TBI / Fuel Injection Build

[pbtv]

(**FI-UPDATE POST: 001**)
Hi All,

I decided that I am going to convert my ’85 SR5 to fuel injection. Out of respect to the many folks who have posted their build experiences on various items for others benefit, I decided I have to do the same 

Some of us may remember this thread: (viewtopic.php?f=3&t=3744 ); If you don’t, basically this guy took a TBI unit of an 80’s GM car and successfully ran it on his Tercel. Then he disappeared! He didn’t owe us anything, but it sure did leave me on the edge of my seat on how to do this.

I’ve been intrigued by this post for years. There are many ways to fuel inject an engine, but this one felt like one of the more “straight forward” ways (not really, ha) to convert our beloved 3A to a more reliable system. The vacuum actuated, carbureted and partially ecu-controlled systems the 3A/Tercels came with are overly complex. It’s not fuel injection and it’s not just a simple carb. You get the complexity of a carburetor (jets, floats, many gaskets) and the “snake oil” of an ecu (electrical sensors). Add a dash of a vacuum spider web combined with 30+ year old rubber and you then have a recipe for mysterious idle and tuning issues. Let’s also not forget the distributor/coil combo which although reliable, can fail suddenly. If you already understand these systems, trust me, you can definetly do a conversion and realize the relative simplicity of a TBI setup.

So were all on the same page as I go through this saga here is the background info on my experience:
- I’ve never fuel injected before and have no prior tuning experience
- I bought the following books to learn about the “engine management” world:
o “Performance Fuel Injection Systems” by Matt Cramer and Jerry Hoffmann
o “Engine Management – Advanced Tuning” by Greg Banish
- I also signed up for tuning courses at hpacademy.com. It was pricey, but I intend on learning on my Tercel and then really getting into this on other builds.

My Tercel:

TercelIntro.jpg

TercelIntro2e.jpg

- I have a 1985 SR5 with 79k original miles.
- I bought this car in 2015 when it only had 54k miles. I used it as a daily for a year or so and then bought another car. The car has been used on occasion since, but I really have not used it much in the last couple of years.
- Last year, I decided to completely go through almost the entire car. I replaced the brake system, suspension, pulled the motor and tranny, rebuilt/resealed the tranny (thank you Robert walker / forum member “xirdneh” for your videos!!!), resealed the engine, timing belt, valve seals, heater core, placed all the behind the dash components for a future a/c system, etc.
- Although this car had amazingly low miles, EVERYTHING was original. That meant EVERYTHING leaked. I mean legitimately original rubber, stickers, everything. It was awesome but a huge pain at the same time.


Why I decided to convert to fuel injection:

- I have a genuine desire to learn
- I’ve done a ton of work to the car; i.e. it was in great shape and worth the pain
- I wanted to reduce emissions that the antiquated system really wasn’t capturing
- Obtain better fuel mileage and a ‘lil more power

Goals for my build:

- Create a logical process that others can benefit from, if interested in conversion. That’s not to say a fool-proof step by step instructional 
- YouTube the process (videos coming soon)
- Create a completely stock looking conversion. That means when the hood is popped open, it will look somewhat like it came that way from the factory.


Let’s be honest; It is much smarter to swap the 3A with the many available fuel injected 4A engine variants (among others) than to convert the 3A. In future posts, I’ll show you exactly why that is (I mean, it really is). Forum member “teranfirbt” successfully converted a 3A to bike throttle bodies/injectors (beast!) and then swapped that for a 5AFE. After completing a good portion of the 3A conversion (not yet posted), that is definitely a smarter way to go. I’m stuck on my path for now though 

Items I am using (as of this posting):
- TBI Unit: GM/Rochester TBI700 (single injector) (Future post on TBI specifics coming)
- Stock exhaust and intake manifolds
- ECU: Megasquirt 2 (MS2) based system.
- Surge Tank (self-built; future post)
- Fuel pumps:
o Stock 3A fuel pump to surge tank
o Walboro GSL395 electric pump from surge tank to TBI
 http://walbrofuelpumps.com/walbro-gsl395-fuel-pump.html
- Wide band 02 sensor:
o JEGS: 017-30-0300 AEM X-SERIES AFR GAUGE/LSU 4.9 combo
 https://www.jegs.com/i/AEM/017/30-0310/10002/-1
o JEGS: 231-11105 O2 SENSOR BUNG STEEL 1/PK
 https://www.jegs.com/i/Vibrant-Performa ... 5/10002/-1
- Trigger Wheel (build/placement on future post):
o DIYAUTOTUNE.com 36-1
 https://www.diyautotune.com/product/6-3 ... ger-wheel/
- Hall Effect Sensor
o https://www.diyautotune.com/product/hal ... on-sensor/
- Sensor Bracket
o https://www.driving4answers.com/product ... cket-v2-0/
- Ignition (coming soon)

I expect this process to take me a couple of months (night work). I’ve completed or am in the middle of a lot of this. As I mentioned before, I plan on using YouTube to assist on my posts. Because of that, I’m also learning editing software (more time!). It’ll all be worth it in the end….right?
Last but not least, I expect a lot of comments to develop during this process. To separate major updates from general comments, I’ll have “(**FI-UPDATE POST: XXX**)” at the top of any of the posts that are major updates.

