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Thread: MAPECU3 On 1990/1988 Toyota Supra (7MGTE)

  1. #1

    Question MAPECU3 On 1990/1988 Toyota Supra (7MGTE)

    Hello,
    I have a MAPECU3 installed on a 1990 Toyota Supra, running a 7MGTE. The wiring harness, ECU, etc, are from a 1988 Toyota Supra. It is a karman vortex system. I have 550cc injectors installed. I've disconnected the factory O2 sensor, so that the ECU's are not fighting each other. Also, I'm running a larger aftermarket turbo, and am targeting 20 psi max, on 93 octane gas.

    I am having a difficult time in a few areas. I'm using the base 7MGTE 550cc map, and overall the entire map is very rich. I've had to pull about 15%-20% fuel across the board, except for the idle area, to even get it to the point where I'm 'on the map' as far as the gauge goes. It was well below 10.0:1 to begin with.

    Settings are as follows:

    Mode: KVF Elimination
    Pressure Sensor Config: -24.4" Hg to +24 psi
    Igniter Configuration: 6 Cyl Distributor (as stated on wiring diagram)
    Max RPM: 8000
    KVF Clamp: 5000
    FCD:
    FCD 1: 4.1v, release @ 22 psi
    FCD 2: 4.2v, release @ 24 psi
    EBC:
    Sensitivity: 80%
    Gain: 3
    Mode: External
    Disable overboost: FALSE
    EBC Pressure: 20.0 from 800 to 8000
    I/O:
    TPS Input: TPS
    O2 Input: OFF
    Analog 1 Input: WB
    Switched Output 1: IGF
    LBR:
    Minimum Pressure: 9 psi
    Maximum AFR: 12.9
    Retard Degrees: 12

    I am seeing many problems, and have been fighting them for many weeks now... Specifically:

    1) The idle air to fuel ratios appear to change all on their own. I've had IAT compensation enabled, and disabled, and this seems to make no difference in this regard. The base map is incredibly rich in this area. Off the gauge rich. So, I had to pull about 20% from this area, which got me down to about 12.5:1. During driving, eventually the idle area always ends up lean. So, I'll add fuel back in. Then, I'll drive some more, and I'll end up too rich, and I'll be back to pulling fuel in the idle area. If I shut the car off for any length of time (15 mins or longer), it will be very lean, despite being fine the last time I was in the idle area. I don't understand why the idle area keeps changing. Is there some other sensor that could be affecting the idle fuel enrichment?

    2) The fuel cut defeat doesn't appear to be working. The original values were 4.7v and 4.8v. This did not work. I eventually dropped this to 4.1v and 4.2v, and this seemed to do the trick. In fact, I overboosted at one point (read about EBC below), which caused the nut to loosen on the intake wheel, contacting the housing, and bent the shaft. I had to replace the turbo due to this overboost incident. Now, no matter what I set the FCD1 and 2 voltages at, I continually get fuel cut and cannot defeat it. Is there some known issue surrounding fuel cut defeat on Toyota Supra's? I've read in the forums that other individuals have given up trying to get the FCD working, and purchased HKS FCD modules. Can you tell me if there is any way to make this work correctly? Is there some wiring I should check, or settings that could be interfering? The fact that I was able to prevent fuel cut during one of the tuning sessions makes me think that it is in fact wired correctly, etc.

    3) The KVF Clamp setting... The setting states this should be set in the range of 100Hz-10KHz. However, any time a frequency greater than 5KHz is entered, I am presented with an error dialog stating that one or more of the settings are incorrect and to verify the settings before continuing. You cannot get out of this error dialog, and return to the settings. Your only option is to click OK, which sometimes writes the settings, and sometimes does not. Which does not make me feel very confident in the software, in all honesty. It concerns me that possibly invalid settings are being written, or worse yet, correct settings are not being written.

    4) The EBC settings... I've tried various options here. The time that I overboosted, I erroneously had the configuration set for Internal FS. I understand that between the issues with the fuel cut mentioned above, and improper EBC settings, probably caused the overboost situation that I experienced. Once I replaced the turbo, I went back through some manuals I found on the MAPECU, and studied various configurations online. I finally found the most common external wastegate configuration, made sure the solenoid was configured properly, and set the MAPECU up with 80% sensitivity, a gain of 3, and 20.0 PSI in the EBC Pres from 800 RPM to 8,000 RPM. Every single time I click OK to save the settings, and try to drive the car, I am now hitting problems at 10 PSI (or very close to it). Looking in the EBC settings, somehow the EBC Pres line changes back to 9.5 PSI across the board. The EBC Duty and EBC CDuty are 0, every time. I'll change everything back to 20.0 PSI, click OK, then go back in and look at the settings, and they are back to 9.5. What causes this, and how do I properly change the EBC Pres settings? I'm evidentally missing something.

