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1989 7mgte swapped mk3
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Discussion Starter · #1 · (Edited)
I'll do my best to paint the full picture of my issues. I have an 89 gte swapped mk3. Some time back i added an fcon and gcc to the car and then a VPC a short time later. Being a noob, the vpc brown wire was never hooked up correctly. The car always ran super rich and the GCC seemed to have no affect.

I just finished installing a DM upgraded 57 trim CT and 550s. I had Gordon Duax burn me the appropriate 550 rom chips for the FCON and VPC. I set the fcon dial to 0, attached the brown opt out wire from the vpc to the fcon and started the car. It idled fine and wouldn't really rev past 2500k rpm. I figured that was a tune issue. The idle was super rich (maxed out at 10 on the wideband gauge) and the vpc seemed to have no affect whatsoever with the afr or idle speed. The GCC 500 rpm range did seem to lean out afr slightly.

I tried to reverse the chip in the VPC wondering if i had installed it opposite. The car started and idled briefly and now will not start. All of the plugs were new and are very black from it running so rich. So i suspect that may be why it won't start.

Ever since installing the 550 chips i get a code 12, 14 and 31. When i was running the 440s and original chips i had no codes.

I noticed that i get no spark now when i plug the brown wire in but when i disconnect it i do get spark.

Any help would be great. I am trying to keep things old school but have just about had it with this fcon.
 

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Hello,

I have a couple of questions for you concerning your setup.

Do you have the GCC plugged into the VPC or the GCC?

What chip do you have installed in the FCON? When running the VPC and the FCON together you only need the 550 chip in the VPC, for the FCON you would need to run the E105 or the E105V. The V FCON chip enables the output on the VPC (Brown wire) to trim the FCON.

The chips only fit one way, if you flipped it you might have erased it or damaged it. With the codes you are getting it seems like VPC is not working correctly.
 

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1989 7mgte swapped mk3
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Discussion Starter · #3 ·
Hello,

I have a couple of questions for you concerning your setup.

Do you have the GCC plugged into the VPC or the GCC?

What chip do you have installed in the FCON? When running the VPC and the FCON together you only need the 550 chip in the VPC, for the FCON you would need to run the E105 or the E105V. The V FCON chip enables the output on the VPC (Brown wire) to trim the FCON.

The chips only fit one way, if you flipped it you might have erased it or damaged it. With the codes you are getting it seems like VPC is not working correctly.
The GCC is plugged into the VPC.

I am running the E105V in the fcon and the SUP009B in the VPC if i remember correctly.

I had Gordon Duax burn me the chips so i have sent him an email to see if i could send the chips to him to see if they retained their memory or had been damaged.

They seemed to go in either way as the pins are symmetric but maybe i wasn't looking closely enough.

Thank you for your help! There was a time that i knew all of this stuff well but i am just now starting to mess with it again.
 

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Seems like you have all parts connected correctly. Here is a page from the VPC install that talks about the ROM facing the correct direction.
 

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1989 7mgte swapped mk3
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Discussion Starter · #5 · (Edited)
Awesome thanks! Hopefully Gordon Duax will respond soon and i can get my current chips checked out. Or get him to burn me new ones. Do you have any references for which direction the VPC chip should be installed?

Edit: i looked at pics of the 440 chip installed in the vpc and it appears the notch was facing the front of the unit. I did have the vpc installed backwards so that chip is probably fubar.
 

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Discussion Starter · #6 · (Edited)
At this point i may just have Duax burn me some new rom chips.

Is Gordon Duax pretty much the only way to get new rom chips made these days?
 

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Gordon's your only source. I'm amazed he still does it, honestly. Reversing the EPROM's is a very bad idea and can cook the whole head unit. Make sure the notch in the EPROM faces the same direction as the one you remove.

I'll be honest, having ran all of that stuff I'd ditch the PFC-FCON entirely and run the VPC/GCC only on the 550's. That will massively simplify your tuning setup and it'll accommodate anything you can do with 550's on the stock ECU.
 

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Discussion Starter · #8 ·
Gordon's your only source. I'm amazed he still does it, honestly. Reversing the EPROM's is a very bad idea and can cook the whole head unit. Make sure the notch in the EPROM faces the same direction as the one you remove.

I'll be honest, having ran all of that stuff I'd ditch the PFC-FCON entirely and run the VPC/GCC only on the 550's. That will massively simplify your tuning setup and it'll accommodate anything you can do with 550's on the stock ECU.
That is certainly an option. Luckily i got in touch with Gordon and he has some new chips heading my way.

I realize there are newer and better technologies but i am trying to keep it old school.
 

