Percy TR6 Posted October 9, 2013 Report Share Posted October 9, 2013 Took Percy on a little spin over the last couple of days - about 300 miles, mainly "highway" but a bit of stop/start town driving too. The first 150 miles were perfect. Car was running well and sounding good. Then I pulled over to go into a shop. When I started the car back up, it didn't sound as sweet as it had and when I pulled away it was distinctly lumpy. It felt as if it wasn't firing on all cylinders. However, as the engine approached 2500 revs, it seemed to come to life again. I checked all the things my simple brain could think of without going as far as dismantling anything - plug leads all seemed to be seated properly, the pipes going to the injectors were all pulsing in synch, the metering unit lever (the bit connected to the choke) was where it should be, oil pressure was good, temperature was good, fuel pump was whirring.... As I headed back up the A1 today, the symptoms continued. Cruising at 2300 or more, the car responded perfectly under acceleration. Pulling away from roundabouts and junctions it was still lumpy at low revs. What should I be looking at first? Quote Link to post Share on other sites
Peter Cobbold Posted October 9, 2013 Report Share Posted October 9, 2013 Points gap closed up? retarding the spark too much until c/f advance comes in. Modern plastic points cam followers can wear in a hundred miles or so unless a smidgeon of grease is present. Quote Link to post Share on other sites
cp25616 Posted October 9, 2013 Report Share Posted October 9, 2013 I presume you have checked all 6 injectors to see if they are spraying the correct 60 degree pattern. Its possible that when low revs are used one or more injectors might be "dribbling" which would not give good idling or low rev usage. When you give your car more revs there is more fuel required so the dribbling tends to go away and status quo resumes. Worth a look and should be easy to check. Alan Quote Link to post Share on other sites
Percy TR6 Posted October 9, 2013 Author Report Share Posted October 9, 2013 I haven't checked the injectors (injectors are new - refurbished - & have only been in a few months) but worth a look anyway. With respect to the points, Percy has electronic ignition so I'd assumed there wouldn't be any points to check? Steve Quote Link to post Share on other sites
cp25616 Posted October 9, 2013 Report Share Posted October 9, 2013 Hi Steve Re-cond injectors are exactly what they say on the tin. Original NOS items are far better but way way more expensive. Just because your injectors are a nice set of re-cons that does not guarantee success. I know I have been there more than once! I wouldn't be at all surprised if this was your problem. All the best Alan BTW I hope like me you are voting NO next year?? LOL Quote Link to post Share on other sites
Steves_TR6 Posted October 9, 2013 Report Share Posted October 9, 2013 I too think it's a fuel issue. Could be injectors, but being as the problem came on so suddenly I wonder if it's a blockage? The rubber fuel lines get eroded by unleaded fuel, have they been replaced? What fuel filter arrangement do you have? Steve Quote Link to post Share on other sites
Percy TR6 Posted October 9, 2013 Author Report Share Posted October 9, 2013 Thanks for the input guys. My levels of knowledge and expertise in these matters are limited to say the least but I do rely on my instincts a lot and my gut is screaming fuel (as in a problem with fuel in the car, not the fact that I am hungry!) I did notice that 5 of the injectors have nice shiny silver "elbows" connecting them to the fuel lines but one has an older rusty connector which also appeared to be damp - fuel I assume. Perhaps that's where I should start? Could the fact something appears to be leaking be due to the fact the injector is blocked? Is it worth sticking some injector cleaner in the tank? Or should I whip them all out and get them checked? With regards to the fuel filter arrangement....I must plead ignorance. It does have a Bosch pump and on of the things on my list for the winter is to become familiar with it, clean the filter etc. Perhaps I need to be doing that sooner? Steve BTW I hope like me you are voting NO next year?? LOL Absolutely!! Quote Link to post Share on other sites
Andy Moltu Posted October 11, 2013 Report Share Posted October 11, 2013 Check it it is injecting on all 6. New injectors may benefit from the little strainer that has long gone from most refurbed injectors (not been available for years) however don't expect a long life from new injectors unless they've had the seals replaced with viton ones. Check the throttles are properly balanced - it's amazing how rough they will sound and run low down when out of balance. Quote Link to post Share on other sites
Percy TR6 Posted November 26, 2013 Author Report Share Posted November 26, 2013 (edited) After all sorts of delays I finally got round to looking at the problem in a bit more detail. I re-checked the pulse of each injector pipe & discovered number 4 was totally dead. I removed the corresponding injector & did a spray test which showed no fuel at all coming through. I then disconnected the injector pipe from the injector & started up again - no fuel there either. I now need a bit of advice - is it likely to be an issue with the pipe itself being blocked or is it more likely to be in the metering unit? I can deal with the pipe but don't fancy pulling the metering unit apart! Steve Edited November 26, 2013 by Percy TR6 Quote Link to post Share on other sites
Steves_TR6 Posted November 26, 2013 Report Share Posted November 26, 2013 I'd try replacing that injector, number 4, with another. If you dont have a spare then swap no 1 and 4 and see if the problem moves to number 1 I suspect it will which indicates a faulty or blocked injector. when you swap the injectors its best to 'bleed' them, search on here for how but basically you want them pointing as upwards as possible so the air in the line works its way out, before you put them into the manifolds. steve Quote Link to post Share on other sites
peejay4A Posted November 26, 2013 Report Share Posted November 26, 2013 It sound a bit more serious than a blocked injector as Steve removed the injector from the pipe and still no fuel delivery. I'd PM Neil Ferguson for advice. He posts as k_raven_smith. Quote Link to post Share on other sites
Percy TR6 Posted November 26, 2013 Author Report Share Posted November 26, 2013 Good idea peejay - I got these injectors from Neil in May...well worth trying to pick his brains. That said, at least swapping the injectors could narrow it down to a single blocked injector so will give that a go too. Quote Link to post Share on other sites
