Diagnoses Please: Intermittent Cut-Out With Xs

[gingerdave 0 1 Cars]

Hi folks,

 

I've recently been having my 205 XS cut out on me, yet several garage trips have not got to the bottom of the problem.

 

What happens is after 20 mins or so of running, the engine will start to struggle like it is running out of fuel, then dies. It will then not restart. If you unclip the leads, no fuel is getting pushed into the carb.

When this first happened, adding a gallon of fuel got the engine running again, but last time I tried this it did not work.

However, what is very reliable is if you leave the car for 60-90 minutes, it will then start first time.

 

There appears to be no vaccum problems, removing the fuel cap makes no difference.

 

Both the fuel pump and filter have been replaced in an attempt to solve this problem, but to no avail. I got the pump changed as when adding a bit of fuel worked we though it might be a weak pump struggling to draw fuel through, requring a greater weight of fuel behind it. But the problem remains.

 

We changed the filter as the problem began after I ran the car down to very low fuel (fuel light on for 10-15 miles; coming back for Xmas so late December), so we though crap had got into the system, and when heated it started blocking the fuel system. But appears not.

I still think its likely that running the car to very low fuel has something to do with the issue though. One other potential source is that over winter the car was regularly exposed to colder temps that is has been used to, so repeated starts in zero-ish temps (its normally in Cornwall so not exposed to those temps).

 

Last time in the garage checked the camshaft to see if it was worn, but it was fine. So now I am back to square 1 with a complete mystery problem.

 

It doesn't always happen, couple of times its been running in the garage for a while without problems. Something heat-related would seem to be a sensible candidate. Had the fuse box replaced since the problem begun, and its a mechanical fuel pump, so don't think there are any relays getting too hot.

 

Any ideas most welcome, its very frustrating!

Edited April 12, 2015 by gingerdave

[pugdamo 111 2 Cars]

My old xs used to cut out/bog down and I striped the carb to find a split in the bottom of the float,I have also seen other people on here have the same issue. Definatly worth a look.I'm sure there are still rebuild kits available for these.

[pugdamo 111 2 Cars]

Just noticed you said your from Cornwall, nice to see another local.

I do still miss my old xs,what a brilliant car

[Tom Fenton 1,526]

Carb icing, is the warm air duct there?

[allye 530 3 Cars]

I would say one of two possibilities, maybe both!

 

Like you said running it low on fuel could have dragged some crap through, without a strip you just won't know. Or float issues, the floats can crack or become porous and useless. Rebuild kits and floats are still available for these for not a massive amount of money.

[Toddy 7]

Since your issue is that you receive no fuel to the carb, have you replaced the 3 rubber hoses, fuel pump to carb, from the fuel pump to the fuel filter & also from the fuel filter to the hard line? These will be past their best, possibly partially collapsing internally.

[trogboy 17]

 

If you unclip the leads, no fuel is getting pushed into the carb.

If I am reading you right you say after the engine has died, if you take the fuel inlet hose off of the carb and turn the engine over no fuel comes out of the hose?

 

You'll need to turn it over for a while as the fuel is going to drain back to the tank under gravity once the pipe is disconnected - look at the in-line filter for air. You could think about clamping the hose before you take it off.

 

If you are sure that these are the symptoms I'd be looking to work back through the hoses in the fuel system - the hose from the mini swirlpot/return to the carb, pot to pump, pump to filter, filter to fuel line etc.

 

I suspect that the issue could be in the tank, perhaps a scrap of plastic etc being sucked onto the intake and then falling off once the suction has slowly dissipated. A friend of mine has a similar issue with in his TVR after the little polystyrene disc from the lid of a bottle of redex stuck to the top of the neck and was poured into the tank. He had to take the tank out and up-end it to recover the disc.

 

I don't think that the issue will be with the floats in the carb as once filled, they'd be over fueling and I think you'd struggle all of the time.

 

Cheers,

 

Adam

[gingerdave 0 1 Cars]

OK cheers guys. I believe the hoses have been checked and are fine, but I'll double check with the garage. I also don't see why the problem with bee intermittent like this if the hoses were collapsing?

I'll also ask them to look into the float, worth checking there before getting the fuel tank off (it was filled recently).

 

They are convinced the problem is electrical, so to eliminate this want to run a slave line from the battery (to where I am not 100% sure, the carb?) that will have a dash-operated switch I turn on and off when I want to use the car. I'm not convinced so will suggest the two options (float & tank) as things to try first.

 

Don't see how carb icing would be playing a role now, unless it had a permanent effect e.g. causing a split in the float?

[Wallby 39]

I had a similar problem on my rallye when I was running an electric square facet type pump. I think it was some kind of air lock, and I could hear the pump running, but not pumping any fuel through.

