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TR4A running/fuel problem


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34 minutes ago, RobH said:

I'm not sure that 'flicking' the points really tells you anything very useful. It is hardly consistent as a method, doesn't test a lot of the components and if the gap from the king lead to earth is wide, the coil is being over-stressed electrically as the HT rises much further than it will in normal use. It takes a lot more voltage to spark over 1/4 inch than it does over 25 thou, and that is stressing the insulation on the coil windings. 

 To me a better test would be to connect everything up but with the plugs out and resting on an earthed surface.  Cranking  the engine.  should show consistent sparks at the plugs.  That way you are testing everything - the points, condenser, dizzy cap, rotor arm, coil and leads. 

Good idea Rob but a bit concerned that petrol vapour will be pumped out of the plug holes so best done outside and maybe clamp off the fuel supply before the pump. After all you are testing for a spark only at the plugs. Sparks and fuel vapour on the other hand............??

Maybe leave the plugs in place to stop fuel vapour being released and just use some spare plugs wired in for this test

What do you think?

Keith

Edited by keith1948
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I wouldn't have thought there would be much fuel vapour if the plugs are out Keith -  at cranking speed the pistons are just sucking air in and out through the big holes rather than mixture from the carbs.  

You could stop it completely by taking the air cleaners off and closing off the air intakes with gaffer tape. 

 

 

Edited by RobH
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The 1/4 inch jump test I have used on other cars for the king lead. Will try cranking rather than flicking the points and see if there is a consistent spark. Jumping 25 thou in free air is not the same as under compression but will have a go and see what happens, may reveal something. Have plenty of spare good plugs.

Melvyn 

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Hi Melvyn,

I‘m pretty shure I know your main technical problem (you may have not only one),

because I also had to go through this deep and dark valley two yours ago (also at the hottest day of the year).

I made a post about and others confirned they had the same problem.

Sadly I can’t find it on the big heap of posts.

Ciao, Marco 

 

Edited by Z320
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Hi again Melvyn

Just wondering; did you ever comprehensively check your fuel tank & pipe work for blockage following my original post to you?
 

Like Marco I had exactly similar symptoms.  Mine appeared to have sufficient fuel initially but I finally traced it to fuel starvation.  Just a thought as there's no luck tracing any electric fault so far as I can see.
 

Regards

David

Edited by Pontious
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When the car broke down the fuel line to the carbs spurted fuel out on cranking, also the front float chamber had plenty of fuel. I'm sure there have been fuel problems but now concentrating on electrical. When it broke down the time before it would not start after endless cranking but started with a bump start which suggests an electrical problem. I have just started it in the dark, started fairly easily. THere was no arcing I could see. Will try the new condenser tomorrow if it arrives and also do this 4 plug test.

Melvyn 

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Some days I'm too tired to answer and explain,

specially when the asker doesn't answer questions he has been asked (very early this thread).

And specially when I cannot expect a "thank you".

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Hello Melvyn

Presumably the battery is ok? They are positioned in the hottest part of the engine bay. Not the best place. Do you have another battery in another vehicle you could connect just to rule it out when the car doesn't start.

Keith

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Tried the test king HT lead and on cranking over did get a spark to ground. New kit arrived points, black lead and condenser. Because of the intermittent nature replaced the black lead as despite the original being less than 1/2 ohm it may have not been good at carrying the load current. Would not start with lead and condenser, left the points. 

Getting fed up so made up a rig to test condensers. Used a known good coil supplied direct from battery in series with the condenser to earth. HT king lead 1/4 inch from earth. Wire across condenser to ground, so on releasing this wire should get a spark. New condenser, intermittent weak spark. Original condenser intermittent slightly stronger spark. Known good condenser (VW one), strong spark with a crackle every time. So the new and existing condensers US, but I had tried the VW one some days ago without success. So now thinking part of the problem was the black lead.

What I did was connect the VW condenser externally to the distributor and it started straight away and ran fine in the drive without any hesitation but no road test with jumper wires that could fall off. Looking at the VW condenser looks  as if I can fit permanent externally. So could then risk road test.

So where/how to buy a good correct condenser, perhaps a silly question. I have a M Minor (same condenser) which soon after purchase misfired and it was the condenser but in the spares box there was a new unopened Lucas one, guess what US. I read of someone who bought 5 only to find one good one. Lucas on the box means nothing.

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As stated before Melvyn - the Distributor Doctor has the good condensers (and other dizzy parts). 

