Tbi swap build thread

[cjracing15]

Wow I can not belive that this thread is still going! Great job RF!!!

[rfmaster]

Originally Posted by cjracing15

Wow I can not belive that this thread is still going! Great job RF!!!

Hey CJ (and everyone else) - Happy New Year! Yes, it has been fun fielding questions about TBI swaps and EFI retrofits. Back in summer of '07 I've finished my C20 TBI retrofit. Henceforward, truck runs like (insert you favorite descriptors here)! Never looked back. Now, I have completed 3 more conversions and I have 383TBI sitting in the garage waiting for a friendly (empty) engine bay to drop into!

//RF

[355bullet]

Happy New year everyone.
Im in search for a External Fuel Pump for the TBI set up.
Fuel pressure is 13-16 right?

[rfmaster]

Originally Posted by 355bullet

Happy New year everyone.
Im in search for a External Fuel Pump for the TBI set up.
Fuel pressure is 13-16 right?

Almost - you want at least 20-25 PSI pump deadhead rating. In actual operation FP has to overcome fuel line restrictions - bends, fittings, and fuel filters. Do not go too crazy with fuel pressure - for example TPI or Vortec style pumps will work but fuel will needlessly circulated and its temperature increased.

If you search the thread - 1st couple of pages - there are suitable FP listed.
//RF

[Chad77]

What is the charcoal filter for? Is it really needed in a off-road rig? Can I just plug off the lines ?

[chevymotocross]

I love TBI!

[rfmaster]

Originally Posted by Chad77

What is the charcoal filter for? Is it really needed in a off-road rig? Can I just plug off the lines ?

Happy New Year Chad.
A charcoal (filter is not a correct name for it) canister is used to trap the fuel vapors. The fuel vapors adhere to the charcoal, until the engine is started, and engine vacuum is used to draw the vapors into the engine, so that they can be burned along with the fuel/air mixture. This system requires the use of a sealed gas tank filler cap. In grand scheme of things 20% of all HC emissions from a car or truck are emitted from the gas tank! In a way this system saves loss of fuel due to gasoline evaporation inside the gas tank. Diagram below is for a carburetor based system - TBI is very similar.



The system does not rob any performance from the engine and as a benefit captures and burns gas fumes that otherwise would have been lost into atmosphere. Since it costs very little I use it on all my projects.

//RF

[Chad77]

well I changed my mind on some of my wiring and I am going to install a relay ....

This is the way someone else has the relay wired
30-12v fused input(should also hook up your org ECM constant 12v to this wire)
85- Gnd
86- 12vdc from ign sw(black wire that was hooked up to the coil +)
87- pink/blk, pink(r)
87- red, white(injectors)

I have done reading and came across this its about halfway down the page their is a demo . http://www.bcae1.com/relays.htm

The way I understand the demo

30 is + from battery along with org ECM constant 12v
85 should be + from coil (key run/start)?
86 should be - from coil
87(A?) ignition, ecm power key off ?
87 injectors key on/run?

[rfmaster]

Originally Posted by Chad77

well I changed my mind on some of my wiring and I am going to install a relay ....

This is the way someone else has the relay wired
30-12v fused input(should also hook up your org ECM constant 12v to this wire)
85- Gnd
86- 12vdc from ign sw(black wire that was hooked up to the coil +)
87- pink/blk, pink(r)
87- red, white(injectors)

I have done reading and came across this its about halfway down the page their is a demo . http://www.bcae1.com/relays.htm

The way I understand the demo

30 is + from battery along with org ECM constant 12v
85 should be + from coil (key run/start)?
86 should be - from coil
87(A?) ignition, ecm power key off ?
87 injectors key on/run?

Please locate and examine posts 113 and 124 in this thread.

//RF

[ironroad9c1]

Nice tread, BUT ,... to anyone who does this later on. Make sure you take the time and swap out the heads, That is the biggest limiting factor for making any kind of power on TBI engines.



You can see how the ramp blocks half the intake port.


This is a regular intake port. You can see how much better this is.

[68 TT]

Originally Posted by ironroad9c1

Nice tread, BUT ,... to anyone who does this later on. Make sure you take the time and swap out the heads, That is the biggest limiting factor for making any kind of power on TBI engines.

