AEM Wideband through D10 ELD

gottabfast · Post by **gottabfast** » Tue Aug 04, 2009 6:57 pm

This is on a 2000 Civic Si...I tried the AEM into the B6 pin (removed R2 and R3) and it read some mystical voltages that looked like my target AF readings. Now I've moved the AEM into the D10 pin (removed R136 and R138) and it's not reading anything. I verified that there is a good signal to the ECU from the AEM wideband(2.4 ~2.5V at idle after startup). The Pin it went to on the stock harness was C8 (knock sensor), is that correct? The closed loop is set up correctly and I am using the stock O2 sensor (wiring untouched) as a narrowband.

I'm ready to buy a PLX at this point, but is there any hope for the AEM, did I miss something in the set up?

allm0t0rGSR · Post by **allm0t0rGSR** » Tue Aug 04, 2009 9:36 pm

try use D12 but must have a 0.1uF capacitor in C42 for the ECU to read the voltage correctly... it work for me

Post by **Spunkster** » Wed Aug 05, 2009 9:31 am

It should not be connected to C8. IT must be connected to D10 on an OBD1 ECU.

gottabfast · Post by **gottabfast** » Wed Aug 05, 2009 10:12 am

It's connected to C8 on the vehicle harness, which was conected to D10 on the OBD1 ECU by the OBD2 --> OBD1 conversion harness.

Post by **Spunkster** » Wed Aug 05, 2009 12:08 pm

Function ELD

OBDI D10
OBDIIA D16
OBDIIB A30

gottabfast · Post by **gottabfast** » Wed Aug 05, 2009 12:28 pm

A30 on my car is the A/C switch, ELD actually goes to A27 on the car harness side. Is it possible I have the wrong harness? It ran perfectly fine N/A.

Either way, I have it connected to C8 and it's not reading anything, it seems like it should at least read something...

Post by **Spunkster** » Wed Aug 05, 2009 1:08 pm

You do not have it connected properly. It must go into OBD1 pin D10. Connecting it randomly to some other pin will not allow it to work.

gottabfast · Post by **gottabfast** » Wed Aug 05, 2009 2:36 pm

It is in the D10 Pin on the OBD1 ECU, the adapter harness has the wire from D10 on the ECU going to pin C8 on the vehicle harness. I wired the Wideband in at C8 on the harness side to match up to D10 on the ECU. I didn't just wire it up to some random pin. I traced the wires, they match up.

Post by **Spunkster** » Wed Aug 05, 2009 2:41 pm

You'll need to find a correct adapter harness as that is not correct.

gottabfast · Post by **gottabfast** » Wed Aug 05, 2009 3:10 pm

I'm looking into a new harness then...

Regardless, the O2 sensor is wired into D10, gets 2.4~2.5V and still does not respond. The car ran perfectly N/A with the same adapter harness, so I'm not completely convinced its in the adapter harness.

Do you have a list of pin connections from OBD1 ECU to OBD2B ECU so that I can verify the harness is connecting the correct pins? I'm actually an engineer for Honda, so I could pull the dwgs for more pinout connections to check.

Thanks!

da_dude · Post by **da_dude** » Wed Aug 05, 2009 10:16 pm

A30, the green/red wire is where you need to tap into on an obd2b. I just did the aem wideband install into my 96 coupe using the ELD pin 2 weeks ago. Of couse, I also cut out r136 and r138. Works great.

gottabfast · Post by **gottabfast** » Thu Aug 06, 2009 5:16 am

A30 on my harness is the A/C switch...

A27 on my harness is the ELD input...

After looking at pinout dwgs for the P2T (00 Si M/T) and the P28 ECUs it seems like the only input I could find that didn't match up was the ELD from the P28 went to the Knock sensor on the vehicle harness. The pinout actually says that D10 is blank and D18 is the ELD input for the P28 ECU. If that's true, unless Hondata changes D10's circuit in the ECU then I should be getting nothing when I plug into D10.

da_dude · Post by **da_dude** » Thu Aug 06, 2009 2:46 pm

I doesn't matter where the ELD pin is on your harness. Once once you use the jumper harness it's coverting to an obd1 plug where it should still be at D10. The ELD pin on my obd2a harness was a D16. Once I use the jumper harness to run my p28 it'll still come back to D10.

gottabfast · Post by **gottabfast** » Thu Aug 06, 2009 6:42 pm

I understand that it doesn't matter where the pin goes on the vehicle's harness (unless I cut out something that was necessary, then it's a problem) as long as the white wire from the AEM goes to pin D10 on the ECU. What I'm saying is that on the Spec drawing for the ECU (the actual Honda pinout diagram) D10 is a dead circuit, a blank pin. The ELD on the P28 ECU is pin D18. Since I'm getting a voltage to the ECU, but not getting a signal that leads me to believe it's a dead circuit or I'm not using the D10 that Hondata intended.

I appreciate the help, I guess I'm doing a poor job of explaining this problem.

For now I'm gonna wire it to D14 until I can get it to Slowmotion Motorsports.

Is there a way I can check D10's function by checking the circuit in the ECU?

da_dude · Post by **da_dude** » Thu Aug 06, 2009 10:29 pm

OBD1 doesn't have a "C" connector.
OBD1: http://www.ff-squad.com/technet/wiring.obd1.htm
OBD2B: http://www.ff-squad.com/technet/wiring.obd2b.htm