Quote:
Originally Posted by performanceisland  xxxJohnBoyxxx can you check my work please, this is my first time making this secondary air pump simulator i want to make sure it is right before i go further.
also the plug that i unplug from the bottom of the sap is the power and ground, but where do i connect the dme and o2 wires to?
thank you. |
Everything looks good. I can't ensure the voltage regulator is in correct by the picture. Looks like you turned it upside-down and wired correctly.
Move to test stage:
1. First test continuity (Meter set to ohms) between DME and O2 wire with no voltage to unit and you should have a dead short. You are ensuring DME and O2 are connected together in the relay when there is no power. If good move to step 2
2. Apply voltage to simulator and listen for relay to click on. With simlator on test voltage positive lead on DME wire and Negative on battery ground. You should see 200mv or .200 volts or close to that. If not adjust the pot resistor to get 200mv or .2 volts on your meter when the unit is active. When completed disconnect power and the unit is tested and calibrated....Ready for install.
+/- connection: SAP positive to Simulator positive so it becomes active only when the SAP is called for by the DME. Negative to any good ground or SAP ground (Your choice ~ Ground is ground)
O2/DME connection: We are only looking for one wire to connect to. The upstream O2 signal...On my car 1997 BMW 318is the O2 signal is grey then goes to the plug and changes to a yellow on the way to the DME. This signal wire is the one we want to tap. You can tap Grey on the O2 or Yellow after the sensor plug which is still the O2 signal wire on it's way to the DME. Cut the signal wire and wire simulator wires O2 to O2 sensor and DME to the wire leading to the DME.
What we are doing here is only putting the simulator in line with that O2 signal wire to fool the DME when the SAP comes on.
Therory ~ When the DME calls for "SAP On" then it expects to see a lean condition on the upstream O2 sensor. If it doesn't see the lean condition from the SAP forcing fresh air in the exhaust it throws a CEL code. This is the
only check for the SAP
SAP On ~ Simulator active. The simulator disconnects the O2 sensor from the DME and sends a false 200mv signal to the DME telling it the exhaust gas is very lean. The DME is "happy" since it expects this signal with the SAP on so no CEL or error codes.
SAP Off ~ Simulator off. DME calls for "SAP Off". The simulator when in a off state: When in the off state the relay is used as a pass through for the O2 signal wire so the O2 is connected like the wire was never cut. Car runs like normal and full Lambda conrtrol is active and car runs normal like nothing was ever changed.