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"Have you tried installing a 2200 ohm resistor instead of the IAT to disable IAT compensation?
The IAT is a NTC device which means it has a negative temperature coefficient. As temperature reduces, resistance increases and as temp goes up, resistance decreases. Hence it is called a negative temperature coefficient, it is reverse. The alternative is to place a resistor in parallel with the IAT so as it cools, it limits the increase in resistance of the IAT and therefore how much richer the AFR's become. The problem with doing that is it will also alter the resistance and therefore AFR at normal temperatures where your AFR is 14.7:1. Some people but a variable resistor (potentiometer) in parallel with the IAT so they can adjust the balance. A 10,000 ohm or 22,000 ohm pot would probably be a good starting point."
I'm currently using a GM IAT. Based on the Toyota IAT table found here (http://www.mkivsupra.net/vbb/showthr...sor-resistance!) and the GM table, found here (http://pe-ltd.com/assets/air_temp.pdf) it looks like the GM IAT is producing resistance values that are consistently greater than what a Toyota IAT would, and thus as a NTC device, in consistently making the ECU think that the car is taking in cooler (denser) air than it is. I may try putting a potentiometer in parallel with the GM IAT so that I can reduce its ohm readings to the point that it is on-par with a Toyota IAT.
I recall reading earlier in this thread that you said it doesn't have too much influence on the fuel map but I'd rather give that a stab as a last-ditch effort before I throw on a SAFC and inadvertently start advancing my timing.
UPDATE!
I adjusted my cam gears to typical suggested 2JZ spec (-3 Exhaust, +1 Intake). The turbo felt like it kicked in harder/lower, and overall power seems to have improved across the rev-range, so will be leaving that as-is. Someday when I hit a dyno I'll confirm the benefits but for now my butt dyno tells me that at least the low-end hit is undeniable. AFR's didn't lean out, however, and still stuck to 10.0:1 and lower.
I installed a 10k potentiometer in parallel with the IAT, and IT WORKED! I did some math and found that at 30'C, the potentiometer should be set to 6.6K ohms to have the GM IAT + potentiometer match the OEM Toyota IAT, so I did so and instantly noticed my AFR's hit 10.2. I then kept dropping resistance (thus letting the ECU think I was pulling in hotter, less dense air than I was) and got my AFR's to as high as 10.6:1. Once I hit near zero it richened up to 9.9:1 again, which must be a fail-safe where the ECU determines that the IAT is faulty and dumps fuel. I backed it down to ~6-7k ohms to play it safe as I didn't know what else would be tweaked with the IAT. The one negative is that the potentiometer obviously won't scale with temp as the IAT will, so I'm going to calculate what the potentiometer should be set-at at a few other values and pick a happy medium.
I'm now content that everything is running as it is and the next step is tuning with the SAFC, so now I'll put that Neo on and see how it runs at 11.0:1 AFR's. It's still stumbling hard under boost, so I'm hoping that leaning it out takes care of it. Otherwise, I may have to look at more ignition related issues (new coil, re-gapping my plugs, etc.). Will report back once I start playing around with the SAFC.
Hey guys just finished up my engine swap and tt ecu mod on a 94 toyota pickup. Have been following this thread for a while now and google has definitely been my friend searching this thread. Solved lots of problems looking at what people have been going through. There is one thing that I haven't found and I'm sure it's somewhere on this thread I just haven't been able to find it.
I have an aem wideband installed and on 60% throttle I'm running lean around 14.7 to 15.7 and at idle its also 14.7 to 14.1.
setup:
no turbo N/A for now
custom ffim
90mm tb
remote iscv (just like what ali did with his long time ago)
gte headgasket
stock fuel rail
440 stock obd1 injectors
bosch 044 fuel pump
-8an fuel inlet
-6an fuel outlet
Fuel cell and custom fuel lines
fuel pressure regulator
I'm running fuel pressure at 60psi because at 30psi my afrs are at 16 to 17 on throttle and at idle its at 14.7.
Now my question. When running a large throttle body do I have to upgrade the injectors or at least have some kind of piggy back to correct the fuel map or is that compensated through the ecu.
