Author Topic: tbi running rich  (Read 13350 times)

Offline Edahall

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  • Posts: 311
Re: tbi running rich
« Reply #15 on: September 05, 2012, 06:23:39 pm »
the truck is a 87 v1500 with a 305 but originally a 350 and i have replaced o2 and the temp sensor with 2 wires but it is still getting the bumper "sooty" any ideas

My best guess is that when they swapped from a 350 to a 305, they used the throttle body from the 350.  The problem is, 350 injectors are higher flowing than 305 injectors.  Anyways, take a careful look at your injectors and if you see any orange or black markings on it like the following picture, it's a 350 injector.  305 injectors will have green and white markings.
http://i29.photobucket.com/albums/c278/Davephoto/inj2.jpg
1990 ¾ ton 4x4 Chevy Suburban
-Cummins Diesel - 12 valve - factory rebuilt
-6 speed bullet proof manual transmission - NV5600
-Gear Vendors Overdrive
-Upgraded Holset HX-35 turbo
-NP205 iron transfer case
-3.73 gears
-2" Lift

Offline rusty but trusty

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  • Posts: 54
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Re: tbi running rich
« Reply #16 on: September 06, 2012, 04:31:34 pm »
my injectors dont have those color marks and i think that the fuel system wasnt changed at all when the engine was changed and when i get it back from the place replacing my flexplated i will begin to get new injectors and a new distributer
87 GMC V1500 305 700R4 NP208 and 10 bolts front and rear

Offline Edahall

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  • Posts: 311
Re: tbi running rich
« Reply #17 on: September 06, 2012, 10:07:00 pm »
my injectors dont have those color marks and i think that the fuel system wasnt changed at all when the engine was changed and when i get it back from the place replacing my flexplated i will begin to get new injectors and a new distributer

Then that would be the reason why it is running rich.  Make sure you buy 305 specific injectors (TJ4) with a green / white marking and a flow rate of 40 lb/hr.  The 350 injectors have a flow rate of 55 lb/hr and will cause exactly what you described when used on a 305 engine.
1990 ¾ ton 4x4 Chevy Suburban
-Cummins Diesel - 12 valve - factory rebuilt
-6 speed bullet proof manual transmission - NV5600
-Gear Vendors Overdrive
-Upgraded Holset HX-35 turbo
-NP205 iron transfer case
-3.73 gears
-2" Lift

Offline rusty but trusty

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  • Posts: 54
  • Newbie
Re: tbi running rich
« Reply #18 on: September 11, 2012, 08:17:13 pm »
sorry for not responding earlier but i have been having problems with the internet lately
but the  information will be used and hopefully solve the problems to all who helped thank you all so much
87 GMC V1500 305 700R4 NP208 and 10 bolts front and rear