That’s all for now. The first post (coming soon) will show what I went through to prep the exhaust manifold. I’m still waiting on a few parts and stuff, but will update every week or two. My goal is to finish this in front of everyone, so we all learn!

Major thanks: Robert Walker (xirdneh) for all the posts that helped me on my other stuff in the past (transmission, carb rebuilds etc.), (Petros) for answering older general questions I’ve had in the past and of course…” teranfirbt” for the big (major) help you’ve already given me via email. After all of your knowledge and expertise I’ve benefited from, I had to contribute back!

[pbtv]

(**FI-UPDATE POST: 002**)

Manifold:
On this week’s episode…the 3A exhaust manifold

The manifold on the 3A is almost** set up for fuel injection. As mentioned in my previous post, the 3A is a computer controlled carb’d engine. As such, the 3A in my SR5 came with a stock 02 sensor and an exhaust manifold that was designed to “sniff”.

After removing the manifold(s), it became clear why the 3A is never going to be a performance beast. Not even worth trying to go down that route (with other similar engines commonly available)!

The reason is the combo intake/exhaust manifold. In this setup (much unknown to me...I was like "what the..." when i came across it), the exhaust manifold contains a heater flap to allow exhaust gasses to heat the intake manifold when starting up. On the “inside” of the exhaust manifold, Toyota placed a coil thermostat that allows the flap to stay open during start up, and eventually close as the manifold heats up. The exhaust gasses then bypass heating the manifold up (as much as it did before anyway) and “out” of the back of the car.

hot air.JPG

Cold-startup is challenging for carb’d cars (as we all know) because the fuel is not atomized enough. Heat helps this process by allowing more of the fuel to combust. In Toyota’s design, a flap allows exhaust gas to pass under the intake manifold to heat it up, then it closes off and changes to route the gas through the tail pipe.

The system isn’t perfect and will still allow exhaust gas to continuously heat up the manifold. Hot air can/will cause pinging if your timing isn’t set correctly. I've noticed our cars are prone to pinging with slight timing changes...I really think this is the reason why. Continuously hot air going through our intake means the incoming air is less dense and much more prone to detonation. This is perfectly OK considering all the factors with a carb’d system and enough timing…but isnt necessary for a well tuned fuel injection system. With that in mind, I decided to eliminate this archaic system.

heaflap_3.7.1.jpg

After looking at the manifold over and over, I really thought the flap was a source of restriction in getting the exhaust out. The mechanism itself, I felt, even when “closed” had too many parts that undoubtedly causes a backup to exhaust flow.
After cutting the flap and bar out, I cut a ¼” plate and tig brazed it in place with silicone bronze. I went with brazing since welding mild steel to cast iron is very prone to cracking. Brazing (with a lot of filler) should handle the heat cycles just fine. Time will tell, but at least I’m not super-heating my intake as much!

silicone_3.22.1.jpg

For the 02 sensor, I will be using a wide-band sensor. I bought the sensor kit and a bung from Jegs for a pretty decent price. For mounting, I removed the stock 1-pice 02 sensor from the manifold and cut of th back half of the 02 sensor off with an angle grinder. I then drilled out the remaining half with a 1in hole saw. The jegs bung was .999 inches wide so the 1in hole saw was perfect.
After cleaning up the 02 sensor plate, I welded the bung in place of the former 02 sensor. I had to be careful to weld in short runs so as not to warp the original plate, but all in all it turned out fine.

02_2.9.1.jpg

drill_2.13.1.jpg

02bung_3.26.1.jpg

For the remaining holes in the manifold (flap swing arm, etc.) I used silicone bronze again to do a plug weld in there place. A little filing and the manifold was ready to go!

flapfinish_3.30.1.jpg

Last but not least, a video on the manifold:

https://youtu.be/bo1kaWeNXwM

I'll be posting videos here as I go, if you'd like to subscribe

[ARCHINSTL]

This is OT, but ... What a nicely organized shop and sweet equipment!
Sigh, for us who have but a driveway ...
Your car is just sweet! Props!
Tom M.

