tbi nightmare, carb swap?

trans1973 · 03-05-2007, 07:33 PM

Hey everyone. I'm new to your board and want to say hi first of all. Next of course is my problem. I have a 89 gmc sierra 2500 4wd. The thing runs like junk. The distibutor was shot, so I replaced it. New fuel pump. New filter. New plugs and wires. No matter what, this thing idles all over the board. I know just enough about fuel injection to be dangerous. I'm sick of messing with it and I want to know what it would take to put a carb on this thing and go to a hei dizzy. I want to keep the tranny, which is I believe a 3L80. What will I have to do to keep the tranny working? What else should I consider. Any help would be greatly appreciated. I have so many questions, I'm sure I'll pester the heck out of you all. Thanks in advance for all your help.

project88 · 03-05-2007, 08:25 PM

i had some problems like that with my truck, 88 1/2 ton, i got a TB rebuild kit, and cleaned the ****** up, helped out a lot! But idle all over the place? that could be sensors, vacume or a host of other things. Id stick with tbi, but that just my opinion

trans1973 · 03-05-2007, 08:30 PM

are the tb's hard to rebuild?

bradrhale · 03-06-2007, 06:17 AM

not hard, autozone sells a rebuild kit that has step by step instructions. i did one in an hour. i agree with project. TB gives the fuel alot better atomization that any carb ever could.

Chevy808 · 03-06-2007, 08:16 AM

I second what brad said. Don't take everythng apart all at once. There's just gasket, filter and O rings to replace. Good Luck.

bradrhale · 03-06-2007, 11:53 AM

i think they come with orings for the injectors also. somehow they come apart. but this has been a couple of years since i have done one. the kit even comes with a new gasket for the TB to intake. watch out for springs. they tend to fly and then only God knows where they go.

trans1973 · 03-06-2007, 03:54 PM

any idea why it would keep eating pickups in the distributor? and also, I went to start it last night and it would start, run for 3 or 4 seconds and then sputter like it was out of fuel. It did this like 15 times than finally it ran, but it ran like absolute garbage. Another thing, what tranny would be in that truck? It does not have overdrive, would that be a 3L80? Thanks for your help guys!

bradrhale · 03-06-2007, 04:36 PM

might be a bad cap. sometimes if you have a cracked cap, water and such can seep in and create further wear.

chevyguy · 03-08-2007, 08:45 PM

These are all good points, But is simplicity is your goal and your tired of this TBI stuff, a simple intake and carb swap with a non computer distribuitor and a fuel pressure regulator will be all youll need to convert to carb. Theh Fuel pressure regulotor will regulatoe it down from factory 9-13 doewn near 7 PSI where it needs to be for carb engines.

03-05-2007, 07:33 PM	#1
trans1973 Junior Member Join Date: Mar 2007 Posts: 8	tbi nightmare, carb swap? Hey everyone. I'm new to your board and want to say hi first of all. Next of course is my problem. I have a 89 gmc sierra 2500 4wd. The thing runs like junk. The distibutor was shot, so I replaced it. New fuel pump. New filter. New plugs and wires. No matter what, this thing idles all over the board. I know just enough about fuel injection to be dangerous. I'm sick of messing with it and I want to know what it would take to put a carb on this thing and go to a hei dizzy. I want to keep the tranny, which is I believe a 3L80. What will I have to do to keep the tranny working? What else should I consider. Any help would be greatly appreciated. I have so many questions, I'm sure I'll pester the heck out of you all. Thanks in advance for all your help.

03-06-2007, 08:16 AM	#5
Chevy808 Senior Member Join Date: Nov 2006 Location: Born & raised in Hawaii had to move to Salt Lake City...bummer Posts: 275	I second what brad said. Don't take everythng apart all at once. There's just gasket, filter and O rings to replace. Good Luck. __________________ '85 Oldsmobile 442 '93 Chevy 2WD C1500 350 Silverado Extended Cab Shortbed '95 Chevy 4WD K2500 454 Silverado Extended Cab Long Bed

03-08-2007, 08:45 PM	#9
chevyguy Senior Member Join Date: Sep 2005 Location: ALABAMA Posts: 3,370	These are all good points, But is simplicity is your goal and your tired of this TBI stuff, a simple intake and carb swap with a non computer distribuitor and a fuel pressure regulator will be all youll need to convert to carb. Theh Fuel pressure regulotor will regulatoe it down from factory 9-13 doewn near 7 PSI where it needs to be for carb engines. __________________ Friends dont let friends use body lifts USMC 92-96 USCG 98 to present

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03-05-2007, 08:25 PM	#2
project88 Senior Member Join Date: Feb 2006 Posts: 135	i had some problems like that with my truck, 88 1/2 ton, i got a TB rebuild kit, and cleaned the ****** up, helped out a lot! But idle all over the place? that could be sensors, vacume or a host of other things. Id stick with tbi, but that just my opinion

03-05-2007, 08:30 PM	#3
trans1973 Junior Member Join Date: Mar 2007 Posts: 8	are the tb's hard to rebuild?

03-06-2007, 06:17 AM	#4
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,024	not hard, autozone sells a rebuild kit that has step by step instructions. i did one in an hour. i agree with project. TB gives the fuel alot better atomization that any carb ever could.

03-06-2007, 11:53 AM	#6
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,024	i think they come with orings for the injectors also. somehow they come apart. but this has been a couple of years since i have done one. the kit even comes with a new gasket for the TB to intake. watch out for springs. they tend to fly and then only God knows where they go.

03-06-2007, 03:54 PM	#7
trans1973 Junior Member Join Date: Mar 2007 Posts: 8	any idea why it would keep eating pickups in the distributor? and also, I went to start it last night and it would start, run for 3 or 4 seconds and then sputter like it was out of fuel. It did this like 15 times than finally it ran, but it ran like absolute garbage. Another thing, what tranny would be in that truck? It does not have overdrive, would that be a 3L80? Thanks for your help guys!

03-06-2007, 04:36 PM	#8
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,024	might be a bad cap. sometimes if you have a cracked cap, water and such can seep in and create further wear.