1997 gmc 5.7l running cool

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mitch
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Joined: Sun Jul 06, 2014 6:26 pm

Re: 1997 gmc 5.7l running cool

Unread post by mitch » Wed Jul 16, 2014 8:29 pm

It is running cooler like the gauge needle is at a quarter and I think that's what I'm gonna do is buy another thermostat. There cheap. The starting problem is when I drive for awhile then stop for a couple minutes and start it again. It cranks over hard and weird ( that's at 70•c) so this morning when it got to a 100•c I stopped the truck and started it back up 30 secondes later and it fired right up so that's why I want the temp to be running around a 100 and not 70. I will let you know what a new thermostat does when I get one in.

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carriedi
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Re: 1997 gmc 5.7l running cool

Unread post by carriedi » Wed Jul 16, 2014 11:36 pm

there might be something else going on there too. the engine should be harder to start when it dead cold rather then when it's at 70C. you might want to check the ecm temperature and what your fuel trims are.

open up the throttle and look down into the intake. See if there is fuel visible in the intake. If you see puddles of fuel you may have a fuel leak inside the intake.
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mitch
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Joined: Sun Jul 06, 2014 6:26 pm

Re: 1997 gmc 5.7l running cool

Unread post by mitch » Thu Jul 17, 2014 6:37 am

Ok how would I check my ECM temperature? Do I need a scanner? And where is it located. The truck runs great when I'm driving I'm just trying to get to the bottom of it running on the cooler side.

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carriedi
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Re: 1997 gmc 5.7l running cool

Unread post by carriedi » Thu Jul 17, 2014 11:55 pm

yes, you need a scanner to see the temperature that the computer sees.

if your car runs in the normal range it will give you better gas mileage than one that runs cold. But performance wise you shouldn't notice a difference in driving. you should use a scanner to look at the engine temp, the operation of the O2 sensor and the fuel trims to see if the engine is running rich if the temp is low. but at 70C temp. you should not see any starting problems
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mitch
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Joined: Sun Jul 06, 2014 6:26 pm

Re: 1997 gmc 5.7l running cool

Unread post by mitch » Fri Jul 25, 2014 1:35 pm

Ok thanks for the info! I have seen lots of scanners out there. What kind should I look at or what should I look at when buying one? Is there any difference from the cheap Walmart ones to the more expensive ones?

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carriedi
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Re: 1997 gmc 5.7l running cool

Unread post by carriedi » Sat Jul 26, 2014 12:10 am

that's a tough question to answer. try going to a parts store and see if they can give you a demo of a decent scanner. Ask them if it has a misfire counter and have them show you how to use it. ask if only does OBD2 engine codes or is it manufacturer specific. will it do abs and other systems. can it graph the data streams. does it have bi-communication abilities.

scanners go from $30 to 10K depending on what's in with it. There are a lot of scanners for under $100. do a search on google and on you tube to see vids of people using their scanners and what are the brands they are using or promoting.
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