Ha oh dang so you were running both the vpc and fcon off the same pressure sensor? Id think that was the problem for sure.
HKS fcon/gcc/vpc combo -- fcon switch/option out not working?
- Thread starter SideWinderGX
- Start date
Nope, I was running the VPC with a sensor and the FCON without a sensor. I swore I read somewhere if you were running both together the VPC was to have the sensor atached and the FCON didn't need a sensor, but maybe I mixed that up with the GCC connection (it should be connected to the VPC not the FCON if running all three).
GM 3 bar sensor came today in the mail, I'll be wiring it up tonight!
GM 3 bar sensor came today in the mail, I'll be wiring it up tonight!
Oh dang ha never read that before. That explains things not working for sure. You get everything wired up yet?
Yup got the GM sensor wired up, although I'm not 100% convinced its working yet.
Before, in ~50*F weather, AFRs at 18 ish psi would be 17:1 (long story short, I set everything max rich and back off as I butt-tune. If it goes too lean I back off and diagnose). Couldn't get it richer.
With the sensor in, in ~25*F weather, AFRS at 18 ish psi are 14:1. That would indicate it IS richening it up, but its going even leaner at higher rpms.
I have no idea what the AFRs are over the entire RPM range, only that its good up until 4k ish and then it starts going lean, which is when I back off. I don't need any expensive repairs.
Now those temp differences and AFRs would indicate it IS working, but just in case I'm grabbing another E164 chip and buying a MKIV fuel pump to swap in, in case it IS working but I just don't have enough fuel.
Thanks for the help by the way!
Before, in ~50*F weather, AFRs at 18 ish psi would be 17:1 (long story short, I set everything max rich and back off as I butt-tune. If it goes too lean I back off and diagnose). Couldn't get it richer.
With the sensor in, in ~25*F weather, AFRS at 18 ish psi are 14:1. That would indicate it IS richening it up, but its going even leaner at higher rpms.
I have no idea what the AFRs are over the entire RPM range, only that its good up until 4k ish and then it starts going lean, which is when I back off. I don't need any expensive repairs.
Now those temp differences and AFRs would indicate it IS working, but just in case I'm grabbing another E164 chip and buying a MKIV fuel pump to swap in, in case it IS working but I just don't have enough fuel.
Thanks for the help by the way!
No problem.
Does seem to be working. At least better than before anyway ha. With my setup it did the exact opposite. Would be real lean in lower rpms then jump to rich or stoich and the car would take off like vtec just kicked in ha. I've got some 550s on the way to take care of that seeing as I was on stock 440s.
Whats the rest of your setup as far as turbo and fuel? Stock pump you said but what injectors, turbo, any afpr, or anything else?
Does seem to be working. At least better than before anyway ha. With my setup it did the exact opposite. Would be real lean in lower rpms then jump to rich or stoich and the car would take off like vtec just kicked in ha. I've got some 550s on the way to take care of that seeing as I was on stock 440s.
Whats the rest of your setup as far as turbo and fuel? Stock pump you said but what injectors, turbo, any afpr, or anything else?
Yeah, just a bit better haha. And that's weird with it being opposite, think the 550s will take care of that for sure?
As far as air and fuel, Alberts 57 trim, cartech IC, 2.5" IC pipes, BIC DDP, BIC 3.5" exhaust, test pipe (sue me), HKS alphabet soup trio + FCD, RX7 550cc injectors, no afpr though.
As far as air and fuel, Alberts 57 trim, cartech IC, 2.5" IC pipes, BIC DDP, BIC 3.5" exhaust, test pipe (sue me), HKS alphabet soup trio + FCD, RX7 550cc injectors, no afpr though.
Dang we have just about the exact same setup. I've got a afpr and it helped out tons. I ran a stock ct26 for a long time on 14 psi and had everything dialed in for that. I was having some lean issues down low. My go to guy has been crisp on here for all my hks questions. We narrowed it down to my fuel pressure. I adjusted it per what crisp and I had talked about and it made a huge difference. With you being on a stock fpr and fuel pump I'd say those are definitely whats holding you back now.
I'm pretty confident the 550s will solve my problem. I never had my stock injectors cleaned properly or tested so I'm sure they aren't flowing what they should. And I've got a 58trim ct on there now at 15psi. So the injectors are definitely not able to keep up now ha.
I'm pretty confident the 550s will solve my problem. I never had my stock injectors cleaned properly or tested so I'm sure they aren't flowing what they should. And I've got a 58trim ct on there now at 15psi. So the injectors are definitely not able to keep up now ha.
Hahaha no way, I ended up PMing crisp when I saw he had a whole bunch of HKS goodies on his car, he's helped me out a whole lot.
Denso MKIV fuel pump on the way, should be here Friday...maybe I'll put it in this weekend. Hope I can hold off on an AFPR I don't want to wait for more parts! Did you end up bumping fp up a few psi to solve that problem?
With all that in conjunction I could see the 440s giving you a problem, you're right. Are you stick or auto?
Denso MKIV fuel pump on the way, should be here Friday...maybe I'll put it in this weekend. Hope I can hold off on an AFPR I don't want to wait for more parts! Did you end up bumping fp up a few psi to solve that problem?
With all that in conjunction I could see the 440s giving you a problem, you're right. Are you stick or auto?
Ha crisp is awesome. Always helps me figure things out.
Oh yeah bumping the fp definitely helped. I think I bumped it about 3 psi over stock pressure. With the new turbo on there its gotta be the reason for the lean afrs. Can wait for the 550s.
Id think the mkiv fuel pump will help out some and the afpr will top it all off and youll be good to go.
Oh yeah bumping the fp definitely helped. I think I bumped it about 3 psi over stock pressure. With the new turbo on there its gotta be the reason for the lean afrs. Can wait for the 550s.
