Supra Forums banner

1 - 20 of 23 Posts

·
Registered
Joined
·
567 Posts
Discussion Starter #1
Ok finally tried out my VPC today, the good news car started idles and drove exactly like it does with the Lexus meter , and this was running it alone with no S-AFC, I then hooked up the S-AFC and didnt notice nor expect any change in the way it ran. The only gripe I have with it is that if you give the accelerator a quick jab from idle there is a hestitation is this just how they are?? It came with two map sensors tried both they both work the same tried hooking the map sensor up to a few different places no change, other than this it works perfectly and even this is not a huge problem you dont notice it when you drive. The temp sensor is mounted in a plate that goes where the cold start injector used to be(never ran one since engine rebuild) If any one has any suggestion or can share how their car compares much appreciated, the fact it runs just fine with no AFC makes me think about using a GCC with it instead.
 

·
Flying Dutchman Pilot!
Joined
·
2,171 Posts
I think you'll find your solution by playing with the mixture. Look at the karman frequency output on the AFC...I know theres varying opinions on this, but at idle, warmed up, 17-23 is normal with an AFM, so you might want to start there. If its too high, lean it on the VPC and it should go down. Don't just lean and expect the results to remain the same 30 minutes from then. When you make a change, drive around for a while so the ECU relearns and you can see the long term effect of your change.
 

·
LEADED FUEL ONLY
Joined
·
2,068 Posts
Play with the response knob on the vpc. I've got mine cranked to about the 5 o'clock position or so. I loose lots of throttle response when I try to run less than that.
 

·
475RWHP 449TQ and climing
Joined
·
5,911 Posts
As al sya pplay with the response nob. Turning to the left or tothe right increases or decreases throttle response!
 

·
Registered
Joined
·
567 Posts
Discussion Starter #5
Thanks for the responses guys I did try that a little and it seemed to help, like I said when you drive you dont know about it even when I did a part throttle at moderate revs in first to full throttle transition(although the VPC bounced around on the floor:) ) Alan had a feeling you would respond thanks, all that other info you gave me was so useful, BTW the resistor value seems to correspond to a normal temparature not hot for the AFM inlet temp sensor. I got the harness but man its impossible to squeeze it in there and close your glovebox(on my RHD car anyhow) so I will be hardwiring it later on. I only dummied it up to see how it works(had wires passing out window into engine bay he he) once my cams go in I will try it again and if it still works OK with them, then I will permanently install it and re tune. I am still amazed that the car runs exactly like with the AFM even without the S-AFC so I am thinking about going to a GCC instead now. On an aside with all the knobs at the 12 O clock position it spits out the same Karman frequencies as the lexus meter with the custom bypass screw so I guess Reg did his homework there, its amazing how even a little tweaking of the idle knob upsets it though I guess after a while the ECU would re-learn. Sorry for the long post again thanks for the responses guys
 

·
LEADED FUEL ONLY
Joined
·
2,068 Posts
Just an FYI.. I set my response knob in neutral. I'd just stab the throttle when it was ideling to see what setting on the response knob gave me best response. Anything less than about 5 or so would lag. I would stab the throttle and see where the rpms stopped climbing. Just stab it quickly, see how far it gets up in the rpm range then adjust. :)

You'll also get more resolution with an afc compared to running a gcc. I think larry anderson has bottomed out his gcc on a tuning session at one time.

BTW, got a line on any cams for sale?? PM if you do. :)
 

·
Registered
Joined
·
567 Posts
Discussion Starter #7 (Edited)
Just an FYI.. I set my response knob in neutral. I'd just stab the throttle when it was ideling to see what setting on the response knob gave me best response. Anything less than about 5 or so would lag
seems like what I saw was normal then. May dummy it up again later on today when the weather cools down and play with it some more, just curious where do you set your idle and gain mine idles best with the idle at zero and the gain I plan to leave at zero also, I noticed adjusting the gain you have to re-adjust the idle to compensate, though maybe the ECU would learn after time.

