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have you check the ECM to see if its throwing any codes? I'm sure that would help alot.. maybe take it down to a local parts store and have them check for codes.
What is...Cracked exhaust manifold for 500 Bob. I've seen where they cause lean condition in cold a weatherWhat's under the hood??? If you have to ask maybe we shouldn't race...
Quote from: 81_Chevy on October 17, 2013, 12:10:45 PMhave you check the ECM to see if its throwing any codes? I'm sure that would help alot.. maybe take it down to a local parts store and have them check for codes.I was under the impression that as long as I didnt have any SES light on the dash then I wouldn't show any codes?
I was under the impression that as long as I didnt have any SES light on the dash then I wouldn't show any codes?
Can you elaborate? Are you saying that possibly the cracked manifold is showing the ECM a lean condition causing it to deliver more fuel than necessary?
What does the fuel pressure measure?Are there any stored trouble codes?Remove the air cleaner and wipe off the tips of the injectors with a rag. Turn the ignition ON, but do not crank the engine. Do you hear the fuel pump run for about 20 seconds? Check the injector tips for fuel - they should be dry. Repeat this cycle 2 - 3 times. Injector tips should remain dry. This step determines whether the injectors are leaking fuel.Refer to the factory manual and check the operation of the Air Management (aka: Diverter) Valve and air injection system - on a cold start it should inject air into the exhaust for about 30 seconds or so to heat the cat.Check the MAP and TPS functions using a voltmeter. You'll need a voltage vs vacuum chart for the MAP. Regarding the TPS, you're mostly interested in the throttle closed voltage (~0.56 v) and a smooth voltage transition to full throttle (< 5 volts).
I just fixed my header collector gasket leak and all I can say us wow I was losing a lot of power. It also caused miss fires at idle and during driving.What's under the hood??? If you have to ask maybe we shouldn't race...
Thanks BD. My exhaust manifold crack is after the O2 sensor. I drip tested the injectors and they appear to remain dry. They also spray an even cone pattern and I see no drips I from injector while running. What controls the fuel & air mixture when the ECM bypasses the O2 sensor? From what you said above it is almost as if once the O2 sensor get heated up then it stops backfiring.I also wanted to ask what would happen if the Coolant temp sensor was unplugged? Would this cause an full time rich condition or lean condition.