 

It was a while ago, but I think fitting a non return valve (cheap on ebay) between the pump and the carb sorted it. Might be worth a try?

[trogboy 17]

On an XS there is virtually no electrics in the fuel system. The carb is totally mechanical, and the fuel pump is mechanically driven from the cam. The only wire in the system is the 12v feed to a small disc resistor on the carb that is used to help heat it, and I'm not even sure that it is present on all models. After 20 mins the engine is up to temp anyway, including the coolant ways in the manifold, so unless it is really cold this won't be the issue.

[Tom Fenton 1,526]

It (carb icing) used to be dead common on old carb fed stuff, if the hot air duct off the exhaust manifold wasnt there they'd drive for 10-15 mins and then die off. No amount of cranking would revive them. Leave it for half an hour and it would start again like nothing was wrong and do another 10-15 mins driving. One that springs to my mind that was especially bad was my mates old Mk2 VW Polo 1050cc. We once pulled the carb off and make no mistake it was almost totally blocked with a plug of ice.

[gingerdave 0 1 Cars]

It (carb icing) used to be dead common on old carb fed stuff, if the hot air duct off the exhaust manifold wasnt there they'd drive for 10-15 mins and then die off. No amount of cranking would revive them. Leave it for half an hour and it would start again like nothing was wrong and do another 10-15 mins driving. One that springs to my mind that was especially bad was my mates old Mk2 VW Polo 1050cc. We once pulled the carb off and make no mistake it was almost totally blocked with a plug of ice.

But I struggle to see how there could be ice left it it now? We've had several days of double figures temepratures and I've driven it a fiar bit (only short journeys) so I don't see how any ice would not have melted?

[jackherer 543]

Driving it creates the ice, the airflow and fuel evaporation acts like a fridge or air conditioner.

 

http://en.wikipedia.org/wiki/Carburetor_icing

[trogboy 17]

Did you get to the bottom of this? I don't recall ever having carb icing issues in any of my TU engined cars and for quite a while I ran without the hot air hose on the rallye.

 

I can remember fuel evaporating out of the float bowl in the carb once stopped when the engine was hot though - carbs are such great fun!

[johnnyboy666 195 1 Cars]

Not sure if you got to the bottom of this, but its worth taking the brass fuel inlet off the carb, as there is a tiny filter inside it. If that is broken/blocked/degraded, it will cause issues, and if its in backwards, it will let a bit of fuel through when you start it, then get sucked in and block all fuel (don't ask how i found that out!)

[gingerdave 0 1 Cars]

Nope not got to the bottom of this. Last 2 times its happened its been started, run for 15 minutes fine, then stopped for a short while (picking someone up or supermarket) then started, and cut out within 5 minutes.

 

How simple is that fuel inlet to get to johnnyboy? I think getting the fuel tank off is going to be my best bet.

[Henry 1.9GTi 36]

had an engine cut issue on my 1.4 single carb engine. Was a GR i think.

 

Turned out to be the ignition amp. I cant remember if I replaced it or just redid the thermal paste on the back side of the module.

 

Hope this helps.

[johnnyboy666 195 1 Cars]

The inlet bit is easy to get to, its the bit the rubber fuel hose attaches to on the carb

[gingerdave 0 1 Cars]

Sorry for the period of silence, basically got pissed off with it and have left it for the last couple of months. Back on it now though.

 

johnnyboy- that filter looked fine so guess thats not causing any issues.

 

Henry - cheers for the suggestion, that does sound like a good candidate, so have ordered a new one and will get a tub of the heat paste and hopefully get that on this week.

 

I've listed it for sale on Pistonheads, gumtree, ebay and Autotrader (don't think I can post for sale links in this section of the forum and can't create a for sale thread myself for some reason, so PM me for details) for £600 as currently not working/will need towing, but if I get it fixed I will be able to keep hold of it.

[gingerdave 0 1 Cars]

So the new ignition amp & paste didn't make a difference.

 

May well still be an ignition problem (but not the amp) as when it starts struggling there is an increased smell of fuel in the exhaust and white smoke when revving then. Ho-hum

[pugdamo 111 2 Cars]

Have you pulled the carb apart yet?To rule anything out with the tank and supply pipes you could set up a remote fuel tank, plumb that into the pump and see if the problems still there.

[Telf 222 2 Cars]

I was looking at your XS on Ebay last night!

 

I reckon you would be better of trying to fix it - It cant be that expensive a fix surely?

 

There's plenty experienced folk on here who will get to the bottom of the issue. I cant help because I know nothing about Carbs or TU engines

 

Good luck