JDexter Posted September 5, 2014 Share Posted September 5, 2014 Good afternoon, I have a 110 V8, 1991, standard carbs etc, nothing exciting. It's always been reliable and starts easily after standing a while. I took it for a 120 mile round trip recently and it started to behave as never before. 50 to 60 on dual carriage way, comfortably enough (well for my hearing anyway) and then it started to slow as if I applied the brakes. Then ran normally. On the way back I was overtaking a lorry and it just died on me so that I had to tuck back behind the lorry up the hill. The engine continued to run but with no response to the throttle pedal. Monday I had a 100 mile trip planned. This time it was even worse. I had replaced the sediment filter thinking it might have been dirty but it wasn't and there was very little sediment at the bottom of the can. This can be a difficult job to seal at first or even second attempts. Driving at speeds of 50, in prevailing traffic and it would be fine. Then it would cut out, coasting to a halt with the warning lights on. Started again easily, revved up easily and off we go. This happened so many times I very nearly turned back but unfortunately it was an appointment I had to keep. Leaving the site I called the breakdown company and they were pleasant but no good at all and the vehicle was recovered. Whether this is standard or not I don't know but the sediment bowl is fitted to the return flow pipe and some large air bubbles could be seen flowing back to the tank. I have removed the tank, extracted the sender and the pump but applying power to the pump produces nothing and concocting a bulb to the power connector has the same result. How does one check the power to the pump and the pun itself and is the cause of the poor running. All electric connections are fine. I have checked the distributor cap and the rotor arm and they look fine but how do I know if it's a fuel issue. Older style fuel pumps such as the Facet ones on S1V8s tick like mad until they start to pump fuel but at least they can heard working. Quote Link to comment Share on other sites More sharing options...
Team Idris Posted September 5, 2014 Share Posted September 5, 2014 Sounds classically like the windings in the pump breaking down. You get less and less fuel as the insulation breaks down as it gets hot. Then you let it cool and it runs again, but for less time every go. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 6, 2014 Share Posted September 6, 2014 Could also be coil, just so you are aware, they can behave similarly. Quote Link to comment Share on other sites More sharing options...
JDexter Posted September 6, 2014 Author Share Posted September 6, 2014 Thank you both for your suggestions. I am a little baffled that the pump doesn't not work when removed from the tank and connected back to the loom, perhaps this is designed to make sure that petrol doesn't go the engine when it's not running, possibly when in an accident. I will check the pump again by wiring it to a separate power supply. In addition, while the gauge will work, the sender doesn't send any information to the gauge so it appears that the tank is empty and the low fuel light is on all the time I suspect a new pump and new sender might be required. I will go down the fuel pump route first and then the coil. Thank you again. Quote Link to comment Share on other sites More sharing options...
JDexter Posted September 6, 2014 Author Share Posted September 6, 2014 An update. I disconnected the pump from the loom and applied power from a battery charger. Pump runs fine but I will bear in mind the comment about its performance when it heats up. Clearly there is a device to stop the pump working if the engine is not running for safety reasons in the event of an accident. Now what it looks like and where it is might be another story. I will try to locate another coil, I am one somewhere but where exactly is another matter. Quote Link to comment Share on other sites More sharing options...
Team Idris Posted September 6, 2014 Share Posted September 6, 2014 Ignition coil is bad for the same thing for sure. Those air bubbles are odd though. I wonder if the pick-up pipe is blocked. Dad had this once on a VW golf and a length of plastic swalf had got wedged up the pipe. I like having a fuel pressure gauge. Now I can tell what is going down Quote Link to comment Share on other sites More sharing options...
JDexter Posted September 6, 2014 Author Share Posted September 6, 2014 Thank you Team Idris. I do wonder why the sediment bowl is on the return rather than the fee side of the fuel system. The whole pipe system has been replaced, albeit temporarily, with flexible hosing until such time as the vehicle is rebuilt with a new chassis. I could try connecting a FACET pump to the system as that doesn't need the engine to be run or I could jury-rig the existing pump. Trouble is, the vehicle runs fine for about 3 miles before it starts its performance Quote Link to comment Share on other sites More sharing options...
ThreePointFive Posted September 7, 2014 Share Posted September 7, 2014 I had exactly this issue, though my engine would cut out more than lose power, in so much as the only reason it was still firing was the momentum of the vehicle in gear, if I put the clutch in then that was it. http://forums.lr4x4.com/index.php?showtopic=64678&hl= There may be a few ideas for you to look into there. In the end I've decided to rebuild my engine because of general age and mileage, though hopefully you won't need to. Quote Link to comment Share on other sites More sharing options...
deep Posted September 8, 2014 Share Posted September 8, 2014 When I first read this, I thought it sounded like a fuel pump issue. Then I remembered having the same symptoms with a fuel-injected Range Rover. Having spent a fortune on the wrong bits, the problem turned out to be in the distributor. Not the pickup, but the spinning part (can't remember what that's called, duh!). Fine cold, then very erratic after a few miles. If you could borrow another distributor, you'll know very quickly... Quote Link to comment Share on other sites More sharing options...