    5) I have an AEM wideband attached to Analog Input #1, and have the input configured as such. When reviewing logs, looking at the fuel table, once I connected the wideband, I ended up with cells highlighted in red. I thought at first this meant that at some point, that area was lean, or some such. However, another test drive showed that this wasn't the case. In fact, the next time I looked at the logs in the map, I had a rainbow of colors to choose from. Red, green, blue, orange, etc... Is there a document which explains what all these colors mean in the map?

    Whatever is happening definitely feels like fuel cut... I just reviewed the logs, and there are a dozen examples (or more) of what I feel... My car starts to build boost, and runs great up to about 9 PSI. Then, the fuel cut (or whatever) hits. The AFR goes through the roof, which supports the theory of a fuel cut being engaged. The car lunges, constantly alternating between building boost and fuel cut. The logs show this, repeatedly. For example, at 137.3 seconds, I am at 10.4 PSI, and 10.8 AFR on the wideband. At 137.4, my AFR begins to rise sharply. At 137.5, I am off the map lean, in a dangerous situation. Boost begins to decline, fuel comes back on, etc.

    I'm attaching a log file and the table from a test drive I just made. I again had the situation where when I started the car, even though when I shut it off, the idle A/F ratio was fine, it was incredibly lean again. I had to add another 12.5% back into the whole idle area to get it back to where it was the last time the car was running (20 minutes prior). During the drive, I made sure it hit (what feels like) the fuel cut multiple times.

    One more note. When the fuel-cut-like behavior happens, I am getting an OEM check engine light. Reading the codes, I get a 32 code, which is an airflow meter / boost sensor error. I thought the MAPECU was emulating a KVF sensor, and preventing the fuel cut by clamping the frequency it sends to the OEM ECU... I've tried various values for the KVF Clamp setting too, from 3.1KHz all the way to 5KHz. I've also tried more than 5KHz, but this is when I get the error dialog about one or more of the settings being invalid (despite the software stating the range is 100Hz-10KHz).

    I could really use some input on these little gremlins. Overall, the MAPECU allows me to adjust my A/F ratio, but I'm getting a bit frustrated. Any advice would be greatly appreciated, at this point...

    201410121535.zip

    Thank you,
    Joel

  2. #2

    Default

    Sorry about the delay getting back to you. You have some many questions/issues, hopefully I cover everything. Apologies in advance if I miss something. Engine swaps can always be troublesome, did the vehicle run with the combination engine, ECU, etc., without the MAPECU3?

    1) The idle air to fuel ratios appear to change all on their own. I've had IAT compensation enabled, and disabled, and this seems to make no difference in this regard. The base map is incredibly rich in this area. Off the gauge rich. So, I had to pull about 20% from this area, which got me down to about 12.5:1. During driving, eventually the idle area always ends up lean. So, I'll add fuel back in. Then, I'll drive some more, and I'll end up too rich, and I'll be back to pulling fuel in the idle area. If I shut the car off for any length of time (15 mins or longer), it will be very lean, despite being fine the last time I was in the idle area. I don't understand why the idle area keeps changing. Is there some other sensor that could be affecting the idle fuel enrichment?
    Usually I would say the OEM ECU is not actually seeing the air flow signal from the MAPECU3, the Blue wire on the 16-way. I did notice you have changed the pressure scale from the default and the maximum RPM settings. The fuel table does not rescale for these changes. The base table was tuned with the default pressure scale of -20inHg to +35psi from memory. Using a more compressed pressure scale will change the tuned table. Try changing back to the default pressure scale with our base table. I am still also a little concerned about the engine swap wiring and ensuring the OEM ECU is seeing the KVF signal.

    2) The fuel cut defeat doesn't appear to be working. The original values were 4.7v and 4.8v. This did not work. I eventually dropped this to 4.1v and 4.2v, and this seemed to do the trick. In fact, I overboosted at one point (read about EBC below), which caused the nut to loosen on the intake wheel, contacting the housing, and bent the shaft. I had to replace the turbo due to this overboost incident. Now, no matter what I set the FCD1 and 2 voltages at, I continually get fuel cut and cannot defeat it. Is there some known issue surrounding fuel cut defeat on Toyota Supra's? I've read in the forums that other individuals have given up trying to get the FCD working, and purchased HKS FCD modules. Can you tell me if there is any way to make this work correctly? Is there some wiring I should check, or settings that could be interfering? The fact that I was able to prevent fuel cut during one of the tuning sessions makes me think that it is in fact wired correctly, etc.
    I am not surprised as it does not appear you have configured or wired any FCD input/output? You have configured the software settings but I cannot see where you have wired the MAP sensor into the MAPECU3. From memory the MKIII Supra fuel cut is based on the voltage from the OEM MAP sensor, correct? That signal must be cut and intercepted by the MAPECU3 to clamp it.

