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View Full Version : CAS, ECU, Detonation, fuel pump, relays, issues.



shane_B
01-03-2006, 09:45 PM
Someone help me clear this up. I read the FSM and the CAS sends a "1 degree" signal to the ECU (telling the ECU the car is running) which controls the Fuel Pump relay causing the pump to turn on. Does it send this same 1 degree signal to the ECU to make the FP turn on for a few seconds before start up? Cuz my fuel pump keeps running while the key is on/car is not running. Also, my battery seems to drain after a few days (albeit its a small battery I still think there might be a drain) Im thinking the ECU could be holding the fuel pump relay on continuosly? Even when the car/key is off?

The deal is I had a cold start problem. Turned out to be the CAS was bad. I got it rebuilt. Cold start problem went away. But now I get some detonation. (Im only running 12 psi, mostly stock motor, with exhaust and intercooler, manual boost controller, factory ECU, SAFC, Z32 MAFS). Subsequently the car idles rough when it starts getting warm now.

So Im thinking the CAS still might not be 100%. Which makes the fuel pump relay constantly stay on. And maybe, now also causing my detonation.

Can anybody here with good ecu tech knowhow tell me WTF is going on or if my assumptions are close to being right? Im just trying to gather some ideas so when I troubleshoot Friday I have something to go off of.

Cliff notes:
Cold start problem, fuel pump contstantly runs (when car is off/key on), battery drains. (dont know if its related)

Cold start fixed, fuel pump still runs continuously, now I get detonation, and rough idle when warming up.