i have to pass california smog which means i have to have a working check engine light. how would i make it stay on in accesory and start, but not run, and not have to rewire the whole thing? its disconnected right now because im changing from a mech speedo to electric. any ideas will be greatly appreciated.

tia.

BTW anyone know what color the check engine light is on a mechnical speedo???

 

Try using the oil pressure switch/fuel pump relay coil power to operate a separate relay. Route ignition power through the NC contacts of the relay and to your light. Any time the fuel pump is off but the ignition is on, you'll have a light. You won't have a light for the first two seconds of ECM power-up, but will after that and until the oil pressure switch is closed/fuel pump is running.

 

i have a carbed car, dont remember seeing the fuel pump light...but ill look

 

You don't have a fuel pump light, but you might have a fuel pump relay. If not, you can use an oil pressure switch.

 

thanks again for the help vader, however i do not remember seeing an "oil pressure switch." i have an oil pressure guage. im not sure if that is what you are talking about; my terminology tends to not be the greatest. if you are talking about an oil pressure light, i do not belive i remember seeing that also. this beign a pain because my smog tech will "overlook" all of the visual except the check engine light. the check engine light HAS to work for the car to be smog legal in california, however, im not sure why.

 

You would have to install an oil pressure switch and the relay for the lamp. Most EFI cars had the gauge sender and a switch, but carbed cars may not.

 

well i have about 5 months to get the car running for smog which is relatively a long time, but i dont wanna wait around for that time to come. i think i am going to carefully go through the electircal under the dash (i think i am getting to good at this) and wire everything up so the ecm works correctly with the rest of the car.

 

As long as you have the time, that is probably the best solution. The ECM really won't limit your performance if you learn how to get around it.