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Not running on all cylinders


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Thought I would quickly change the plugs, points dist cap and rotor arm , wish I hadn't touched any off it as now have have the Car running rough and like it's not on all cylinders. Will spend tomorrow retracing my steps and swapping bits back. But in case my patience runs out anyone recommend a garage that is local to Ipswich that knows what they are doing with a tr that could help?

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Check plug leads are in the cap in the correct firing order: 153624

The front cylinder lead #1 is usually at about 6 or 7 oclock in the cap, and then 5 etc are anti-clockwise to that.

As it runs its probably just a couple that are swapped.

Peter

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Managed to find the problem. Plug lead order was all ok as i moved leads one at a time to avoid slip ups. Last resort put the old cap back on and it's all fine! Time to find a better quality replacement I think

I use only Distributor Doctor for ignition parts.

http://www.distributordoctor.com/

I avoid anything that comes in a Luc*s box.

Peter

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My 6 developed a mystery misfire a couple of years ago, running erratically on four cylinders.

 

Turned out to be a breakdown of the distributor cap with tracking across the cap between adjacent HT lead sockets, fixed straight away by a new cap. The old cap wasn't that old, maybe 2-3 years. It's even more worrying if the same thing has happened with a brand new cap on your car.

 

Could it be a topic for the PQI to look at??

 

 

Nigel

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Annoyingly the issue returned today. Spent most of the day swapping old bits back and forth but no further forward. Car idles very lumpy and clears after 2000 rpm + and then it's fine.

Guessing ignition timing to check next

I'd gap the points then check timing.

But butterflies gone out of sync can do that too.

Peter

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  • 2 years later...

Hi all, first of all a big hello as I'm a new member with old problems.

I own a Tr6 pi CR from 1973, the problem: when startin the car cyliber 4&3 are not running, only when I drive does it seem to run on sll six, but it seems even after 30 mins of driving, at idle 3&4 are still not firing.l put new sparks in, new distributor cap, contacts and condenser as well as new ignition cables, and checked the injectors in a jar to see if spraying at idle, which they do.

Where else could I look? I'm not really knowledgeable on car engines.

Thanks for all the input.

Pascal

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On 8/21/2016 at 9:48 PM, Ed209 said:

Annoyingly the issue returned today. Spent most of the day swapping old bits back and forth but no further forward. Car idles very lumpy and clears after 2000 rpm + and then it's fine.

Guessing ignition timing to check next

Before going to other causes, it's likely to be something you touched. Check there is a spark at all plugs first when you have this symptom, double check the points gap and timing (my pulley is out so I had to make new marks) then you can look at other things like injectors and syncing butterflies after. 

Gareth

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Gareth quoted a post from August this year, but I suppose he was repying to "El Condor" (!).

EC, how do you know that 4 & 3 are not working?   As above, after installing new,  careful checking that the right leads to right cylcinders (3 & 4 next to each other).

John

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1 hour ago, Mk2 Chopper said:

Before going to other causes, it's likely to be something you touched. Check there is a spark at all plugs first when you have this symptom, double check the points gap and timing (my pulley is out so I had to make new marks) then you can look at other things like injectors and syncing butterflies after. 

Gareth

Ok will do.

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26 minutes ago, john.r.davies said:

Gareth quoted a post from August this year, but I suppose he was repying to "El Condor" (!).

EC, how do you know that 4 & 3 are not working?   As above, after installing new,  careful checking that the right leads to right cylcinders (3 & 4 next to each other).

John

When idling I pull the the ignition cable to spark plug 3&4 and engine running as before.

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Hi Pascal

A little bit of history would help. How long has it been like this and did you do  anything before the problem occured. This might point to the problem. I assume you put all the new bits on after the misfiring developed. If so it could be the butterflies out of sync. Are the spark plugs wet when pulled after idling and have you checked that 3 & 4 injectors have not been swopped round when put back.

Best of luck

Roger

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37 minutes ago, Rogcastle said:

Hi Pascal

A little bit of history would help. How long has it been like this and did you do  anything before the problem occured. This might point to the problem. I assume you put all the new bits on after the misfiring developed. If so it could be the butterflies out of sync. Are the spark plugs wet when pulled after idling and have you checked that 3 & 4 injectors have not been swopped round when put back.

Best of luck

Roger

Hi Roger, ok I will check, don't know how to adjust the butterflies, but first will do the simpler things first.

The car was standing almost a year, so thought it gad dirt in the system, found that one injector wasn't working well so got new one, now they work well but problem persists.

The car starts right away now which wasn't the case prior to changing the spark plugs/cables, distributor cover and contacts and arm, so defenitely better, runs also well, but idling only on four cylinders.

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2 hours ago, john.r.davies said:

Gareth quoted a post from August this year, but I suppose he was repying to "El Condor" (!).

EC, how do you know that 4 & 3 are not working?   As above, after installing new,  careful checking that the right leads to right cylcinders (3 & 4 next to each other).

John

Sorry you are correct wrong post! I'm guessing you've replaced a few bits because of the problem. 

2 hours ago, El condor said:

When idling I pull the the ignition cable to spark plug 3&4 and engine running as before.

Have you swapped injectors to different positions to see if the issue moves? Have you confirmed you have a spark on 3 & 4? What about your valves (tappets) been adjusted or checked? 

If you can adjust the idle speed with the bypass screw and bring it up and then pull the cable on each plug does it make any difference? 

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This has been the best tool I've bought, will tell you if things are sparking or fuel.   https://www.halfords.com/workshop-tools/tools/hand-tools/laser-ht-lead-ignition-spark-tester

I know somebody will say its only 4 for a 6 cylinder engine, but they can be bought singly

John

Edited by John L
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So it's quite lumpy until the other two cylinders kick in? 

Have you done a compression test on those cylinders? 

Possibly the throttle bodies (butterflies) might be out, a flow meter would tell you what's going on.

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Hi Pascal

If I was you I would double check that 3 & 4 plugs are sparking at idle if they are I would then swop either 3 or 4 injector with another injector to see if problem is transferred to that cylinder. If it doesn't I would check the balancing of the butterflies with particular attention to 3 & 4. It's not too difficult using a 2 thou feeler gauge. You should be able to just slide it in at the bottom of each butterfly. Have you got a manual as that will help.  Next maybe compression check or Tappets.

By the way have you recently bought the car. Interested to know as to whether it was like it when layed up.

Best of luck

Roger

 

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Give the car an Italian tune-up.  It gets the little air bubbles out of the PI. At tick over each squirt of fuel is a mere cubic millimetre or so. A tiny bubble can kill the spray volume leanig the mixture. Revving a stationary engine wont do the job, it needs  to be loaded, so give it a blast.

Peter

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23 hours ago, Peter Cobbold said:

Give the car an Italian tune-up.  It gets the little air bubbles out of the PI. At tick over each squirt of fuel is a mere cubic millimetre or so. A tiny bubble can kill the spray volume leanig the mixture. Revving a stationary engine wont do the job, it needs  to be loaded, so give it a blast.

Peter

Not driven mine in a couple of weeks, and it was a bit sluggish when cold earlier today, didn't sound like all cylinders were firing, but after a bit of a mild blast it was running sweetly again, so certainly good advice.

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