JDexter Posted September 8, 2014 Author Share Posted September 8, 2014 Good morning and thank you for all the helpful replies. I should have added the fact that I have an electronic distributor, no points, just a wheel with spikes (probably called a reluctor) and an amplifier on the side of the distributor. I suspect I might be wise to remove the distributor and try another, either points or electronic. I might change the coil too. I have the tank being sandblasted and will then re-fit with pump and possibly a new sender as the current one is as much use as an ashtray on a motorbike. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 8, 2014 Share Posted September 8, 2014 Oh in that case, add to the list ignition amp! (the bit bolted to the side of the dizzy) Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 8, 2014 Share Posted September 8, 2014 I was just going to say ignition amp too, they are a classic "gets weaker with heat then dies" kinda failure. Quote Link to comment Share on other sites More sharing options...
Tanuki Posted September 8, 2014 Share Posted September 8, 2014 Also check the oil-pressure switch: V8s often have a 3-terminal one. One terminal drives the usual "your engine has just seized" orange warning-light; the other 2 terminals are wired in the fuel-pump power feed to cut the power to the oil-pump if the engine stalls. If the wiring to these fuel-pump-feed terminals is defective, or the swithc has started to leak oil into its insides, it can cause all sorts of intermittent starting/running issues. Quote Link to comment Share on other sites More sharing options...
JDexter Posted September 8, 2014 Author Share Posted September 8, 2014 Thanks to all for your comments. Now I have quite a list of possible causes! Later this week, work permitting I shall start with the pump to see if it can run for a while before stopping. While doing that I can check the oil sender, change the coil (if I can find an alternative in my store of parts) and then the amplifier and oil pressure switch. Quote Link to comment Share on other sites More sharing options...
V8Pete Posted September 9, 2014 Share Posted September 9, 2014 Just to add to the potential problems, I had something similar on my V8 and found that the inside of some of the fuel lines was breaking down. Nothing came loose so didn't appear in the fuel filter (which should be on the feed not the return) but every now and again it would be starved of fuel. May not be the problem if your flexible pipes have been replaced recently but the higher ethanol in fuel nowadays cause problems with old flexible hoses. Quote Link to comment Share on other sites More sharing options...
JDexter Posted September 15, 2014 Author Share Posted September 15, 2014 Thank you all for your comments. Update. New fuel tank fitted and a new inline filter in the return fuel pipe. I, too, had thought that it should be in the feed, rather than the return but that's as it has been since I bought it ten years ago. I asked an auto electrician to attend thinking that he might be able to check the ignition amplifier which he didn't. We started the engine and it ran fine but it does tend to run hot, up to the orange mark on the gauge which he thought might have something to do with the problem. He checked the distributor a/retard but it doesn't move when a good, decent, suck is applied to the vacuum pipe. However, that's just a timing alteration not a cut-out matter. I listened to the fuel pump using the length of wood technique and doing the same we both agreed the pump was running fine, albeit when stationary. Disconnected the fuel pump and the engine ran for a while until it began to run out of fuel. It was suggested that the coil was on the warm side and that the cooling system was pressurised rather highly but the engine continued to run at a fast idle. Once the man had gone I sneaked off down some quiet country lanes and gave it about a 3 mile run. Fine for the first 1 1/2m then the engine slowed and refused to respond to the accelerator pedal. I carried on like that for a while and it seemed to pick up when I turned round to come home. Hardly an expedition but I have that 100 mile journey to drive on Wednesday and I don't want another 1st September performance. Something is causing the vehicle to act as if starved of fuel and the only thing I can think of is the fuel filter attached to the bottom of the pump. It wasn't clogged but after twenty odd years it's a little darker than it might have been when new. I thought I would really put my foot down and it accelerated in first gear, changed to second and all seemed fine until I had the un-responsive bit again. Back home and now £s lighter and no further forward. Quote Link to comment Share on other sites More sharing options...
Tanuki Posted September 15, 2014 Share Posted September 15, 2014 You say the engine's running hot - you could be getting heat-soak and so fuel-vapourisation problems. [Fixing the advance/retard would help reduce underbonnet temperatures - which can go way-high if the timing is off!] Also your fuel-filter fitted in the return pipe sounds odd. Are you sure you've got the feed and return pipes the right way round? There's meant to be a small-bore restricter in the return line - if the pipes are the wrong way round you'll have all sorts of issues! Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 15, 2014 Share Posted September 15, 2014 Yes, filter in feed is a must, not the return! Otherwise bits end up in your carbs... Quote Link to comment Share on other sites More sharing options...
