Author	[Modern View]
Lanse 01-27-2013 07:40:27 206.55.217.126 Report to Moderator	Goodmorning everyone!! So, after a little thinking and a lot of internet surfing, Im strongly considering keeping the existing TBI on that 305 V8 in the tractor project... Next question, is how to wire it in? I know this tractor isnt going to have any electrical requirements that even resemble that of the truck it came out of... No windshield wipers, air conditioning, etc... Pretty much just a few lights... Two front... Two rear... Two turn signals... And I'd really like to have an oil pressure and temperature gauge setup as well... Someone said something about using simple mechanical gauges, sounds great to me... This thing basically just needs to start and run, with it's stock TBI system... I'm not really sure where to even start here, are there any charts, or anything along those lines for a build like this? Any ideas/thoughts/input? Anything is appreciated... Thanks guys... Have an awesome weekend! :) [Reply]   [No Email]
chvet73 02-01-2013 18:59:21 97.93.136.159 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to Lanse, 01-27-2013 07:40:27   I have a TBI setup on my Corvette. Works great. Just keep all the wiring,tank and fuel pump plus the sensors and it will work. The dash gauges have nothing to do with it. LilFarmer said it right [Reply]  [No Email]
buickanddeere 01-30-2013 07:35:00 184.151.63.251 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to Lanse, 01-27-2013 07:40:27   Lance keep us posted on the project and don't let the Ludits scare you. [Reply]  [No Email]
mkirsch 01-30-2013 07:21:32 64.80.110.74 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to Lanse, 01-27-2013 07:40:27   Seriously guys, do you realize how expensive some of your recommendations are? "Just" get this. "Just" get that. "Just" get a whole new engine... "Just" buy a whole new intake and carb... Good grief, he's not building a competitive race car here. He's building a modern day DOODLEBUG out of a $200 junked pickup and scrounged parts. Lanse, like some have said, you need the original ECM and wiring harness. With that it's mostly plug-n-play. Guys that build rock crawlers do this kind of stuff all the time, so maybe you can find a rock crawler forum and glean some information from them. [Reply]  [No Email]
Centex Farmall 01-29-2013 16:32:16 166.137.116.49 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to Lanse, 01-27-2013 07:40:27   Other than the obvious of preserving the wiring and sensors, be sure and pay attention to the fuel setup. IIRC the TBI wants between 10 and 14 PSI. Closer to 14 is better. The stock setup is with a bypass regulator and the extra fuel going back to the tank. I've found the factory ones spot welded to prevent adjustment, so if that becomes and issue you can get some nifty aftermarket ones with a wide range of adjustment. [Reply]  [No Email]
David G 01-28-2013 08:23:29 205.215.206.18 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to Lanse, 01-27-2013 07:40:27   Look up megasquirt, it is a barebones ECM that you can put custom settings into. The factory sensors will wire right up. I am putting one on my MH44. [Reply]  [No Email]
Owen Aaland 01-28-2013 06:11:22 216.47.32.228 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to Lanse, 01-27-2013 07:40:27   You really don't need much to make the run engine with the ECM. You will need a throttle position sensor, map sensor, engine temp sensor, and O2 sensor. The engine speed will come from the distributor. The main output control is pulsing the injectors. Timing will be controlled after the engine is running above 600 RPM. Until then the timing is done only by the distributor. The O2 sensor will only control fuel trim for better economy after the ECM goes into closed loop operation. A few more things, such as an intake air temp sensor, may be needed depending on the ECM. You need to have enough of the required inputs to allow the ECM to enter closed loop. This post was edited by Owen Aaland at 00:39:31 01/29/13. [Reply]  [No Email]
GordoSD 01-27-2013 20:16:37 216.106.242.91 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to Lanse, 01-27-2013 07:40:27   Dump the 305, get a 350 mouse with a carb, or even a 327/283 and build it. It's time you took a break from welding and learned some engine building skills. Just apply the same mindset and learning skills you learned in welding. My Grandpa watched and talked, and helped as little as possible, while I pulled the flathead out of my 40 Ford and rebuilt in his toolshed on the farm, with the car in front of the shed. (refridgerator boxes are indispensable)I was 14. And he made me pay for a lost 5/8 combination and a 9/16 and 5/8 1/2 drive sockets. [Reply]  [No Email]
Inno 01-28-2013 07:24:08 206.172.0.204 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to GordoSD, 01-27-2013 20:16:37   Quoting Removed, click Modern View to see If he were building a classic car or truck I'd say that's the way to go but for his homemade tractor I think the TBI 305 would be a great engine. [Reply]  [No Email]
