Difficult Cold-Starting

I have adjusted the plug gaps to almost 28 thou and the mixture slightly richer.
It seems to start easier now, but the temperature is not too low at 10 degrees C. We expect a temperature drop in the next days, so i can see how it behaves in serious (for our climate anyway :D ) cold.

Steven, the mixture was not over lean to start with. It was something like 2,5 % CO at idle. I know it runs more happy at 3,5 % CO but i thought to give it a try anyway. Certainly it run without any misfires and the exhaust note at idle was steady as it should be with the lean setting. What you mention about melting pistons can happen in extreme conditions, i.e. wide open throttle for prolonged periods with high load and a really lean mixture. But i don't do this to my car anyway. :wink:
 
Demetris said:
I have adjusted the plug gaps to almost 28 thou and the mixture slightly richer.
It seems to start easier now, but the temperature is not too low at 10 degrees C. We expect a temperature drop in the next days, so i can see how it behaves in serious (for our climate anyway :D ) cold.

Steven, the mixture was not over lean to start with. It was something like 2,5 % CO at idle. I know it runs more happy at 3,5 % CO but i thought to give it a try anyway. Certainly it run without any misfires and the exhaust note at idle was steady as it should be with the lean setting. What you mention about melting pistons can happen in extreme conditions, i.e. wide open throttle for prolonged periods with high load and a really lean mixture. But i don't do this to my car anyway. :wink:
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Just my view, but I've always found economy to be better if it runs happy. ie Happy = Efficient :) 2.5 % sounds ok for a later car IMO but lean for a Rover. Don't forget to double check your ignition timing after playing with the plug gaps, especially if it wasn't spot on before :)
 
I agree with you. But sometimes we need to experiment to discover the obvious. Especially when there is nothing more serious to fiddle with. Now i have to find what happens in the No 3 cylinder. :?
 
Is there any possibility that the timing marks on the flywheel will not tell you the truth?
I have checked the ingnition timing yesterday with a timing light and it seemed to be something like 10 degrees BTDC, at 700 rpm, vacuum pipe disconnected.
However, the car was not pinking with 99 RON unleaded ( i was told that the engine has been rebuilt with 10:1 pistons, even if the serial number points to a 9:1 engine).
I adjusted the timing to an indicated 6 degrees BTDC and the idle speed dropped. I readjusted the carbs to compensate and went for a test drive. It certainly felt less responsive, especially at low revs. Not as it should be.
The mechanical advance seems to work as the timing marks on the flywheel dissapear when i rev the engine, and the vaccum advance seems ok too (the timing advances when i suck on the capilary and it also holds the vaccum).

As a last thought i have seen that the number on the distributor (although close enough) does not match any of the correct numbers for a 4 cyl P6 engine, let alone a 10:1 TC.
Unfortunately it's the same for the distributor of my spare engine.
So, does anyone have a correct 10:1 TC distributor (Lucas 25D4 - 41085) in decent condition that doesn't need any more?
 
Demetris,

Just a thought, but you mention about not splashing out on a new battery. My car became a real pig to start, despite being nicely set up. After flattening the battery many mornings I bought a new one & the car starts almost first time, every time now! :D
 
Phil Robson said:
Demetris,

Just a thought, but you mention about not splashing out on a new battery. My car became a real pig to start, despite being nicely set up. After flattening the battery many mornings I bought a new one & the car starts almost first time, every time now! :D
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Hi Phil,

there are no starting problems any more, now that the plug gap is correct. Of course, with the difficult starts the battery was not at its best, but after a good 24 H recharging at home, it has now enough juice to spin the engine fast enough to start. Even today that the temperature is around the freezing point.


Brian,
thanks for the tip, at the moment i will use the good old listen and feel method, until i will fit the right dizzy for the job and start from scratch.
What puzzles me most, is how i set up the timing in the first time when i installed this engine. I do remember using the timing light, but i cannot recal any similar issues. My memory is not at its best, i know....
 
I had the same issue many years ago with my first Rover, a '69 2000TC. It had lumenition so I had set the plug gaps to about .030". When on holiday in Coromandel, the car refused to start one morning. We called the AA and the local garage proprietor turned up in an immaculate Leyland P76! He very quickly went for the plugs, regapped them to .025" and no more trouble. Its one of the first things I check now.
 
Hello,

Time to revive this thread, I'm afraid. My father has been driving my TC for the past year but has had increasing trouble starting it, and can't start it at all now that winter has settled in. I'm contemplating installing an electric fuel pump (I have one I bought for my P5 but didn't use)--any technical advice or specifics?

I've also read that a weak coil can contribute to the starting problem. Any thoughts on this? If a hotter coil is in order, is any particular one recommended?

Thanks--I've been so focused on my hapless P5 that I've been a little out of the P6 picture.

Gordon.
 
Although the calendar says "Spring", it will arrive much later here. I have had cold starting problems, as in NEVER Starting. The battery is fully charged and will turn over long enough to raise the oil pressure up and keep turning. I have rechecked the static timing, have electronic ignition, fuel in the carbs. I try starting without the choke, then with the choke. The plugs will end up wet. There is spark, there is fuel. I reset the plugs to 25 thou after reading this thread: no change. Occassional as I let up on the start key I will get a single backfire. Once the car starts, (when it it much warmer out) It runs smooth and fine.
The engine is still new and has not seen road use yet, but we are still hoping.My only untested thought is to recheck the valve timing on the chance the chain has shifted.
 
It's unlikely the timing chain has shifted from where you set it, although it is worth checking in case it wasn't quite right when you set it up. It should always need choke to start, so it's not a good idea to try starting without, if it was to start it would only prove that it was running far too rich. Also check the ignition timing dynamically using a strobe. If there's a backfire when you release the key it could be the timing out, or a weak coil that only gives an adequate spark when there isn't the drain caused by operating the starter.
 
I can't recall whether you've ever had it running? If not, then I'd be inclined to think plug leads misplaced. The backfire is often a dead give away for that! If you have, then I'd plump for timing. There is also an outside possibility you have water in the fuel - did you leave the tank full over winter? - if not you could have got a lot of condensation in there. I presume there's no chance of ice in the fuel? Reluctant starters often respond much better to being bump started or towed than on the starter motor.

Chris
 
How old is the fuel you are using?
Stale fuel doesn't help at all, and modern fuels go bad in no time at all.
 
The Coil is new along with the solid state ignition.Plug wires also new. Shows spark while turning over, although I can't determine the quality of the spark. Fuel could be a problem, although it doesn't smell rancid, it looks a little jaundiced.
I also imagined low spark while using the starter,yet it turns over quickly. (I also rebuilt the starter).
I ran a lead directly from the battery to coil to rule out ignition wiring.
The fuel tank was cleaned before any gas was put in, but the fuel could be too old. I will add some fresh, and see what happens.
This engine is all fresh and has 200 lbs in each hole.
 
If it's not too hard to rig it up to run from a can of fresh you can soon eliminate the fuel issue :D
 
After trying everything else, including adding a couple of gallons of fresh petrol, I decided to drain the tank and lines,clean the carb bowls and put completely fresh petrol in. It tried to fire as soon as I turned the key, and after a little coaxing it got going. Rough at first, and it took a long time to dry out the exhaust system.Now I can fine tune, and fix a few problems I know of. Some tappet noise, and the usual cracked manifold. I get chain rattle on the decel when "goosing" it.
But for today I'm happy
 
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