njc
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Posts posted by njc
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Interesting chat!
I swapped back to a Lucas pump and filter under the tank... The Bosch unit failed and left me stranded. It didn't seem any more reliable to me than the Lucas set up and had pipes and tubes in and out of the boot to the wheel arch. Went back to the original Lucas set up with all the mountings in the right place but driven by new positive and negative wires to the battery (with fuse!) and switched via a relay from the old wiring (relay also in the boot next to pump)
In hindsight, I wish I had fitted a fuel tap at the same time so I could drain/shut off fuel and work on the system.
I also fitted a coil over pump to try to keep it cool but it doesn't seem to get that warm! It's not let me down yet and puts the car back to original design. In my view, it is the Lucas PI system that makes the TR6 stand out from the crowd. So if it works why change it?
Neil
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Hi Alan,
Yes the fuel pump has both positive and negative wires back to the engine bay. I found the pump needed a good earth and I couldn't find a good enough path to negative in the boot so ran both wires back to the engine bay.
The voltage was fine - c. 13.7 volts at pump. I was conscious that I had abused the battery this last few years. Never left on trickle charged and used infrequently. Like you say if you can start the car and the load that puts om the battery then it is unlikely that a low voltage would cause the pump issues. It just wouldn't start in the first place.... I was just conscious that the wiring loom is 45 years old and I have had a few issues with it before. I replaced all the spades with new but often had to cut back quite a way to find copper rather than copper ore/dust! Even if the battery gives good volts there is resistance in the cable and it might be significantly lower by the time it gets to the pump.
I spent ages setting up the manifolds to be balanced using an air flow meter. Now having rebuilt the dizzy I can get him idling at 300-400 rpm like a sewing machine
Everything is well with the world again
I will fit new points and set timing at the weekend then he's set for summer 
Neil
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Hi Alan,
Yes the fuel pump has both positive and negative wires back to the engine bay. I found the pump needed a good earth and I couldn't find a good enough path to negative in the boot so ran both wires back to the engine bay.
The voltage was fine - c. 13.7 volts at pump. I was conscious that I had abused the battery this last few years. Never left on trickle charged and used infrequently. Like you say if you can start the car and the load that puts om the battery then it is unlikely that a low voltage would cause the pump issues. It just wouldn't start in the first place.... I was just conscious that the wiring loom is 45 years old and I have had a few issues with it before. I replaced all the spades with new but often had to cut back quite a way to find copper rather than copper ore/dust! Even if the battery gives good volts there is resistance in the cable and it might be significantly lower by the time it gets to the pump.
I spent ages setting up the manifolds to be balanced using an air flow meter. Now having rebuilt the dizzy I can get him idling at 300-400 rpm like a sewing machine
Everything is well with the world again
I will fit new points and set timing at the weekend then he's set for summer Neil
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Chaps,
I'm happy to report that my car now running fine. I think it was worn contact breaker points (could also have been condenser). The plastic arm looked worn and the gap was more like 0.6mm than 0.4mm. Other than that nothing else was obviously wrong.
I've put some grease on the cam to lubricate it and reduce wear. Having rebuilt, oiled and greased the dizzy, it also seems to be idling smoother too.
Thanks for everyone's help with this.
Neil
PS What to time it to? It's a standard CR 2.5PI with 40K on the clock. I use Octane booster other than that, normal everyday petrol. I can experiment but I would appreciate some guidance on roughly were I set the timing to.
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HI Steve,
I'm 10 minutes from Bury St Edmunds in Suffolk. If anyone is nearby and could lend me a hand I would appreciate the help getting to the bottom of this problem.
I took the distributor to bits and put back together last night. I checked points functionality with a mulitmeter. No shorts and electrically they work fine. Ran out of time to start the car and put the strobe on to check distributor functionality. Hopefully get this checked tonight. I found nothing obviously wrong though. The points gap was more like .6mm than .4mm but that was about all. The weights and springs appear to be working fine. Nothing is sticking. I swapped points and condenser with an old spare set I had (new set still on order) and got everything set to spec. ready to start the engine.
