Low gas pressure?

**Pedro_The_Swift** · 9th March 2015, 09:54 AM

Since the new regulator was installed the system has been faultless(all of 2 months

)
Towing from Ballarat to Hamilton it developed a miss only on gas. When switching backwards and forwards from gas to pulp it would take quite a while before the gas light would come on.The miss would start at roughly the same time (from switching) each time gas was selected, regardless of load. The LPG guy I saw in Hamilton Friday fitted new plugs and leads and checked the system with his laptop. Towing from Hamilton to Mount Gambier it took 25 kays to switch over from a cold start and then after a short while started to miss.
It really feels like low gas pressure.
But I am never right about these things!

car runs faultlessly on pulp.

**p38arover** · 9th March 2015, 10:26 AM

What is the gas pressure?

Mine has been faultless since I increased it from 0.74 Bar to 1 bar

**Pedro_The_Swift** · 9th March 2015, 01:38 PM

obviously it cant be low gas pressure as the system is designed to swap over to pulp when this occurs,, and that doesnt happen.
What has started to happen is the bad starting, again. (switch it off on gas and it starts badly, switch it off on pulp and it starts instantly, this problem dissappeared when the new regulator was installed)
The black exhaust confirms over fuelling.

Are there any tests that can be done on the coil paks in the car?

**p38arover** · 9th March 2015, 01:45 PM

Originally Posted by Pedro_The_Swift

The black exhaust confirms over fuelling.

Do LPG vehicles blow black smoke when overfuelling with LPG?

**Pedro_The_Swift** · 9th March 2015, 01:53 PM

Originally Posted by p38arover

Do LPG vehicles blow black smoke when overfuelling with LPG?

I,, dunno.

I just assumed the black was from the car when it was missing.
usually the pipe is, well, pipe coloured, (maybe a small rust stain?)

**Mick_Marsh** · 9th March 2015, 02:07 PM

I have had my converter (the bit that has the hot water passing through it) replaced about three times now. They fill with a wax/oil type substance.
I've never been happy with the way it runs on gas though. Maybe a good tune is needed. There are some gas installers out there who think they know what they are doing and even less that actually know what they are doing.

**p38arover** · 9th March 2015, 02:36 PM

Originally Posted by Mick_Marsh

I have had my converter (the bit that has the hot water passing through it) replaced about three times now. They fill with a wax/oil type substance.

Pull it apart and clean it yourself. Buy a new diaphragm kit and fit that at the same time. It's pretty easy to do. I think I took a series of photos when I did the converter I had on the P38A prior to fitting the injected system.

**bee utey** · 9th March 2015, 04:42 PM

I'm thinking the hot water supply to your converter isn't sufficient or its blocked entirely. It eventually gets up to engine temp from radiant heat and then chills and lets liquid LPG to the injectors. It would also then run rich and soot up the exhaust. Next time it starts missing, pull over and open the bonnet. Touch the converter carefully and see if its hot or icy cold. You could also have a faulty temperature sender on the LPG that's confusing the ECU.

**Pedro_The_Swift** · 9th March 2015, 06:17 PM

As far as I know its always been connected from the throttle body heater hoses (long time disconnected).

**bee utey** · 9th March 2015, 06:56 PM

Originally Posted by Pedro_The_Swift

As far as I know its always been connected from the throttle body heater hoses (long time disconnected).

I did a P38 that way myself last year, strangely the owner's recently reported similar problems with slow changeover. I wonder if its a function of a thermostat that's failing, it was all right when I fitted the LPG injection to it. I'll be looking for blockages when he comes in next week. If I can't find it, the converter might get tee'd into the heater hoses instead.

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