Need to start on gas .. but worried

[ryncharlton]

Hi

The petrol pump has decided to fail on my v8 discovery.
its got a single point gas system which can be set to start on gas.. but ive also told this is dangerous especially given the fact its -2 outside at the moment.

Am i going to damage it starting it on gas .. to go get the new petrol pump fitted


Thanks - also would i need to pump the accelorator starting on gas from cold?

[rossko]

No and No.

If you drive really enthusiastically immediately after a cold start, there is a small chance of vaporiser icing before engine heat gets to it. In the real world, just start up and drive normally and there won't be a problem.

Different engines may start more easily with the throttle in different places, but pumping won't achieve anything.

cheers, Ross K

[jayc]

My disco never saw petrol for 2 years once converted. No issues with starting no matter how warm or cold it was.

Mine started easiest with a smidge of throttle but as Rossko says different vehicles will require a different amount of vacuum to draw the vapour through.

[mfd70]

I have also got a fuel pump problem, see my post about the omvl system, but I've got my S10 blazer started on gas OK, it needs to get a bit warm, just as the temp guage needle moves before driving as the autobox don't like it if the engine's not running right.

[junkcatcher]

I have just had a couple days on running on LPG only due to an in tank petrol filter module coming apart (not unknown on some model years of Rover 75), I found a kettle of boiling water over the vapouriser helps a lot when the temperature is close to or below zero.
A small squirt can of Eezistart also helps.

All fixed now ---- but it wasn't a pleasant job

[Gilbertd]

Out of interest, I assume yours is an injection system junkcatcher? Just goes to prove that it is possible not only on a single point system.

I've just changed my car to start on gas as I was using way too much petrol for my liking. I used a tenners worth in two weeks! Although it starts on petrol then immediately switches over to gas, on a cold start the cold start injector squirts vast quantities of petrol in. As I've been doing lots of very short journeys (taking wife to work), it's been going down at a far greater rate than I would like. What's the point in having a couple of gallons in there to get me home if I run out of gas and using it?

[junkcatcher]

Yes running Stag-4 sequential there is a 2 degree minimum setting switchover temp that can't be over ridden. Normally the system switches to LPG pretty quickly even on cold mornings but I have been toying with the idea of an 230 volt engine pre-heater for some time but the Kenlowe is too expensive. Last year an ebay seller was selling German units at about 80pounds but I can no longer contact the seller.

In the USA & Canada a lot of coolant pre-heaters are available but most are 110v which could be an advantage but they are also usually too large or the seller isn't willing to export.
However one US seller has silicone pad heaters which can be glued to the "oil pan" in various sizes in 12v, 110v and 220v. see ebay item 220287346801

I have also been looking at the the 12v coolant heater glow plugs used on some VW group diesels and the 12v fuel pre heaters used by the bio fuel groupies.

[bxman]

Junkcatcher

For what it is worth For the past month I have had a diesel glow plug installed in my thermostat housing apart for not finalizing the control system it works quite well. However there have been two occasions when I have forgotten to unplug it and after turning the engine off when I have discharged the battery and required a jump start.
It would appear that the water stop's it getting excessively hot. I was fully expecting that I would be replacing it the first time I forgot to unplug the temporary connection in the cigar lighter.
The Mk 2 with twin plugs in a spare stat housing is ready for installation once all the other important jobs are dealt with.
Has anyone modified a regular glow plug controller to give a time period of 3 or 4 minutes. or devised a suitable system that might help?

I am also looking for a suitable transformer as I imagine I could equally well use AC as a power source for preheating.

[Gilbertd]

Not being a diesel person, how much current do they draw? I could knock up a simple timer controlled relay in an hour or so but would a standard automotive 30A relay be up to the job or would it need something a bit meatier? The same question would need answering to know how to achieve a suitable AC power supply.

[rossko]

For what it is worth For the past month I have had a diesel glow plug installed in my thermostat housing...

Is that at the bottom on this car? For best effect, you should try to heat low down in the water jacket so as to get some convection going, but not so low down as to let heat escape to the radiator via the bottom hose.

[bxman]

cheers Girlbertd.
as far as I can make out
THE glow plugs draw about 20A each dropping to 12-15A as they warm-up
it will also very much depend on the voltage at the time. Initially there was a 20 amp fuse in the cigar lighter which lasted a while before it blew. I now have upped it to a 30 . So a 30amp relay would cope with one plug but probably not do 2 in parallel for more than a couple of minutes.

Thanks rossko I have explored the bottom input manifold and already messed up one of them . I am hoping to find one from another engine that has the necessary meat on it sometime soon.

16v pug/citroen 1.8l

[SimonHobson]

Is that at the bottom on this car? For best effect, you should try to heat low down in the water jacket so as to get some convection going, but not so low down as to let heat escape to the radiator via the bottom hose.