    3) The KVF Clamp setting... The setting states this should be set in the range of 100Hz-10KHz. However, any time a frequency greater than 5KHz is entered, I am presented with an error dialog stating that one or more of the settings are incorrect and to verify the settings before continuing. You cannot get out of this error dialog, and return to the settings. Your only option is to click OK, which sometimes writes the settings, and sometimes does not. Which does not make me feel very confident in the software, in all honesty. It concerns me that possibly invalid settings are being written, or worse yet, correct settings are not being written.
    You are running standard KVF Elimination with has a 0-3400Hz range, which is why 5000 is too high. Try a figure like 3000 and it should accept it.

    4) The EBC settings... I've tried various options here. The time that I overboosted, I erroneously had the configuration set for Internal FS. I understand that between the issues with the fuel cut mentioned above, and improper EBC settings, probably caused the overboost situation that I experienced. Once I replaced the turbo, I went back through some manuals I found on the MAPECU, and studied various configurations online. I finally found the most common external wastegate configuration, made sure the solenoid was configured properly, and set the MAPECU up with 80% sensitivity, a gain of 3, and 20.0 PSI in the EBC Pres from 800 RPM to 8,000 RPM. Every single time I click OK to save the settings, and try to drive the car, I am now hitting problems at 10 PSI (or very close to it). Looking in the EBC settings, somehow the EBC Pres line changes back to 9.5 PSI across the board. The EBC Duty and EBC CDuty are 0, every time. I'll change everything back to 20.0 PSI, click OK, then go back in and look at the settings, and they are back to 9.5. What causes this, and how do I properly change the EBC Pres settings? I'm evidentally missing something.
    The duty cycle is the main control value for the EBC, the PSI is purely used to determine when you start bleeding pressure and for over boost. To be honest, with the other problems you are having, I suggest we get the AFR's under control before trying to get the EBC working. There are too many variables.

    5) I have an AEM wideband attached to Analog Input #1, and have the input configured as such. When reviewing logs, looking at the fuel table, once I connected the wideband, I ended up with cells highlighted in red. I thought at first this meant that at some point, that area was lean, or some such. However, another test drive showed that this wasn't the case. In fact, the next time I looked at the logs in the map, I had a rainbow of colors to choose from. Red, green, blue, orange, etc... Is there a document which explains what all these colors mean in the map?
    Have you read the MAPECU3 and MAPCAL3 PDF manuals? There is in a section on logging. Essentially you configure the colour to the parameter and the colours of the data boxes at the bottom of the screen match.

    I hope that helps to start with, I think we need to break down the issues and solve them one by one rather than trying to working on lots of things. Get the fuel and AFR's right is the first and most important thing. A screenshot of the MAPCAL dashboard at idle would help a lot.
    Last edited by MAP-ECU Man; 16th-October-2014 at 10:42 AM.
    MAP-ECU Support

  3. #3

    Default

    Regard the FCD, sorry I was confused with the MVIV Supra. The MKIII does not have a OEM MAP sensor so the FCD function is performed by the KVF Clamp, not the voltage based FCD functions. Unless, your MKII has an OEM MAP sensor which differs from ours!
    MAP-ECU Support

  4. #4

    Default

    Sorry about the delay getting back to you. You have some many questions/issues, hopefully I cover everything. Apologies in advance if I miss something. Engine swaps can always be troublesome, did the vehicle run with the combination engine, ECU, etc., without the MAPECU3?
    No problem... Sorry that my post contains so many questions. Been struggling with various issues, and just getting frustrated. I appreciate your help.

    First off, let me state that this is NOT an engine swap. This is a 1990 Toyota Supra, with the factory 7MGTE.

    The engine management system (ECU, wiring harness, sensors) are from a 1988 Toyota Supra. The wiring harness was over 20 years old, and was severely damaged. I found a running parts car, and swapped the full wiring harness, ECU, and sensors over to my Supra.

    The fuel injectors have been upgraded to 550cc units. I used to run a Lexus IS300 KVF sensor due to its increased size. A larger turbocharger was installed. I then had problems with spark blowout, so I installed a set of Lexus coilpacks in place of the factory coilpacks. This eliminated that problem.

    Yes, the vehicle ran, albeit very rich. Hence the purchase of the MAPECU3. I need it to reduce the amount of fuel being injected, and also to adjust the ignition system timing.

    The KVF has been eliminated, and is running with the MAPECU installed. It is driveable. Thus, I have to believe that the OEM ECU is in fact seeing the emulated KVF signal. In my testing, I found that without proper KVF signal, the car will not start, let alone drive down the road. Of course, the KVF is no longer installed, and thus the MAPECU is generating the frequency. Also, the only time I've received any malfunction codes is during the fuel cut situation I discussed in the original post. I'd like to think that if the OEM ECU didn't have proper KVF (or emulated KVF) signal, I'd be getting a MIL code indicating such all the time. I'll certainly triple check the wiring, though. Never hurts to check again.

