TBI install on my 40 (1 Viewer)

[samc2447]

So through the years I've been on a quest to undo the 'upgrades' my PO did on my 40, but at the same time make it more reliable and suited for my needs. When I got it, it had a Weber carb as seen below. I've had cars with Webers and consider myself adept at getting them running properly. After playing with it, re-jetting, etc. I just wasn't happy with it, so I moved to an aftermarket replica carb. The performance was night and day different and I was happy.

Fast forward a couple of years and there were some noticeable performance issues. I acquired an Aisin carb and intended to rebuild it and replace the aftermarket carb. This was about the time @wngrog put an AFI EFI system on his truck in this thread:
Blue '84 gets a fresh start- AFI EFI and more

So I decided that EFI was the way to go. I came across Downey's instruction here in Post #66:
Downey Off Road

While going with a 'kit' from AFI, Howell, etc. would be easier, I decided to follow Downey's instructions and piece together my own kit. So over the next few months I sought out the components and put it together. I did have one stroke of luck by finding an unused Howell EFI harness and computer on E-bay while I was looking at GM 4.3 harnesses. So I snatched that up and got to work on the rest.

Here is a photo of the completed install. I'll detail the process over the next few posts.

 

[samc2447]

Next up were the parts necessary to make it run.

I bought a re-manufactured GM TBI. I also picked up the TBI to manifold adapter from @Downey (not shown is the adapter plate he includes that allows mounting the throttle cable - I'll show this a bit later). His adapter is very nicely made and additionally it rotates the TBI 90* so it won't interfere with the brake booster or cylinder and allows clearance next to the valve cover. He sells them on his E-bay store or through his normal contact methods.

 

[samc2447]

For the distributor, I decided that since I was going through the trouble of adding a computer, O2 sensor, MAP sensor, etc. I wanted to full computer control of the timing and spark control.

If you look at AFI's kits, you'll know that this is one of things they offer as an option using a Performance Distributor DUI HEI . You can easily add the DUI HEI with vacuum advance and make it work well, but adding computer control requires changing some of the HEI components. Again I got a bit lucky and found a Toyota geared DUI (getting one with the Toyota gear is critical) on Craigslist. It was unused and according to the shipping label on the box it was about 7 years old. I called Performance Distributor in TN and asked them if they would check it out and convert it to computer controlled for me. No problem and only $95 if I remember correctly. They removed the vacuum advance and installed the necessary components and shipped it back to me.

The only minor issue I had was that my engine did not have the dented side cover. A quick message to @cruiserjunktion and he let me know he had a dented side cover so I bought it and got it cleaned, painted and installed. Stabbed in the dizzy and tightened it down. I did crank the engine without starting it to ensure oil pressure built.

 

[samc2447]

Next up, test fit the TBI and work out the throttle cable mounting and routing.

I removed the throttle pedal, boot and linkage from my 40. I built a plate to mount the new throttle cable to the firewall.

Then I cut my throttle pedal linkage and found some scrap tubing that fit over the end of the pedal linkage. I cut an L shaped slot for the cable end to drop down and twist in to. Sort of like a keyed slot that it fit down. I think this will ensure that there is no chance for the cable end to pop out or work it's way out.

Once I was satisfied with the fit, I welded it up and painted it. I should note that on the cable end I did but a piece of hard plastic tubing, sort of like a sleeve around it to make it snug inside the metal tubing. This made everything nice and snug when I assembled it and there is no free play.

 

[White Stripe]

Nice!

 

[74fj40]

Looking good, you’ll love it

 

[samc2447]

Next up, I installed the MAP sensor on the firewall. This needs to be mounted with the port facing down, so the sensor is horizontal.

I ran the harness along the firewall and found a suitable location for the various relays and fuses. I added a couple of relays to control the O2 sensor, since the harness I found was only for a 1 wire O2 sensor, and I knew I would need to run a heated O2 sensor. I also added a relay to provide direct battery power to the DUI. These dizzy's need full power, and using the stock wiring has the potential for voltage drops that could affect the dizzy. I used existing mounting points for the relays and fuses temporarily, as I plan to add a Vintage AC system, and wanted to get that installed before I came up with a permanent solution.

I ran the harness through the firewall and mounted the computer in the glove box on an aluminum shelf I made. I used the heater hose pass through hole for the computer harness and fabricated a plate to enclose the hole and fit around a grommet I cut to fit the harness.

 

[samc2447]

Since the harness I found was fairly basic, I had to add a 4 wire harness to control the dizzy from the computer. I used the pin out diagram for the GM computer and wired in the distributor low reference, high reference, bypass and EST connections. I added a weather pack connector and connected it up to the distributor.

The fuel pump is an in-line model, and is supposed to be mounted near the fuel tank. On my 40 there just isn't anywhere practical to do this on the inside of the frame rail. There just wasn't enough clearance for my comfort next to the transfer case and transmission, so I ended up mounting it right next to the charcoal filter and put a fuel filter just before it in almost the same location that the stock fuel filter goes.

