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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: ilovebeingme87 on January 18, 2011, 09:52:24 am
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Okay so I got the truck back together last night. Let it run for about 10 mins after being down for two weeks. It started up fine sounds good. However half way through the 5 mins into the run it starts throwing black smoke. Before it was white smoke and thats why I replaced the gaskets. So I asked some buddy's and they said possibly timing and or the EGR valve stuck. Any Suggestions? Maybe I got a vaccuum line on wrong or an injector decided to go out on me. I dont know. Pretty much I need a list of where to start and what tools and test I might need to get and perform. Thanks Guys.
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How about some info on what you're working on here?
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87 chevy R10. I let it run for about 20 mins after operating temp. Thankfully the smoke went away. (Pheww) I dont have time to troubleshoot anything else. I needed this truck a month ago. Im freezing on my motorcycle.
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Black smoke means the fuels too rich somewhere, so look for things that would give it too much gas, or things that would restrict the air it can get.
Were you extremely careful with the O2 sensor? that controls the fuel mixture, and they go bad if you look at them wrong, so it might be that. Also certain gasket makers/ sealers can harm O2 sensors. If you just can't figure it out and we can't help ya, try a new O2 sensor. I kinda think the O2 sensor may be involved because you said it didn't make smoke right away. right when you crank up the truck, the O2 sensor doesn't work until its warmed up. so it kinda sounds like when it went out of loop mode, the sensor started telling it to give too much gas.
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Did a check engine light come on
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Make sure the vacuum line is connected and has vacuum to the map sensor.