Third fuel pump in 7 month. Is the LPG at fault?

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kikovuk · #1 Post by **kikovuk** » Tue Aug 15, 2006 11:35 pm

Hi, I have a Vauxhall Vectra 1.8 SXi with factory LPG conversation. Since I bought it last year I’ve had numerous problems first with the engine management lamp and recently with the petrol pump. I’ve had it replaced under warranty beginning of February once, then mid April for second time and this morning after failing to start I was told that it is again the petrol pump(inside the petrol tank). Anyway the first two times the pump was replaced under warranty but today I had a call saying that because the pump was damaged by contaminated fuel it won’t be covered by the warranty. Apparently there was some green residue at the bottom with a very strong smell of paint which was the cause of blocking the pump and subsequently everything seized up. The last time the fuel tank was touched was in April when I had new pump fitted. Now on top of the bill for the new petrol pump they will need to replace the petrol tank which brings the total to around £740. Ironically I will have to pay for petrol tank and pump and I would hardly use them. Anyway after the shock passed I got myself together and called the warranty people to ask them is this normal to have 3 fuel pumps gone in 7 months. After explaining that I haven’t even put any petrol since April and I’ve been driving the car on LPG since then (have used only about 10ltrs) they told me that they wouldn’t know If I was telling the truth (it’s common sense that if you can pay 41 ppl instead of 95 ppl you will go with the cheaper option). At the end they agreed to send an engineer tomorrow to check the car and tell me if the will cover the cost. I don’t know what to do. I know that they will have to pay for it but I don’t how to deal with the garage. Has anyone experienced any problems with the fuel pumps when converted to LPG?

kikovuk · #2 Post by **kikovuk** » Tue Aug 15, 2006 11:37 pm

few more questions if you can help will be great. Does the fuel pump work nonstop even though I’m driving using gas, or does it stop after the initial 30sec-2min? I was thinking that if there is a fault with the cut off system of the petrol supply the pump might be pushing the petrol into the system an as it is closed it might be inflating it like a balloon and eventually will burn as it is working to hard? I have noticed (can hear if you get close to the petrol tank) that the pump is constantly wining. Any help will be appreciated. I don’t thin that the techs in Vauxhall know about the LPG cars.

lpg_auto_conversions · Wed Aug 16, 2006 12:15 am

The normal cause of fuel pumps burning out is the lack of fuel in the tank. The pump is cooled by the petrol when you run out of fuel the engine stalls and the pump stops how ever when you are runing on lpg the pump is running all the time you should keep at least 1/4 tank of petrol

kikovuk · #4 Post by **kikovuk** » Wed Aug 16, 2006 12:27 am

Hi, thanks for the reply. usualy keep the tank full so i dont think this was the cause. . Funnily enough previous time, in April the tank was full and when I got the car back it had less than ¼ left. Somebody forgot to put the extra fuel back (I was happy it was covered under warranty so I didn’t make a fuss and just refilled it back to full later that day). I personally think that the garage screwed up and don’t want to pay for the new pump. They are trying to get the money of the warranty company but they won’t have it as it will third time paying for the same job and as we all know they are a bit tight. I’m considering going tomorrow to citizen’s advice to see what my options are before getting it done.

richy_boy · #5 Post by **richy_boy** » Wed Aug 16, 2006 9:10 am

How comes you need 1/4 of a tank of petrol at all times? As long as your car doesn't suffer fuel starvation on petrol with that amount of fuel in, it should be fine running on LPG with such an amount - or am I missing something? It mystifies me why a relay isn't fitted as standard to LPG conversions to shut the pump off after it switches to gas on normal cars?! Granted, it wouldn't work on my car as it somestimes drops back to petrol when 100% injector duty is reached.. Is the problem due to the pump holding maximum pressure all the time when driving as no petrol is being used? (Forgive my lack on knowledge on how the injector rail system works) Rich

