ECU Check Engine Light with 0 error codes - help?

Chronus · Post by **Chronus** » Sun Oct 22, 2006 1:04 am

So here's the story. I socket the ECU myself. I checked everything over, all the connections are fine, and the chip is being read. The problem is the check engine light is on and i'm capped at 3300 rpms. I took it over to a shop to get the error codes looked at, comes up with nothing, no error codes show up, try and reset the light, nothing happens, still shows up. I'm running the s300 on a 1994 Acura Integra P74 stock ecu, so it's OBD1, and the only modifications on the car so far are a GReddy EVO2 exhaust, plus lowering springs and stuff that don't really matter.

My question is, why is the check engine light on and why wont it go away?

HRED · Post by **HRED** » Sun Oct 22, 2006 1:30 am

socketing is wrong, ECU is running with the backup CPU and not with the S300

Chronus · Post by **Chronus** » Sun Oct 22, 2006 1:33 am

but all the contact points soldered well, and everything was soldered exactly by the manual, except that one resistor, i couldnt find R54, so i figured my ECU didnt have one. P74's don't have the R54 right?

Post by **Spunkster** » Mon Oct 23, 2006 10:36 am

Can you upload to the ecu, or datalog?

Chronus · Post by **Chronus** » Mon Oct 23, 2006 6:14 pm

The upload option comes up, and when i click on it, smanger says it goes through, but i dont see any significant changes. I tried datalogging and it didn't seem to work.

According to some manuals i found online, it says that the P72 is the only ecu without the R54, but i looked high and low on my P74 and I don't see any. I also tried the other ECU i has laying around, also a P74, and that doesnt have one either, am I just missing it or are the instructions I found wrong? They said it was right below the J1, but all i see around J1 is a R52 and a R49, and nothing right under the J1.

Post by **Hondata** » Tue Oct 24, 2006 8:52 am

See http://www.hondata.net/forum/viewtopic.php?t=5226

If you can upload but not datalog, it is the socketing.

Chronus · Post by **Chronus** » Tue Oct 24, 2006 9:19 am

Why dont you guys anwer the question, i already asked twice, Does the P74 have an R54 or not? If so where is it?

Post by **Spunkster** » Tue Oct 24, 2006 9:29 am

Straight from the Smanager help file:

1. Remove the ECU circuit board from the ECU case.

2. If there is no IC in IC4, solder the 20 pin 74373 latch IC into IC4.

3. If there is a socket in IC3, desolder and remove the socket.

4. Solder two strips of 14 male pins into IC3.

5. If there is a connector in CN2, desolder and remove the connector.

6. Solder 4 male pins into CN2 (pins 1-4)

7. Install the supplied jumper into J1

8. If the ECU has R54 (right next to J1), then install the supplier resistor into R54.

9. Cut and/or remove J12.

10. Install the ECU circuit board into the ECU case. Using the s300 USB connector as a template, mark the ECU around the USB slot. Cut the slot using a hacksaw or milling machine.

Chronus · Post by **Chronus** » Tue Oct 24, 2006 11:00 pm

i guess i'll de solder and resolder it.

Jaker · Post by **Jaker** » Thu Oct 26, 2006 7:41 am

If you're not extremely careful with heat management when soldering in the 373 chip, you can fry it.

crluver123 · Post by **crluver123** » Sun Oct 29, 2006 12:04 pm

Chronus wrote:Why dont you guys anwer the question, i already asked twice, Does the P74 have an R54 or not? If so where is it?

no, the p74 does not have r54. so you dont need to install that resistor

Chronus · Post by **Chronus** » Sun Oct 29, 2006 12:06 pm

thank you, finally someone answered the question.