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Fuel will definitely still come out with the vac lone removed from reg.

Perhaps that could solve the problems, spray car with fuel, light, turn 360 and walk away...

HAHAHAHA.

I think you meant 180.

I bet your fuel pressure regulator has a hole in the diaphragm and is sucking in extra fuel under vacuum. Remove the vacuum line from the reg as the car is running and I bet you fuel pours out. As a mechanic, I've seen this several times on Falcons and the symptoms are exactly as you describe. Also, I've seen gas systems that keep the fuel pump running, even when switched to run on LPG, (they just cut the signal to the injectors) so the rail would still be pressurised and the hole in the fuel reg diaphragm would still be sucking in more fuel.

This sounds spot on, the fuel pump does keep running when its switched over to LPG, when I took the manifold off to put some new injectors I found some large pools of liquid too, was still there after a few days sitting so not sure if it was fuel.

When It would start playing up was after cruising for a while and coming to a stop at traffic lights, then after flogging it for a few minutes it calmed down a bit but still rough. Im going to get a new reg to rule this out and see how it goes.

The last few days its behaved itself, ive got 15L/100kms on petrol and 17L/100kms from LPG, so its come down a bit and ive blocked the vacuum lines near the Map sensor which are the blow by return and fuel vapour lines.

I was a Ford mechanic for a few years. I've changed 6 TPS's in my time there due to a flatspot, cutting out, running rough. They tend to wear out right on the cruise spot, where it sits most of the time.

Check with a multimeter. Unplugged, check resistance from idle to WOT. If connected, probe & check voltage from idle to WOT.

In both cases of diagnosis, you'll see zero volts or infinite resistance when you hit the spot.

I couldn't get any volts or resistence with my tester but autoelectrician said on his tester it was showing response to the throttle, ive bought a new TPS just incase its playing games on me, It does seem to happen at right at that cruise spot where the

throttle is hardly open.

So will next replace Coolant sensor, TPS and fuel regulator and see how it goes. If still playing up will consider an exorcist or lighting it up and pushing it off a mountain.. lol

Some pics for those interested,

post-70965-0-47117600-1399078171_thumb.jpg

These are the Map sensors, the orange Map sensor is from my other Dedicated LPG ute ( Genuine ford, made in Germany), the blackish one from the tickford ( made in Italy), not convinced the tickford one is faulty but swapped it anyway,

post-70965-0-69990800-1399078312_thumb.jpg

Edited by AngryRB

Ive replaced the TPS but the coolant sensor snapped off and half of its stuck in the head still, unbelieveable place to have a sensor, can't get a spanner on it cause of the way it sits.

Havnt got round to the Fuel reg yet, all these sensors are eating my $$$ up, and its been running without any black smoke or stalling for about 500km's now, so for now just waiting and see.

The engine seems to have constant tappet noise and recently noticed some noise that occurs under load hot and cold, its sounds like in the cylinders, probably the start of piston slap , took the oil cap off while it was running and seems to be a bit of blow by, wondering if the blow by return (which ive blocked) could have been messing with the map sensor which sits close to it. funny how since I

blocked the blow by return and fuel vapour return it hasn't missed a beat.

  • 3 weeks later...

So I think I finally have the answer, Someone had got mixed up the Vapour line and the Fuel return line on the fuel pump,

The vapour line has a restrictor to stop fuel from flowing to the charcoal canister, which had a few hundred ml's of fuel in it when I pulled it off, so fuel was being sucked into the manifold and pooling there , when on light throttle

the vapour was causing overfueling and stuffing up the Map sensor probably. So finally got to the bottom of it, so anyone using a shitload of fuel , check the fuel pump was plumbed up properly.

last fuel consumption was around the 11L/100km, which is a big improvement, I wonder if the return line being plumbed into the restrictor was causing higher fuel pressure in the rail too but not sure.

thanks for everyones input and help.

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