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Melvyn

Try Holden of Bromyard

https://www.holden.co.uk/p/25d4_25d6_22d_dm6_etc_condenser

This on is £4.38 They also do an uprated one at £10.20 DCB101X

I did say the black lead might have been a problem. This connects to the plastic bit that slots into the distributor and then a red lead goes from that connection to the condenser connection. Dodgy spade connectors and maybe wire corroded and breaking down inside the insulation. Use a new black wire and crimp and solder the spade connectors. Doesn't take much to create an electrical fault on a TR as various posts on the forum will testify. They didn't call Lucas the prince of darkness for nothing. After many years running a 4A (same car for 32 years) I have found that dodgy connections or bad earths, loose wires and mods by previous owners account for most electrical problems. The components either work or they don't (or fall to bits in the case of switches).

Good luck

Keith

p.s. You might get one to try out from your local Halfords.

Edited by keith1948
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17 minutes ago, keith1948 said:

They didn't call Lucas the prince of darkness for nothing. After many years running a 4A (same car for 32 years) I have found that dodgy connections or bad earths, loose wires and mods by previous owners account for most electrical problems.

Is it not rather unfair to continue this slandering of Lucas then ?  ..particularly as so many after-market components, even those made half-a-century later, have such an unenviable reputation.  So many times I've heard something to the effect of "rebuild the original, or buy genuine NOS, don't buy a new one - even those in Lucas packaging - they are xxxx !"

..just saying like.  

Pete

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31 minutes ago, keith1948 said:

 They didn't call Lucas the prince of darkness for nothing.

After many years running a 4A (same car for 32 years) I have found that dodgy connections or bad earths, loose wires and mods by previous owners account for most electrical problems.

So nothing to do with Lucas components then ;) At least with original Lucas stuff you can take it apart clean it up put it back and it will go on again for years. Age and DPO fiddling has nothing to do with the quality of the original component so stop denigrating Lucas.

Stuart.

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Oh dear struck a nerve there. Sorry chaps. Yes I have Lucas stuff that has lasted for years but equally had some that has been faulty from the start.  Personally had mixed experience with Lucas and yes you can rebuild some of it. I have been there. 

In this case though Melvyn is experiencing problems with faulty condensers that appear to be Lucas (on the box). Personally not sure about quality of some of modern "Lucas" branded parts. Again I have had mixed results with these.

Anyway lets park the debate about pros and cons of Lucas and see if we can help Melvyn with his problem.

Keith

 

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Hi,  

"the problem" is the Lucas extra way to fix the condensator inside the distributor.

I don't know why they did this, they may had a serious reason.

This causes a single model and a limited number of producers and sources.

Indeed you can fix ANY condensator outside the distributor,

connected to terminal "1" on the ignition coil like most other producers did - and I did it too on my TR4A with a Bosch condensator.

P1180678-b.JPG.62b91268133299ed3ca56ad31802fa8e.JPG 

P1180680-b.JPG.03d371d80d11cdaf0c994983208d4cbd.JPG

This is out of service at the monent (Pertronix 1 fitted) and I sell it "German engineered and SRA (Special Road Approved)" for 29.95 GBP direkt from me.

Melvyn ist out, because from his posts I know he knows and did this and is relaxed.

In my opionion the condensator is not the reason for his problems.

Ciao, Marco

Edited by Z320
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2 hours ago, keith1948 said:

Oh dear struck a nerve there. Sorry chaps. Yes I have Lucas stuff that has lasted for years but equally had some that has been faulty from the start.  Personally had mixed experience with Lucas and yes you can rebuild some of it. I have been there. 

In this case though Melvyn is experiencing problems with faulty condensers that appear to be Lucas (on the box). Personally not sure about quality of some of modern "Lucas" branded parts. Again I have had mixed results with these.

Anyway lets park the debate about pros and cons of Lucas and see if we can help Melvyn with his problem.

Keith

No problem with me Keith ;)  I was just saying like. 

And like yourself, I've had far more issues due to neglect, moisture, and prior-owner's efforts n' upgrades than with the original components ..including switches, sensors, dynamo & regulator, distributors, lamp assemblies, etc ..some which on my motorcycles are possibly 70 years old, and perhaps 50+ years old on the TR.

I, like I'm sure many of us, would be glad very much like to help Melvyn get to the bottom of this problem, but I fear too many helpers in the kitchen have detracted from the pragmatic process of elimination.  Still my door remains open.  

Pete

 

1 hour ago, Z320 said:

Hi,  

"the problem" is the Lucas extra way to fix the condensator inside the distributor.

I don't know why they did this, they may had a serious reason.

This causes a single model and a limited number of producers and sources.

Indeed you can fix ANY condensator outside the distributor,

connected to terminal "1" on the ignition coil like most other profducers did it - and I did it too on my TR4A with a Bosch condensator.

