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Title: HPE VX fuel system Post by: tonylanciabeta on December 19, 2008, 11:39:55 PM From: Gkar0 Sent: 20/03/2007
I think I've got problems with lack of fuel to carb. There is a plastic see through fuel filter before the carb and it hardly has any fuel in it. When I giggle it the engine dies. I'm hoping this could explain my engine cutting out! Either that or an electric fault! Before I get my hands dirty, has anyone got a HPE VX fuel system diagram? Thanks, Tony From: GuyMayers1 Sent: 19/02/2008 I've had ally tanks welded before and the hero who did it attached the removed tank to a vehicle exhaust and ran the car for 20 minutes to get rid of any remaining fumes. Not that I wasn't still nervous..... Guy From: Omicron Sent: 19/02/2008 Yes, be very careful when dealing with fuel tanks. For major fuel tank reconstruction - eg rusty seams, we fill them with nitrogen which makes them safer to handle. Andrew From: Mikeymikemcmike Sent: 18 February 2008 From: Mikeymikemcmike If you can solder and weld it is possible to cut open the tank and re-solder the pick-up pipe to eliminate any internal air leakes. BEWARE: Make sure the tank has been completely purged of petorl and throoughly cleaned out with water first otherwise you will become part of an explosion... The pickup pipe is soldered to the tank at the outlet and also soldered to a bracket which holds it in place above the swirl pot. Unsolder these and you can remove it, resolder the joints and then replace it. After that weld the tank up where you cut it open! Mike From: Mikeymikemcmike Sent: 31/05/2008 Well the fule starvation problem is back again! I've had the car laid up over winter amd done a few jobs including new gearshift bushes. Today I took her out for a spin and unbelieveably the fuls starvation problem is back! Exactly the same symptoms as before: Judders then cuts out under load (i.e. going uphill) then can be restarted after a couple of minutes! Last year I changed the fual tank and fitted a new fuel pump and thought I had it nailed! I'm gutted! From: hutch6610 Sent: 01/06/2008 You sure its fuel starvation this time? I mean, have you come to a complete halt and checked to see if you have fuel in the carb? you will have to drive with the air filter set up removed to do this. When you come to a complete halt, open the bonnet up, manually (by hand) open and close the throttle and observe the fuel pumped out of the accelerator pump jets - do this about ten times because this part of the carb holds a fair bit of fuel. If it passes this test and you have fuel, then this is not your problem Possible this time have a faulty ignition amplifier - gives all the symptoms of a lack of fuel and yes in a lot of cases will start up after a few minutes. Just thought it's worth a try. From: Mikeymikemcmike Sent: 01/06/2008 That's a good idea. I'll try that next time it's not raining lol.... Something else that might be of significace is when I boutght the car there was a "heatsheild" (i.e. piece of metal lol) which has been installed on the radiator right where the carb is. This rad was beyond resurrection and I replaced it with a new one. I didn't re-fit this heatshield because I had no idea why it was there in the first place. So now I'm wondering if it was connected with this problem???? hmmmmm From: hutch6610 Sent: 01/06/2008 20:46 You had rain! Lucky you, been miserable overcast and humid here. Could have sponged down the bird crap on the car and let the rain do the rest. From what you describe somebody made a heat shield to stop the carb from getting too hot in operation. Doubt this would be the cause of fuel starvation - if that is what your car is/was suffering from. Do you have the inlet manifold temperature control gubbins installed and working? From: Mikeymikemcmike Sent: 09/06/2008 19:37 Yep we had rain! But it's the Australian winter isn't it now? Anyway: I tried your suggestion - checked the carb when I had come to a halt - nothing from the accelerator pump jets, and the fuel filter was empty. Took quite a while before I could full the fuel filter again and get home! So it's definitely fuel related and here's a few things I've noticed:- It only happens when things get hot under the bonnet - i.e. in hot weather with hot air passing through the radiator. In fact I could get it to die back home by leaving it running and letting the fan kick in a few times. Eventually it started to splutter and die- again virtually empty fuel filter. Here's the (possibly) interesting bit: When I pulled the fuel pipe off the carb inlet there was a great deal of "escaping gas" noise and general sputtering - it definitely wasn't nice cool liquid in there. So I reconnected the pipe and the filter filled up and the car started again. So: Is this vapour lock? It seems as though it might be to me - between the pressure regulators etc and the carb inlet? Mike From: pt68 Sent: 10/06/2008 10:06 Did you change fuel pump recently, see if there is a tight hose angle at the pump, happened to me last year. Peter From: hutch6610 Sent: 11/06/2008 Vapour lock - possible, never seen one before but there's always a first time. Its possible one or more of the three fuel regulators is playing about. Try