TBI to Carb..... HOW??

[Cowboy_Customs]

OK, so I have been tinkering with the 91 for a couple days now, I have no puter codes, and no bad sensors, and just replaced the plug wires, cap, rotor, and coil. Still it runs like crap, and wont idle.

What do I need to do to convert a 454 TBI to Carburation? I know I need an intake and carb, and fuel regulator. But what about the TPS, and all the sensors? I have a 4L80E Trans and plan on keeping it. Thanks guys!

[HAULIN IT]

Cowboy, Have you done a compression check,fuel pressure,ect.? I would think for the money it would take to convert it nicely, you could probably make it run correctly. To me that just seems to be going backwards. Lorne

[Captkaos]

You can get it running correctly, just gotta figure out what is wrong.  Your going backwards if you go from a TBI to a carb.  The ECM needs all the info from the senors to shift the 4L80E AFAIK.

[VileZambonie]

Is that your only concern is a poor idle? Here's some things to check:

Disconnect the EGR valve.

Check your fuel pressure.

Check your TBI base gasket.

Verify proper ignition timing.

Verify injector operation at both injectors.

[Dragon]

So lets see, the easiest way to do it would be to swap in

1) Carb manifold(Say $75-350)
2) temp sensors for your gauges and fans($5-30)
3) decent sized carb  for the 454($50-275)
4) Jet stand-alone controler for the 4L80E(Say $1100-1300)
http://www.jetchip.com/products.asp?pid=21698
5) Standard HEI Dist($40-300)

Note this is a basic starter, I'm sure there are others that will happily filling in anything that I may have left out....

BTW: if it's not idling, I would start checking all of the hoses(Make sure they aren't cracked, properly routed, not disconnected), check all of the sensor electrical connections(Make sure there isn't any breaks in the wiring,anything disconnected,etc), and finally I would also verify that the sensors are working correctly(Even if a Idle Air Control(IAC) sensor has checked out with an Ohm Meter, it still could be shorting out internally, causing it to pulse/surge/not maintain proper idle)...

[Redneckchevy]

Did you check you pcv? And vacuum lines? and fuel filter? make sure u got good clean gas? you probably did already cause thats the basic stuff...

[Cowboy_Customs]

Hey thanks for all the fast responces guys, im going to update this thread http://forum.73-87chevytrucks.com/smforum/index.php?topic=7421.0 as I have decided to keep the TBI. Ive always wanted a big nutz 454, and doing it with a TBI makes it more interesting/fun. 

[Dragon]

Glad to hear! TBI/FI to me is the best way to enjoy getting the most out of your 454, especially when it is tuned in properly!

[autorepr]

Whew,,, that was a close one.  Seriously that TBI set up really is a simple low pressure system, an electric pump in the tank, a few sensors telling a computer what the engine is doing, the comp. telling the injectors when to open and close and for how long, and telling the idle control valve how much to open to control idle. Your making the right decision keeping it, 9 times out of 10 the problem exists because of something that's plagued engines since the beginning regardless if they're carbed or EFI. ( vacuum leak, egr leak, ignition problems, etc. etc. etc.) If need be have someone check it for you.