Hi,
I have MS1 V3 running a 2 litre Zetec. This is a dual fuel car set up conventionally at present, that is to say MS runs petrol, while a separate ECU (Stag-300 Isa2) piggy backs the Ms to run LPG. It all runs very well, in fact much better in all respects than it did with the old Ford EEC-IV ECU.
I've been aware of the possibility of running both fuels directly from the MS using table swapping for both fuel and ignition. I decided against this as the LPG ECU also handles Gas temperature and pressure correction as well as simple things like the LPG level gauge. However, this would not stop me having two sets of Tables, VE3 and Spark 2 for LPG. As I understand it, if I arrange for JS9 to be pulled low when LPG engages, I can select VE3, Spark2 or both.
Having done a bit of research, it seems to me that the Spark table is most critical for LPG as more advance is needed at low to mid RPM, while either less advance, or it needs to plateau sooner, at high RPM. VE is less of an issue and is handled anyway by the LPG ECU.
I've more or less decided to make the mods to pull JS9 low when LPG is on and first of all to only select Spark 2 from TunerStudio and leave VE alone for the moment. Once I have this working OK I might give more thought to selecting VE3 as well.
Does this seem like a reasonable approach? Does anyone have any other thoughts on the matter?
Thanks - Michael
LPG Petrol table switching
Moderators: jsmcortina, muythaibxr
Re: LPG Petrol table switching
Hi, Michael.
If I read your post correctly, you're running spark and fuel on gasoline through the MS, and spark-only (MS) and fuel only (Stag-300) when on LPG. If that's how you want to go, then have at it - it will work. I assume you're de-powering the gasoline injectors when swapped over?
If I read your post correctly, you're running spark and fuel on gasoline through the MS, and spark-only (MS) and fuel only (Stag-300) when on LPG. If that's how you want to go, then have at it - it will work. I assume you're de-powering the gasoline injectors when swapped over?
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QuadraMAP Sensor Module -- PWM-to-Stepper Controller -- Dual Coil Driver
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QuadraMAP Sensor Module -- PWM-to-Stepper Controller -- Dual Coil Driver
Coming soon: OctoMAP Sensor Module
TTR Ignition Systems
Re: LPG Petrol table switching
Yes that's the general idea, and yes, petrol injectors are powered down when on LPG. - Thanks Michael
Re: LPG Petrol table switching
An update for anyone who might be interested:
2.0 Litre Zetec
Dual Fuel: Petrol and LPG.
MS1 v3 Petrol Fuel and Ign, LPG Ign.
Stag-300 to control LPG fuelling based on MS.
Implemented planned change so now when it switches to LPG, either automatically at 50DegC or manually from the dash switch, Spark table 2 is selected.
I picked off 12v from the vaporiser solenoid (goes high when LPG selected) fed that through an Opto-Isolator to pull JS9 on MS low.
First, using Spark table 2, I got Idle right on LPG by increasing Ignition advance for best idle, then added an arbitrary 6Deg to all the original spark table settings in the cruise areas. and left the upper rpms above 3000rpm unchanged.
Because LPG burns more slowly than petrol at lower RPMs so more advance, up to an extra 10Deg may be needed. At higher rpms the burn rate increases so less advance is needed.
The mod works a treat, it has reduced fuel consumption and makes the engine much more lively. This addresses the shortcomings of most LPG conversions which only control fuelling but do not have any control over ignition. It might stand a bit more advance in the cruise, and overrun areas - but that's for another day!
I've also implemented the option to switch to VE3 for LPG, at this stage just to improve LPG idle slightly. On the whole the Stag-300 handles the fuelling side of things quite well. As stated earlier I would run the whole LPG side from MS, but the Stag-300 also takes care of Temperature and pressure corrections and runs the LPG guage amongst other things so its easier to keep it in place.
Why Stag-300? Its is an LPG conversion carried out some years ago when the car still had its Ford EEC-IV ecu.
Best Wishes - Michael
2.0 Litre Zetec
Dual Fuel: Petrol and LPG.
MS1 v3 Petrol Fuel and Ign, LPG Ign.
Stag-300 to control LPG fuelling based on MS.
Implemented planned change so now when it switches to LPG, either automatically at 50DegC or manually from the dash switch, Spark table 2 is selected.
I picked off 12v from the vaporiser solenoid (goes high when LPG selected) fed that through an Opto-Isolator to pull JS9 on MS low.
First, using Spark table 2, I got Idle right on LPG by increasing Ignition advance for best idle, then added an arbitrary 6Deg to all the original spark table settings in the cruise areas. and left the upper rpms above 3000rpm unchanged.
Because LPG burns more slowly than petrol at lower RPMs so more advance, up to an extra 10Deg may be needed. At higher rpms the burn rate increases so less advance is needed.
The mod works a treat, it has reduced fuel consumption and makes the engine much more lively. This addresses the shortcomings of most LPG conversions which only control fuelling but do not have any control over ignition. It might stand a bit more advance in the cruise, and overrun areas - but that's for another day!
I've also implemented the option to switch to VE3 for LPG, at this stage just to improve LPG idle slightly. On the whole the Stag-300 handles the fuelling side of things quite well. As stated earlier I would run the whole LPG side from MS, but the Stag-300 also takes care of Temperature and pressure corrections and runs the LPG guage amongst other things so its easier to keep it in place.
Why Stag-300? Its is an LPG conversion carried out some years ago when the car still had its Ford EEC-IV ecu.
Best Wishes - Michael