Please let me know what you guys think any kind of advice will help. I've checked my wiring numerous amounts of time because of some wiring mistakes I've made when I was doing the harness. Everything checks out for the sensors also. tested the map sensor even swapped it out. Bought the gm iat brand new. Coils are brand new and even swapped out with other used coils. brand new spark plugs double checked spark plug gap. Checked coolant temp sensor for the ecu that checked out. Coolant temps run at 180F. Checked timing and tps. timing is at 10 degrees and tps idles down the car when timing the car. Also adjusted tps how the tsrm does it through ohms and feeler gauges. I'm at a loss but I'm sure it's going to be something obvious as it always is for me. Here's a picture of my swap. Excuse the zipties those arn't permanent.
OEM fuel pressure is 43.5 PSI. And I believe the reason you're running "lean" is because you're not giving it enough throttle to get the car into closed loop operation.
OEM fuel pressure is 43.5 PSI. And I believe the reason you're running "lean" is because you're not giving it enough throttle to get the car into closed loop operation.
Hey High PSI thanks for the fast response.
Please correct me if I'm wrong but I believe the engine goes into closed loop when the engine is warm and when the o2 sensors are sending signals to the ecu. It goes into open loop when the engine is cold or wide open throttle.
The tsrm says fuel pressure is set to 28-34psi when the vacuum is connected to the fuel pressure regulator. Sorry if I was unclear with that. My fuel pressure I mention is idling, engine warm, and the fuel pressure regulator is connected to vacuum. I don't know if it makes a difference but my fuel pressure regulator is an aeromotive a1000 1:1 raising rate fuel pressure regulator.
Also when I say 60% throttle I mean a 3rd gear pull from the bottom of the gear to about 5k rpm so there's a significant amount of load going into the engine enough to where I should be 12:1 afrs or at least see something close to that when I put my foot down.
these ecu's tend to hold stoich or 14.7 until you get into boost to help with transitions and mpg I think, they generally don't swing rich until you hit a few psi or mash the throttle all the way down. it wasn't really tuned for optimum power for a n/a but for a turbo, where you don't want it to swing rich until you have already crossed the boost threshold... well that is what I think is going on anyways but I have observed that. I had noticed its easy to build a few psi going uphill even at part throttle and the ecu will generally hold stoich until you build significant boost or mash on the pedal. yuo may be missing out on some power until you go turbo. you could go larger injectors and then open loop will have more fuel but you would be need a piggyback to pull fuel most of the time then. I would prob just leave it until you can install a turbo.
for those guys that want to stay n/a, you can always use a JDM 2jzge ecu which uses map sensor and is tuned for n/a, I think it might use a different map sensor and probably uses small injectors but it would have the proper n/a tune on it.
Yeah well at least on the sides there is a lot of room in the trucks.. not so much in the fronts you usually have to use pusher fans like shown above but if its holding 180 degrees that is pretty solid!
I usually use the stock fuel regulator so I don't know the specifics of setting it, but stock is a 1:1 so that is what you want.
if idle is able to keep the 14.1-14.7 range sounds like you are in the right range.
it should swing rich when off throttle and before o2 correction and then move towards 14, if its leaner and then richens up towards 14 when idling then you might have your base fuel wrong (fuel Pressure or vac leak somewhere).
also when you say 440cc stock obd1 injectors I am assuming you installed new 440's cause the stock usdm ones are 330cc.
Frankielal, what mounts and trans are you running if you don't mind sharing, are they the Cressida mounts? thanks.
Hey High PSI thanks for the fast response.
Please correct me if I'm wrong but I believe the engine goes into closed loop when the engine is warm and when the o2 sensors are sending signals to the ecu. It goes into open loop when the engine is cold or wide open throttle.
Also when I say 60% throttle I mean a 3rd gear pull from the bottom of the gear to about 5k rpm so there's a significant amount of load going into the engine enough to where I should be 12:1 afrs or at least see something close to that when I put my foot down.
Apologies, it was late...that's what I meant. You're not getting into open loop or the WOT maps.