So, if car starts tonight and does not mis-behave it must be points/condenser. If still a problem then I think I need to check voltage at pump and (if I can) the pump pressure. I am wondering, when car is at low revs the alternator voltage is lower hence voltage at pump lower and this might make fuel pressure too low and starve engine of fuel. BUT I know this is fed with modern thick wire from battery terminals (via fuse) to a relay in the boot. It should be fine but I will check it out. Maybe the relay contacts have some resistance and the pump is under voltage or something....
A pressure gauge on a T connector would be a good test of the pump pressure with respect to engine RPM.
I'll follow up tomorrow...
Neil
Neil
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Alan,
Looks interesting. Where/how do you mount the sensor? I am assuming at the entry to the metering unit. I guess it is an old imperial thread and will need some in line adaptor to make it all fit. It would be nice to have this on the dash board but the ones I have seen had the fuel measured direct at the gauge - meaning 110psi petrol at the dashboard. This put me off doing it.
If a sensor could be fitted in-line and left in-line and then a simple electrical connection to a gauge; This would be really nice. It could be a permanent dash fixture or a quick connect to a diagnostic gauge.
Anyway.... I'll check the electrical system first. That's the likely culprit but I have always wanted an easy way to measure fuel pressure to check the pump and PRV are working effectively. I might look at this at some point in the near future.
Neil
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Hi Alan,
Thanks for that snippet of info. I'll check this. It was balanced quite well prior to this problem. I had an air flow meter on each inlet and have set the linkages as best I could (it's a pretty rubbish set up. Not one of Triumphs finest engineering masterpieces!). But it did idle pretty well. It was a while ago since I last looked at it so something may have slipped last week. It was fine one minute then has been running badly since then. I can start the car. Keep revving it and it sounds right. The moment I leave it to idle it starts to miss a beat. It tries to keep running but something is wrong for sure. It's missing a beat (but injectors are firing - hence me feeling it is electrical). Eventually it stalls - possibly after 30 seconds or so.
I'll check the linkage out.
I think its electrical but I am a bit stumped since I have yet to see what is causing it. New coil (new coil wire feed from fuse box and see a steady 12V with a meter on the coil wrt chassis when running), new rotor arm and cap. Leads and plugs fine. I'll check points, condenser and distributor movement tonight then move on to throttle linkage.
I guess if I draw a blank then it must be the fuel system. Need to measure the fuel line pressure but need to get hold of a kit to do it. Is there anyone in Suffolk that could lend me one?
Neil
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Good idea on the timing gun - didn't think of that!
above 1500rpm it revs but doesn't really pull that well. i.e. higher revs masks the problem but it is still there.
I'll check the points tonight. I don't think they have slipped. I had a quick look with the cap off and all looked well but will need to rock the engine to see the point move to check the gap. I'll report back later
Thanks for the tips!
Neil
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HI Mike,
Yes choke lever fully back. Its like electrical power is being cut briefly before being restored. I think either the distributor is sticking in a certain advance and missing the timing of the piston or the power feed to the plugs is being interrupted briefly. The LV feed to coil is fine. Need to check points and condenser still but I do not think they are at fault. I'm really struggling to put my finger on the fault.
DIzzy cap and rotor are fine (distributor doctor red rotor). Leads and plugs also fine. Coil is a flamethrower 3 ohm unit fed from 12V feed (non ballasted)
Fuel system is a newish lucas system. I can hear a trickle of fuel back to tank so I think pump and PRV are fine. It must be electrical but I can't find the issue! A process of elimination as so far drawn a blank. That's why I am beginning to think distributor advance is sticking.
Neil
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HI,
My TR6 CR series is playing up. It start fine but soon starts to idle 'lumpy' as if its misfiring but trying to keep running. I don't think it is fuel starvation but I am keeping an open mind....
I think its electrical but wanted some advice on what to check. I have already checked plugs and leads and measured voltage at coil (12.2 volts) when running.
I have yet to check points gap and condenser but I believe they are fine. (Next job on the path to working out what's wrong)
Question: Has anyone had issues with a sticking distributor? Weights sticking or advance plate sticking? The engine starts fine but soon starts to play up after revving the engine.
I think it is electrical but it could be fuel pressure or blocked return line/breather pipe perhaps or even fuel metering unit? I can feel the injectors pulsing strongly and the pump and PRV are pretty new so I think it is unlikely to be fuel related.
I think it is an electrical problem but what do you think?
