Will not start when warm.

[clive]

I’ve owned my 3 litre (Mk 1a) for about 25 years and I love the car very much and it’s given me and my family an enormous amount of pleasure but I’m having an increasingly hard time with the old girl in last 3 years.
I’ve paid out countless hundreds of pounds to try and sort out a problem that seems so simple yet so far unsolvable!
The car runs like a dream and starts perfectly well from stone cold but once it’s warmed up it wont start again unless you leave it for about half an hour to cool down.
I’ve been stranded in so many places now that I find I’m starting to lost the enjoyment and confidence in the car.
My local mechanic, who’s used to older cars and highly regarded and honest has completely run out of ideas to what can be causing it. I see the embarrassment on his face when I bring the car back with no improvement!
I’ve had all the ignition changed points, condenser, including two new coils, the car was running hot so the radiator was refurbished and now runs cooler but no change with it not starting.
The petrol pump is fine and the petrol is getting though ok.
Please, is there anyone out there that might have had the same problem and cured it?
I’m seriously getting to the stage in not wanting to use the car anymore, which is very sad after 25 years of ownership.

[roverp5b]

Clive, its a long shot but at this point any shots a good one, I had an old Hillman Minx years ago that did the same thing, like you did evereything I could to no avail. In the end I sold it to a woman neighbour for a song having made her aware of the on going problem, her mechanic looked over the car and found the problem to be a small hole in the fuel tank, how or why didnt come in to it but a new tank and the problem was resolved, spooky but you never know, dont give up on the old girl you will get there in the end.

[Phil Nottingham]

Sorry to hear of your troubles but there seems nothing too serious as otherwise it would not start well from cold, run well or after brief rest.

Distributor earth wire?
Tappets too tight?
Fuel pump weak?
Poor ignition/coil feed - try hot wiring?
Timing wrong?
Needs decoking?
Coil polarity wrong?
Incorrect plugs/gaps?
Sticking float needle?
Sticking jet?
Sticking dashpot piston?
Are you using additive in the petrol?
Does it seem to flood when trying to start it ie petrol smell?
Are you getting spark?
Faulty rota arm? - new ones may be no good - try a red one from the distributor doctor
Cracked dizzy cap?
Sticking vac advance?
Blocked carb economiser/collapsed specail bango washer?

[stoneRover]

I had a similar problem in both my first Rover a 72 P5B Saloon and when I had the same problem in this one at first I just put up with it - just another quirk

I used to drive where I was going and found that when I switched off it wouldnt start again straight away - just nothing - no clicks - silence untill 20mins later it would start again as if nothing was wrong

In my case I had an Auto Electrician to find a faulty relay unrelated and asked about this problem - he had a sort round and found that it was the mechanical pin in the Inhibitor Switch on the gearbox was sticking sometimes ( probabley through lack of use)
but gave me an Emergency get out by putting an Emergency wire in Engine Bay to cut out Inhibitor Switch that I could use to get me home BUT CAN BE STARTED IN ANY GEAR and said that More Use might cure if not New Inhibitor Switch

Hope it may be another place to look at

[clive]

Thank you all very much for the suggestions, I’ll print off these posts and show them to my mechanic.
There must be something here he hasn’t looked into.
I didn’t mention in my first post that the car turns over very well but refuses to fire up when warm, no smell of petrol.
I still run in on 4 star leaded petrol, I’m lucky to be close to a small privately owned petrol station that still supplies it.
As the weather improves I want to enjoy the car and I’m determined this year to sort out this problem, it’s been going on far too long.
I just hope it isn’t going to cost me a small fortune, it’s probably something very simple but it’s the time involved in locating it.

[enigmas]

It can only be 2 things lack of petrol or ignition. Although taking it to your local mechanic seems like a good idea it may not be the best option especially if he is busy. It's a pity that you don't have rudimentary mechanical skills or perhaps access to a sympathetic mechanically inclined club member to resolve the problem.

You've had the car for 25 years. Given that, the switches, wiring and fuses are probably 50 years old? This is not an issue if you've taken the time to clean the fuse junctions and check the wiring at the switches (ignition switch?) as wire will develop a resistance at the terminals and junctions over time. You'll have to remove the instrument binnacle to check the connections at the back of the switches.

Since it still has points ignition I'd hot wire it first. Run a wire from the battery + to the coil + and see if that works when it's hot. If it does the fault is in the wiring probably at the ignition switch. Remove the coil lead from the distributor and secure it close to the engine block (3mm) near some clean metal. Get someone to crank it over while you watch. You should see a strong spark.

When was the carburettor last serviced. There's some weird economiser devise (Phil where are you?) running from the fuel bowl to the back of the carburettor, that could be causing this problem. If you remove the air filter from the carb you can squirt a small amount of petrol into the carb throat. Then crank it over and it should fire. If it does the problem is in the carburettor.

It's all very basic and there's nothing mysterious about why it won't run, but you're looking at 50 year old components, wiring and switches.

[stantondavies]

Had the same problem for some years until I reversed the connections to the coil.
Aren't the early cars positive earth, perhaps someone has fitted the coil connections thinking it is negative earth? Worth a try!

[Phil Nottingham]

I mentioned both the hot-wiring and the economiser! Ignition switch is favourite for me - if it gets warm then its past it

To test the economiser - when idling, just squeeze the rubber tube rom top of float chamber to air filter, flat. The engine should stall immediately. If it does not stop or makes no differences the orifices may be blocked in the air filter elbow or metal tubes from top of float cahmber to rubber tube and/or carb or rubber tube is perished/holed or collapsed or the special fibre washer for the banjo on the top of the carb is missing or a plain one is fitted or it is so compressed or damged it is blocking the air passages

[Ken Nelson]

We can buy "starting fluid" over here in the US which is just an aerosol spray can of ether. Is it sold in UK? If so, a squirt directly down the throat of the carburetor will make it run if it's getting a spark, and indicates a carb problem. Remember to lift the carb piston with a finger while spraying (But NOT while cranking). If it wouldn't fire with ether it must be an electrical problem. If so I would think hot wiring would then get it running.

[Warwick]

Aerostart is the UK product Ken. It's sold down here too, although we have a local equivalent called "Start ya bastard".

[Phil Nottingham]

Yes we have it here - it can get like a drug once used it is hablt forming (for the engine).

3 litre engines should start easily even on the handle so something is amiss

[Deleted]

I had a problem like that, start first time but when warm she would start to splutter and stop, then just spinn over and not start for a half anhour, I striped the carbs time after time convinced it was petrol problem..turned out to be the coil breaking down when it got warm...!

[Deleted]

have you solved the prob yet Clive?

where abouts in the country are you? never know you might be down the road

[Warwick]

Jun 22, 2010 20:56:35 GMT @davidtreadwell said:

have you solved the prob yet Clive?

where abouts in the country are you? never know you might be down the road

David,

He just joined the forum, asked a few questions, and hasn't been back since. His last log-on date was a few days after he started this thread.

If you want to try and contact him, I'd use his e-mail address.
Sending a PM probably wouldn't work as he's unlikely to have set up for e-mail notification.