A750F 5-speed auto tranny w/ paddle shifters in an 80? Yup.
- Thread starter alaskacruiser
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Hmm they did it with the diesel not sure that helps us poor blokes with the petrol motors.
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- #3
True, but considering they use the HGM Compushift controllers for both gas and diesel applications, I'd be surprised if a petrol version isn't in the works.
True but what we found out from my A750 thread is that the biggest hurdle for us appears to be the bell housing.
honest question here so take it easy on me....
what is to be gained to offset the cost? every single time i toss around crazy ideas for my cruiser it always comes back to a vortec swap simply for the gain vs dollar that the chevy setup gives me or leave it factory. not trying to rain on anyone's parade, just an honest question. seems like a bunch of work and money for minimal gains.
what is to be gained to offset the cost? every single time i toss around crazy ideas for my cruiser it always comes back to a vortec swap simply for the gain vs dollar that the chevy setup gives me or leave it factory. not trying to rain on anyone's parade, just an honest question. seems like a bunch of work and money for minimal gains.
The gains are simply:
Improvement in efficiency probably around 11% according to Toyota, if that is true it would be an increase of roughy 11% power to the ground increase.
The lower first gear for offroad
The higher 5th gear for hwy
Is that enough to cover the cost? --No I am sure that it isn't. But I don't know about most people, I have a lot of s*** on my truck that costs more then the benefit.
Improvement in efficiency probably around 11% according to Toyota, if that is true it would be an increase of roughy 11% power to the ground increase.
The lower first gear for offroad
The higher 5th gear for hwy
Is that enough to cover the cost? --No I am sure that it isn't. But I don't know about most people, I have a lot of s*** on my truck that costs more then the benefit.
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Neato. Not that I would do it, but still pretty darn cool. That is a classy shifter too 
What are you guys going to do about the check engine light that will come on if no using the FZJ's ECU to control the transmission? And at least @alaskacruiser needs to worry about that, being in Cali and all.
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- #11
TrickyT- letting others know about something cool like this doesn't necessarily mean I'll be going this route. But I have looked at some of the ECU details in the past with the A442F (see attached image), and I'm curious about this whole CEL with aftermarket trans ECU issue. I think the situation will be similar with the A750F since, either way, it is the '97 80 factory ECU that would potentially be producing the CEL. Would be interested in any details you, Scott, or anyone else may have as to what missing/altered signals might produce the CEL. I think that, as long as the throttle input is split between the factory ECU and the aftermarket ECU, there shouldn't be a problem because everything else is an output from the factory ECU to the transmission. I am wondering if I missed any feedback inputs from the transmission to the factory ECU?
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There's a longer explanation in this post: H151 5spd conversion in parts for sale classifieds, but the short answer is the FSM says the ECU uses signals from the throttle position sensor, the air-flow meter, and the crankshaft position sensor to monitor the lock-up clutch for the torque converter and then compares the state of the lock-up clutch with the "lock-up schedule" stored in ECU memory to detect if there's a problem. If lock-up does not occur when it should a P0770 is thrown and the MIL comes on. The thread I quoted was all about doing a H151 manual transmission conversion, so a different application to be sure. But the point is the OEM ECU expects the transmission to react in specific ways to the commands it sends the solenoids and if it doesn't it throws a code. I don't see how you could be sure that won't happen here too without someone doing the swap. But then what are you gonna do if the MIL comes on, swap the A343F back in?
EDIT: The MIL light is only an issue if you live in a state/region where having a MIL causes you to fail smog inspection.
EDIT: The MIL light is only an issue if you live in a state/region where having a MIL causes you to fail smog inspection.
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From CaDmv:
probably an easier route than attempting to override/fool the ECU.
There are six counties that require smog certifications within certain Zip Codes only. These counties are: El Dorado, Placer, Riverside, San Bernardino, San Diego, and Sonoma.
probably an easier route than attempting to override/fool the ECU.
