Running too cold on LPG

Mallard · 16-05-2012, 08:04 AM

I picked up an AUIII Futura duel fuel a couple of weeks ago and have noticed an issue with the LPG.
Most of the time it runs pretty sweet but on the trip home from work it develops what feels like a miss.

To make some sense of it, I drive from Wollongong to Sydney every day and on the trip home, going down Mount Ousley is a 9k roll down the hill where I don't use the throttle at all. I drop it in to 3rd (auto) and coast. Even then I need to brake occasionally to keep it around the 80k limit.

From what I've read LPG cars need warm coolant to help vaporise the gas. I expect by the bottom of the hill, the thermostat is firmly closed and the water in the system (apart from what is in the engine) is relatively cold. The heater certainly has lost a lot of heat.

In normal driving the thermostat sits between the N&O (Ford fitted the new one just after I got it). I replaced the plugs with NKG IGR5C13 plugs as that was what the NKG site recommended for both petrol and gas. Leads to be changed this weekend. I want to put a larger CAI and K&N filter in but am worried it might aggravate the problem.

I expect this problem to get worse as the weather gets colder unless I can find a solution.

Any help greatly appreciated.

Rambunctious · 16-05-2012, 08:22 AM

Quote:

Originally Posted by Mallard

I picked up an AUIII Futura duel fuel a couple of weeks ago and have noticed an issue with the LPG.
Most of the time it runs pretty sweet but on the trip home from work it develops what feels like a miss.

To make some sense of it, I drive from Wollongong to Sydney every day and on the trip home, going down Mount Ousley is a 9k roll down the hill where I don't use the throttle at all. I drop it in to 3rd (auto) and coast. Even then I need to brake occasionally to keep it around the 80k limit.

From what I've read LPG cars need warm coolant to help vaporise the gas. I expect by the bottom of the hill, the thermostat is firmly closed and the water in the system (apart from what is in the engine) is relatively cold. The heater certainly has lost a lot of heat.

In normal driving the thermostat sits between the N&O (Ford fitted the new one just after I got it). I replaced the plugs with NKG IGR5C13 plugs as that was what the NKG site recommended for both petrol and gas. Leads to be changed this weekend. I want to put a larger CAI and K&N filter in but am worried it might aggravate the problem.

I expect this problem to get worse as the weather gets colder unless I can find a solution.

Any help greatly appreciated.

Might be worth talking to your mechanical/gas people about fitting a higher thermostat to keep the water in the engine longer, hence it should get hotter.
I'm in Brisbane , never gets very cold here, and I recently dumped all coolant from my cars and refilled with inhibitor only.
Just my 2 cents worth.

mik · 16-05-2012, 02:09 PM

n and o seems to be normal operating temp for AU`s, mine does`nt have gas though , but that`s where mine sits , always has, in the old days (non computer cars) i used to change thermostats for summer and winter, i`d run a cooler one in summer and the hottest one i could get my hands on for winter to keep the heater toasty, but i`m of the belief that the thermo`s are ecu controlled on the modern cars and the tempreture is kept pretty stable,

as evidence to this some time ago when i had a big towing trip to do in summer i put a cooler thermostat in my vct , only to find the the ecu just changed the frequency of the fans and the tempreture stayed pretty much the same, however it did take a little longer to warm up.
i`d wait an see how the lead change goes.

all4fordau · 17-05-2012, 08:56 AM

Does the temperature guage move lower on your run down the mountain? My uneducated guess is maybe the wrong thermostat has been fitted to your car. The thermostats are different for petrol and lpg fitted vehicles. Lpg thermostats dont have the lower brass shut off that controls the temperature to the lpg converter and you need to check whether an lpg one was fitted or a standard one was fitted.
A possible check you can do is when you get to the bottom of Mt Ousley, pull over somewhere safe and see if the gas converter has iced up??? Even after a long down hill it should still be warm enough to avoid icing up. Also go to the LPG Forum on here as the guys here are the real gurus on all this stuff and should get you sorted. Dont forget to post back and let everyone know what you found.

Mr Hardware · 17-05-2012, 09:37 AM

yeah do what all4fordau suggests. check those two things.

Mallard · 17-05-2012, 10:59 AM

I put the dash in diagnostic mode last night going home. The thermostat rose to 92.0 and then sat on it the whole way home including the trip down the mountain. That temp seems fairly consistent with other numbers I've seen on here.

I hope they put the right thermostat in. It was done at the Ford dealer so you'd kinda hope they noticed the LPG set up.