 

[samc2447]

The throttle cable snakes up and around a bit more than I would have liked, but with the orientation that the Downey adapter puts the TBI, this is necessary. I fabricated a bracket and cable clamp using some pieces I found in my junk drawer and they turned out ok. They mount the cable just where it needs to go to give it a direct path to the TBI. The throttle cable doesn't come with any type of connection to the TBI, nor did the TBI have any type of direct connection for the cable.

After a bit of searching I found that an automatic transmission kick down cable end would fit the bill. I had to bore out the cable hole slightly in the cable end to allow the thicker throttle cable to fit through, but after that it fit perfectly and snapped into place. A simple cable end secures the throttle cable in place.

 

[FJ60Cam]

Nice score finding the harness and dizzy!

Does the Howell harness have provisions for the computer distributor control, or did you have to add that back in?

 

[SteveH]

Great work on all the fabrication. I just installed AFI TBI and went through most of that.

 

[samc2447]

Nice score finding the harness and dizzy!

Does the Howell harness have provisions for the computer distributor control, or did you have to add that back in?

No the Howell harness does not have provisions for the computer distributor control. In fact they use one of the pins for spark control from the computer and the tach signal to some sort of filter that I found in the harness. Not exactly sure what the filter was for, maybe some type of VSS? It didn't connect to anything else except a ground.

Adding the computer control for the distributor is just 4 wires and very easy to add in yourself. The GM computer was designed with timing and spark control. The connections on the computer are: distributor low reference, high reference, bypass and EST.

 

[samc2447]

I'm skipping some steps that were fairly straight forward, like the temperature sensor, connecting switched and un-switched power as needed, etc.
For the fuel lines I routed up the firewall around the back of the engine. I had intended to use the existing hard return line and make an new hard feed line that followed it's path. However, when I pressurized the system the first time fuel came spraying out of the hard return line. This is when I discovered that the PO had managed to screw a self tapping screw through the firewall and directly into the center of the return line. Thanks PO!
So for now I am running rubber fuel lines for feed and return and will bend up new hard lines in the future.

I should mention when I put the new HEI dizzy in I was careful to stab it in with the rotor matching where my old dizzy was when I pulled it. I figured this should get me close enough to get it to start.

So with everything connected I turned the key and let the fuel pump prime. No leaks. I turned the key and it instantly fired up, and I mean instantly. So much so that it surprised me as I was expecting to have to troubleshoot something. I took a quick video and texted it to my local cruiser buddies and shut it down.

 

[SteveH]

You might consider re-routing your rubber fuel lines FAR away from the exhaust manifold. Or, do them in steel.

 

[samc2447]

You might consider re-routing your rubber fuel lines FAR away from the exhaust manifold. Or, do them in steel.

Thanks. Yes I’m building steel ones now. The return line had a hole in it due to PO putting a self tapping screw through the firewall. Using the old line as a template.

 

[wngrog]

You might consider re-routing your rubber fuel lines FAR away from the exhaust manifold. Or, do them in steel.

View attachment 1685316

I used some old OEM lines on the firewall to get the fuel from the driver to the passenger side.

 

[toyotaspeed90]

The fuel pump is an in-line model, and is supposed to be mounted near the fuel tank. On my 40 there just isn't anywhere practical to do this on the inside of the frame rail. There just wasn't enough clearance for my comfort next to the transfer case and transmission, so I ended up mounting it right next to the charcoal filter and put a fuel filter just before it in almost the same location that the stock fuel filter goes.

View attachment 1683671

You might have problems with either enough pressure or longevity of the pump.

These pumps aren't puller pumps like a mechanical - they are meant to have little to no resistance on the supply and is why they are recommended to install as close to and below the tank.

While not optimal, mine went under the passenger seat running a AN lines along the trans hump and a high performance filter. I'm *hoping* it's close and.low enough I don't have problems.

Just food for thought for yourself and others

(Black and red is the filter)

 

[wngrog]

Yeah I’ve never heard of using the electric and mechanical in line.

Would like it if that’s an option but I did not see that in my instruction pack

I’d like to run Electric at the tank and then to the OEM mechanical but I doubt that would prime correctly.

 

[samc2447]

You might have problems with either enough pressure or longevity of the pump.

These pumps aren't puller pumps like a mechanical - they are meant to have little to no resistance on the supply and is why they are recommended to install as close to and below the tank.

While not optimal, mine went under the passenger seat running a AN lines along the trans hump and a high performance filter. I'm *hoping* it's close and.low enough I don't have problems.

Just food for thought for yourself and others

(Black and red is the filter)

Thanks for the info. I suspected that long term I might have issues with the pump where I've put it. Short term I will carry a spare pump, but I plan to install a larger tank in the rear with an in-tank pump and eliminate the stock gas tank altogether. This will give me more fuel capacity and keep the pump cooler and at the preferred location.

 

[samc2447]

Yeah I’ve never heard of using the electric and mechanical in line.

Would like it if that’s an option but I did not see that in my instruction pack

I’d like to run Electric at the tank and then to the OEM mechanical but I doubt that would prime correctly.

I don't think this would work, the stock mechanical pump doesn't put out enough pressure for the EFI which is why it has to be removed.