Purge cut solenoid?

[CSMsi311]

Well, I've been reading up on how to do the TPS hack. Sounds like a great idea to me. I understand how to do everything except get the voltage source from the Purge Cut Solenoid. My problem is i don't know what the purge cut solenoid looks like. I understand the rest of the circuit stuff. My schooling has finally payed off.

I really wish I would have installed my supercharger or at least helped out with the install.

Also, I was reading that I have an old version of the JRSC kit. One without an extra support bracket. And the old pressure switch. Do you think JR would update my kit for free?(hoping) Or is it not that important to get the updated hardware. Here is a link that i found on hostboard. Greg Holden is the author and he seems very educated to me. http://home.nycap.rr.com/ghjrsc/new_vs_old.html

Thanks
Jason

[CSMsi311]

i finally found out what the JR MAP controller actually does. if anyone is interested here is the link: http://www.jacksonracing.com/pages/hondapps/mapcon.html

sounds a whole lot like what this TPS "trick" does. only it is packaged a lot nicer. I think I might have found one used on Club Si for $100.

Question:
It says "With the new MAP Controller installed, the MAP sensor is now able to read boost without illuminating the "check engine" light."
Then is my map sensor NOT reading the boost?

Jason

[john]

Purge Cut Solenoid? What's that? TPS as in Throttle Position Sensor?

What exactly are you trying to do?

[exciv2000]

Originally posted by CSMsi311
Then is my map sensor NOT reading the boost?


Exactly. The reason is because your map sensor is before the SC on the top of the TB, so it sees nothing but vacuum. The map controller covers that hole, and runs a hose from your intake manifold aft of the SC to the map controller, so that it does see boost. Then the map controller senses this boost and throws the ECU into open loop mode but prevents the CEL by limiting the voltage that the ECU actually sees. Basically if you were to let the map sensor see boost without the map controller, it would throw a CEL because the voltage the ECU is seeing is too high, and also it's pretty useless since the ECU does not have any boost fuel maps. Hence why we need add-ons like the map controller to take the place of the IAT+pressure switch that JR oringinally included with our kits, giving us tip-in detonation.

[CSMsi311]

John: For the TPS trick they use the PCS to supply the voltage for the new signal. I'm not going to mess with the PCS, just use the voltage from it. Basically the trick is to send the normal (.5V) signal to the ecu for the car to run in closed loop mode when there is no boost. When there is boost, it will send a signal (4.5V) to the ecu to run the car in open loop mode

Scott: Thanks for the info. it makes a lot more sense now.

From what I understand now. having the MAP sensor read boost is useless b/c the ecu can't do anything with that signal. I may as well just use the TPS trick to send to signal for the ecu to run in open loop mode.

Jason

[exciv2000]

No, the map sensor CAN read boost, just that the ECU cannot, hence why the map controller senses the boost for the ECU, and changes the voltage to force the ECU into open loop mode. The map controller is basically a TPS trick, except that it has other goodies in it too like making your car run super rich under boost.

[CSMsi311]

So now it is just a matter of deciding how i should get my stuff tuned.

1.) J&S Ultra safeguard: makes sure i don't screw up my engine. also can pull timing as boost increases
2.) MAP controller or TPS trick
3.) Something to control the fuel. I like the SMC, but i think you have to run really big injectors.

Jason

[exciv2000]

TPS trick is cheaper, but map controller is better, and to control the fuel I'd recommend a V-AFC, as a lot of dyno tuners like to tune with that I've noticed. Also a Cartech 20005 FMU goes a long way in reducing the rich 5:1 rise rate of the JR FMU to something more respectable like 3:1 by completely replacing the JR FMU. Although I have the J&S ultrasafeguard, i don't have it pulling any timing at all with 8 PSI... It's nice to have if something were to go wrong like bad gas or change in altitude

[CSMsi311]

thanks for all the help scott. so you don't have anything pulling any timing?

i do have the problem of driving my car back home a few times a year. I did read about the Cartec 20005 FMU. I'll have to look more into it.

Jason

[exciv2000]

I have the cartech if you want to see it in action/ask questions about it. Nothing is pulling timing right now, although just a flick of a knob on the J&S will pull timing if I want it too... It's on 91 octane pump gas at 8 PSI with stock timing, and the map controller significantly helps in this dept.