they could get erased.

 

The second N333 ECU with the Rtek installed runs great!