Percy TR6 Posted November 26, 2013 Author Report Share Posted November 26, 2013 Good idea peejay - I got these injectors from Neil in May...well worth trying to pick his brains. That said, at least swapping the injectors could narrow it down to a single blocked injector so will give that a go too. Quote Link to post Share on other sites
flatlandsman Posted November 26, 2013 Report Share Posted November 26, 2013 OK have a go at this: You've removed the injector basically from the MU and there's no fuel coming through- brave move, but demonstrates that the injector is probably OK but fuel supply to it isn't. It's now worth removing the no 4 outlet union from the MU; shame it's no 4 BUT you should still be able to access it using the right size of Whit/BSF socket. See if you can purloin another union from someone else to replace it, if you can't then swap say no 1 outlet union (thats one the top of the MU at the front (the rear is no6) This will be easier to get at than no 4. Replace the no 4 union with the one removed from no 1 and similarly put the no 4 one back on to no1 outlet on the mu. Tighten everything up (don't replace the keeper plates for the injectors. Switch on ignition, leave for a couple of minutes and then attempt to start engine. Bleed injectors as required until hopefully there's a decent spray from at least nos 2.3.4.5&6 injectors. If so hey presto you've discovered the fault. I would also (as per the venerable Doctor M above) check the synchronicity (fine album by the Police!) of the individual throttle actuating rods. They must all 'crack' at exactly the same time, and they must close completely too. Hope this helps. Quote Link to post Share on other sites
Percy TR6 Posted November 26, 2013 Author Report Share Posted November 26, 2013 Thanks all for the input, however, the plot has thickened a little! I swapped injectors 4 & 2, expecting the problem to move to 2, but when I started the car it fired up first time & sounded quite healthy. I checked the pulse of each injector pipe and all were strong, so I took the car on a quick test run. I still don't think its 100% but it certainly feels and sounds a lot better. I've spoken to Neil, who suggested a few other things to try - which I will do as time allows - but for now I'm a bit confused to say the least! Steve Quote Link to post Share on other sites
RogerH Posted November 27, 2013 Report Share Posted November 27, 2013 Hi Steve, back to even more basics - is the pump performing correctly. Is the pressure correct etc. Roger Quote Link to post Share on other sites
Andy Moltu Posted November 27, 2013 Report Share Posted November 27, 2013 Blow the injector through with an airline or foot pump (an airbed adapter with the tip cut off enables you to shove it into the injector to make a seal makes this easier). It's not uncommon to get bits of debris getting into the injectors, particularly when newly assembled. Quote Link to post Share on other sites
wheeler Posted November 27, 2013 Report Share Posted November 27, 2013 Are you sure it is not an ignition problem? A few years ago I had very similar symptoms below 2500rpm I messed about with the injection system for ages all to no avail until a friend suggested ignition leads I bought a set of Luminition leads and that solved the problem. Hope this helps Bill Quote Link to post Share on other sites
marki Posted November 27, 2013 Report Share Posted November 27, 2013 Hi Percy Had a similar problem with a miss at low revs, chased it through the fuel and ignition system . Turned out to be the electronic ignition. I've got through three sets and now given up.....back to points and sticking with them. Good luck worth a try Mark. Quote Link to post Share on other sites
ijonsson Posted November 28, 2013 Report Share Posted November 28, 2013 Hi Percy Had a similar problem with a miss at low revs, chased it through the fuel and ignition system . Turned out to be the electronic ignition. I've got through three sets and now given up.....back to points and sticking with them. Good luck worth a try Mark. Hi, which electronic systems have you used. I've had some suspicions about mine (Optronic) from time to time this summer. Quote Link to post Share on other sites
marki Posted November 28, 2013 Report Share Posted November 28, 2013 Hi I've had a few, from cheaper up to ignitor. Have now given up, don't know what caused them to go. The symptoms were all different from the odd miss to missing at low revs from pull away. Now back on points and has never ran better.... Good luck Mark. Quote Link to post Share on other sites
Guest ntc Posted November 28, 2013 Report Share Posted November 28, 2013 The problem lie's in the amount of voltage they can consume Quote Link to post Share on other sites
Percy TR6 Posted November 29, 2013 Author Report Share Posted November 29, 2013 Hi all. Thanks for all the input & suggestions. The bottom line is, I'm not sure it's not any of the things mentioned but I am pretty it was a blocked injector. I've blown them all through & Percy now starts more easily, sounds happy & tick over and has a nice growl when revved. But, just to keep me on my toes, Percy moved the goalposts this afternoon. Straining to hear every beat of the engine as we drove along, I felt that all sounded well but there seemed to be a distinct lack of power. Pondering this as I pulled away from the lights I suddenly noticed that the throttle pedal had travelled about 50% before there was any reaction from the engine at all! Back home, with the engine off, I confirmed that with the pedal to the floor, the throttles barely moved. So, I guess I need to address that before worrying about anything else. Every day is a school day. :-) Quote Link to post Share on other sites
Percy TR6 Posted November 29, 2013 Author Report Share Posted November 29, 2013 (edited) Duplicate Post Edited November 29, 2013 by Percy TR6 Quote Link to post Share on other sites
lachouette Posted November 29, 2013 Report Share Posted November 29, 2013 We all know that with carburettor engines, 95% of the time its electrics. However with Triumph injection motors its the other way round. 95% of the time its fuel supply. And in my experience, the most frequent culprit is a blocked or stuck injector. I now run on carbs. It eliminates half of the potential problems. 0.5 problems = 2x trouble-free TR6 motoring. Simples! Andy Quote Link to post Share on other sites
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