Car stalls intermittently on motorway journeys!

Post by **5lab** » 31 Mar 2005 07:01 pm

i think a blocked jet is unlikely if its loosing fuel.. the leak is (imo) most likely, but i cant think why it only happens some of the time.. guess it must be heat related, but cant work out how..

one idea - next time it happens, unplug the fuel hose and turn the ignition, if fuel spurts out then you know its not the fuel supply

Post by **foggyjames** » 31 Mar 2005 07:37 pm

It's not necessarily loosing fuel....just using a hell of a lot of it!

It could be a lot of things....ignition, worn carb parts (unlikely as it's a recon), a leak (but why intermittant), mucky bits, even air leaks....etc, etc...very hard to tell.

Look for a leak, try cleaning the jet, and if that doesn't work I think it's time to find a car doctor...

cheers

James

Post by **V6 Man** » 31 Mar 2005 08:25 pm

I know it sounds daft, but it could even be a piece of dirt in the fuel tank that is occasionally drifting across the pickup screen causing either a partial blockage causing the car to run lean and use more fuel, or a full blockage and thus a stall.

Post by **daffodil** » 31 Mar 2005 09:22 pm

hi ...make sure that you have the original are filter assy on, if you have it is very important to make sure that air going into the carb is heated from the manifold....check flap in air filter box is not broken
also make sure the pipe is there from the air filter to the manifold
without this working correctly the petrol freezes up with the cold air going into the carb....good luck

Post by **huskyracer** » 01 Apr 2005 07:20 am

I am with dafodil on this one, It sounds very much like carb icing, check all the things dafodil has mentioned, and if it does it again, quickly pop the bonnet and have a look at the carb, if it is covered in condensation, thats a sure sign its icing up

Post by **redline** » 01 Apr 2005 08:47 am

If you can get to Uxbridge it would be worth taking it to power engineering , also one of our members works there, not saying you would get a discount but he do's have extensive knowledge of these cars dont you Iain

Post by **december_boy** » 01 Apr 2005 09:14 am

Wow... this is amazing.

I'm going to take it to a garage tomorrow in Wembley - I live in NW London. I could get to Uxbridge if I needed to - do one of you have a garage there? Of course I would pay for your time!

Can someone explain Carb Icing to me? This sounds intriguing. I'm going to print all this out and take it to the garage with me tomorrow.

It's such a frustrating problem as the car seems to run beautifully when this issue isn't happening.

Post by **5lab** » 01 Apr 2005 10:02 am

i think carb icing is where the carb gets very cold due to all the air flowing over it (??) and petrol evaporating i think, and therefore it stops working properly (or something)..

Post by **foggyjames** » 01 Apr 2005 01:06 pm

Carb icing is where the jets (maybe not just the jets?) freeze, stopping (or restricting) the flow of fuel. I discounted it for two reasons, but then what do I know

1) I've only ever heard of it happening soon after the car has been started - most cars have heating elements (either electric or from coolant) to prevent it.
2) There isn't any correllation with the weather (I did ask), and carb icing only generally happens when it's seriously cold...

....However as I'm far from discounting it!

As an aside, my dad once had a very similar problem on his 240. It took literally months to track down, and proved to be a loose baffle in one of the boxes on his stainless exhaust system...ie: the last thing you'd expect. Leave no stone un-turned

I think a trip to PE (or any garage....but since our very own Huskymeister is there, and if they're happy to have you...) would be an excellent idea.

cheers

James

Post by **5lab** » 01 Apr 2005 01:09 pm

ooh i hadnt thought of that - it could easily be something blocknig the exhaust - to such a point that pressure builds up and stops the engine running eventually.. stick your hand on the back of the exhaust straight after turning it on (otherwise it'll be too hot) and see if lots of exhaust is coming out

Post by **december_boy** » 01 Apr 2005 01:22 pm

PE?

Huskymeister?!!

Tell me where I need to go and I'll go....

I did find this on Carburettor Icing... so I am confident this is the issue:-
"When an older car with carburettors splutters to a halt on the motorway, as you write in your Book of Motoring Answers, all too often the problem is carburettor icing. The trouble is, in the short time it takes to call out a rescue service, residual heat in the engine usually melts the ice, removing the airflow obstruction, and the car runs perfectly again.

The symptoms are always the same: the engine suffers a loss of power, the fuel needle races towards empty and, usually within a few miles, one is forced to pull over. The expansion of air after being drawn through the restriction of the venturi, combined with the chill of cold fast-moving air, cools the carburettor sufficiently to ice the fuel, which then gradually closes the intake to air and sucks more fuel to equalise the manifold depression.

Almost all cars have a system which takes hot air from around the exhaust manifold and feeds it into the air intake in cold weather. The hot air feeds through a flexible tube (basically cardboard covered in silver foil) which disintegrates over time, until it falls off altogether. If you are having carburettor icing problems, almost certainly it is because this tube is damaged or missing. If the tube is in place, the problem is probably with the mechanism that controls the flow of hot air according to air temperature. Check the pipework to this mechanism (which is mounted somewhere on the air filter housing). If the pipework is OK, the vacuum operated flap which regulates the air filter is faulty. Replace the complete air filter housing with one from a scrap car."

This describes my issue perfectly. Especially why the petrol gets used.

Post by **bodejodel** » 01 Apr 2005 01:33 pm

Crap... You beat me to it... I was just going to mention the expanding air theory about the icing...
It's a simple thing to fix... all you need is a new piece of tube...

Post by **foggyjames** » 01 Apr 2005 01:40 pm

Interesting...I might have to re-fit mine...

PE = Power Engineering, Uxbridge. Huskymeister = Huskyracer = PE employee and 340 turbo builder extrordinaire! (sp?!)

cheers

James

Post by **5lab** » 01 Apr 2005 02:01 pm

that tube is missing on my car too

basically it should be silver tubey stuff that runs from the exhaust casing to the bottom of the air filter iirc (thats on a 1.4)..

i nicked the replacement on nessy from a 740 - it was EXACTLY the right diameter - but i guess halfords might sell some

what site was that info from? looks promising

Post by **foggyjames** » 01 Apr 2005 02:16 pm

My problem is that the guts of the valve are missing....need to remember to get bits from a scrapper.

cheers

James