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- #15
Tom- nice work. You made some pretty good progress on your H151 post. I agree. It looks like we'd have the following issues:
1. Solenoids 1 and 2
The ECU would likely see a problem with solenoids 1 and 2 (S1, S2) because the Vehicle Speed Sensor (VSS) doesn't match the S1/S2 states as defined in ECU map.
CEL result: S1 = P0750, S2 = PO755
2. Lockup Solenoid
It would also likely see a problem with the lockup solenoid SL if it's not locked up when the ECU expects it to be, again as defined in ECU map.
CEL result: SL = PO770
3. Open / Short detected on Solenoids 1 or 2
To avoid the ECU detecting an open or short circuit on S1 or S2, we would need to make sure S1 and S2 on the ECU have the appropriate resistances based on expected S1, S2 operation. Which is to say we need to avoid this:
(a) Short = Solenoid resistance is 8 Ω or less (short circuit) when the solenoid is supposed to be energized
(b) Open = Solenoid resistance is 100 kΩ or more (open circuit) when the solenoid is supposed to be not energized
CEL result: S1 = PO753, S2 = PO758
4. Open / Short detected on Transmission Temperature Sensor
Finally, assuming the tranny temp sensor has been disconnected / connected to a standalone tranny ECU, to avoid ECU detecting transmission temperature problems, we would need to make sure the resistance between the OIL and E2 terminals on the factory ECU is within range to avoid the following conditions:
(a) Short = Temp. sensor resistance is less than 79 Ω
(b) Open = After the engine has been operating for 15 min. or more, the resistance at the temp. sensor is more than 156 kΩ
CEL result: PO710
Since I live right by HGM, I will ask them if they miraculously reverse engineered the shift and lockup patterns from the factory 80 petrol US ECU. If so, the timing might be close enough to be in the clear. This would be ideal, but I think it's pretty unlikely. If not, we'd need to devise some circuitry to address (1-4) above:
1. Modify VSS input to ECU based on S1, S2 outputs from ECU and TPS input
2. Modify VSS input and <unknown> input to ECU based on SL output from ECU and TPS input
3. Modify S1, S2 resistances as follows: 8Ω < S1, S2 < 100kΩ
4. Modify OIL to E2 ECU terminal resistance as follows: 79Ω < Tatf < 156kΩ
Regarding <unknown> input in (2) above, one question I have relates to this statement in the FSM: "The ECM uses the signals from the throttle position sensor, air− flow meter and crankshaft position sensor to monitor the engagement condition of the lock−up clutch. Then the ECM compares the engagement condition of the lock−up clutch with the lock−up schedule in the ECM memory to detect mechanical trouble of the shift solenoid valve SL, valve body and torque converter clutch."
What are the input(s) to the ECU that tells it the "engagement condition of the lockup clutch"? If the answer is TPS/AFM/CPS, how might these inputs indicate lockup condition? Note I have all tranny to ECU I/O listed in that graphic above.
Reference: 1996 80 series FSM, starting on DI-143 (pg 593 of the PDF)
Edit: updated with additional to-do's to avoid open/short CELs for S1, S2, temp sensor
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Thanks!
If think it is the TPS, AFM, and CPS. I'm only making an educated guess here, but when the TC locks up, then the rpm of the engine will drop and the speed of the transmission output shaft (sensed by vehicle speed sensor #2 -- VSS2) should be able to be determined only by knowing engine rpm and what gear the transmission is in. If the speed of the transmission output shaft doesn't match what the ECU has calculated it to be, then the torque converter must not be locked up and the ECU throws a P0770 code. Page AT-57 in the 1997 FSM provides a hint about this too: "The gear shift point and lock-up timing are controlled by the ECM based on the signals from this vehicle speed sensor [VSS2] and the throttle position sensor."
Subbed, have been waiting for this.