The electrical gremlin might have been around for a while but I do so few miles year to year it might have just been hidden when I thought I had performed a 'fix'. I swapped out the electronic ignition (Ignitor) back to points when the electrical system last played up (~ 2 years ago). I found at the time that the ballast resist wire was reading low (I think the wire was tired!) which meant higher current (V=RI) delivered to the Ignitor unit which I think caused it to fail. I think it damaged the Ignitor in the process. When diagnosing this fault, I replaced with standard points, swapped the coil and fed from 12V (from the fuse box) bypassing the ballast wire in the loom. All has been well for a few years but yesterday the electrical gremlin resurfaced. It feels like the same issue!
I am wondering if it is a problem with the distributor mechanical parts sticking (infrequently) causing the misfire? I can rev the car and it runs fine but left to its own devices the tick over gets lumpier and lumpier until the car stalls. Has anyone experienced the same problem? I was going to take out the distributor and take a closer look but before I do, I wanted to know if anyone else has had a similar experience.
Any ideas?
Many thanks!
Neil
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Could be coil voltage. >4000rpm it starts to reduce in output. Try standard points and wire coil direct to 12 volt (assuming 12 volt coil)
I had similar issue with electronic ignition and balasted coil plus tired wiring. When revving above 4000 rpm power faded
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Hi Chris,
I agree the wiring to the coil is the problem. The initial problem started with low volts at the coil (causing a reduction in power after 4000 rpm). I measured the voltage at the coil with the ignition on but the engine not running and got approx. 5V. This problem occurred at or a few days after replacing the old starter motor with a new high torque motor. It could be a coincidence but I suspect they are related problems.
Regarding the petronix ignition, if it is fed by 12V constantly I agree it wouldn't give issues with the higher 12V voltage on starting but when coupled with a 1.5 ohm coil used in ballasted systems it would mean the coil would draw more current (I=12/0.5=6A as opposed to I=12/3=4A) which could damage the petronix unit if running constantly and also potentially cause the coil to breakdown since the high voltage side would be significantly higher. It is normally 40 000Volts in a ballasted system when running but with 12V feed could go as high as 60 000 Volts (normally only for a few seconds when starting). Running in this 60 000V mode constantly, it will get hot and potentially breakdown the insulation in the wiring between the primary and secondary windings and cause the coil to fail.
My ignition circuit is pretty standard and unmodified other than this wire not being connected to the starter motor. Reading Bruce's description of the wiring then if I have left the 12 feed to the coil (on starting only) disconnected at the SM then the coil would be fed with 9V during starting and normal running.
The things I know:
1. 12V non ballast feed disconnected at SM. Car ran ok for a week or so.
2. Coil voltage measured at ~5V causing low voltage above 4000rpm to spark plugs and lack of top end power (coil efficiency drops after ~4000RPM) - First problem
3. Bypassed ballast feed and fed coil direct from 12V. This fixed 4000rpm problem but soon after (<20 miles) Petronix failed - Second problem
It seems to me that the Petronix failure is to do with the wiring; The ballast wire cannot deliver the required current and the voltage is thus low at the coil and hence the current high. I have changed the spades to make sure they are not corroded but the copper is very dull and I had to strip it back a way to get away from the green oxide. The Petronix failed due to too much current draw.
This could possibly be due to ageing wiring loom but coincided with SM swap so makes me wonder if it is to do with the disconnected wire at the SM. Perhaps the best explanation I can come up with is, when starting the car and cranking the SM, this pulls the battery volts down and the result is the ballast wire feeding the coil is feeding more current during starting, the result being a cooked and ageing ballast wire.
My solution I think is to fit a 3 ohm coil, standard points and a direct 12V feed from the white ignition wire. No ballast and a simpler ignition system. With the new SM in place starting is not a problem.
I have not used the car for 6 months since I was concerned it would let me down. Hopefully when the new 3 ohm coil arrives in the post I can fit it and be confident of a reliable car and use it regularly.
Thanks Bruce, Chris for all your comments.
All the best
Neil
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Thanks Bruce! That makes a lot of sense. I will check my car at the weekend to see what I have done.
Cheers
Neil
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HI,
I have a 1974 CR series TR6. It has a ballasted ignition system.