More importantly, if you stick it in the top of the engine, especially the thermostat housing, then the likely result is ... to heat just that bit of water, open the stat, and let the hot water out to the radiator.

Personally I wouldn't have thought a heater plug would do all that much good. It's under 200W for just a few minutes, so it's not going to do a great deal. It takes 4.2kW to heat 1l of water by one ˚C per second - so 200W is going to take 21s to raise 1l of water by just 1˚C. That's 3˚C/minute for 1l of water - my engine holds 'a few litres' of water and also surrounds it with a big lump of metal so I suspect 1˚C per minute would be generous

Also, I definitely wouldn't do it without a second battery and split charge system. This is the sort of thing that's needed when it's very cold - and that's when you least need to take charge out of your starting battery. A sit is, in the sort of cold weather we had recently I find I need to put the charger on occasionally to top off the battery.

[bxman]

Thanks for the interest my diversion has created

The glow plug is in the thermostat housing for the simple reason that it is intended to help in reducing the time of petrol running.
It was also very simple to fit once I had got hold of the 12x 1.25 mm tap.

I do not normally plug it in until after the engine has fired-up so all the heat generated proceeds directly to the vaporizer.

I do have a BRAY 240v bottom hose heater (which are sadly is no longer manufactured ) these are a cast iron elbow with what looks like an old fashioned electric kettle element mounted in the tube again not that easy to mount but it was very effective on my last car.

There is as Junkcatcher says the option of £245 +vat for the Kenlowe hot-start , with it's built-in circulating pump.
O.K. for some with both RR tastes and SPACE.

The big advantage of the glow plugs as I see it, is they take up so little room.

Once I have got it all correctly wired. I envisage the temp switch on the vaporizer should be able to disconnect the heater relay and so long as the engine is running there will not be any battery drain.

I could possibly drill and tap the sump to heat the oil from a mains powered configuration. Anyone got an A/C aluminum sump for a 1.8 Citroen going begging. Oh to have the TIME

Back the the OP what additional fittings do you need to get a fuel injected system to start in winter directly on gas apart from a nice warm engine?

[rossko]

Back the the OP what additional fittings do you need to get a fuel injected system to start in winter directly on gas apart from a nice warm engine?

The OPs question was about a singlepoint system. 'All' you need for that is the capability to gas-start designed into the controller. That would take the form of a means to force gas start, usually by setting the switch. In the case of Leonardo type systems, which usually expect to see some RPM before changeover, you may need to make software changes.
Some systems also provide a 'prime' function - usually when you key the ignition on and its set for gas start it dabs the gas on for a second or so to help starting. Not essential.

----

For a multipoint, its mostly down to software settings, You'd need to eliminate any "change after starting" delay, which isn't easy on many systems. You'd need to change the "minimum temp" settings, which isn't easy on many systems. You'd need to change the "minimum RPM for change" settings, which isn't easy ... etc. It all depends on the system. It's a doddle to persuade Prins systems to "changeover" during cranking and start on gas for example ; but practically impossible to get AEB systems to do it automatically.

However, some multipoints provide an "emergency override" in the form of holding the switch down or somesuch when starting.

For slave-type multipoint systems expect it to run like a pig while the petrol management is applying all sorts of unnecessary cold running corrections.

[billynoband]

I can't stop smiling thinking about all the ways my relatives used to use to stop their diesel lorries gelling up when I was a kid. Controlled fires etc.

[Gilbertd]

About 25 years ago I used to work in a place that had an overnight lorry park opposite. It was quite amusing on a cold morning watching the drivers lighting bonfires under their fuel tanks, not quite 'controlled' fires, more just a case of set fire to anything that was handy and would burn!

[mirajkc4p]

Out of interest, I assume yours is an injection system junkcatcher? Just goes to prove that it is possible not only on a single point system.

I've just changed my car to start on gas as I was using way too much petrol for my liking. I used a tenners worth in two weeks! Although it starts on petrol then immediately switches over to gas, on a cold start the cold start injector squirts vast quantities of petrol in. As I've been doing lots of very short journeys (taking wife to work), it's been going down at a far greater rate than I would like. What's the point in having a couple of gallons in there to get me home if I run out of gas and using it?

Hi Gilbertd,
Would u plse let me know what changes you made to start the car on gas. like yourself I make lot of short journeys. Mine is an injection system fitted with stag4. Thank you for your help.

[Gilbertd]

Most injection systems can't be made to start on gas, but older mixer systems can and that is what I have. It appears that Junkcatcher has got one of the very few injection systems that can be configured that way although whether the Stag can or not, I have no idea.

[rossko]

Search for 'Prius' for a Stag-relevant thread on minimising changeover time.

Have you read p.27 in the Stag manual?
"In order to start the engine on LPG ..... "

[colingel]

The good all days burning diesel below tank etc been there done that