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Discussion Starter · #9 ·
Alright I've installed some replacement chips the correct way. Car runs fine now with no CEL. It seems to have a slight miss at idle once warmed up but that may be the tune.

Does anyone have info or advice on how to tune the GCC, FCON and VPC? I have the brown wire hooked up and the dial set to 0 in the FCON which is about as far as I've made it.

Thanks for the help!
 

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Almost every 7M-GTE on a stock ECU or stock ECU+ piggybacks has a slight hiccup at idle. I've only seen it completely disappear with a modern ECU running with clean crank angle and cam angle sensors.

I ran a PFC-FCON, then PFC-FCON/GCC, then briefly VPC/FCON/GCC, then a VPC/GCC and finally VPC/SAFC. This all took place between 2001 and 2006.

I found that the engine had better throttle response and seemed to rev much more freely on just the VPC vs the VPC+PFC-FCON. Peak HP was unaffected by removing the FCON. IMHO the only value of the PFC FCON is allowing someone to run 15-16psi with 550cc injectors as a plug-n-play, no tuning required option. That was much more valuable when dynos and tuning was violently expensive and wideband O2's were rare.

As far as tuning, first you'll need a wideband O2. Then verify base timing at the CPS is 10*BTDC. Install new spark plugs with an appropriate gap. For VPC/GCC levels of HP I'd go with the NGK 4644's gapped to around .024" to .028" depending on how healthy your coil packs are. Change the oil to a suitable oil, for a 7M-GTE on stock bearing specs, particularly an old 7M-GTE, I'd personally recommend the Mobil 1 Euro 0w40 or Valvoline VR1 20w50 depending on your preferences.

I'd book a dyno session, and warm the car up to operating temp first. Then I would disconnect the battery to reset the fuel and spark trims. Reconnect the battery, then proceed with dyno tuning. Use the main 'fuel' knob on the VPC to get it as close as you can to a nice 11.5:1 A/F across the powerband in boost. Fine tune with the GCC.
After that's dialed in at WOT, adjust the idle to stay below 1200 RPM and adjust the VPC's 'idle' knob until it's around 14.5-15:1. In my experience it will always oscillate between 14.4 ish to 15.2 ish regardless of how much you tweak the HKS stuff, but get it to within that window. Leave the OPT out knob alone, that adjusts the FCON's curve and I found it to do more harm than good.

Good luck, and we'd love to see pictures! 🍺
 

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Discussion Starter · #11 ·
Those are some great tips! I was out in the garage playing with it some today and noticed that when I have the brown wire hooked up to the FCON, the gcc has no control over anything. For example I had the supra idling and was adjusting the 500 RPM dial on the GCC and with the brown wire plugged in, the green green light on the GCC was the only one illuminated. When I unplugged the brown wire, I noticed that the gcc could adjust the AFR's as I would expect it to. I was able to verify this on the wideband gauge I have installed.

Maybe like you said - at this point it may not make sense for me to run the FCON and only run the VPC and GCC?

Anyway, I appreciate all of the help. There was a time where I knew this stuff well. I realize there are better options available, but my power goals aren't huge. I kind of just want the car to be a fun/streetable power level and have period correct piggyback fuel mods.
 

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Those are some great tips! I was out in the garage playing with it some today and noticed that when I have the brown wire hooked up to the FCON, the gcc has no control over anything. For example I had the supra idling and was adjusting the 500 RPM dial on the GCC and with the brown wire plugged in, the green green light on the GCC was the only one illuminated. When I unplugged the brown wire, I noticed that the gcc could adjust the AFR's as I would expect it to. I was able to verify this on the wideband gauge I have installed.

Maybe like you said - at this point it may not make sense for me to run the FCON and only run the VPC and GCC?

Anyway, I appreciate all of the help. There was a time where I knew this stuff well. I realize there are better options available, but my power goals aren't huge. I kind of just want the car to be a fun/streetable power level and have period correct piggyback fuel mods.
Yes, ditch the PFC-FCON entirely and run the VPC with the GCC connected to the VPC. You'll have the adjustment you're looking for and it will work great for almost anything reasonably achievable on 550cc injectors and pump fuel. Bear in mind that the VPC's mapping is not perfect and atmospheric & weather changes will shift things a bit. If you drive the car up a mountain to thinner air you will have to adjust things, often richer than you'd expect because of the way the VPC does the math. I can't explain why it does that but I know it does from mountain drives going from 6000ft DA to 11,000ft+ DA.

So keep the wideband in play and pay attention to it. You'll be just fine on most bolt-ons.
 

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Discussion Starter · #13 ·
Ok cool! The only thing that i am not totally sure about is that i believe the fuel cut defender is spliced into the fcon harness. Would i just move it over to the vpc harness?
 
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