Does anyone have a procedure to check it? The wiring on my car is now quite old and some of the copper is turning back to copper ore! I want to be sure it is working properly. I have also fitted a new high torque starter motor and I wonder if I have managed to disconnect the ballast system and am now feeding the coil with a constant 12V feed rather than the lower 9V when engine started.
Can anyone explain where the ballast wire connects? I don't think it is directly at the coil. Is it connected on the alternator and switches in once the car starts off the battery? i.e 12V supply from battery to start and 9V supply from alternator to ignition system? What about the other end of the wire?
The 74 series car seems to do something different with the ballast resistor connections than the later cars, or so the wiring diagrams seem to show but it isn't too clear. It seems to be linked in with the starter motor. I changed the starter motor last year to a new high torque one that only had one connection on it. My old one had a smaller white and red wire attached (which is now disconnected) as well as the thick battery feed wire.
I am wondering if this wire is needed to make the ballast circuit work correctly. Since I changed the starter motor although the car now starts well I have had no end of trouble with the ignition circuit. The electronic ignition died (Pertronix system) so I am now back using points and wondering if this small wire that connected to the SM actually needs to be connected some how.
NB there are three wires going to the original starter: The main think battery cable to power the motor, a smaller wire to engage the motor and a third white and red wire. The latter is not connected any more with the new starter.
Any advice greatly appreciated!
Neil
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Thanks chaps!
I'll get a 3 ohm coil. The 1.5 ohm coil as I suspected is too low a resistance so the current drawn through the ignitor will slowly cook it. If 3 ohm works fine then I prefer the longer lifespan of a lighter loaded ignitor.
Neil
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Hi Paul,
I thought it would be the other way around i.e. the lower coil resistance causing the Ignitor to fail.
You have confirmed my suspicions though! I think a 3 ohm coil is in order. A shame since my coil is nearly new!
Neil
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Hi Chaps,
A quick question regarding my 74 CR series TR6
I have been having trouble with the car misfiring over 4000 RPM. I have traced it down to low voltage at the coil.
I think the problem is to do with the ballast resistor wire - a special wire that is 1.5 ohms resistance. The wiring is a bit tired and I measured only 6.5 volts at the coil. I have now bypassed it and run a red wired direct from the coil to the white wire (switched 12V) on the fuse box. It now runs really well and pulls right until the red line without a misfire.
My questions:
I have a pretty new Flamethrower 1.5 ohm coil and an Ignitor 1 electronic ignition system fitted. I am worried about damaging the electronic ignition.
Has anyone had any issues with a 1.5 ohm coil and ignitor 1 system running without a ballast resistor? The Ignitor manual says that it is ok to use a 1.5 ohm coil with it if the engine is a 6 or 8 cylinder unit. However, I suspect it is at the top end of what the Ignitor can do.
Normally non ballasted systems have 3 ohm coils not 1.5 ohms. A 1.5 ohm coil will output a larger voltage/ bigger spark. The electronic ignition will have to handle twice as much current for a 1.5 ohm coil than it would for a 3 ohm unit. I don't particularly want to buy a new 3 ohm coil since the one I have is pretty new. I just want to have confidence that the electronic ignition is not going to fail and leave me stranded.
Anyone had a similar experience converting from a ballasted ignition to a non ballasted with electronic ignition?
Cheers,
Neil
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Brilliant! A lot of work has gone into this. Well done!
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Mike,
Save your money and get the Lucas reconditioned.
All the after market replacements are no better than the Lucas. My car had a Bosch and it lasted just about as long as a Lucas so fitted the Lucas back. The mods to make it work with extra filters and plumbing around the bottom of the tanks are not worth the effort. The wiring also needs updating and relays fitting to cope with the excessive current used by the Bosch pump.
Fit a cooling coil around the Lucas pump and get it reconditioned and you will be fine for another few years.
Neil
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Hi Vegard,
I fitted B&B 5+ years ago and haven't had any issues yet,
Some pointers from my experience:
Double up the bushes on the cross shaft. There is just enough room for two per side rather than one. Definitely use a bronze bearing carrier that isnt pinned so can rotate. I don't think it is necessary to have a return spring on the slave cylinder. Also use an uprated pin between cross shaft and fork. Might also be worth putting in a roll pin 90 degrees to the pin for extra strength. Breaking pins are common failure modes. On reassembly, make sure you align the box with dowels or drill bits in the locating holes before doing up the bolts. Slightly misaligned it will reduce the life span of the gearbox and or clutch! Oh - also align the clutch plate with the special tool so it is central on the fly wheel.