Inno 01-27-2013 12:05:41 70.49.196.16 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to Lanse, 01-27-2013 07:40:27   I would retain the TBI for sure, might be a pain at first to get it all set up but your performance and reliability would be much better with it than without. Besides, building your own tractor tells me that you like a challenge so go for it, it definitely can be done! [Reply]  [No Email]
Jim in MN 01-27-2013 10:47:38 166.152.226.239 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to Lanse, 01-27-2013 07:40:27   A friend of mine who builds hot rods swears by Painless Wiring and EZ2Wire. Both have websites. Good luck! [Reply]  [No Email]
buickanddeere 01-27-2013 10:39:43 184.151.63.147 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to Lanse, 01-27-2013 07:40:27   Lilfarmer has the better answer. Why not have a nifty and crisp running engine instead of a Ludit machine. [Reply]  [No Email]
husker44a 01-27-2013 09:53:01 199.47.66.57 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to Lanse, 01-27-2013 07:40:27   That's going to be a pain it rear. I would suggest you get rid of that TBI and go with a simple carb. A lot easier to deal with. As other have stated you MUST use the ECM, all sensors and probably the GM instrument cluster for the electronics to function properly. Carburated GMs will run with two wires. One HOT wire to starter and one HOT to the distributor. Keyed or push button for the starter solinoide. Why make it any harder then what it actually is? Other then having fuel injection. [Reply]  [No Email]
Buzzman72 01-27-2013 12:45:51 74.134.25.51 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to husker44a, 01-27-2013 09:53:01   Name a new car or truck sold in the US built in the last 20 years that came with a carburetor installed from the factory. Didn't think you could. Lanse is UNDER 20 years old...so there have been NO carbureted new cars or trucks in his lifetime. Sure, carbs ARE simpler...but not nearly as trouble-free to run as EFI, whether port or throttle body injected. Sure the SETUP's a bit more complicated; but with EFI, it's all about understanding the technology. And I've generally found that those who fear the technology usually don't understand it. [Reply]  [No Email]
Glennster 01-27-2013 08:36:04 99.90.9.201 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to Lanse, 01-27-2013 07:40:27   Lanse, one of my techs at the shop built a custom jeep cj with a tbi small block chevy. I beleive he isnrunning a programmable aftermarket module. I will ask him tomorrow and post back. [Reply]  [No Email]
LilFarmer 01-27-2013 08:28:45 69.160.179.245 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to Lanse, 01-27-2013 07:40:27   Hi Lanse, If you haven't destroyed them already, keep all of the wiring harness looms from the truck. ALL OF THEM, including the engine wiring harness and the one that runs back to the fuel tank. Also the one across the dash that hooks to the computer. This will give you all the wiring and connectors you need to hook to the various sensors and controls. You will need to have an electric fuel pump capable of 9 to 13 lbs of pressure. You should run an O2 sensor, but isn't absolutely required. Computer will go into default mode without it and engine will just use more fuel. [Reply]  [No Email]
Buzzman72 01-27-2013 08:00:21 74.134.25.51 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to Lanse, 01-27-2013 07:40:27   Lanse, of course you realize that you're going to have to run the ECM for everything to operate. Now, I know a LITTLE here and a LITTLE there...like, the TPS has to have a reference voltage of 5 volts... Your main voltage HAS to be 12.6 to 14 volts for everything to function; once the system goes below 10 volts, funky and not-so-funny things begin to happen. So make sure your battery, cables, grounds, and alternator are in AAA+++ condition to begin with...'cause this ain't gonna be like dealing with a 6V system with a generator and a magneto, that'll continue to run with a wimpy electrical system once you get it started. There's a chart of the pin-outs for some of the common ECM's GM used, in the link below. Should be somewhat helpful...I hope. I know some of the "aftermarket" TBI systems use the GM #1227727 ECM, but I don't know if perhaps it's not as common now as it used to be. ECM pin outs [Reply]  [No Email]
Buzzman72 01-27-2013 08:47:45 74.134.25.51 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to Buzzman72, 01-27-2013 08:00:21   This link may be MORE helpful... GM ECM cross references and schematics [Reply]  [No Email]
john730d 01-27-2013 07:59:34 208.73.228.5 Report to Moderator	Re: Wiring a 305 tbi to run? in reply to Lanse, 01-27-2013 07:40:27   I don't have the answer for you Lanse, but I think you will have to have a computer to make a TBI work. Might check out some hod rod sites, or even Summitt Racing. [Reply]  [No Email]