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TOPIC: Hot start and fuel evaporation while moving

Hot start and fuel evaporation while moving 3 years 10 months ago #36962

So after ironing out all sorts of other issues im still left with this one.

After about an hour of driving, say at speed on a motorway, when I then go onto slower roads and stop at lights etc the power starts to disappear more and more until unless Im revving like a mad person it will just die. Usually at traffic lights or somewhere awkward. It then won't start until cold again.

The last time it did this i noticed no fuel was in the inline filter, but then when it had gone cold again a bit had reappeared and it started again.

It happens pretty much every journey, any ideas? Could the pump be faulty? it has a slight leak on it it seems.

The fuel lines themselves are virtually new. I assumed it was fuel evaporation at the carb but it seems like its not even getting that far.

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Hot start and fuel evaporation while moving 3 years 10 months ago #36963

Grant, does the cars "cough" and then "bdbdbdbdbdbdbdbdbd" before dying, regardless of how hard you slam on the throttle pedal?

Mine went through a phase of fuel starvation issues, took me a whole weekend to rectify and even now, I'm not completely sure of what I did to resolve it.

www.x1-9ownersclub.org.uk/forum/virtual-...56-poor-running.html
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Hot start and fuel evaporation while moving 3 years 9 months ago #36965

Hi Hywel,

Reading that thread it all seems depressingly similar to my experience. I tend to be able to get further and the instances are more random. In April I made it from Manchester to Brooklands, last weekend it only went for 30mins and then cut out.

Ive replaced the fuel lines, filter, cleaned the carb, fitting an electronic ignition, cleaned the earth...

Next to try is an electric fuel pump but it sounds like that might not be a certain cure either.

Its maddening how something that seems so simple can have everyone, garages included, completely baffled.

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Hot start and fuel evaporation while moving 3 years 9 months ago #36966

I did at one stage have similar problem after I had changed a fuel tank.
Root cause was OEM element filter on bottom of fuel pick-up pipe inside the tank was clogged with 30+years of grot. Changed it for a cleaner one that was in my old tank. Sorted.

(Disconnect battery. Undo all fuel pipes from tank inside engine compartment, Undo earth, undo ring of small nuts, extract fuel gauge sender and with fuel pickup pipe with filter on end.Clean and reassemble)

Perhaps this helps?
Fiat x1/9 hillclimb car (competition modded)
Fiat X1/9 road car (bsically standard)
Saab 9-5 2.3t 'Maptun'
Porsche 911 (996)
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Hot start and fuel evaporation while moving 3 years 9 months ago #36970

I had the same symptoms and fitting a new manual fuel pump cured the engine dying and hot starting problems. Old pump was full of crud. Easy job and pretty cheap so worth a try if you haven't already
Kev
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Hot start and fuel evaporation while moving 3 years 9 months ago #36977

I bought an exxy a couple of years ago that had this problem - I spotted that the fuel lines had not been fastened back to the bulkhead as they should be, they were floating around in the space between the cylinder head and the bulkhead. Once the fuel lines were clipped back to the bulkhead normal service was resumed...

I'd also check for the presence or otherwise of the heatshields between the carburettor and the exhaust.

Modern fuel is more volatile than the 4* that these engines were designed for, so every little helps.
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Hot start and fuel evaporation while moving 3 years 9 months ago #36979

Thanks everyone, I think ill start with replacing the fuel pump and see if that makes a difference first. Is there a particular electric one anyone can recommend?

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Hot start and fuel evaporation while moving 3 years 9 months ago #36984

the in-line Bosch ones are good and easy to mount although I'm not sure whether they deliver too much pressure? - The one I use on the SPI Tipo engine is 1 bar? This engine and injection set up doesn't suffer from vaporisation at all.

I guess its just the car float chamber etc that heats up. Does your carb cooling fan work?

The heat shields were also fitted to the tipo/tempra and possibly the mk1 Punto sporting also? The heat shield on mine still looks like new so if you can find one it might be worth a try.
Who needs 4th gear anyway...

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Hot start and fuel evaporation while moving 3 years 9 months ago #37005

An electric fuel pump cures the fuel vaporisation by the continuous flow of cool fuel through the carb. However you need a pump for a carb not injection, 1 bar is way too much. The other issue is that the pump must be capable of lifting the fuel around 70 cm as the X19 tank is vertical, a lot of pumps can't do this reliably. Facet do a very good range of pumps but check the specs and I would also fit a regulator as well. 3 or 4 psi is about what you need. The carb cooler fan is a waste of space in my opinion and most people ditch them if they have an electric fuel pump.

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Hot start and fuel evaporation while moving 1 year 1 week ago #40609

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Hello all

just joined after researching the issues causing my car's similar misbehaviour.

