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Fuel trims

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Old 03-16-2017, 08:39 PM
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Default Fuel trims

I have read up on this but still looking for the wonderful advice I get here. Checked my fuel trims today and bank 1 is about 8 positive and bank 2 is about 24 positive. Also I get a really rough idle but throwing no codes. Any ideas??
 
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Old 03-17-2017, 04:23 AM
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Hot engine, parked. If you get those at idle, rev to about 2500 and see what happens. If either drops much (well, the 8 is only a bit out) then you would expect an air leak.
 
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Old 03-17-2017, 10:13 AM
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Checked fuel trims again this morning. At normal operating temp at idle bank 1 reads +4-8%. Bank 2 reads +24%. At 2500rpm both go close to zero. Now, to find leak
 
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Old 03-17-2017, 11:00 AM
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Since it's only bank two the intake manifold an gaskets is a good place to start.
 
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Old 03-17-2017, 11:05 AM
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That's what I'm thinking. Thanks
 
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Old 03-17-2017, 06:08 PM
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Get valley hoses as long as your going in.
 
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Old 03-17-2017, 06:35 PM
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I recently did all that. Water pump, housing, and all hoses and new intake gaskets( bet I screw up somewhere)
 
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Old 03-17-2017, 07:46 PM
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Always the place to look for trouble is something I fixed.
 
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Old 03-17-2017, 08:26 PM
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Yeah, me too. Got quite a bit in front of me. Have whitexkr's gauge set on order along with oil pan gasket and transmission filter, gasket, and new transflo pressure valve. While I'm waiting I'll go back and find my intake leak
 
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Old 03-18-2017, 09:21 AM
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Mass air flow sensor, part load breather, cam cover leak, missing oring on oil dipstick. cracks in air intake tube or full load breather. Just monitor your full trims and spray areas with carb/brake cleaner when they start pulling you've found a leak. past this I would say your injectors have a crappy spray pattern. I would pull them(easy) and send them off for rebuild, cleaning and flow testing like to www.injectorx.com
 

Last edited by Brutal; 03-18-2017 at 09:25 AM.
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Old 03-18-2017, 04:34 PM
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Brutal, you hit the nail on the head. MAF sensor was dirty. I cleaned and worked fine. Thanks
 
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Old 03-18-2017, 08:03 PM
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This should be the first post on every Fuel Trim problem! We miss you Brutal!!

Originally Posted by Brutal
Mass air flow sensor, part load breather, cam cover leak, missing oring on oil dipstick. cracks in air intake tube or full load breather. Just monitor your full trims and spray areas with carb/brake cleaner when they start pulling you've found a leak. past this I would say your injectors have a crappy spray pattern. I would pull them(easy) and send them off for rebuild, cleaning and flow testing like to www.injectorx.com
 
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