claicerrig · #6 Post by **claicerrig** » Wed Aug 16, 2006 6:15 pm

Richy I have had to replace 2 petrol pumps in mine since i had LPG installed. Its deffinatly fuel starvation caused by the low petrol level and sloshing around in an unbaffled tank . I know Sx are notorious for pumps going at around 70K but the wife admited that she run the car very low on petrol, then virtually drove nonstop from London to Anglesy via the Old A5 twice. Now on our Honda Crv we have driven that 6yrs now on gas to very low levels with no problem.But there petrol pump is external with a low tap off point in the tank

richy_boy · #7 Post by **richy_boy** » Wed Aug 16, 2006 8:08 pm

Yea, I can understand if you run it around with a VERY small amount in the tank, but 1/4 of a tank? Even on a race track I've not have fuel starvation with about 1/4 of a tank, so on the road I'd expect much less of an effect due to fuel sloshing about. As long as you stay away from the red I can't imagine you'd have a problem? Maybe I fitted my uprated fuel pump / feed pipe a touch lower than others then? I know Kev has gone through several on his 200sx too! Rich

kikovuk · #8 Post by **kikovuk** » Wed Aug 16, 2006 10:14 pm

Today I went to the garage to take sample from the fuel and to pick up the damaged fuel pump. I’ve taken a photo from the petrol tank compartment. It looks very cloudy and it definitely there is some dirt at the bottom which I think has caused the problem. My theory is that they never actually cleaned the tank before replacing the pump. If this is not the case I really don’t know where all this would come from. Any ideas? I spoke today with Vauxhall customer services and I was assured that I will get a call either today or tomorrow at the latest. Well today has gone and no attempt has been made to get in touch with me, maybe tomorrow who knows. I got estimate too from the vx dealership for £781. I’ve decided to get a quote from my local trustworthy garage too and was told they won’t change the tank just flush it which straight away will cut the cost with £400. Tomorrow will find out how much they will charge me but I’m sure it will be much less than the vx garage. I’m running out of options and I’m 90% sure that I won’t get it done for free. I’ve decided to get it done in the local garage and then I’m sorry to say that the car has to go. Shame about the 16 months warranty left, hopefully will manage to get it transfer to the new owner, unless there is some small print which will prevent me of doing so. Anyone wants to buy LPG Vectra?

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go_lpg · #9 Post by **go_lpg** » Thu Aug 17, 2006 9:05 am

Ritchy, The advice to always carry at least a 1/4 of a tank of petrol comes from myself and my site. Yes you are missing something. If you choose not to follow the advice, the risks are; 1. Less petrol will of course go straight to one side of a tank due to centifugal force, resulting in pump cavitation and eventual damage. 2. How many cooling systems do you think your engine has? The most common reply is 'One'. This is not correct. It has five. Your engine has (1) the normal liquid cooling system, (2) Removal of heat by virtue of engine oil to the sump (where the heat is lost to atmosphere by radiation) (3) Direct cooling due to airflow over the engine, (4) loss of heat through exhausted products of combustion and (5) REMOVAL OF HEAT FROM THE CYLINDER HEADS by virtue of the FUEL RAIL to the PETROL TANK. Your petrol tank is indeed a secondary radiator that you didn't know you had. If you don't beleive that, run 50 miles on gas and then put your hand on the petrol tank. If it is an internally mounted one its temp. will have risen significantly but remember that it has already lost a lot of heat that you will not detect. If you do not have sufficient petrol in the tank the temperature of the tank will rise more than it is designed to do, the tank will be less efficient at losing that heat because there is less direct contact between it and the petrol due to a reduced 'wetted' surface area. This would not only reduce the efficiency of the overall heat loss arrangements but cause a rise in the temp. of the pump itself which is designed to run cool, not hot.

