Propane? - Toyota Yaris Forums

07stlYaris · 10-30-2013, 12:45 AM

Here's my thought. If I were to install my impco carb and vaporizer and the rest, could I run my Yaris on propane? The old trick was to cut the ground wires on all the injectors and basically add a switch. By allowing the ecu to signal the injectors but not allow the injection to occur would the ignition sequence still burn the propane being introduced? Would the ecu see an overpressure situation since the injectors would not actually spray? How can I fool the ecu into thinking the engine is running normally without gas but with propane?

CTScott · 10-30-2013, 07:08 AM

There is not a sensor for fuel pressure and the regulator ensures that it stays where it should. You would need to add dummy loads though in place of the injectors as the ECM does look for those to be present.

07stlYaris · 10-30-2013, 02:44 PM

So I should measure resistance across each injector or is there a range the ecu looks for? Second question. Is the ecu doing a preliminary check then forgets afterwards or is it constant? My thoughts have revised overnight to this. If I start the engine on gasoline but time the propane to come on and the gasoline to shut off as soon as the starter decides the engine is running (the joys of touch-start) could I set a relay to "pull" the ground from the injectors at the same time? Thanks CTScott for your initial response.

CTScott · 10-30-2013, 03:47 PM

Quote:

Originally Posted by 07stlYaris

So I should measure resistance across each injector or is there a range the ecu looks for? Second question. Is the ecu doing a preliminary check then forgets afterwards or is it constant? My thoughts have revised overnight to this. If I start the engine on gasoline but time the propane to come on and the gasoline to shut off as soon as the starter decides the engine is running (the joys of touch-start) could I set a relay to "pull" the ground from the injectors at the same time? Thanks CTScott for your initial response.

The injectors measure 11.8 ohms, so ideally you would want to use 12 ohm 2 Watt resistors. The ECM constantly checks and will go into limp mode if it doesn't see an injector.

For your start on gas, finish on LP, you could use two DPDT relays to switch between the injectors and the dummy loads.

07stlYaris · 10-30-2013, 06:02 PM

That was exactly my thought. I figure I could either trigger the relays off of the release of the starter or off of maybe a N/O pressure switch off of the oil gallery. (pressure closes that way if the engine dies it would open the circuit feeding the propane solenoid valve shutting off the propane flow) I'll update if this even works. Hopefully the carb can be cobbled to the inlet of the Blitz. Should be interesting running boost and propane. Gotta keep a close eye on AFR so don't end up cooking something.

Ha...Propane....cooking something... I just got it.

10-30-2013, 12:45 AM	#1
07stlYaris If Its Not Blown It Sucks View User's Garage Drives: 07 Yaris LB Meteorite Join Date: Nov 2011 Location: STL Posts: 117	Propane? Here's my thought. If I were to install my impco carb and vaporizer and the rest, could I run my Yaris on propane? The old trick was to cut the ground wires on all the injectors and basically add a switch. By allowing the ecu to signal the injectors but not allow the injection to occur would the ignition sequence still burn the propane being introduced? Would the ecu see an overpressure situation since the injectors would not actually spray? How can I fool the ecu into thinking the engine is running normally without gas but with propane?

10-30-2013, 07:08 AM	#2
CTScott ULTIMATE View User's Garage Drives: 09 5dr LB, 2x 08 3dr LB Join Date: Oct 2008 Location: USA, CT Posts: 13,460	There is not a sensor for fuel pressure and the regulator ensures that it stays where it should. You would need to add dummy loads though in place of the injectors as the ECM does look for those to be present. __________________

10-30-2013, 06:02 PM	#5
07stlYaris If Its Not Blown It Sucks View User's Garage Drives: 07 Yaris LB Meteorite Join Date: Nov 2011 Location: STL Posts: 117	That was exactly my thought. I figure I could either trigger the relays off of the release of the starter or off of maybe a N/O pressure switch off of the oil gallery. (pressure closes that way if the engine dies it would open the circuit feeding the propane solenoid valve shutting off the propane flow) I'll update if this even works. Hopefully the carb can be cobbled to the inlet of the Blitz. Should be interesting running boost and propane. Gotta keep a close eye on AFR so don't end up cooking something. Ha...Propane....cooking something... I just got it. Last edited by 07stlYaris; 10-30-2013 at 06:13 PM. Reason: Funny Thought

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10-30-2013, 02:44 PM	#3
07stlYaris If Its Not Blown It Sucks View User's Garage Drives: 07 Yaris LB Meteorite Join Date: Nov 2011 Location: STL Posts: 117	So I should measure resistance across each injector or is there a range the ecu looks for? Second question. Is the ecu doing a preliminary check then forgets afterwards or is it constant? My thoughts have revised overnight to this. If I start the engine on gasoline but time the propane to come on and the gasoline to shut off as soon as the starter decides the engine is running (the joys of touch-start) could I set a relay to "pull" the ground from the injectors at the same time? Thanks CTScott for your initial response.