Don't forget to change the cam while you are at it. The stock TBI cam is ridiculously small: .350"/.384" and 179/194 degrees at .050" lift.

If you don't have the money for a head swap then just a cam swap will make a huge improvement as long as you can tune for the changes it will make in the engines operating parameters.

[Doc Hollywood]

Hello everyone,

I have just about finished a '91 4.3 swap into my toyota and this thread has helped me out a whole lot.

At the moment I am having a few issues. When I start the truck it runs fine. When I rev up the engine and let off the gas the RPM's drop quickly, but once the engine warms up to operating temperature when I rev the engine it is slow to return to idle. It does return though.

Any ideas?

I want to get everything in order before I have to take it to the referree station to get my new VIN sticker.

[rfmaster]

Originally Posted by Doc Hollywood

Hello everyone,

I have just about finished a '91 4.3 swap into my toyota and this thread has helped me out a whole lot.

At the moment I am having a few issues. When I start the truck it runs fine. When I rev up the engine and let off the gas the RPM's drop quickly, but once the engine warms up to operating temperature when I rev the engine it is slow to return to idle. It does return though.

Any ideas?

I want to get everything in order before I have to take it to the referree station to get my new VIN sticker.

You may want to clean and reset IAC. If you search through this thread there is a set of instructions how to do that. The other suspects can be flaky TPS - or sticky throttle. Also double check that you CTS is reporting correct temperature.

Before going to referee station make sure that you have ALDL connector wired and bolted, as well functional SES light.

Good luck

//RF

[Chad77]

So if I understand this is how I need to wire it then?

[rfmaster]

Originally Posted by Chad77

So if I understand this is how I need to wire it then?

Yes, it should be correct - love the sketch.

Minor clean up


//RF

[Chad77]

Thanks! I was kinda in a hurry when I posted that!

[grandfisher]

Great thread! I've finally read through it all. Lots of good info. Pretty much every question I had was already answered. I've messed with TBI engines a bit and I'm pretty familiar with the components and their functions. After much reading and research I've just started my own project and with the help of this thread I've got my donor harness rewired for my application. It's a 92 454 harness originally equipped with an auto trans. Here's my first hangup. There no wire in the B7 pin. The first page of this thread indicates that this is designated "ESC, Knock Sensor signal to ECM". This harness has no ESC or KS plug in the harness. The harness had not been tampered with. Is the ESC not necessary?
Great diagrams and schematics!!!

[rfmaster]

Originally Posted by grandfisher

Great thread! I've finally read through it all. Lots of good info. Pretty much every question I had was already answered. I've messed with TBI engines a bit and I'm pretty familiar with the components and their functions. After much reading and research I've just started my own project and with the help of this thread I've got my donor harness rewired for my application. It's a 92 454 harness originally equipped with an auto trans. Here's my first hangup. There no wire in the B7 pin. The first page of this thread indicates that this is designated "ESC, Knock Sensor signal to ECM". This harness has no ESC or KS plug in the harness. The harness had not been tampered with. Is the ESC not necessary?
Great diagrams and schematics!!!

Welcome to the thread
Some of 454 HD applications did not use KS and ESC module. These 454 HD (BCC) calibrations deliberately keep spark advance low thus keeping engine from knocking when under load. The purpose of KS and ESC module is to provide indication back to ECM when engine knock is occurring.
The question is what you're trying to do with your TBI swap - i.e what engine are you trying to EFI (350/454) and trany?

IRC HD 454 calibrations were used on on 3/4 and 1 ton trucks.

//RF

[Jonboy]

I am on the downhill slide of my swap also. I fired it tonight, but it is idling terribly high. My TPS is showing 1.18V @ idle, that's the lowest it will go. I will swap it out tomorrow. Will the high TPS voltage cause a really high idle?

[rfmaster]

Originally Posted by Jonboy

I am on the downhill slide of my swap also. I fired it tonight, but it is idling terribly high. My TPS is showing 1.18V @ idle, that's the lowest it will go. I will swap it out tomorrow. Will the high TPS voltage cause a really high idle?

Yes, ideal idle TPS voltage should be between 0.4 and 0.9 Volts, later ECM have auto zero logic. Make sure that minim idle screw is backed out - it may have been tampered with.