Id think the mkiv fuel pump will help out some and the afpr will top it all off and youll be good to go.
SideWinderGX;1803371 said:
Huh. You would think they would "talk" to each other. So basically, the VPC is installed, then the PFC-FCon modifies that signal? Seems like 3 left turns to go right. All because 3P didn't decode 3 decades ago.
That's what I thought...having two sensors attached to the same system seems stupid and redundant, but whatever.
Not sure which one modifies the other signal honestly. And I'm keenly looking over 3P's shoulder every time he posts
Forgot to mention: I'm not entirely convinced it's working because the option out knob, as well as SW2 inside the FCON, still don't seem to do anything. It runs richer but there's no sure fire way to see it working. 0 is still rich, and 1-9 all seem to be the same, whether its revving, light load or full throttle.
New chip arrives tomorrow, supposed to arrive today but mailman forgot to put it in the box (I had another package as it was). Doubt that's the problem, but maybe I fried the chip when splicing in the VPC, who knows.
Not sure which one modifies the other signal honestly. And I'm keenly looking over 3P's shoulder every time he posts
Forgot to mention: I'm not entirely convinced it's working because the option out knob, as well as SW2 inside the FCON, still don't seem to do anything. It runs richer but there's no sure fire way to see it working. 0 is still rich, and 1-9 all seem to be the same, whether its revving, light load or full throttle.
New chip arrives tomorrow, supposed to arrive today but mailman forgot to put it in the box (I had another package as it was). Doubt that's the problem, but maybe I fried the chip when splicing in the VPC, who knows.
You do have the vpc and fcon connected to each other via that brown wire right? At least mines brown. With those connected the fcon is supposed to be set to 0 at all times. Changing it probably wont yield any changes in the afrs.
I dont know about changing signals between the two but its my understanding that hooked together the fcon does nothing but provide improved fuel maps and injector timing. The option out knob just tweaks the maps a little bit that the fcon uses.
When I install my 550s im actually going to be running my vpc and fcon independently from each other. Ive been talking with the guy I bought the vpc from and hes run a vpc and fcon like this and it worked better than having them connected to each other.
I dont know about changing signals between the two but its my understanding that hooked together the fcon does nothing but provide improved fuel maps and injector timing. The option out knob just tweaks the maps a little bit that the fcon uses.
When I install my 550s im actually going to be running my vpc and fcon independently from each other. Ive been talking with the guy I bought the vpc from and hes run a vpc and fcon like this and it worked better than having them connected to each other.
The PFC-Fcon modifies the output signal to the injectors. The VPC replaces the KV meter and similates the Hz signal. They don't need each other. However, I would have guessed them to operate closed loop when you install that GCC.
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Yup that brown wire is connected, although I had to take a wire out of this rx7 harness I have because if wasn't in mine to begin with.
edit: It was from my understanding that the option out knob on the VPC, when connected to the fcon, would function the same as the SW2 switch inside the FCON...the same as the gain knob on the VPC really. In order to work SW2 has to be on zero, then the knob works correctly.
How is he running them individually, brown wire disconnected? What else is there out of curiosity?
Nick: thanks, makes sense!
edit: It was from my understanding that the option out knob on the VPC, when connected to the fcon, would function the same as the SW2 switch inside the FCON...the same as the gain knob on the VPC really. In order to work SW2 has to be on zero, then the knob works correctly.
How is he running them individually, brown wire disconnected? What else is there out of curiosity?
Nick: thanks, makes sense!
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Yeah that makes sense about the option out knob. I never really saw any changes though with mine when I turned it though.
All this guys told me was to disconnect the brown wire between the two and run them separately. Wasn't anything else to it. That everything functions properly and with 550 chips in both units it can support 750cc injectors. I figured with my setup I could run a 550 chip in the vpc and the stock chip in the fcon and have enough fuel. He confirmed it for me saying it should definitely cover my needs.
All this guys told me was to disconnect the brown wire between the two and run them separately. Wasn't anything else to it. That everything functions properly and with 550 chips in both units it can support 750cc injectors. I figured with my setup I could run a 550 chip in the vpc and the stock chip in the fcon and have enough fuel. He confirmed it for me saying it should definitely cover my needs.
Aha, I might try that in the future. Curious to see what the differences are, thanks for the info!
Got the pump in last night, test drove it today because it wasn't snowing. Full gain and full fuel at 5000 and 6500 (3500 is leaned out) sees 10-11 ish AFRs with the stock FPR at 18 psi on Alberts 57 trim, 32 *F out. Now granted the roads were pretty slick and my tires have little tread, but they spin up to 75 ish and the AFRs stay rock solid throughout all my goofing around.
If I ever need more fuel I might have to pick up an AFPR like you did and bump it up a few psi.
Got the pump in last night, test drove it today because it wasn't snowing. Full gain and full fuel at 5000 and 6500 (3500 is leaned out) sees 10-11 ish AFRs with the stock FPR at 18 psi on Alberts 57 trim, 32 *F out. Now granted the roads were pretty slick and my tires have little tread, but they spin up to 75 ish and the AFRs stay rock solid throughout all my goofing around.
If I ever need more fuel I might have to pick up an AFPR like you did and bump it up a few psi.
Nice! Good to see it all working out. Real test will be when the weather conditions are right. Wouldn't think any numbers would change all that much but a better pull with traction will definitely tell more. Either way though thats good news!
I'll be putting my motor in this tuesday and hopefully have the car registered and all soon after. So I'll keep you posted on my findings on running the two units separate.
I'll be putting my motor in this tuesday and hopefully have the car registered and all soon after. So I'll keep you posted on my findings on running the two units separate.