    I am not surprised as it does not appear you have configured or wired any FCD input/output? You have configured the software settings but I cannot see where you have wired the MAP sensor into the MAPECU3. From memory the MKIII Supra fuel cut is based on the voltage from the OEM MAP sensor, correct? That signal must be cut and intercepted by the MAPECU3 to clamp it.
    Your other post discusses this. So, the problem is that I did not lower the KVF Clamp setting far enough. The lowest I went was 3100, and the problem continued. As soon as this happens, I receive an airflow MIL code (34). I will try 3000 and see if that helps the problem at all. I couldn't understand how the voltage settings were coming into play, since the airflow signal is based on frequency. I was assuming that the MAPECU was doing some magic to use those values to limit the upper KVF frequency somehow. I was questioning why there was a KVF frequency clamp and FCD settings referring to voltage, though.

    You are running standard KVF Elimination with has a 0-3400Hz range, which is why 5000 is too high. Try a figure like 3000 and it should accept it.
    Excellent info! I tried to find what the maximum frequency the ECU expects to see, but Google was not of much help. I understand that other systems may use higher frequencies. I just did not know what the maximum was on these particular KVF sensors. Oh I get it. The higher frequencies come into play with that KVF HF Elimination modes. I get it now.

    Have you read the MAPECU3 and MAPCAL3 PDF manuals? There is in a section on logging. Essentially you configure the colour to the parameter and the colours of the data boxes at the bottom of the screen match.
    I've been sleeping with the MAPECU3 manual. I wake up with papercuts. However, the MAPCAL3 manual, not so much. Better print that out too. Hopefully I won't bleed to death from the additional papercuts I'll no doubt inflict upon myself.

    I appreciate all of the suggestions. I will re-re-recheck the wiring, re-scale the maps back to the defaults, drop the KVF clamp frequency to 3000. I'm sure the ECU is seeing the KVF signal, as from experience I know that the car will not run without a KVF signal of some sort, whether that be the KVF AFM, or the MAPECU.

    Just to reiterate, this is not an engine swap. 1990 Supra, with the factory 7MGTE engine, 550cc injectors, Lexus coilpacks, a larger turbocharger, 1988 ECU, wiring harness, and sensors, and a MAPECU3.

    Thanks again for your advice. I'll give all your suggestions a try this weekend.

  5. #5

    Default

    Thanks, good to know it is not an engine swap. You are probably right that it is "seeing" a signal on the KVF input.

    Just a thought, have you wired an IAT sensor or resistor to pins 1 & 2 of the air flow meter harness as per the note at the bottom of the wiring diagram?

    Keep some bandaids handy for those paper cuts...
    MAP-ECU Support

  6. #6

    Default

    Just a thought, have you wired an IAT sensor or resistor to pins 1 & 2 of the air flow meter harness as per the note at the bottom of the wiring diagram?

    The IAT is wired to the mapecu, and sensor installed about 3-4" in front of the Throttle body. The resistor is installed in the pig tail of the AFM (and elec. taped for now...when everything is running properly ill solder it in permanently).

  7. #7

    Default

    Ok, I just wanted to check that the OEM ECU sees a replacement for the IAT sensor as it can default rich if it is not seeing a sensor. The resistor looks like a sensor.
    MAP-ECU Support

  8. #8

    Default

    Still having an issue that feels like a fuel cut.... I'm open to any advice you may have... Seems to happen randomly, no matter the RPM, boost, TPS %, etc. I cannot seen to find the correlation. I'm sure there is one, I'm just not seeing it.

    FUELCUTISSUE_log.zip
    FUELCUTISSUE_tbl.zip
    FUELCUTISSUE_pic.zip

    Any thoughts would be appreciated.

    Thanks.

  9. #9

    Default

    Thanks for the files. It is very difficult to figure out if the problem is random. Is it possible there is a bad electrical connection causing the OEM ECU to loose the KVF signal from the MAPECU?

    There appear to be some spikes in the log but other than that, the log looks OK. Certainly the output frequency of approx. 400Hz is low so that should be fine. You don't appear to be pulling boost either. Can you please tell me the number of seconds in the log where you are feeling fuel cut?
    MAP-ECU Support

  10. #10

    Default

    13.5 sec. is pulling fine.....13.6 sec hit fuel cut pressure starts to drop, & wideband spikes. 13.8 sec let off throttle as not to damage anything (running super lean due to fuel cut issue). Where are you seeing the 400 hertz frequency measurement? It would be amazing helpful to be able to watch the output frequency, to better diagnose this issue.

    Every single connection has been properly soldered, not crimped/twisted/taped/etc. I will triple check the connections, though.

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