[teranfirbt]

That's pretty sweet, I've never used silicon bronze (although I've watched enough Welding Tips and Tricks videos on it).
I went through the hassle of baking/welding/baking/welding/baking/welding to plug up the intake manifold hole on my stock manifold. It took awhile and I definitely learned a lot about welding cast iron, lol.

[Petros]

all cars, including fuel injected cars, have means of heating the manifold. it prevents ice formation in cold damp climates behind the throttle plate.

though usually they use engine coolant circulated round passages in the intake manifold to keep it warm.

this exhaust heating is to help make the extra rich mixture after cold start get vaporized, otherwise raw liquid fuel accumulates in the manifold under the carb until it all warms up. it is a problem with fuel injection as well, you do not get a fine mist, but rather relatively large droplets coming out of the injector. with port injection, you will not get the fuel accumulation when cold, but with a single throttle body injector it is still a risk, and there should be some way to warm up the manifold quickly.

The exhaust heated manifold would heat up faster than using coolant, and even faster than an electric coil, so as primitive as it may seem, it is simple and reliable.

the biggest limitation to producing power with this engine is the 8 valve configuration. It does not breath very well, and coolant does not circulate properly around the hot zones in the head either, making risking head gasket damage if it get overheated. the paired exhaust valves causes hot spots in the head, in my thread on head gasket replacement I show how to improve coolant flow around the exhaust valves.

adding fuel injection to this obsolete head configuration would help some, but you really need to up date the head design with the several 16 valve head configurations that will fit on the 3a (and 4a) engine block. that means not just covering to EFI, but also a whole new exhaust header and system design and installation.

[pbtv]

This is OT, but ... What a nicely organized shop and sweet equipment!
Sigh, for us who have but a driveway ...
Your car is just sweet! Props!
Tom M.

Thanks a bunch, sir! I am a Craigslist vulture, lol. 95% of everything i have i got off Craigslist. The rest is pretty much Harbor Freight, Amazon or Northern Tool. It honestly looks better in the vid. I did wire in the recessed can lights (~$150 on amazon) a few weeks back just to do this. Man, lighting makes such a huge difference on work and motivation.

[pbtv]

That's pretty sweet, I've never used silicon bronze (although I've watched enough Welding Tips and Tricks videos on it).
I went through the hassle of baking/welding/baking/welding/baking/welding to plug up the intake manifold hole on my stock manifold. It took awhile and I definitely learned a lot about welding cast iron, lol.

Hey brother! Honestly it was my first time "tig-ing" with silicone bronze. I had brazed with a torch before so i figured it would be the same; it definitely was. Like you, Welding Tips and Tricks on Youtube got me primed. I figured id use a good amount of filler to get a solid bond. I think it'll be just fine

Big props for doing the welding/baking method though! that's serious patience!

[pbtv]

adding fuel injection to this obsolete head configuration would help some, but you really need to up date the head design with the several 16 valve head configurations that will fit on the 3a (and 4a) engine block. that means not just covering to EFI, but also a whole new exhaust header and system design and installation.

Petros; roger, i hear ya. I honestly thought long and hard about doing a swap on this. This is what changed my mind though; the 3A had an original 79k on it. With good maintenance, we've seen these motors go 300k+. Thats a lot of life left on the table to toss it aside. IF i was at 200k or even 130k, maybe. but since i was 20k below "100", i had to stay loyal to it. The benefit of staying with it is anyone with a 3A or 4A will be able to follow the thread and do this, too. In my upcoming "tbi" episode, ill go over more on the TBI unit...but it originally came off of a 2.0L and was used up to a 2.4L. I think there's a 'lil power to be had. I will also be doing a larger downpipe on this. Something about a <1.5in downpipe (stock unit) screams "low flow". 1.5L and thats all Toyota gave this poor little engine lol.

As for the heat, i think it'll be just fine. True, this is a TBI swap BUT, the manifold is always heated by the head. Add to that the "2 in1" setup on the 3A where the exhaust manifold is touching the intake permanently...I there's enough there. To me, the trade-off with having exhaust circulating under your intake means that your startups will be easier (with a carb), but you're running hot air all the time. After studying that flap, I don't think there's any way it directs exhaust as well as it should. ITs probably why Toyota did away with it shortly after the "A's" received EFI.

Im going to run though this TBI exercise and run it for a while. I may still do a swap down the line. I already have the engine in mind and its definitely not any of the A series or anything from the 80s/90s

[pbtv]

(**FI-UPDATE POST: 003**)

I finished the trigger wheel! Summary video of the build process:

https://youtu.be/8Kpbw1E--VM

Write up to follow soon...