go_lpg · #10 Post by **go_lpg** » Thu Aug 17, 2006 9:07 am

Best results for petrol tank heat loss are found above 1/4 full and that is the reason for the advice being a minimum 1/4 tank of petrol. This is also a good reason for not cutting the petrol pump off during gas operation. No circulation of petrol = No cylinder head cooling. Also note that submersible pumps rely on being 'wet' for lubrication of their bearings as grease filled ones cannot be used. Regards Steve <a href="http://www.go-lpg.co.uk" target=_top>www.go-lpg.co.uk</a>

bob · #11 Post by **bob** » Sat Aug 19, 2006 4:33 pm

What happens to a car that is continaully ran with less than a 1/4 tank of petrol. I know of a few people who do exactly that with vauxhalls that are petrol only they stick a tenner in it and drive around until they need another tenner's worth. I suspect that the real problem is that the pump is continually pumping the releif valve open and working to hard, because no petrol is being used. A solution would be to cut the power supply to the pump and re-route a heater pipe next to the fuel rail replacing the rubber pipe with copper tubing. To get 15mm domestic copper pipe to fit 16mm heater hose solder an olive on to the copper pipe and clamp behind the olive. I dislike LPG cars that run on petrol for starting because one of the major advantages of LPG which is no petrol wash on cold starts is negated. Plus cars use a surprizing amount of expensive petrol when on "choke" Bills of £781 for a problem caused by LPG makes LPG an expensive fuel. £781 buys a lot of petrol 781 litres more or less. Also the Vauxhall man who said that you may have been running on petrol and dirty tank is to be expected is talking out of his exhaust because I have seen many cars do 200k miles and the tank has never been cleaned and they are still on the same pump.

kikovuk · #12 Post by **kikovuk** » Sat Aug 19, 2006 8:25 pm

Hi, thanks for the comments. It is definitely not the quantity of fuel at fault as it has always been full. I think the garage is covering for their mistakes. I asked them to file a claim with the warranty company and they promised that they will on Wednesday. As usual nobody called me since, however after phoning the warranty company yesterday I discovered that the garage has told them that the tank lining has been melted and it has caused the pump to seize up. The warranty doesn’t cover the tanks so I couldn’t claim for it. Does anyone know if it is possible the lining of the tank to melt or dissolve, seems a bit weird to me.

go_lpg · #13 Post by **go_lpg** » Sun Aug 20, 2006 8:44 am

I have seen tank lining material fall off due to improper bonding to the tank metal but not seen a tank that has gotten so hot that the lining 'melts'. The thought of this is too scary to ponder! Of course, if the tank is plastic it will not have lining of any kind...... An intersting aside to petrol tank heating due to the cooling process I described earlier; Land Rover switched to plastic tanks at the end of the series 1 Range Rover production and found that as the tank warmed up it would 'belly' downward. The petrol pump was not then reaching the bottom of the tank. Their solution was to make the pump telescopic by virtue of a sliding pump 'leg' and spring loading it so it could move up and down as the tank was heated and later cooled. As all injection systems are designed to supply too much petrol and return the surplus to the tank under all driving conditions (thus ensuring that ample supply is always present) any releif valve is working when running on petrol only on an unconverted vehicle. This is not an LPG only condition.

kikovuk · #14 Post by **kikovuk** » Sun Aug 20, 2006 11:45 am

Hi, thanks for the reply, I will upload some photos of the pump and the tank to have a look. Thanks <img src="http://www.my90.co.uk/lpgforum/messages/898/3408.jpg" alt="tank"><img src="http://www.my90.co.uk/lpgforum/messages/898/3409.jpg" alt="">

bob · #15 Post by **bob** » Sun Aug 20, 2006 4:46 pm

absolutely right that the fuel pump always supplies more fuel than the engine can handle and therefore the extra must be retured to the tank vai the relief valve. But all the fuel is being returned all the time and this maybe enough to tip the balance and ruin the pump. At idle on petrol most of the fuel would be returned to the tank but 2 mins later the lights go to green and the car is reved and the engine uses more fuel giving the pump a bit of a rest. Then five minutes up the road the car is at idle again and when cruising the pump has a longer rest. I wonder what would happen if the car was left idling on petrol for say 10 hours would this ruin the pump, maybe it might. In any case Vauxhall fitted the conversion and therefore they are the experts and therefore they are responsible for the pumps.