JDexter Posted September 16, 2014 Author Share Posted September 16, 2014 Thank you to all those who have answered. I was about to remover the distributor, having found an external amplifier that bolts to it when I wondered if that should be checked first. I have other electronic distributors fitted to two EFi engines but they have wires leading to a remote amplifier, or the ECU. (Somewhere!) I will remover the distributor in a moment and replace the amplifier and see if that helps. Quote Link to comment Share on other sites More sharing options...
JDexter Posted September 16, 2014 Author Share Posted September 16, 2014 Well, I changed the coil and took it out. Even shorter journey before it kept fluffing, back home, coil hot. Change amplifier for one I had on the shelf. No good, engine does not even start now so that amplifier must be u/s. I have noted that the main hose from top of radiator is hot but the water in the header tank is cool. Quote Link to comment Share on other sites More sharing options...
JDexter Posted September 22, 2014 Author Share Posted September 22, 2014 Good afternoon,I have had an informative discussion with someone at Powersparks. The gold coil, with white top, fitted to my vehicle is the wrong one but it's been on the vehicle since I bought it ten years ago. I have ordered a new module and coil and will see how that proceeds.However, I managed to persuade the engine to run after I had removed the distributor to remove the old ignition module.This produced a rotor arm in the wrong position but after some checking I had the rotor arm roughly near 1st cylinder left bank. All well and good but I needed to rotate the distributor quite a few degrees anti-clockwise before it ran smoothly and I suspect rather further than it should be.A friend suggested that the distributor drive might have come out of position when removing the distributor the first time and when it dropped back it was a tooth out of place.The drive is male and the distributor female but as I don't have a pair of long nosed pliers that is long enough I tried to turn the shaft with a screwdriver and it goes round and round. Forgive my ignorance but having worked on Daimler V8 engines the drive to the distributor is from a long shaft that is driven by the camshaft and that drives the oil pump as well and the shaft cannot be rotated. Is the Rover V8 markedly different? Should I be able to rotate the shaft as much as I can? Quote Link to comment Share on other sites More sharing options...
Inigo Posted September 22, 2014 Share Posted September 22, 2014 My understanding is that you can (I certainly can on mine), I think it is even possible to drive the oil pump via the distributor drive to build up oil pressure after a rebuild before running the engine for the first time. Quote Link to comment Share on other sites More sharing options...
JDexter Posted October 8, 2014 Author Share Posted October 8, 2014 I thought I had fixed this problem. There is a PAC relay on the bulkhead. No idea what it is supposed to do as it's not connected to any other component. Two thin wires, one to the positive side of the coil and one to earth. One thick red to the battery area and one thick brown which ran down the side of the engine bay and to the output of the alternator. Very brittle and with broken insulation in places. I removed this and went for a test drive where everything seemed fine. Just return from another abortive trip. Kangaroo petrol performance, engine dying then reviving itself. I have replaced the amplifier and coil and will send the distributor, complete with leads and cap, to Powersparks for them to test later today. The only thing left is to change the fuel pump. The engine does tend to run rather hot but then it had done that before without incident. Quote Link to comment Share on other sites More sharing options...
JDexter Posted November 20, 2014 Author Share Posted November 20, 2014 I sent the distributor, complete with leads, to Powersparks and they ran it on their test bed. The distributor itself was fine but they did diagnose a poor earth on the amplifier and returned the set-up with an additional lead from the amplifier for me to run to an earth. Fitted the distributor, started the engine and it ran fine. Out on to the country lane for a test run and the dreadful mis-fire and kangaroo petrol had both gone. I did hope that the poor running might have been cured but after about a mile and a half the engine started to behave as if I had turned off the ignition. The engine did not respond to the accelerator pedal and I slowed to a halt. Engine kept running, although slowly but then it would speed up slightly, to its correct idling speed. It did this a couple of times, almost as if it had used all its fuel and had been waiting for the supply to be replenished. Now that I have changed the coil and amplifier, had the distributor checked surely the only other problem can be the fuel supply as suggested before. I would really like to have the vehicle back on the road, it's been insured constantly and re-taxed since August but without a valid MOT I can't use it. Quote Link to comment Share on other sites More sharing options...
Tanuki Posted November 20, 2014 Share Posted November 20, 2014 Are you sure the ignition controlled +12V power supply to the coil is OK? I've had symptoms like you describe caused both by a very poor connection in the LT wiring [corrosion had left only one strand of the wire to a spade-terminal available to carry the current] and similarly by a bad contact in the ignition switch which only showed up after the engine had been running for some time and the contact had heated-up. An idea: get an old sidelamp bulb and holder (you must have one lying around somewhere). Connect 2 wires to its terminals. Connect one of these wires to the + terminal on the coil, the other to a good earth. Feed the wires out the side of the bonnet and duct-tape the lamp to the bonnet where you can see it while you're driving. If there's any noticeable flickering of the light when your 'kangaroo' mode kicks in it means you're not getting a reliable 12V supply to the coil. Quote Link to comment Share on other sites More sharing options...
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