Charlwood22 Posted May 25, 2020 Report Share Posted May 25, 2020 Hello - I'm a newbie on the forum so apologies if this is a repeat of anything already posted. I have a fully restored, rebuilt 74 CR PI that until today has been running really well. Started it today, fired first time as usual but noticed tickover was lumpy so checked injector hoses for a pulse and number 6 was dead - obviously had air in it so I bled it accordingly - few taps on the jar and I got a good spray cone- I put it down to hot weather and lack of use, although it has been started most weeks. I took it out for a decent run -I've just got to 3,000 miles so decided to drive it harder than usual today hit 5000rpm a few times and the car was fantastic but then on another hard acceleration the engine coughed, exhaust backfired and I lost power but didn't cut out. Managed to limp home but any revs over 2000 had backfires and no power. Engine ticks over OK and I have good pulses at all the injectors. Checked all obvious (to me anyway!) things like vacuum pipe, HT leads, and coil connections etc. Running a Prestige Bosch style pump, Metering unit injectors etc. new fuel lines and so on. Any suggestions of where to start looking would be much appreciated Quote Link to post Share on other sites
Mike C Posted May 25, 2020 Report Share Posted May 25, 2020 I'd start with checking the timing- make sure it hasn't slipped. Quote Link to post Share on other sites
John Morrison Posted May 25, 2020 Report Share Posted May 25, 2020 Distributor tight? and welcome by the way. John. Quote Link to post Share on other sites
foster461 Posted May 26, 2020 Report Share Posted May 26, 2020 Still using points and condenser ?. A few things you can check there and coils often go wonky only when they get hot. A warm welcome from me too. Stan Quote Link to post Share on other sites
John McCormack Posted May 26, 2020 Report Share Posted May 26, 2020 95% of the time it is ignition. In this case I would replace the condensor first. It causes exactly these symptoms and it is cheap and easy to do. I carry a few spare condensors in my 'TR' travel bag for the TR2s (my 6 has electronic ignition.) If that doesn't sort it the coil is next. I carry a spare coil in the boot so can just swap it over. Then distributor cap for cracks and the centre lead is OK. Replace the points if fitted. Plug leads then plugs. Another one is the alternator, sometimes the car will start and run but if the alternator isn't producing the electrons at revs it can cause these symptoms. It is unlikely to be fuel but if all the above fails start there. Do it one thing at a time so you can identify what has failed. Quote Link to post Share on other sites
Waldi Posted May 26, 2020 Report Share Posted May 26, 2020 Welcome to the forum and TR-tinkering. All of the above. If the distributor rotor has a rivet, replace it by a red rotor stamped with DD. It is from DizzyDoctor. The riveted repro’s are a known weak part. Waldi Quote Link to post Share on other sites
Charlwood22 Posted May 26, 2020 Author Report Share Posted May 26, 2020 Thanks for all the replies everyone! I have powerspark viper ignition coil and electronic ignition fitted - timing OK and distributer tight. Metred the coil today and both readings seem ok but as a start have orderd another one to see if that sorts it. 65 AMP new alternator fitted so would be surprised if thats at fault I have to find time to pull the plugs out but they are NGK Iridium ones and I will swap the HT coil lead as I have a spare. I will reply when I have found out more Thanks again for replying its much appreciated Cheers David Quote Link to post Share on other sites
Andy Moltu Posted May 26, 2020 Report Share Posted May 26, 2020 Suck on the vacuum pipe to the metering unit. A split diaphragm might explain things. Quote Link to post Share on other sites
John L Posted May 26, 2020 Report Share Posted May 26, 2020 Some of the Hall effect electronic modules don't like restive plugs, hope those iridium are not restive. Also only use silicone HT leads not wire ones. John Quote Link to post Share on other sites
John McCormack Posted May 27, 2020 Report Share Posted May 27, 2020 8 hours ago, John L said: Some of the Hall effect electronic modules don't like restive plugs, hope those iridium are not restive. Also only use silicone HT leads not wire ones. John John, I'm interested in this. I put an Accuspark hall effect in my TR2 and the car ran fine for about 4,000 miles. It then refused to rev above about 3500rpm, missing and carrying on. The supplier sent me a new one free of charge and we overhauled the distributor at the same time. Same problem. I put the points back in and problem solved. The car has a generator/dynamo and I believed that this could be the problem. The Accuspark apparently doesn't like the higher voltages that generators charge at. I didn't change the plugs or leads. Can you expand on the plugs and leads as an issue with hall effect points? Quote Link to post Share on other sites