You may want to reset IAC - there is a set of instructions (use search ) to bring idle speed down.

//RF

[Jonboy]

Thanks RF. I am having a little trouble running down an adjustable TPS, (The two I have at teh house are non adjustable units too), but I just started early this morning. The drivability guys at work think it may be thinking I am on the throttle with the high TPS, and backing the IAC out as a result. We will see how it goes tonight with a new TPS.

[rfmaster]

Originally Posted by Jonboy

Thanks RF. I am having a little trouble running down an adjustable TPS, (The two I have at teh house are non adjustable units too), but I just started early this morning. The drivability guys at work think it may be thinking I am on the throttle with the high TPS, and backing the IAC out as a result. We will see how it goes tonight with a new TPS.

Yes, just make sure that throttle plates are closed (throttle shaft is also known to wear out throttle body and become sticky in very high mileage TB's). Check if the minimum idle screw has been tampered with - i.e. turned clockwise to increase idle speed by opening throttle plates excessively.

IAC is used to add air bypassing throttle plates to control idle speed. TBI ECM has no idea about actual IAC pintacle position. It has to calibrate its position by commanding IAC into fully closed position on reset (0 step count). After reset ECM will command IAC into wide position (160 counts in most calibrations). During start ECM will move from full open toward reduced air bypass.

1.18V TPS is just of idle - so ECM may increase IAC counts.

Do you 454 injectors on top of 350 engine?? Does your ECM has 454 calibration (BCC)??

//RF

[Jonboy]

I bought the engine and trans as a package from a friend here. The engine was replaced ~15K ago, but the stock TB and injectors were still in place. The injectors are 350 units as far as I know (he was wanting to upgrade them before he went to LS power). I did add a TB spacer, since it came with all of the parts. I will definitely check the min. idle screw; I had to somewhat assemble the TB, so it's entirely possible it has been moved. I am having a little trouble running down an adjustable TPS, though. Has anyone opened up the mounting screw holes to allow for any TPS adjustment? I thought maybe there was room for a Dremel tool (or similar) to get in there.

[rfmaster]

Originally Posted by Jonboy

I bought the engine and trans as a package from a friend here. The engine was replaced ~15K ago, but the stock TB and injectors were still in place. The injectors are 350 units as far as I know (he was wanting to upgrade them before he went to LS power). I did add a TB spacer, since it came with all of the parts. I will definitely check the min. idle screw; I had to somewhat assemble the TB, so it's entirely possible it has been moved. I am having a little trouble running down an adjustable TPS, though. Has anyone opened up the mounting screw holes to allow for any TPS adjustment? I thought maybe there was room for a Dremel tool (or similar) to get in there.

Can you post a photo of your TB - looking at TPS sensor. Early TB's (pre-90) had a lever style TPS, later TB's were direct shaft coupled. Early TPS were slotted since ECM did not have auto minimum auto reset capability. Later (90+) ECM have ability to auto zero idle voltage. Corresponding later TPS is direct shaft coupled (non lever style, compact connector). It is possible to use later ECM with older TPS style sensors, but not the other way around (old ECM with non adjustable TPS may give you fits).

To put this issue to bed please post TB service number stamped on the left front and ECM service and BCC numbers:


In the photo above TB service number is 17093030

Non adjustable TPS:


SBC TB 17093030

Early 87-90 BBC TB



Note different style IAC connector and large size TPS connector


Vacuum port identification - some TB's may not have them all

[Jonboy]

My TPS is the earlier one, that is the lever type, but it does not have the 90 degree bend for the electrical connection. I went and looked at the parts store around the corner, and I think I will be able to engineer my own adjustment. I have the '87 ECM, and one from a '91 Suburban I parted out as well. I used the wiring harness from Fuel Injection Connection, and it gave me enough wire to put the ECM under the driver's seat. That makes it a lot simpler to swap out the ECM.

The TB has the same vacuum ports as the one you posted. I have ditched the EGR and vapor canister, so I plugged those, as well as the A/C port. The FIC harness doesn't support the smog, and I figured the effect would be negligable on my '74. I will get a picture of the TB, as well as the service # of both of the TBI's I have on the shelf and the ECMs also. You can never have too much info.