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Saabeh said:
I do not have a wideband unfortunately. Under boost it is rich enough, that is not what I am worried about. I could crank the fuel pressure way up on the FMU to cope with tons of boost. It is just the rest of the time it is not perfect.

Is the turbo ECU a plug in change with no modifications for a 1993 truck?
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I don't know but aren't both OBDI systems. I saw MA plates, where are you located? I've got a innovate WB if you want some more accurate readings.

I'm more familiar with the 80 series OBDII FI system. Toyota wants the system to run FT% +/- 20%. The first 10% of that is for air density changes do to altitude and air temp. The second 10% is for component error. So staying within that second 10% for injector sizing should still allow the ECM to function well. With the 340s you are 80% out.

Stock 80s with the vane style AFM when boosted tend to lean out under boost. These trucks don't take to piggy backs very well if at all. One person said he had similar experiences with pickups of that same age. Just some food for thought if you are looking into going that route.

How are you at electronics? I bought a spare ECM for my truck and believe I have an injector hack worked out but haven't tried it yet. I'd still pick up that ECM and check out the circuitry for the AFM and try and get a handle on how Toyota deals with the larger injectors. My experience has shown me that Toyota is very consistent through out model years and their entire line when it comes to the ECMs. I designed a MAF housing for my 1996 LC that uses a sensor from a 2005 Camry. The end result was better throttle response, smoother idling, better fuel economy and it fixed a lot of the rich running condition that people had with boosted applications because it can read higher air flows than that of the stock sensor. This kind of reverse engineering takes some time though.
 
The engine is not stock compression. It is rebuilt using brand new turbo pistons.

FMU's are rising rate FPR's. This FMU increases fuel pressure as boost goes up. The truck has no problem running rich under boost, it is just running poorly sometimes when not under boost. It is just slow to react to boost sometimes as well. Like if you just punch it, it will be lean for a second then rich. I don't like this because the turbo spools very quickly, and running lean is not fun.

I am located in Westford MA.

I understand where you are coming from with the whole reverse engineering process. When my father and I took up this project, we didn't really know it would go this far. We are going to work on timing, and tuning the FPR a little more. I think I will try to snag that ECM as well.
 
I had a revelation of sorts and I might have a plug and play solution for you. This is a little long but I want to make sure you understand where I'm coming from.

Theory:

As i mentioned Toyota likes to have things as common amongst applications as it can. This applies to the AFM output from engine to engine.

So at idle all these different sized engines will basically output the same reading for very different amounts of air passing through them. Think about your 2.2L verses a 4.2L. Almost half the air flow but the same output from the AFM.

This is achieved by changing the size of the chamber. Your chamber is sized smaller to fit you 2.2L and the 4.2L is larger to fit it's displacement. It's easier to think in terms of air speed through the sensor and that is common throughout the applications.

The ECM then takes this reading and calculates the base duty cycle for the injectors. So all these different engines basically have the same idling duty cycle.

History, mid 80s Supras:

In the mid 80s the Supra came on the scene and tuners quickly wanted to install larger injectors to support more boost. Those Cars had a Karmen Vortex AFM in them. One ingenious guy used the theory that I mentioned above to "trick" the stock ECM into using larger injectors. These same Karmen Vortex AFMs where used in the Lexus line on the LS400.

The Supra came with a 3.0L and the LS400 came with a 4.0L. So when the LS AFM was installed on the Supra the air's speed though it dropped from it's larger size. When the ECM saw this drop in air speed it would calculate a lower base duty cycle for the injectors. This lower calculated duty cycle would then allow them to install a larger injector and the ECM would never know the difference because the lower duty cycle and larger injector would balance each other and the proper fuel would be metered.

A side effect of this was better air flow from the larger AFM. This is something that is still being done today with those cars.

Your situation:

I think the Supra trick applied to your truck would work just as well as it does for them. You need to source a vane style AFM from a vehicle in the 4.0L size engine. As it turns out the 91,92 and the 93,94 land cruisers both have these style AFMs. The 91,92 is a 4.2L and the 93,94 is a 4.5L engine. These trucks are being parted out here on MUD all the time and the cost of one of these AFMs is dirt cheap as they aren't a failure item. My first choice would be the 91,92 as it's a better fit for the injectors you are running.