first by checking the solenoid operated one - disconnect it and fit a piece of pipe and blow through. Cross the operating switch - sure its the one bolted to the top of the blower and you will here the solenoid click. No click means the fuse is knackered or the relay bolted to the wing is not working (corrosion or duff relay or knackered solenoid) The amount of fuel when hot or cold is controlled by this. Cannot remember which way it operates but i will check for you and post later! If this checks out by-pass it for the time being by leaving it out of the plumbing, you can reconnect it later. Try driving it and see what happens. Still no good? You are now left with two in circuit - a small black one and a larger metal one in that order after the "Y" piece. They must both be connected the right way round - just look closely they are labeled or have an arrow showing fuel flow direction Whats the fuel flow like after the "Y" piece, should be a pretty good flow? If it is - leave out the small black one and see what happens - it should run ok without it. If no difference (still giving a vapour lock) then it can only be the metal one. If you leave this out you will flood the engine because the float valve cannot cope with the pressure. Unfortunately without another to substitute its hard to tell if it is faulty but something is stopping the fuel from getting to the carb. Its almost impossible to diagnose a fault like this via the "web" From: Mikeymikemcmike Sent: 05/07/2008 Hi Hutch, thanks for the advice. Checked the solenoid valve: working fine. Bit worried about leaving out the black regulator - won't that mean very high pressure gets through to the rest of the system: Anyway I think I have a big clue as to what's happening. If I start the car and let it warm up 'till the fan starts to kick in, eventually I see air bubbles coming into the fuel filter. What happenes is gradually the filter gets more and more air in it until it seems to have no fuel in it at all. If I stop the engine and pull the feed off from the carb all this air spurts out at high pressure. Then when I reconnect the feed to that carb and start the engine the filter fills up with fuel. Then gradually the bubbles come through and fill the filter with air again. I assume this air is getting in before the fuel pump so I am going to check the hose before the pump. Mike From: hutch6610 Sent: 05/07/2008 14:25 Leaving out the black regulator was only to see if it was faulty but it was a last resort. If you are getting air coming from somewhere further up line from the pump (or perhaps the feed pipe from the tank) then it wont be necessary. Hope its the pipe and not the tank again. From: Mikeymikemcmike Sent: 07/07/2008 Hi, Well I checked the feed pipe from the tank to the pump and it looked ok so I decided to remove the tank (again!) and do a test. As you can see from the attached pic substituted a handy milk bottle for the petrol tank so I could see what was going on. Firstly I made sure the feed and return pipes were both well into the bottle so there was no chance of getting any air in. Running the car like this for a long time produced no air whatsoever in the filter. I then pulled the return pipe up so it was out of the fuel and therefore causing air bubbles in the bottle as the returned fuel poured back. I could see this air getting picked up by the feed pipe and sure enough after a few minutes the filter started to fill up with air. Before long it was pretty much full of air. This I think proved conclusively that the cause of the problem was air being drawn up from the tank. Having removed the tank I took the sender unit off and had a look around inside. What I noticed was that the pickup pipe had a ring of solder where it is supposed to be soldered onto the metal bracket that goes across the top of the swirl pot. What had happened is that this solder had become detached from the bracket and allowed the pickup pipe and the gauze filter to move upwards. There was a gap of about 1/2 inch between where the solder was and the bracket. What has happened is that because the end of the pickup pipe is now higher up in the swirl pot it disrupts the way the swirl pot works, allowing air to be drawn up by the pump. The interesting part is that this problem will only show itself once the overall level of fuel in the tank falls below the top of the swirl pot. So I de-soldered the end of the pipe from the tank outlet and then cleaned up the surface of the bracket, smeared some flux around the joint in the tank and got the blowtorch on the pipe inside (needless to say I had THOROUGHLY flushed all traces of petrol from the tank first!) . Then when everything was good and hot and the solder had meltet I pushed the pipe down and added some extra solder around the joint. As a result the pickup is now much lower and hopefully this will cure the problem! From: hutch6610 Sent: 09/07/2008 So after all that (tank again) problem sorted? From: Mikeymikemcmike Sent: 09/07/2008 20:55 I don't know yet I just need to re-paint round the fuel outlet where I desoldered it! From: hutch6610 Sent: 10/07/2008 22:46 ill keep my fingers crossed for you - and while i am at it sacrifice an offering to the Beta god. What do you reckon on Gordon Brown? |