You'll also get more resolution with an afc compared to running a gcc. I think larry anderson has bottomed out his gcc on a tuning session at one time.
I know what you mean about that with my modded CT-26 I have my AFC set at -28 at full boost to still have very rich mixtures at 20 psi.. The GCC wouldnt have enough adjustment though maybe if I back the gain off too on VPC it would work out, though I'd prefer to leave the VPC knobs at 12 0'clock except for the response. HOWEVER when I put my bigger turbo on next year I know I wont need to back the mixtures off as much so the GCC should work fine though the rpm points dont seem to facilitate a great degree of fine tuning, I like the pnp nature of it though. What rpm range does the newer version with knobs offer?

BTW, got a line on any cams for sale?? PM if you do
sorry I dont if I ever know of any I will let you know though I have two friends here who want some too. I hope to post dyno figures for them soon, the plan is to tune the car with VPC but with the Lexus meter in place to give before/after comparo with the cams, then remove the AFM and see how that affects things.
 

·
475RWHP 449TQ and climing
Joined
·
5,911 Posts
When you hooked the afc up to the vpc what wires off the vpc did you use. The gray wire going in to the ecu at the afm pinout or the blue pressure sender wire. I hear this makes a difference in tuning the vpc. Correct me if I'm wrong but the gray wire going to the stock ecu pinout for the afm is the wire needed to tune the vpc properly, not the blue pressure sensor wire.

By the way what rpm does your car idle at with the vpc Al, HKS?
ARe you using pressure unit settings or kv frequency settings for afc. Which should be used.
 

·
LEADED FUEL ONLY
Joined
·
2,068 Posts
Not too long ago, HKS_TRD wrote..

seems like what I saw was normal then. May dummy it up again later on today when the weather cools down and play with it some more, just curious where do you set your idle and gain mine idles best with the idle at zero and the gain I plan to leave at zero also, I noticed adjusting the gain you have to re-adjust the idle to compensate, though maybe the ECU would learn after time.

I think I have my idle maxxed out. I really don't remember. I'd go with what makes your car idle best. Oddly enough. Mine idles best with the vpc high, and hte afc low. I'm problee cancelling each other out. :)

What rpm range does the newer version with knobs offer?

I'm not sure. I have the older 1st gerneration afc. The one with the 5 points of adjustment.
 

·
Registered
Joined
·
1,437 Posts
Al and Dave B. helped me with mine because I had mine running on the blue psi sensor wire and the car had a rough idle to it. It would idle fine then seem to load up and range alittle. It would also surge when it was cold. I switched my wiring around as instructed to the gray wire coming out of the vpc and the difference was amazing. The car with the vpc (550 chip) and the afc and 680 cc injectors runs better now off boost as well as on than it ever did with the Lex/550 and tuning screw combo. If you hook it up on the gray wire you have to use the karman vortex wires on the afc and monitor it thru the kv or kf which ever it is on the afc. I screwed up and hooked it up the first time thru the pressure sensor wires and it will run just not monitor anything correctly because the vpc puts out a karman vortex signal. My car idles fast right now at 890 rpm but smooth as glass. I have a wideband coming so I can lean it out because I'm really rich. My knobs are all in the 12 o-clock range now except gain where I have it set at +4 for safety and my base fuel psi is 35. This is rich especially with the 680's but the car run great and I can't wait to get it dialed in. Again thanks to Al and Dave B on this.
 

·
475RWHP 449TQ and climing
Joined
·
5,911 Posts
Thanks for your input Al, and X-man. The emanage goes in this week and I was just checking my notes. Hks says go off the pressure sender but all others say kv input. Thats the way I'm hooking up the emanage.
 

·
LEADED FUEL ONLY
Joined
·
2,068 Posts
QWIKSTRIKE writes...When you hooked the afc up to the vpc what wires off the vpc did you use. The gray wire going in to the ecu at the afm pinout or the blue pressure sender wire. I hear this makes a difference in tuning the vpc. Correct me if I'm wrong but the gray wire going to the stock ecu pinout for the afm is the wire needed to tune the vpc properly, not the blue pressure sensor wire.

Use the grey wire. Keep the afc on the KV setting and you should be good to go. Installing the afc this way will clean up the dirty vpc signal.

By the way what rpm does your car idle at with the vpc Al, HKS? ARe you using preeure unit settings or kv frequency settings for afc. Which should be used.

