CEL on with no codes.

[fryguy190]

i am running a p28 in an Eg civic.

the serial number on the s300v2 is: 22176

so driving the car and all the sudden it cut out on me like its a ignition problem.

went to restart the car and it runs like shit. wont idle on its own.
sometimes when i turn Key to Run to prime pump. pump doesn't prime and CEL is dim.
then it would prime fine and CEL will still be on. all this with no codes.
a couple times the pump primed and 5 seconds later it would primp again on its own.

im able to upload and datalog just fine. green light on when ignition on. and red flashing light on other side of board when dataloging.

i had a co-worker install it for me. (He built boards for Superchips, and now for Cobb)
all connections look good. the only thing i could think it could be is the voltage regulator.

[Spunkster]

Try the ECU in a known working vehicle, if hte problem persists then it sounds like a problem with the ECU. If the problem goes away in a different vehicle you have a problem with the main relay, ignition switch or wiring in the vehicle.

[fryguy190]

in know its not the main relay. i put a known good relay in and it did the same thing.
ill try the ecu in another car tonight.

[fryguy190]

ok so i put the ECU in another civic and uploaded a map so that it would work on the car. car runs perfectly fine...
i dont see how it could be the ignition switch because the car turns over and runs.

another thing i had noticed is that there is no CEL untill i hit the gas. when i do CEL pops on and the car no longer wants to idle.
im completely stumped on what it could be. ive never ran into a problem like this.

[fryguy190]

OK well i figured it out and i feel like in idiot for not checking it before hand...

the ECU ground on the Thermostat housing was loose. tightened it up and the car runs great now