Because these AFMs are designed to meter air for an engine twice the size of yours they should work well up into the boosted range unlike the stock unit you have now.

The first step would be to verify the pinouts of the sensor and the plug configuration to see if the install is doable. I believe they are all the same.

After thinking about it, this would be my approach to your situation if it were my truck. I can get schematics scanned and such if you need them.


BTW; it wouldn't surprise me at all that this is exactly what Toyota did for it's Turbo application to begin with. The stock engine has a 190cc injector. Now take the AFM from a 3.0L application which is roughly 50% bigger and you need an injector of 285cc to compensate for it.

Also the 93 3.0L Supra TT used a MAF style sensor that was physically the same size and shape as that of the LC with the same plug and pin configuration. The LC engine was 50% larger than the Supras.

Like I said, Toyota is pretty damn consistent.
 
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Wow, that is a really interesting idea. I didn't know Toyota was that consistent. I will certainly have to try this soon. Right now we're working on putting the interior back together and installing cruise control.
 
How similar do you think the AFM's are? I guess they would have to be compared side by side to know exactly. I wonder if the connector is the same.

Do you know where I could find one right now?
 
I took a look through ebay and they had a couple of 4runner V6 ones for like 15.00. These work out to be a better match for the 390cc. Look here on the site in the "parting out" section for an 80 series LC one.

From what I can tell the connector is the same. From my work with MAF sensors what Toyota does is change the pin out configuration so that one sensor will only work on that truck. So what you need to do is re-arrange the pins in the connector to get the new AFM to work.

Physically I'd expect the AFMs for the larger engines to be physically larger as well. I believe the air pipe on the 93-94 LC to be around 3" ID.

I'd start with the 4runner v6. These sensors have an operating range and there might not be enough air flow with the LC installed to get any reading from it at all.
 
2ndGenToyotaFan said:
I was just throwing out another option that appears to be a plug and play electrically... :D
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No offense to the guys on that forum but I'd have to check that out with the schematics first. But if it is, it's a slam dunk but would probably require a larger air tube.

I had instructions that allowed people who had OBD1 equipped cars to read how much the ECM was controlling the fuel trim. It gave basic info as no adj though full rich or full lean. This was the only way to evaluate how balanced the AFM/Injector choice was. Being here in MA near sea level you would like to see a no adj reading.

I'll see if I can find it.
 
You can monitor the ECM activity through the Diagnostic port in the engine compartment with a digital meter. It breaks down the ECM's efforts into 5 units.

[0 volts] Maximum Lean, reduction of the fuel mixture from the BASIC FUEL CALCULATION

[1.25 volts] Minimum Lean, reduction of the fuel mixture from the BASIC FUEL CALCULATION

[2.5 volts] No correction at all to BASIC FUEL CALCULATION

[3.75 volts] Minimum Rich, increasing the fuel mixture above the BASIC FUEL CALCULATION

[5 volts] Maximum Rich, increasing the fuel mixture above the initial calculation

This is read through the E1 and Vf pins anytime that the E1 and T1 aren't jumped.

It would be interesting to see where the truck's ECM is right now. I'm thinking it's at 0 volts.
 
how many horses would you happen to be getting out of that beast? o and what about ft lb of tourque?
 
At 15psi probably 240hp and 250lb ft. These are just estimates, it really needs to be put on a dyno, there are just too many things that need work right now.
 
dayum thats fricken awesome! i bet that little truck scoots... hahaha sorry for the old grammar it kinda sounded batter that way. awesome rig man!
 
hey dont be puttin down the IFS. even though it may be a little bit inferior it still does some serious work offroad and on road
 
Needing a Turbo ECU

Definitely check out the 22rte forum ( 22RTE-Trucks.com ) as this is a common swap/upgrade. In slightly reading into this, along with the AFM upgrade look into a Megasquirt. It will run around $400 on top of the turbo ecu but with the correct programming (can be pre-programmed with your setup considered)... run smoother. By just moving over to the stock ECU you'll hit a fuel cut problem above 11psi or so.. some easy work arounds but not consistant an reliable without the MS upgrade. Again, hit the forum.. helped me get to 15psi without leaning out :) .. oh.. I'm running the Supra AFM and 440cc injectors

Cheers!
 
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