It idles at around 700 or so. Its a solid idle. Doens't move around from that point much if at all.

I'm using kv settings on my afc. If you install it on the grey wire, you must use kv settings. The vpc's output (grey wire) is a kv signal, so using pressure isn't going to work.
 

·
Registered
Joined
·
567 Posts
Discussion Starter #13
What still has me stumped/pleased is how the car idles and drives perfectly with just the VPC on its own. It may be possible that the Mines computer is having the same effect as using an S-AFC etc.. I do have a standard ECU here but didnt think of this unitil after I dropped the car off today to have the cams put in. When I get it back I will try the standard ECU also though it may be harder to judge idle quality then. I did toy a little with the response knob, couldnt notice a huge difference though once the car warmed up or becuase the ECU got a chance to learn the hesitation got smaller. When I plugged the AFM back in the hesitation was still there for a bit so maybe it is the ECU learning, hopefully get my car back in time to play with it some more on the weekend. Alan in reference to old and new tuning units I was talking about the old GCC with screwdriver settings and the newer one with the five knobs, not sure what RPM points the newer one(GCC) lets you adjust at. Anyhow it seems impossible to fit the harness in and shut the glovebox let alone install the piece that covers the ECU, this now explains why there was a big square cut out of my glovebox later filled in with a piece of plastic, there must have been an F-CON on my car prior to the fitting of the Mines ECU, in Japan
 

·
475RWHP 449TQ and climing
Joined
·
5,911 Posts
You can get it up by manuvering the wire from the fire wall up, then twist the hks harnes in between the abs ecu, and the ecu.
My gove box closes fush with it there. It just takes time and patience to get it set in right. I'm gonna put in the emangage today or tomorrow if time permits. I dont see why you would use gcc over an afc afr or emanage. Hks technician told me the afr is way more tuneable than the gcc fcon combo. He said thats why they were discontinued. The techs at HKS told me the afc/afr is the better way to tune any vpc and of course they reccomend the afr since it's their product.
 

·
Flying Dutchman Pilot!
Joined
·
2,171 Posts
do you guys no if the 89-92 harness uses the grey wire or the blue wire?
 

·
Registered
Joined
·
1,437 Posts
The best thing to do is look where the vpc harness plugs in to the ecu and see what color the wire is that runs into the original afm signal wire. On the 87 to 88 harness this is a gray wire. I think Alan hard wired his.
 

·
LEADED FUEL ONLY
Joined
·
2,068 Posts
X-man said:
The best thing to do is look where the vpc harness plugs in to the ecu and see what color the wire is that runs into the original afm signal wire. On the 87 to 88 harness this is a gray wire. I think Alan hard wired his.
Roger that.

The grey wire coming out of the vpc is wire you need to find. The kv sensor wire for the ecu input is green with a red stripe on my 89 model. Yours may be different.
 

·
Registered
Joined
·
567 Posts
Discussion Starter #19
You can get it up by manuvering the wire from the fire wall up, then twist the hks harnes in between the abs ecu, and the ecu.
OK I will try that I guess it will be tight, when I looked in there I thought if there was no ABS ECU life would be easier and perhaps on LHD Cars the ecu connectors dont go between the EFI and ABS ECU. Could you get the black plastic piece that covers the ECU back in??? Do U have a pic by any chance, I feel kind of sorry for the harness to squash it like that but hey its got a job to do...

I dont see why you would use gcc over an afc afr or emanage. Hks technician told me the afr is way more tuneable than the gcc fcon combo. He said thats why they were discontinued. The techs at HKS told me the afc/afr is the better way to tune any vpc and of course they reccomend the afr since it's their product.
True I was just brainstorming/thinking out loud
 

·
475RWHP 449TQ and climing
Joined
·
5,911 Posts
I don't have a picture, but I can get one and e-mail it to you with the glove box in. And yes the green and red wire is the kv signal. You want to use the gray wire from the hks harness. Make sure you pick the right gray wire since there is 2. just match the pin out on the ecu for the kv signal and mark the wire you need. Thats what I did to get it done right. The blacl plastic cover is in and flush like it never happened. I ran the wires through the hole in the plastic.
 
1 - 20 of 23 Posts
Top