Coughing and overheating

[Deleted]

Last Sunday when I was on my way home on the motorway on a 180 km long journey, my car started coughing and lost power. It happened on a quite steep part up on a mountain, I succeeded to drive with a speed of ca 30 km/h in to a service station. When I stopped at the service station the engine was very hot. After a while I succeeded to drive home with a speed of max 90 km/h.
First I thought that I had blown the head gasket or burnt a valve, due to overheating (I know my rad needs a new core), but today I made a compression test and all 6 is OK ca 8 bar on all So I don´t think I need to lift the head.
My question is: is it the petrol pump? unfortunately I am driving on the reserve because my main pump don´t work so I can´t check the easy way. The car is still coughing if try to drive to fast.
A new pump is £ 170+ Wat from Burlen and a service kit is £ 50 for both side. Is it easy to rebuild a pump yourself or is it a job for a specialist ?

Regards

Lars

[Phil Nottingham]

It is dead easy to rebuild the pump and it does sound like it is this. That is why there are 2!

Well worth replacing points/condensor though and checking over leads/cap/rota arm and earth lead if not done recently.

Have ignition points closed up

[Deleted]

Thanks Phil

I will order a double service kit and rebuild my pump. I have recently changed my leads, plugs, rotor and cap, but it is some time since I changed points and condenser so it is time.
Normally the car runs excellent on the motorway, just put in the overdrive and you can run for hours in 70 mph +
You know a 3 litre don't wander on the road, you can take your hands off the wheel in 70, no problem.

[Warwick]

I was a bit worried for a minute when I read your heading Lars.
Sounded like swine flu.

[dmaxwell]

You might also check the fuel filter, it can cause the engine to lose power.

David Maxwell
Tehachapi, California

[stantondavies]

Seems as if this is a combination of factors causing your problem, not just the pump and fuel starvation. Follow the good advice above and recore the radiator with THREE cores. Regarding the pump, just a sharp tap might 'get you home' but I'm sure that cleaning the contacts on both pumps will work wonders whilst sourcing a service kit.

[Deleted]

Thanks all, I will recore my radiator overhaul my pump.

I will let you know.

Regards

Lars

[Phil Nottingham]

3 Litres handle far better than V8's although understeer is more!

I concur with the 3 core rad - the 3 Litre cooling is not as overstressed in the UK as it is with V8's but the extra cost is minimal. You could try descaling it - I did with mine onece and it worked well - tried it with others but failed

Beware allowing it to overheat to often - I persisted with a blocked rad and its overheating and ended blowing the headgasket and distorting the exhaust manifold which they are very prone to

[Deleted]

Blocked fuel filter. Simples

[Deleted]

A update

I have checked my pump, fuel pressure is OK.
I have adjust the tappets, two of the exhaust was to thigt.
I have changed points and condenser.
Compression is OK on all cylinders.

The car is much better but not completely cured.
I have found that I have a exhaust leak between the manifold and down pipe. I think it happened when my problems started.
Is it possible that the leak make the engine cough?

Regards

Lars

[dmaxwell]

Is the engine cough rough running or is it just an exhaust leak sounding like coughing? With an exhaust leak, the car is louder and can sound like it's not running right when it really is.

David Maxwell
Tehachapi, California

[Phil Nottingham]

The 3 litre exhaust manifold is notorious for distorting which can make a coughing/spitting/tapping noise like a tappet. Occasional cough could well be a sticking valve try some UCL Redex poured into the intake when on fast idle.

Tight tappets/sticking valves result in burnt valves so a decoke/valve grind may be due with new exhaust valves (old ones have habit of loosing their heads!)

[Deleted]

The leak is not very loud, it is the joint between the manifold and down-pipe. I bought a new manifold from JRW last year and it is OK, the problem is the down-pipe I have to adjust it so it is completely straight in relations with the manifold.

I to suspect the valves,
I have burnt valves before and the symptoms was exactly the same, thats why I made a compression test. I don't know if I can get Redex in Sweden, I can use Wynn's, it is a common brand in Sweden, they have a product call Combustion Chamber Cleaner, you use the vacuum intake on the inlet manifold.
I think I will try that. I hope it will help.

The worst case is that I have to lift of the head and replace the valves, but the compression is still OK, so I hope it will not be necessary.

Regards

Lars

[Phil Nottingham]

You are correct about the downpipe position - the setting of the gearbox clamp is crucial too and this can crack the manifold if incorrectly positioned.

The Wynns stuff sounds ideal so it is worth trying first

[Deleted]

I don't seems to sort this problem.
I have checked the petrol, pressure is OK
I have replaced all ignition components and adjusted the ignition.
I have made a compression test all cylinders is OK.
I have tried Wynn's Combustion Chamber cleaner no effect.
I have sorted my exhaust down-pipe.

The engine start directly and have a even tick-over, when i accelerate through the gears everything is OK up to fourth gear, when I accelerate on fourth gear, first the engine starts pinking and then coughing and loses power. I have tried to retard the ignition but that result in that the engine is difficult to start and runs badly.

I have not serviced the carburetor yet, maybe thats help.

Anyone that got any idea?

Regards


Lars

[Phil Nottingham]

Have you replaced coil and in any case are connections correct. Assuming it is a modern coil and you have a negative earth Mk3 then + is ignition feed and - goes to dizzy.

If you have a SW/CB markings it could be a positive earth coil so SW will be dizzy etc instead of other way round. The dizzy earth tag could be shorting out or breaking.

The carb economiser washer may be broken/missing/fitted incorrectly or the holes blocked or tube perished.

It is unlikely to be carb as it would shopw up in other gears as would sticking or burnt valve or head gasket but stranger things have happened.

The pump pressure may be OK but the contacts can burn or pump stall - does it do it on both reserve and main?

[Deleted]

Thanks Phil

You gave me some new ideas, I will check this.

Regards


Lars

[stantondavies]

Lars, you say you have replaced all ignition components. Does this include the distributor? If not, it may be time to have it overhauled, as the advance curve is probably inaccurate due to wear.
If the carburettor hasn't been touched, then I would have it refurbished. I am doing mine at the moment for the second time in 20 years. (Tickover is uneven due to wear in the throttle spindle.)

[Deleted]

I have thought of the distributor,
The engine always starts pinking before it starts coughing. If i retard the ignition, the engine gets difficult to start and runs uneven on tick-over, if I adjust the ignition to get a direct start and even tick-over, it starts pinking on higher gears and then coughing. It looks like it is something wrong with my advance-curve.
I think I have to start to sort a lot of things and see if the pinking and coughing disappear.

Regards

Lars

[Deleted]

HI,sounds like inlet manifold leaking,start her up and try spraying wd40 round manifold see if you get any air bubbles. Hope this helps.

[Phil Nottingham]

It is not unknown although rare for the inlet gasket to go and also manifold actually crack..

Remove dizzy base plate to see if the advance weights are pressent including the springs

[Deleted]

I have checked the dizzy, it looks OK all parts on the right places, but that don't mean it works OK.
The inlet manifold is a new idea, I haven't thought about that, I will try with wd40.
Thank you for your help. I will let you know.

Regards

Lars