Anyone know how the HFS-1 could be triggered by the map sensor from a Prosport boost gauge?

 

Can I assume the prosport gauge has a 0-5V output MAP sensor signal? If this is the case, the DDS3 can read it.

 

I found out that it is a 0-5v sensor. Unfortunately when I tap into the signal wire the boost gauge goes to zero and stops responding. Any idea what would cause this?

 

Are there any wires going into pin 17 of the DDS3? Other than the the comes from the 0-5V boost sensor?

 

No, there is only one wire connected to pin 17.

Also the instruction say to ground pin 17 to test the system. I've found that simply unhooking pin 17 from any signal causes the system to activate.

My DDS3 gauge takes 10 or 15 presses of the button before it turns on, is this common?

Thanks.

 

sounds like something isn't hooked up right or loose connection somewhere. the boost gauge also shouldn't stop responding when you tap into its sensor signal. the DDS3 should have a high enough resistance where it wont effect the signal wire. if you have a connection elsewhere that is incorrect, or not good enough, it can cause funny things to happen. i would double check your wires in the DDS3 box, as well as how good the connections there are. try using a dab of solder on the tip of each wire that gets clamped in the junction box. this will help keep loose strands of wire from wandering into the connections adjacent to them.

 

I went through everything and there are no wiring issues. I ended up tapping one of the injector wires and the system works perfectly. The Prosport gauges do not use a controller like other electronic gauges, that might be the reason they are more sensitive. I will try and solder the ends of the wires, but I don't see any stray strands sticking out.

 

a MAP sensor doesn't require a controller. it just requires +5V input, ground, and it outputs a signal (0-5V).

did you have the jumper on the junction box switched to the MAP settings?

 

Yes, it was set to the mps setting. The same wire, connected to pin 17 works fine when the jumper is set to pwm and the line tapped to the injector wire.

 

I'm having very similar problems trying to trigger my HFS-5 using my 3.5 bar AEM MAP sensor. Wired to pin 17. System activates at key on/motor off, and then once running it won't trigger even up to 23 psi gauge pressure. Haven't tried a voltmeter on the pin since I just can't manage that by myself in the car while driving.

 

If you guys like to send your controller to me, I can boost the output current capability for you. I can also send you a DIY circuit diagram how to do it - you need a solder iron.

 

Can you explain what the issue might be? I gather it has something to do with current?

 

Most in-circuit pressure transducers can only output a maximum current of 0.5mA at 5V (output) or similar to connecting a 10K resistor inline. If a third party device has an input impedance of 10K. You wil only read 50% of the actual signal voltage.

0.5mA, althought small but is plentiful for internal circuit works. The DDS3 draws about

By adding a operational amplifier between the third party device and the transducer, it will avoid signal amplitude loss due to loading. All operational ampflier has a minimum input impedance of 1M ohms, some have 100Mohm+.

1 Mohm draws 0.005mA at 5V (5uA)
100mohm draws 0.05uA at 5V (50nA)

Apply those impedances to the transducer with 10K output impedance:

1M will load the 5V down to 4.95V
100M loads the 5V down to 4.9995V

Most operational amplifies have any output impedance of 250 ohms or 20mA. It cost about 50 cent.