P1180678-b.JPG.62b91268133299ed3ca56ad31802fa8e.JPG 

P1180680-b.JPG.03d371d80d11cdaf0c994983208d4cbd.JPG

This is out of service at the monent and I sell it "German engineered and SRA (Special Road Approved)" for 39 GBP direkt from me.

Melvyn ist out, because from his posts I know he knows and did this and is relaxed.

In my opionion the condensator is not the reason for his problems.

Ciao, Marco

Thank you Marco,  I'd never seen that and yet it is so very obvious !   well shared my friend.

I think the reason for its integral condenser may simply to expedite inexpensive vehicle production - the distributors with points & condenser fitted, gap set, cap with rotor arm and HT leads, etc, were tested-rig checked before they came from Lucas by the lorry load, ready to be bolted on. The coil would be bolted to the engine and the distributor assembly dropped into place and rotated to the right ignition timing. This would have been done at the end of the engine + transmission assembly line.   In effect, for Triumph.. just four Champion spark plugs & four bolts and the car's ignition system was good to go.   ..with nothing but the wiring loom connections needing to be added. 

Pete

 

 

Edited by Bfg
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Today bought a Lucas DCB101 (in a Lucas box)from a Land rover parts place, only £3  so worth a try plus expecting a replacement from the last supplier. If these do not work will fit the VW one externally, only need to drill out the bracket so as can mount/ground via the coil bolt.  Not paying big money or might as well go electronic but would need a 1.5 ohm coil as well. Anyway will road test and take any other good condensers with me. 

If it stalls/wont restart it must be another problem.

Melvyn 

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Interesting that Marco shows a distributor with external condenser looks just like the one I had on my classic Beetle (recently sold). Should be plug and play but on mine the condenser was mounted where you could not get at it without rotating the distributor, anyway that's another story.

So on to the TR. Replacement condenser arrived so tested this with the one bought from Land Rover. Did this on my test circuit and both gave a spark with a crack which would jump well  over 1/4 inch. So now 3 good ones with the VW one. Doing a sort of plug and play, the VW one mounted externally and bolted under the distributor nut. Car started and ran in drive with no problem. Put the Land Rover one inside the distributor but did not connect the wire/terminal, just insulated with tape. So there just in case the external one failed. Now the road test, around 20 miles no hesitation, kept idling at junctions and got home without drama. 

So maybe all good now but a longer drive needed to be sure. The clue that the car bump started but would not start cranking points as said to electrical fault. The condenser was clearly one problem but also the black wire in the distributor (now replaced)I think was not carrying the load current and being robbed by the starter motor.

There were and maybe still fuel problems but none in the short road test.

Melvyn 

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Problem returns. After a 15 mile run stopped switched off engine. Then cranked and would not start. Left for 40 minutes and then it started. Ran for 30 miles idled fine at junctions then 3 miles from home stalled and would not restart. It is no longer electrical. No fuel coming out of pipe feeding the carbs on cranking. Glass fuel bowl full. After a few minutes cranked  again, got fuel and it started. Got home (3 miles) switched off and again would not restart but did after some minutes.

So I did have an electrical fault now sorted but the underlying fault appears to be fuel starvation. So looking at what has been said on here perhaps it is the pipe from the tank that is getting blocked. Despite fuel in the glass bowl it would appear that this cannot be pumped to the float chambers if there is no fuel feed to the pump. 

Melvyn  

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11 hours ago, eng622 said:

Problem returns. After a 15 mile run stopped switched off engine. Then cranked and would not start. Left for 40 minutes and then it started. Ran for 30 miles idled fine at junctions then 3 miles from home stalled and would not restart. It is no longer electrical. No fuel coming out of pipe feeding the carbs on cranking. Glass fuel bowl full. After a few minutes cranked  again, got fuel and it started. Got home (3 miles) switched off and again would not restart but did after some minutes.

So I did have an electrical fault now sorted but the underlying fault appears to be fuel starvation. So looking at what has been said on here perhaps it is the pipe from the tank that is getting blocked. Despite fuel in the glass bowl it would appear that this cannot be pumped to the float chambers if there is no fuel feed to the pump. 

Melvyn  

I had similar fuel starvation and found a very short very old piece of rubber pipe joining 2 rigid pipes running along the chassis just in front of the rear wheel. Turned to jelly inside stopping the flow. I put an elec tyre pump on the line from the engine bay and you could hear the pressure build then give as it temporarily cleared. 

B5386DE3-3BE3-40D4-9B60-F28620BCD95C.jpeg

Edited by Hamish
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