go_lpg · #16 Post by **go_lpg** » Mon Aug 21, 2006 2:20 pm

Robert, The petrol pump will supply typically 10 to 20 times the amount of petrol required to run the engine at full chat. This is done to provide the cooling of injectors and some cooling of local engine areas. Some pumps will deliver a gallon a minute although thankfully there aren't many cars that use fuel at that rate! Note that the pump is running all of the time the engine is running and never gets a rest. It is also under LESS load when in recirculation than when any relief valve is closed. You can prove this easily by squeezing a petrol supply pipe - The pump will work harder against the restriction and will likely burn out earlier, whereas if the restriction is removed it will have to work less hard and cool down. This leads us to another cause of pumps burning out, e.g. blockage of the fuel lines or filters by debris or contaminants. I do agree that in the case of a VX car converted by themsleves they are liable for the whole car and all its systems. Where they will wriggle (they may be correct) is in the case of fuel contamination. A car that runs for 10 hrs. on petrol with a full tank will have a nice cool pump at outset as most of the petrol is being recirculated (it flows a huge amount) keeping it cool. Later, when there is only a small amount of fuel remaining (say a litre) it will naturally run a lot hotter as there is less petrol acting as a coolant and not wetting the tank sides for radiation. This is when the pump is most likely to burn out. Sort of proves my original point, for if you keep 1/4 of a tank of petrol at all times, the pump will not overheat.........

bob · #17 Post by **bob** » Mon Aug 21, 2006 9:43 pm

Bad design if by running low on petrol the pump burns out. I am glad that I have a Rolls-Royce which never fails to procede because it is properly designed and over engineered. And over weight!! BTW. It is not a good idea to idle any engine for a long period because weird things can happen. I saw a 20 litre diesel engine that hydraulic up and wreaked it self. because the water pump directed a fine stream of coolant at one small place on No1 cylinder liner and cavatated on that spot bored a hole through the wall and suddenly filled the cylinder with coolant. I didn't believe what I was seeing and it took many people and hours of discusionn before the penny finally dropped. What had happened was that the alternator was not charging and the driver was on a week end break so he left the engine running down a quite counrty lane for 2 days.

go_lpg · #18 Post by **go_lpg** » Tue Aug 22, 2006 8:46 am

Most things on cars are not designed to last more than 5 yrs at average mileages. The more downward pressure on prices (and therefore profits) by consumers and competition there is, the more likely it is that things are designed down to a limit and just (very just) do the job they were intended for. This used to be different for prestige cars like yours, the engineers of the time had the financial freedom to design the best part for the purpose. I'm not so sure that this is the case now. Interesting story on the Diesel.

bob · #19 Post by **bob** » Wed Aug 30, 2006 5:32 pm

Buy the petrol for your car from the same dealer who fits the pump. Keep the receipt. If the tank is plastic shave a slither of plastic off the tank with a craft knife and put the slither in a jar of petrol. I wonder if the petrol is attacking the plastic of the tank. Modern petrol is not "petrol" and contains lots of other stuff, maybe ethanol which is nasty stuff that can attack plastics. guessing here!!

woody · #20 Post by **woody** » Wed Aug 30, 2006 9:29 pm

Thinking outside the box here, does the engine run ok on petrol?? if for instance the fuel pressure reg was faulty this could result in a no circulation scenario which would massively overload the pump. In all the years i have been converting cars i have only ever had 1 pump fail and that was on a Lexus LS400, apparantly there was a manufacturers fault with them, unusual for a lexus i know.