I'll pull over tonight and have a look when I get to the bottom of the hill and see what it looks like.

Thanks for the suggestions so far.

Mr Hardware · 17-05-2012, 11:03 AM

yeah that sounds about right - i think from memory my diagnostics mode reports 86 or 87.

just because your motor is maintaining that temperature doesn't necessarily mean that your gas converter is receiving the warm coolant. also, how old is your gas converter? could it be shot?

Mallard · 17-05-2012, 11:33 AM

Quote:

Originally Posted by Mr Hardware

Also, how old is your gas converter? could it be shot?

The conversion was done in 2006 so I would think it should still be OK. Is there anything to look for when checking it?

mik · 17-05-2012, 12:43 PM

have a feel of the heater hose tempreture going into and out of the mixer, if the hose/hoses are cold you have a problem.

Mr Hardware · 17-05-2012, 04:18 PM

Well Mallard I had my Converter replaced in 2006 and had to have it re-kitted last year. So don't rule it out!

Mallard · 18-05-2012, 06:14 AM

Pulled over last night at the bottom of the mountain and checked the hoses. Nice and toasty warm. This weekend, I'll changed the leads and check the plugs to see if there is any fouling/damage. They are only a couple of weeks old so they should still be pretty pristine.

If that doesn't help, it might be a trip to Ford for an LPG service.

GK · 18-05-2012, 10:08 AM

Both my dual fuel AUs run between the "N" and "O".

I have only recently done a hose change on both of my AUs and replaced the thermostat on my SR.

I reckon check your thermostat. It's easy to do, just two 13mm IIRC bolts and pop it out for a lookie.

I'll almost bet that the temp range is correct, but the thermostat doesn't have an extra hole in it to allow the coolant bypass that the converter needs.

I'll take a pick of my old 92 degree thermostat for you to compare yours with.

If it's missing the extra hole, just drill one. Quick, cheap and easy enough to do in 15 or so minutes!

Stay tuned for the pic.

GK

GK · 18-05-2012, 10:54 AM

Hope these help.

You can see the jiggler pin on one side and the extra hole on the other. If your thermostat doesn't have the extra hole, drill one and see how that fares.

Cheers,

GK

Mallard · 18-05-2012, 12:42 PM

Quote:

Originally Posted by GK

You can see the jiggler pin on one side and the extra hole on the other. If your thermostat doesn't have the extra hole, drill one and see how that fares.

Thanks, I'll have a look tomorrow.

ps. Love the quote in the signature

GK · 18-05-2012, 01:18 PM

Quote:

Originally Posted by Mallard

Thanks, I'll have a look tomorrow.

ps. Love the quote in the signature

No worries! A look is quick enough to do.

GK

Mallard · 20-05-2012, 08:45 AM

Leads replaced and thermostat checked. It did not have the hole so I've drilled one. Running well so far but the test will be tomorrow night when I head home from work. See how it runs then...

Stay tuned...

atec77 · 20-05-2012, 09:18 AM

Quote:

Originally Posted by Mallard

Leads replaced and thermostat checked. It did not have the hole so I've drilled one. Running well so far but the test will be tomorrow night when I head home from work. See how it runs then...

Stay tuned...

If the problem continues you might need a converter de-wax and clean

GK · 20-05-2012, 05:32 PM

Quote:

Originally Posted by Mallard

Leads replaced and thermostat checked. It did not have the hole so I've drilled one. Running well so far but the test will be tomorrow night when I head home from work. See how it runs then...

Stay tuned...

Will do!

Hope it sorts out your problems though.

GK

Mallard · 22-05-2012, 06:53 AM

Couldn't do a proper test run last night. It was too warm outside and it was too slow a run down the hill. There was a radar gun at the top so everyone decided to cruise down the hill at 10ks under the limit. I'll try again tonight.

Having said that, so far she's running well. This weekend I'll drop a K&N hi-flow filter in and put an XR snorkel on when I can get hold of one.

Mallard · 22-05-2012, 07:36 PM

It was a good run home. It dropped to 87 deg by the bottom of the mountain. Warmed back up in k or so though. I might get another thermostat and drill a smaller hole in it for the colder months.

All good though. Thanks for all the help.

all4fordau · 22-05-2012, 08:44 PM

Thats good news. Thanks for keeping everone up to date with how it is going. Everyone on here loves to help when things start to play up, and they all really love to here the results of their help.

GK · 23-05-2012, 02:55 PM

Glad it's sorted!

Cheers,

GK