Low gas pressure?

[Pedro_The_Swift]

Since the new regulator was installed the system has been faultless(all of 2 months:angel:)
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!:D
car runs faultlessly on pulp.

[p38arover]

What is the gas pressure?

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

[Pedro_The_Swift]

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]

The black exhaust confirms over fuelling.

Do LPG vehicles blow black smoke when overfuelling with LPG?

[Pedro_The_Swift]

Do LPG vehicles blow black smoke when overfuelling with LPG?

:o

I,, dunno.:angel:
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]

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]

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]

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]

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

[bee utey]

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.

[p38arover]

If I can't find it, the converter might get tee'd into the heater hoses instead.

That's how mine is.

[Pedro_The_Swift]

Yep,
drove into town this morning, took 20 kays to switch over to gas, started to miss, pulled the bonnet and cold regulator!

Bloody Victoria!!:p
The friendly gas man has given me all the tee's and pipe and clamps to redo the heating system.
I thought it might be a good idea to route ALL the heater water through the reg,, :confused:
I just cant see how ANY water circulation will happen using Tee's in the heater pipes.
But the gas man says no.

just waiting for the engine bay to cool,,
shouldnt take long,, got down to 5 (:eek::eek:)here last night,, only just 10 now:angel:

[p38arover]

I thought this had been discussed once before and the answer was to T off the heater circuit, not put it in series. I haven't done a search for it though.

[bee utey]

Some years ago I tee'd an injection converter off the P38 heater circuit and the result was a loss of heat output from the heater as the converter was a much shorter path and robbing the flow. I put a 6mm restrictor in the converter line to fix that one. Using 10mm hoses to the converter you might not need the restrictor. Full flow through the converter would be OK if the converter had large fittings and little restriction, older Commodores all ran full flow converters in series with the heater.

[p38arover]

On mine the converter is over on the LHS of the engine bay, the heater points are on the RHS so the converter has a much longer flow path. The heater core is approx 10mm diameter tubing on a P38A.

I've never noticed a loss of heat but then I'm not in a very cold climate.

https://www.aulro.com/afvb/images/imported/2015/03/1170.jpg

[Mick_Marsh]

Bloody Victoria!!:p..........got down to 5 (:eek::eek:)here last night,, only just 10 now:angel:
What do you mean? It's beautiful, fine and sunny. A pearler of a day.
It's a good job it cools off at night as it is quite warm during the day. I'm always looking for shade to stand in.

[loanrangie]

Do LPG vehicles blow black smoke when overfuelling with LPG?

No they dont so you cant use exhaust colour to determine if rich or lean.

Sent from my GT-I9300 using AULRO mobile app

[Pedro_The_Swift]

Ok, so all done.:banana:
it switched over to gas in about 2 minutes.:cool:
didnt miss a beat on gas into town(20 Kays to Hamilton) and back. Needs a small coolant top up before tomorrows trip.
That new hose you can see on the left fits great and connects easy as to the reg, the closer of the two runs down and forward in a loop to the new alternator earth strap, then over the rear of the alt, under the two accelerator cables and then down under the air inlet ducting.
The previous heating hoses (throttle body hoses) have been rearranged, the outlet from the middle of the block has been turned 180 deg to the drivers side (one accelerator cable bracket bolt needs to be removed so the hose can be turned--) and joined to the catchtank hose. nice.:cool:

[bee utey]

No they dont so you cant use exhaust colour to determine if rich or lean.
With respect, that's only true in a narrow band of mixtures. When there is a fault and you're way over rich then soot is the result.

[jsp]

It took me a while to work out my heater matrix was blocked, I am lucky to use the heater once a year.