What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

TBI Swap Tips?

mikey_d05

mikey_d05

1 ton status
GMOTM Winner
Joined
Nov 23, 2004
Posts
10,453
Reaction score
0
Location
Minnesota
About to swap a TBI setup onto a Scout II. Not looking for power, just driveability.

Anyone have any tips relating to TBI swaps? Just simple things that get overlooked and cause issues. Looking to have this vehicle back up and running ASAP so we'd like to do all we can to avoid hiccups. :thumb:
 
Motor is a bone stock IH 345 V8.

We would be rebuilding the carb, except the powers that be decided that this particular device is a "throwaway" carb, and therefore no soup to nuts rebuild kits exist for them. It was either spend the money on a brand new carb for a factory spec engine (that there are no upgrades in the works for) or spend the money to swap EFI onto a classic truck that will get driven daily if it acts right. Temps go from -20 to 100 here and he drives to Laramie once in a while to see his parents (~7000' elevation change). I'm sure you can see the merits of injection.
 
tbi is stupid simple and great for easy of driving.

thats why my trucks all have it over carb.

search a few threads here in this section and you will find great info and few guys that KNOW there stuff on them.
 
I recently helped with a TBI on a 1971 Scout 304. This Scout owner purchased an off the shelf "TBI Kit" from a popular aftermarket "TBI Kit" supplier which included a hybrid IH/GM distributor. The only problem with this "TBI Kit" was that it did not include a GM Ignition Coil, or state in the instructions that a GM Ignition Coil was REQUIRED! Once the GM Ignition Coil was correctly installed the engine would run, but WAYYYYYYYYY to rich. Best I can figure is the PROM chip must have been programmed for a 345.:confused: A new set of spark plugs was fouled mostly because of the old points coil would not work with the IH/GM Hybrid distributor and the programming for the PROM Chip was flat out WRONG!

I made some PROM Chip Programming corrections. Now the Scout is running the best it ever has, according to the Scout owner. I also installed a 3 wire heated O2 sensor in the header collector.

dave w
 
This swap is going to be fuel-only until we can source the proper dizzy to convert it to fuel+timing. We pulled the TBI setup off of a 350 today and it'll be going on a 345, so we're guessing/hoping it'll be pretty darn close to right for now.
 
The only way to go fuel only is with a MSD 6 or better and use the tach filter in it. It provides the proper square wave signal needed not to burn up the ECM. If not you need to buy a harness with tach filter because no one will sell them. Used to sell them at $75.

There's a grumpy ol guy at BinderPlanet that has a section with all the how to's for a duraspark distributor conversion he stole from CustomEFIS. My HyBrid distributor designs are there and at link in my signature.

If you need help otherwise click on my signature.
 
Welp, guess we're going duraspark sooner than anticipated then. Thanks for the info!
 
other than what was mentioned keep in mind what you plan to do with the vehicle speed sensor. Also, might need to re-Prom if trans is different than donor (auto vs stick).

As with most TBI abusers on here, I have a prom adjusted to the different cam, but as long as you have the same vac in the binder as the chevy (15-17 lb) you should be fine
 
You can run without a VSS with a 1227747 ECM but it will throw a code if it was not turned off in chip. the VSS does make them perform a little better and gives a more stable idle.
 
You must log in or register to reply here.

Latest Posts

Top Bottom