John L Posted May 27, 2020 Report Share Posted May 27, 2020 If you go to the Accuspark site https://simonbbc.com/ its well explained, you have to read thru a bit though. You could also give them a call, I spoke to them yesterday for a kit for a MG TD. Hope that helps John Quote Link to post Share on other sites
RobH Posted May 27, 2020 Report Share Posted May 27, 2020 (edited) 3 hours ago, John McCormack said: The Accuspark apparently doesn't like the higher voltages that generators charge at. ???? The voltages are the same unless the regulator is wrongly adjusted. They are electrically noisier though because of the commutator and the contacts in the regulator. I believe these Hall-effect switches are very sensitive to radio-frequency noise so are rather picky about the HT side of the system. Hence the statements about not using copper leads and resistive plugs, the technical reasons for which are never properly explained by any of the makers. Edited May 27, 2020 by RobH Quote Link to post Share on other sites
John McCormack Posted May 27, 2020 Report Share Posted May 27, 2020 15 minutes ago, RobH said: ???? The voltages are the same unless the regulator is wrongly adjusted. They are electrically noisier though because of the commutator and the contacts in the regulator. I believe these Hall-effect switches are very sensitive to radio-frequency noise so are rather picky about the HT side of the system. Hence the statements about not using copper leads and resistive plugs, the technical reasons for which are never properly explained by any of the makers. You will find a generator will regularly charge at over 15 volts. Put your multimeter on it and check. I have seen over 16 volts with a low battery and a properly adjusted regulator. I was told afterwards that the system didn't like more than 14.2 volts. Quote Link to post Share on other sites
Charlwood22 Posted May 27, 2020 Author Report Share Posted May 27, 2020 John L thanks for the information - very interesting I have silicone leads fitted but I will have to research the spark plugs- I have not heard the term restive before but will later . I've got plenty to check out now! Quote Link to post Share on other sites
Mike C Posted May 27, 2020 Report Share Posted May 27, 2020 I use NGK BUR6ET resistive plugs out of consideration for people around me using car radios. I've never used my radio but my Pertronix Ignitor has lasted well. Quote Link to post Share on other sites
DRD Posted May 27, 2020 Report Share Posted May 27, 2020 12 hours ago, John L said: Some of the Hall effect electronic modules don't like restive plugs, hope those iridium are not restive. Also only use silicone HT leads not wire ones. John I would have thought it was the other way round - i.e. non resistive ones may cause interference with the electronic points? Quote Link to post Share on other sites
Charlwood22 Posted May 27, 2020 Author Report Share Posted May 27, 2020 John L thanks for the information - very interesting I have silicone leads fitted but I will have to research the spark plugs- I have not heard the term restive before but will later . I've got plenty to check out now! I'm using NGK BPR6EIX iridium plugs that have ceramic resistors according to the spec on the NGK website so I would assume they wont be interfering with the distributor I have discovered that the HT leads are Not silicone after all so will start by replacing those Quote Link to post Share on other sites
John L Posted May 27, 2020 Report Share Posted May 27, 2020 Basically they have to be the carbon string, not wire, and shouldn't have resister plug ends either, when I talked to Accuspark, I wanted to fit resister plug ends to stop a bit of radio interference but they advised not to. Their site is good with a lot of information in the small print. I have fitted many of their kits to lots of friends cars and my own and not had any problems. hope I haven't jinks it now. John Quote Link to post Share on other sites
Charlwood22 Posted June 5, 2020 Author Report Share Posted June 5, 2020 Thanks for all the helpful replies New silicone leads and ignition module fitted along with the tiniest fuel weep found on the Sytec filter has cured the problem Incredible what you learn owning one of these cars! Quote Link to post Share on other sites
Jctr6EFI72 Posted June 5, 2020 Report Share Posted June 5, 2020 Hello i have had in the past exactly the same symptoms on a porsche....after quite long search and some electric part replacement, looking further inside the engine showed 2 valve springs broken ...if it can help... Quote Link to post Share on other sites
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