[teranfirbt]

Nice! The flap disk is easily my favorite grinder disk after the .040" thick cutoff wheels

[pbtv]

Haha, yesssiir. I had no shame...i zoomed in on that!

Actually after doing about three, 1in long welds, i took the weld length down to about 1/4in runs. I was really concerned about warping the ring so i turned the amps up to about 140 (really hot) and did super short runs. the end result was not great...a bunch of start stops, but penetration was (i felt) perfect.

I then started thinking about how the inevitable imbalanced weight of the beads would affect the assembly at higher RPM's. I decided to grind her down with a worn out 80grit flap disc (less harsh) and then follow up with a D/A palm sander with an 80grit pad. The result was smooth to the touch. It probably is still a bit imbalanced but at least its not too bad (i think).

[pbtv]

(**FI-UPDATE POST: 004**)

So if you’re going to fuel inject your car, you need a trigger wheel/sensor combo for the computer to read. I won’t go into the fuel injection principle-side of things (lots of info out there) but there are a few options for the 3A or 4A…mostly thanks to the following and aftermarket support from the 4AGE crowd

Sensor Bracket:

For my sensor bracket, I ended up ordering the “Driving for Answers” 4AGE bracket. Luckily, it fit the 3A engine perfectly. The bracket is great quality and honestly for a custom machined piece…a super deal. I believe it was $60 shipped all the way from Bosnia. If you haven’t seen the D4A YouTube Channel, its worth checking out. https://www.youtube.com/watch?v=Zutw5z2bIeg

I bought the “Ford” style bracket (meant for Ford sensors) and instead used a Cherry hall-effect sensor (more on that below). The bracket fit the Cherry sensor perfectly.


Trigger Wheel:

There are a few options for your trigger wheel. After consulting with forum member “teranfirbt”, I decided to take his suggestion and get the trigger wheel machined to the diameter of the pulley. This cost me $75 at a local machine shop. I had to welderup of course, but I enjoyed that process 
If you don’t want to go that route, you could bolt the trigger wheel to the pulley following this article:

https://www.diyautotune.com/support/tec ... k-trigger/

And last but not least, you can also go full racer and buy one of these with a pulley (also suggested by teranfirbt):

https://technotoytuning.com/toyota/ae86 ... nt-adapter

Either way, you have fabrication and non-fabrication options. The trigger wheel is something you’ll likely need even swapping in an already EFI engine, so hopefully this info will help.


Sensor:

For fuel injecting, you have a few options when it comes to sensors. From what I’ve seen, most people either install a “Ford” style VR sensor or an LS based “GT101” hall effect sensor. The bracket above can be ordered for either and includes a “fix” for adjusting the gap of the sensor to the trigger wheel. Since the hall-effect style sensor is “more better”, I went with that style of sensor. I ended up ordering the following sensor:

https://www.diyautotune.com/product/hal ... on-sensor/

Because this sensor is a hall effect type but not the GT101 LS (chevy/gm) based body, I did some measuring and ordered the “Ford style” bracket from D4A and the Cherry sensor. The combo worked perfect with the Cherry hall-effect sensor and “Ford Style” bracket! That also did away with the washer adjustment method seen in the D4A YouTube video above.

More to come!

[pbtv]

(**FI-UPDATE POST: 005**)

Hi all!

Good news: still working on the project

I am currently working through setting up the fuel system, surge tank and TBI. This isn't a full update but I did want to show y'all these:

adptr.jpg

manifold.jpg

side.jpg

front.jpg

What we have here is a successfully CAD'd, modeled and printed TBI700 to our stock 3a manifold adapter! The good thing is I'll have a .dxf file that i can send to a machine shop to have milled out of aluminum. Potentially, if anyone wanted to also set up a TBI, we'll now have an adapter for our cars

That's all for now. Full update coming soon-ish.

[NWMO]

Nice work pbtv,

I’ve been enjoying my rebuilt 4a engine with stock 3a carb. I also went with a Delta cam (272) that was recommended here. I am really enjoying it, however, long, steepish hills still suck the life out of her enough that I downshift now and again. And my project Tercel includes A/C and the higher gears when I get to it. For these reasons I am considering a repower with a diesel engine OR more likely a 4afe engine.

I am thinking of going distributorless ignition to get around the distributor location and possibly using the distributor base to fabricate a “trigger” as needed. Keep up the great work!

Chris

[The Professor]

Interested in sharing that .dxf file with the community, so we don't lose all that hard work if a computer crashes?