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- #18
So let's say your educated guess is how it works, and we use a data logger to capture what we need. What specific data would we need? In addition to the simple resistor mod for S1, S2, temp, I think we only need to address the following (note that input and output here are all w/rt factory ECU):
1. Modify VSS input to ECU based on S1, S2 outputs from ECU and TPS inputs
Method: Monitor TPS inputs and VSS input vs. S1, S2 output under different conditions. Use this data to determine VSS based on TPS, S1, S2 and feed this VSS data into the factory ECU to fool it.
2. Modify VSS input to ECU based on SL output from ECU and TPS inputs
Method: Monitor TPS inputs and VSS input vs. SL output under different driving conditions. Use this data to determine VSS based on TPS, SL and feed this VSS data into the factory ECU to fool it.
See any holes in this? I do. What about CPS, AFM? Do we need this data, too? If so, how might we use it? Let's see...I would guess CPS data is used for things like going uphill, where you might have large TPS input, large CPS input, but smaller VSS input vs. on flat road. This would likely affect shift/lockup patterns (S1,S2,SL outputs) in hilly conditions, but it also shows us we can't just use S1, S2, SL, TPS to determine VSS; we also need CPS to determine VSS for situations like hilly driving conditions. Does this sound right to you? If so, we now have this (note I combined S1, S2, SL because they go together as part of determining VSS):
1. Modify VSS input to ECU based on S1, S2, SL outputs from ECU and TPS, CPS inputs
Method: Monitor TPS, CPS, and VSS input vs. S1, S2, SL outputs under different conditions. Use this data to determine VSS based on TPS, CPS, S1, S2, and SL and feed this VSS data into the factory ECU to fool it. Sounds like you have some background with microcontrollers? I'm more of an FPGA guy (EE) and I could implement something like this on an FPGA pretty easily, given enough sample data. Any pros and cons you can think of one way or the other? A flash-based FPGA (Microsemi) would eliminate the small bootup delay associated with SRAM based FPGAs (Xilinx/Altera).
2. Modify S1, S2 resistances as follows: 8Ω < S1, S2 < 100kΩ
3. Modify OIL to E2 ECU terminal resistance as follows: 79Ω < Tatf < 156kΩ
Questions:
1. Now what about AFM? Any other inputs we're potentially missing?
2. The FSM mentioned speed sensor #1 will be used if speed sensor #2 (VSS) isn't working properly. If we create the VSS (#2) input as described above, is there any comparison vs. speed sensor #1 that will create problems for us?
Note: updated my prior post above to address open/short CELs relating to S1, S2, ATF temp
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This sounds like a reasonable approach @alaskacruiser, with the first step being to monitor all those existing ECU inputs and outputs you listed under different driving conditions and see if they behave as you expect. The more challenging problem is to get your modified VSS2 signal to do its thing without throwing any P07xx codes, and the only way to know for sure you can do that is by trial and error. It would be a bunch of work for sure, and that's assuming you can address the bell housing mating problem and any other gotcha's along the way like proper distance between the crankshaft and torque converter, etc. And what do you propose for a transfer case? VF4B chain-drive, or the hundy case?
My FJ Cruiser has an A750F in it. Definitely a nice transmission. But, man, this sounds like a ton of work and $$$ just for an extra gear in an 80. Cheaper just to trade up to a hundy, and then you'd have more time available to spend on trails too.
My FJ Cruiser has an A750F in it. Definitely a nice transmission. But, man, this sounds like a ton of work and $$$ just for an extra gear in an 80. Cheaper just to trade up to a hundy, and then you'd have more time available to spend on trails too.
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- #20
Hey Tom- please see the edited version of my post above for some questions I've posed (guessing you missed these since I was still editing it up until just now).
I think if we had enough data on flat road, hills (up and down), crawling/lo range, etc. we could simulate the VSS2 close enough, but yes trial and error would be part of it.
As for the bell housing and other mechanical issues, I'm a EE and my expertise ends right there.
Moreover, I was looking at this CEL issue as it relates to A343F vs. A442F, where there are no issues beyond the electrical.
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