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06-14-2013, 08:16 PM | #1 |
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Join Date: Dec 2010
Location: NC
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electric fans - cool down after engine off
Fired my engine up for the first time night before last. Everything looks to be checking out great! I have a question about the elec fans though. I'm running fbody dual fans through the pcm control. The first fan is set to come on at 185 and I'm not sure where the second is set :\ Sitting in the shop idling the engine is running at 200-204 and the primary fan runs fine but the second fan only twitches. It does not engage, but it is definitely moving some. To eliminate the possibility of a bad fan motor I swapped the plugs and then the secondary fan runs fine. I think it has to be the connector that plugs into the second fan is just bad?!?!? Why would the fan just twitch though and not fully engage?
My main question though: is it possible with just a pcm and no bcm to tune the computer to run the fans to cool the engine down after the truck is cut off? Right now my fans cut off as soon as the engine dies. Any wiring mods needed? Or just something in the tune? Posted via Mobile Device |
06-14-2013, 08:46 PM | #2 |
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Re: electric fans - cool down after engine off
No need, Without water flowing the fan will not cool the engine.
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06-14-2013, 10:27 PM | #3 | |
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Re: electric fans - cool down after engine off
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06-15-2013, 10:20 AM | #4 |
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Re: electric fans - cool down after engine off
They are not supposed to run after the engine is shut off. The factory used to do that, but not any more, at least on GM LS engines. I think they realized it wasn't really helping like Cline said. As for your second fan not coming on, check your tune to see what temps it's set to come on and go off at. I've seen a lot of people have the second fan relay just click on and off, and the think that it has to be a tune issue.
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My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html |
06-23-2013, 08:46 PM | #5 |
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Re: electric fans - cool down after engine off
Cline is right about it not doing any good without the water pump turning. I have often wondered if the fans being on would move a little air under the hood and help some, if so its probably minimal.
To answer your question though, Yes the ecm can be programmed to run for a period of time after the key is turned off.
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72 Chevy CST K5 HIGHLANDER BLAZER Getting a 6.0,NV4500,NP205,14BFF (Currently laying all over the place in little pieces) 72 Chevy swb step-side "LS" 6.0 Here's a build thread of sorts 2002 HD2500 Crew Cab, 8.1L Allison 4x4 Daily Driver Check it out www.lsdyno.com |
06-23-2013, 08:49 PM | #6 | |
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Re: electric fans - cool down after engine off
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06-24-2013, 11:54 PM | #7 |
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Re: electric fans - cool down after engine off
I use EFI Live and it's very easy, not sure what your guy uses but I'm sure it's simple regardless.
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72 Chevy CST K5 HIGHLANDER BLAZER Getting a 6.0,NV4500,NP205,14BFF (Currently laying all over the place in little pieces) 72 Chevy swb step-side "LS" 6.0 Here's a build thread of sorts 2002 HD2500 Crew Cab, 8.1L Allison 4x4 Daily Driver Check it out www.lsdyno.com |
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