As I've been pointing out in this thread, my car has been running extremely rich under WOT...but at the same 60% throttle you're talking about I'm seeing close to stoich, and that's even with a bit of boost behind it. As Ali said, these ECU's don't seem to richen up until you're heavy into the throttle and really pushing some air, so your car looks to be running as expected on that front.
Aristo non-VVTI ECU's are very common. Since Aristo's only came in automatics, my question is can I use one on my M/T '92? If so, is there any additional modifications needed?
you can use an aristo ecu on a manual car but you need to do the a/c fix its one of the steps on the first post.
the rev limit will be slightly reduced and it drives a hair different like when the ecu thinks its shifting but mostly it will drive the same and most people won't notice.
Cool thanks for all the knowledge everyone. Now i know what to expect for the next swap. I had this huge post for a response to ali's question for the motor mounts with pictures and everything but im just waiting for moderator approval. I've already been waiting a week for approval.
To answer the questions in case I don't get approval for some reason. Yes im using 330cc injectors. I thought all the 2jzge injectors are 440cc, my mistake. The transmission mount and motor mounts are from cx racing. I don't suggest buying these motor mounts because of the quality you get for the price you pay. Very sloppy cuts for the slotted "adjustable" bolt holts. Bolt holes are extremely over sized where I was afraid the bolt head could fall through the hole without washers. The motor mounts hold onto the motor with only 1 bolt on each side. On top of that its only a grade 4.8 bolt. The adjustable holes on the transmission mount are side to side and the adjustment on the motor mounts are front to back so theyre not adjustable. With all those problems these motor mounts cost $500. I was going to make them myself but I thought I would save more time than money. Now I've wasted both. I've heard of other people with cx racing products with the same type of quality. Of course I find out after I buy the motor mounts. Lesson I learned don't buy anything from cx racing.
As for the room up front I can't even fit my finger in between the water pump and the radiator. Pusher fans are the only fans you can use. Even on the intake side, the brake booster gets pretty close to the engine so the intake manifold has to be custom.
Yeah if you are running the tt ecu, then you will want o upgrade to 440's and that will help with the rest of the fuel issues you are having.
the ecu can compensate some in closed loop, but when in open loop you will be leaner than you want and it goes into open loop on most transitions.
that weird with the mounts, I think those were the old kind for 2wd trucks so maybe that is the issue.
you can post that stuff in here since its related to the tt ecu mod, the moderators don't mind about that in this thread (I was a moderator once upon a time ago).
if you have a 4 cylinder truck originally you can look into the cressida mounts from Xcessive manufacturing. There are 2 year ranges and I think it was the older style which have the same mount position as the 22re trucks and are slotted in the correct direction for adjustment, they are also super beefy! those are the ones I was going to use when I had my truck but ended up parting it out. if you had a v6 3vz then you may need other mounts unless the slots allow for that much adjustment but you can always give them a call and see, I think they are aware of the truck swaps now.
That sounds odd that you are still that rich in boost with 440's. maybe they are a bit higher flowing? make sure the wideband is reading right also.
what turbo are you running, I forget? I was definitely closer to the 11-12 range at that psi for me I didn't really need a piggyback, that was with 440's and aem iat.
are you running an after market fuel pressure regulator cause that could do that also.
If it is that rich and you are using a stock or 1:1 regulator, you can use pretty much any safc you want, you can use safc1, safc2, neo etc.. they will all adjust for injector changes that you need. if you want the newer looking screen then go for the newer one. generally you should just be making an across the board adjustment so while the newer units have more adjustment points, you will usually be setting these all the same anyways so you can even use an older one.
Stock fuel pressure regulator. Only thing i can think is my injectors are bigger than 440s.. or my TT fuel pump denso is pushing my fuel presure too high.. i was thinking about going with an aftermarket fuel pressure regulator and limiting it to like 43 psi.
I remember reading on the oside tiger box that they were more cc's at a higher pressure. and 440s at like 42 psi or 43psi
I havn't put a fuel pressure gauge on it yet, that would eliminate some guessing
07-31-17, 06:44 PM
It's still stumbling hard under boost, so I'm hoping that leaning it out takes care of it. Otherwise, I may have to look at more ignition related issues (new coil, re-gapping my plugs, etc.). Will report back once I start playing around with the SAFC.
