Affordable Fuel Injection (1 Viewer)

[thecrazygreek]

I have been around 30f the past few days. Starts and idles great.
I Recently had an issue with stumbling and backfiring out of the tbi. Fixed it with a change of the gas filter. Fuel delivery is prob the most common issue these things have. Keep new filters in place, and keep an eye on pressure. And even if pressure is good, volume of fuel could be low with clogged pump/filters.

 

[SteveH]

thecrazygeek's comments may have helped me figure this out. I reset the timing and idle speed to AFI's base settings. So, it idles at 950 RPM, which is what it did when I got it - too high for me, but not crazy-high.

When warm, it ran perfectly, so I filled the truck with gas and noticed a big difference. Formerly, when it was 90% out of gas, and you turned the key before starting, the fuel pump (under the pass. floor pan) would gurgle a lot - clearly it was cavitating. When I filled the truck with gas, the fuel pump was smooth and quiet when you turned the key. So, the head pressure of a full tank of gas has an effect on how this truck runs.

I started the truck yesterday at 35F, and it ran perfectly when cold. The sagging and stumbling and bogging under throttle were gone. I think (per thecrazygeek) I have fuel supply issues - either air in the lines or pressure/volume issues.

For starters, I'm going to move the clear plastic fuel filter back closer to the FJ40 gas tank and further from the pump, to see if this might even out the fuel flow going to the pump. I have checked all the lines and clamps on the filter, and nothing is leaking either gas or air. I have dealt with 7.3 Ford diesel fuel systems and know that air in the fuel lines is evil for power and noise.

All this points to why an in-tank pump is the REAL solution for any EFI setup. Not sure I'm ready to do that, but it could be a good long-term project. 'Cause we all need projects, right?

 

[SteveH]

An update almost 2 years later. The AFI TBI in my FJ40 continues to run very consistently and well. I have had the truck to 12,500' (Tincup Pass) and it ran well (albeit down on power). I started the truck at 20F and it started just fine. Starts just as well at 90F, which always taxed my carburetor. I bought their legacy kit (not the new OBDII one) and upgraded to their modified FJ62 distributor for another $295. I also bought the 48" harness so that I could put the ECU in the glove box. I left the timing and idle speed at AFI's recommended settings. When I tried to adjust either, I got very poor results.

Overall 'perceived power' is very good - when you floor the truck at 60, it's soon going 70. It may not have more actual horsepower, but it feels a lot more responsive and more like a modern engine. I 'lug tested' it and at about 500 rpm on my tach, it just shuts down. You can't lug the engine any slower than that. I could lug the carburetor to about 400.

Two things that bug me: when you start it cold, about 45 seconds into the warmup cycle, it misses slightly (while idling in the driveway). It always done this, every time. Not really a problem, but it seems out of place in the EFI world. The 2nd thing is that if you upshift too soon while driving (or don't downshift going around a corner in town), it will bog rather obviously. I don't know if this is a programming issue, elevation issue, or a physical issue (like the size of the throttle body). The solution is just to run it to higher RPMs in each gear. If you do this, it tears up the road with glee. So, some driver cooperation is needed.

For the price ($1300 back then) and effort, it has turned my truck from a cantankerous/dangerous thing into a turn-key driver and simply more fun to bomb around in, without worrying about hot soak and stumbling, etc. I am no longer 'that guy' with carb issues on offroad runs.

I would love to drive a Holly Sniper setup, since that's the new hot babe on the block, but I can't say I'm unhappy with the AFI setup.

Steve

 

[SteveH]

Time for another AFI TBI update - 2 years later.

Last night, I drove the truck and it ran ok, but at hot idle in my driveway, the exhaust was sputtering and putting out tiny puffs of black smoke. I read the installation/troubleshooting manual and the first thing it mentioned under 'running rich' was to check the vacuum line to the MAP sensor. I checked the line, and it had rotted/hardened and cracked at a bend. I replaced it with new hose, and it the richness/sputtering disappeared and it runs as before.

So, word to the wise - inspect your AFI TBI system every now and then for melted wires/cracked vacuum lines, etc. - just like you would any carbureted engine. It's easy to ignore fuel injection systems!

 

[DeskJock]

@toyotaspeed90

I'm using the harness provided in the AFI kit, that goes from the distributor to the ECU. I have to assume that they are doing this properly and using a shielded cable.

I tried keying the engine quite a bit to get it to TDC but no avail, I guess I need to have a little more patience (or get the wife involved so I don't have to keep keying and then running around to check) - or I get a under hood crank button thing.

Just to confirm, I'm looking for the lines in the picture here.

View attachment 1700652

is there a process other than patience to see the line, zero and the mark to the right?

I've taken the distributor cap off, lined up #1 and #3 with the rotor. and, then slowly bumped the FJ40 forward and backwards for the roster to move 1/4 to 1/2 inch either way when lining up #1 and #3 on the top of the distributor.

and, only see these weird indents.

I want zero, per AFFORDABLE FUEL INJECTION specs. I only see a white mark when using the timing light .. and, I can't see enough detail to determine if it's just a mark or if there is a zero on it or around it.

looking thru the little tiny window is more than a pain.

 

[DeskJock]

this is a snap shot using the time light .. I see this line. I'm currently assuming that is TOC.

MARCH 1975 FJ40. Affordable fuel injection ( according the the manufacture, the fuel jets are from a 1990 Chevy 2010, and the Distributor is from a 1989 FJ40((using it's electronic ignition)

 

[Downey]

I'm not going to take the time to read all the previous 7 pages of this thread, but this last page has my interest. First, your idle problem almost sounds like you did not use a 2 pulse vehicle speed sender, they work with the 02 sender to control idle functions. Second, surprised you have gotten away with using a Landcruiser Distributor. The TBI requires a sine wave signal, and your are giving it a square wave signal. Has something changed dramatically since I left the Landcruiser accessory business in 2009 ???

 

[DeskJock]

I'm not going to take the time to read all the previous 7 pages of this thread, but this last page has my interest. First, your idle problem almost sounds like you did not use a 2 pulse vehicle speed sender, they work with the 02 sender to control idle functions. Second, surprised you have gotten away with using a Landcruiser Distributor. The TBI requires a sine wave signal, and your are giving it a square wave signal. Has something changed dramatically since I left the Landcruiser accessory business in 2009 ???

Thanks Jim for the response. If I'm supposed to create a new thread, please let me know.

My situation, no idle problem. I've purchased this FJ40 about a month ago. Prev Owner installed the Affordable Fuel Injection system that included using the 1989 FJ40 Distributor. So, it's set and they are linked together. my information is from AFFORDABLE FUEL INJECTION (AFI)customer service ( which has been outstanding) .

So, I understand the difference between a sine wave and a square wave .... I'm thinking that the AFI ECU is taking care of business.

At purchase and for the first week, I had serious backfire into the intake manifold, AFI stated it was common that their kit were installed not changing top dead center (TDC) to zero. So I've retarded the timing; but, I'l like to met AFI specs first before I settle into how I run her. (under load, sometimes the throttle control results in a flat or somewhat retarded acceleration around 40 to 60% of throttle.

so ... I want my human on the water scaling is being used on the fly wheel ... and, I can't believe I can see it.

Prev Owner did install your air box, certainly cleans up the engine bay!!!!

 

[wngrog]

AFI will modify the fj62 distributor to work with their system so that is not odd.

 

[DeskJock]

AFI will modify the fj62 distributor to work with their system so that is not odd.

Agreeed. And they removed 4 fins from the middle armature- at least that’s what the manufacturer stated.