I would use a clutch kit as a complete set and not use a mix and match solution.
Hope of some use
Neil
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Sorry in earlier posts I mentioned 1974 wiring diagram. It is in fact the 1973 diagram!
Sorry for the confusion!
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Hi Chaps,
An update on the starter motor swap and misfire problem..... Its gone away so I assume it is not starter motor related. Possibly warm fuel? I'm not sure what it was but I took the car out early this morning and it didn't skip a beat.
The wiring must have been modified from the '73 TR6 wiring diagram. The yellow wire at the starter is now disconnected (I taped it back into the loom) but the coil still has power. My coil only has the yellow/white wire fitted to the +ve (there is no ballast wire fitted). I still need to check if I have a ballast coil or a regular coil or if a ballast resistor is used instead of the ballast wire. I have had a good look and I can't see a resistor.
I would like to see where the coil is getting its 12V feed from.
I also can't see a starter relay so I assume there isn't one. The only relays I have are for the horn, the fuel pump and the fan.
SO I think the misfire was just one of those things that happens occasionally. Thanks for all the posts offering advice!
Neil
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Hi Roy,
It is the smaller hi torque unit. Starts the car in a second!
The wiring instructions are a bit vague. Coupled with that, the 1974 TR6 model year did something strange with the ballast wire. It is different to all the other model years before and after. The drawing I have doesn't indicate where the yellow/white wire connects other than at the SM and coil. It must connect somewhere else since I have disconnected from SM and the coil still has power.
Neil
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Hi Andrew,
Thanks for getting back to me.
>Im at work at the moment, so havent got access to the wiring diagrams, but shouldnt the ballast wire be bypassed when cranking the engine over, and feed the coil with 12V unballasted?
Id assume this cable would go to a relay of some sort in order to perform the change-over (drop in-drop out the ballast).
Yes it should be but I can't figure out how it does this. I only have one yellow/white wire on the coil feed +ve. I have checked connectivity with the yellow/white wire at the starter motor and they are one and the same wire. However if I leave the starter motor end disconnected, the coil still has power. It must therefore be wired elsewhere in the wiring loom to something else. I can't figure out what though! There isn't a relay in the system I can think of, other than I thought it might have been part of the old starter motor. i.e. when it cranks the motor it feeds 12v to the coil and when cranking ceases it reverts back to 9v. The new starter motor doesn't appear to have this functionality. It just has big power for the motor and solenoid engage wire (red and white)
How do you tell if your coil is a ballasted type or not? I recollect you can measure the resistance of the low voltage side and it reads either 1.5 ohms or 3 ohms depending on ballasted or un-ballasted. I can't remember which type I have on the car. I need to go and look at my old bills to see which one I fitted.
My current thinking on the misfire is that when the coil is fed from the alternator as the alternator spins up the voltage rises to ~15 volts and if this is feeding the coil (whilst charging the battery), the coil is breaking down at this high voltage. However, I'm not convinced this is the cause of the problem! But assuming I had no misfire prior to changing the starter motor and now I do have a misfire over 4000rpm it is the only explanation I can think of. I also have electronic ignition fitted in the distributor too.
My assumptions are also based on the fact that:
a. Misfires at higher revs from my experience are normally electrical and not fuel.
b. If it was an injector they normally misfire at lower revs or all through the rev range. It doesn't feel like any one cylinder missing, more a reduction in power from all cylinders as if the spark is changing/weakening.
I'm a bit stuck where to start with zooming in on the problem. I was going to measure the DC coil voltage during start up and compare with normal running and check the coil type. I am thinking keeping it all 12V and doing away with the ballast system. If that all checks out and the problem still remains I am stuck what to d next.
Neil
Misfire electrical or fuel?
in TR6 Forum
Posted
Good job I ordered fibre points
Yes, timing light shows distributor working as I rev the engine.
So 11 degrees BTDC it is at 800rpm then tweak using the vernier adjust until pinking goes away.
Electronic ignition... I had it on the car a while back but went back to points when it died. Points= simple and I do such little mileage I only need set them every few years so works fine. Cheap as chips too
Neil