Club126UK
Fiat 126 Chat => Fiat 126 Mechanical Problem Solving => Topic started by: 126cab on January 09, 2006, 08:32:19 PM
-
Hi i seem to have one of those little silly faults i cannot seem get my head round on my 500 Giardiniera estate, the car will start fine cold and tick other, then as it starts to warm up starts hunting some times flooding and then will stall if i dont put some revs on, it will then not start unless i have full throttle on, the spark plugs are black with soot, ah you are all thinking punchured float, faulty needle valve, no both checked both ok, i have striped the carb down completely and boiled the carb housing, cleaned internals and jets ect with carb clean, renewed all fuel lines cleaned and treated petrol tank, still runing rich. Any one got any ideas please as i dont know what else to do. :cry:
,
Ps fuel pump pressure not accesive.
-
Have you checked the setting for the idle adjustment screw? Also check that the choke lever is not partially on!
-
Thanks for your quick responce m8, yes checked both and both ok,
-
Have you checked the bob weights are not sticking in the distributor? It's a well known fault on the 500 and 126's it also causes an erratic tickover! It's worth taking the distributor out to check the weights and also do the points and timing at the same time.
Also worth checking valve clearances which again can cause tickover problems.
Good Luck
C
:)
-
Hi there,thanks for your quick reply no i have not checked bob weights or valve clearenc but have checked timing, i will check them tomorrow and let you know how i get on.
-
For the bob weights take the points and top plate off the distributor, give the bob weights a good spray with WD40 then make sure they are not sticking.
C
:)
-
Also change the air filter - it may be clogged or just crap.
-
does the BIS distributor have bob weights?
Chris
-
Sure does!
-
they wont affect the fuel mixture though, just the advance and retard. how many turns out is your mixture screw? also, the tiny rubber O ring on that screw perishes, and then your mixture will sef adjust!
-
Hi Fiatfsm, thanks for your reply, the mixture screw is approx 2 1/2 turns out from fully in, (does not make any difference 1/2 turn each way) the mixture screw has no o ring on it m8, my other cars mixture screws has no o rings either. im just at a loss as what to do next appart from big hammer lol. :cry:
-
Hi Cab, have you checked the petrol inlet needle valve and seat, have you checked the the float to make sure its not punctured, and have you checked the float level which is adjustable by bending the tag that rest against the inlet needle valve, this has to be set to the correct measurement to allow the petrol to be shut off at the correct level, i've tried to find out what this is but know luck, maybe someone out there has this info
-
If you are sure its not the carb (it may not be dirt - could as easily be wear), air filter or valves then check out ignition. Swap out the condenser, coil and set the points and timing.
-
Hi Pedro126, thanks for your reply, i have checked all that you mention m8 and all seems ok however i am going to get a new valve needle just to be sure, as a matter of interest the float setting is 7.5mm from to of carb gasket to top edge of float on the estate car.
-
thanks for that info 126cab, don't know what else to suggest (scratches his head) try what the other members have suggested i've had the same symtoms on an old viva that turned out to be points and condenser, let us know how you get on,
-
no O ring then? Weird, because on the 126, at least Polish ones there is, and without it the mixture screw vibrates one way or the other! Maybe the 500 screws fit better?!
-
Hi there every one thanks all for your help in trying to fix my 500, but at long last i have fixed it, to cut a long story short, it was all down to fuel pump pressure (too much) yes i know i said i checked it which i did, it did not seem excssive which it was, so its now ticking over like a little sewing machine and im chuffed to little mint balls :lol: Many thanks again for all your help.
-
Too much fuel pressure did all that? Crikey, better check mine. What was yours showing and how much is ideal - 3psi or something?
-
Hi, i dont know what the correct pressure is m8, i just kept adding shims/gaskets until it stopped flooding, i can see the fuel is still going through looking at the filter. it has got 4 shims & 2 gaskets fitted.
-
I am glad you got it sorted m8!
the fuel pressure data for the 500, 126 & Bis is quoted:>
Fuel pump delivery pressure bar: 0,15-0,20
Not sure on how you test it? but may be of help to someone?
C
:)
-
Hi Cars, thanks for that m8, mine was just guess work but seams fine now.
-
Nice one.
The carb should not flood. The float valve should shut off the supply if the chamber is full - the pump should just idle, so it looks like the carb will be in need of repair or replacement at some point, unless the pump is the wrong one? The 500K had a different pump to the various models used on the 500 and 126 as the K engine is pretty much gravity fed apart from when going down hill.
I can't find a part number for the K pump - there were at least 4 for the 500F and probably many more for the 126.
Axel Gerstyl do a pump (18 euro) for the K, they also do the bakerlite spacer etc. They do a repair kit for your carb for 21 euro.
(https://ssl.kundenserver.de/shop.fiat500126.de/10577b.jpg)
the 500/126 center (Fiatclassic.com) have a set for 15 euro or a carb for 131 euro (ouch).
(http://www.fiatclassic.com/Bilder/B5067.JPG)
-
Hi Paulb, thanks for the info, the needle valve is ok as i cannot get air through when shut and i can also create a vacum in the fuel pipe when needle is closed, the pump that is fitted on the car was fitted new the day before i bought the car so im asuming it was just too much pressure from it as once i added the shims all was well ie plugs nice colour no flooding/ hunting and no stalling. :lol:
Ps perhaps tho after 43 years i should get one of the kits you mention m8
-
If it works it works, so I guess there's no use in fiddling with it any more. Its a shame Fiat didn't put a fuel return on he 500 as it avoids all this and helps keep the fuel and carb cool - especially handy on an aircooled.
-
i may fit an oxygen sensor from my EFI nissan to the exhaust so i can hook up an air/fuel ratio guage. thats always a good way to see what your mixture it like, takes the guess work out of adjustments