I have a 1973 Chris Craft Commander 41 refitted with 1999 PCM 7.4L MPI engines. One engine is running very rich at idle, to the point raw fuel is coming out the exhaust. I have the scanning software for the engines, so I have access to all the operating information.
So far I have replaced the MAP sensor with no change. I have also checked fuel pressure, temp sensors, compression, and distributor. Timing is set at 10 BTDC at idle.
From running a few trials with the scanner plugged in, the ecm is calling for about 15% more fuel on the rich engine than the good engine.
I’m at a loss for what else to check and what would case the increased demand if the MAP sensor and Temp sensors are good.
So far I have replaced the MAP sensor with no change. I have also checked fuel pressure, temp sensors, compression, and distributor. Timing is set at 10 BTDC at idle.
From running a few trials with the scanner plugged in, the ecm is calling for about 15% more fuel on the rich engine than the good engine.
I’m at a loss for what else to check and what would case the increased demand if the MAP sensor and Temp sensors are good.