In an earlier post on this thread there was a link as follows:

www.x1-9ownersclub.org.uk/forum/virtual-...56-poor-running.html

it does not seem to work but i'd like to see it in case it sheds light on my car cutting out every time 20 mins in to the drive. If any one can check the link or re-post, that's be great.

cheers

RDS

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Hot start and fuel evaporation while moving 1 year 1 week ago #40628

I recently had a similar issue, thought it was fuel system so changed pump, pipes, cleaned, rejetted carb to no effect. Turns out by it was an open circuit ignition lead which was still working but it meant higher voltage generated by the coil, the coil itself became hot and failed intermittently. Changed leads and coil and all is well. So check leads with ohmmeter thoroughly first, can also check coil resistance and temperature when running, ours was too hot to touch. Sounds like yours is caused by temperature too. Good luck

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Hot start and fuel evaporation while moving 1 year 6 days ago #40634

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Hi RDS, could this be the thread you are looking for? It’s in a club member only part of the forum....

www.x1-9ownersclub.org.uk/forum/5-faults...56-poor-running.html

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Last edit: by NRG.

Hot start and fuel evaporation while moving 1 year 6 days ago #40636

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Yes that must be the one thank you NRG. Alas i do not have access!

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Hot start and fuel evaporation while moving 1 year 6 days ago #40637

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kevin tibbetts wrote: I recently had a similar issue, thought it was fuel system so changed pump, pipes, cleaned, rejetted carb to no effect. Turns out by it was an open circuit ignition lead which was still working but it meant higher voltage generated by the coil, the coil itself became hot and failed intermittently. Changed leads and coil and all is well. So check leads with ohmmeter thoroughly first, can also check coil resistance and temperature when running, ours was too hot to touch. Sounds like yours is caused by temperature too. Good luck


Hello Kevin

many thanks for this and commiserations!
However, please can ask:
1 did you mean one of the HT leads was open circuit? I checked mine for resistance and all were within the range 8.7Ohm to 9.3Ohm although getting a good reading on the cap end terminals was annoying.
I also fitted inline spark indicators to two or three of the plugs (the fourth would not fit) which showed there were sparks for as long as i had the items fitted (this is not the sale as saying that they were always firing however, as you have found out). Nevertheless, there was no characteristic lumpiness of an engine firing on three out or four cylinders. As a result i assume that things are ok at the HT end.
2 my coil is also hot but my calcs indicate (from memory) that the wattage would be around 48W and a 40W light bulb is too hot to handle also. I meant to compare the heat to others at a car show on Saturday but of course forgot to do so!!
3 as the cut off is so abrupt i am wondering, like you, if there is a connection that is failing when hot and re-setting when cooler eg in the ignition switch. Any views on this welcome!

Thanks again for all your input.

cheers

RDS

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Hot start and fuel evaporation while moving 1 year 6 days ago #40638

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The ‘fix’ from that thread was a little vague so may not help:

At the risk of giving it the kiss of death, I appear to have fixed it. Not 100% convinced, mind you.

After my tantrum yesterday, I gave it an hour and then went right back to basics. Ignoring it's Italian-ness, I stripped off the fuel lines in their entirety. I checked the sender unit for damage and ran a thin cable down it to ensure it was clear.
New fuel hose between tank and pump, routed as far away from the engine as possible. New hose from pump to carb, also routed as far away from the engine as possible. New in-line filter fitted into this hose, so filtering after the pump but before the carb.
Plugs removed, cleaned and gapped. Points checked. Condenser removed and it's contact/earth cleaned and re-fitted.
Carb jets & tubes removed and cleaned/blown through. Accelerator pump removed, checked, cleaned and refitted. Carb inlet gauze filter washed in fresh petrol and refitted. Floats cleaned and checked. Same for the float valve. Float chamber emptied, blown through with compressed air, washed with carb cleaner. Carb reassembled.
Air filter housing was wire brushed, washed with carb cleaner, dried and refitted.

I took it out for a test drive and got a 15 mile run out of her with no problems at all. I've done another 15 today and she's still fine.

Which leaves a nagging doubt is that I couldn't point to any one thing that looked wrong or broken. There wasn't a large chunk of rust in the float chamber, fuel filter was clean. The coil looked old but may well have been fine. Hence my hesitation in declaring all is well.

Honestly, as one point yesterday, I would have sworn that the car had some kind of proximity sensor on it, that prevented it being driven more than 500 yards. I was looking at manhole covers and waiting for the dreaded "cough-brbrbrbrbrbrbrbrb" which would signal me stabbing the hazard lights and looking for somewhere to pull over without blocking too much road. And then practice my swearing for a few minutes.

The engine bay looks like a dogs dinner now, and I have a minor weep at one of the pump hoses (I think that clip is all but stripped - I'll sort it out in the week, the car isn't being used for a few days).

Thanks for hints and tips, gents, and sorry for being a drama queen about it. I reckon another 100 miles or so might have restored my faith in it somewhat

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Last edit: by NRG.
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