Technical Uno Fire 93 gets dangerously close to the red when idling or standing

[Seanlr]

Hi (Again)

My uno Fire 93 gets dangerously close to the red (hot) when idling or standing still at stop streets and while waiting for the lights to change.

the idling does not sound as good as it should either and the car has trouble idling in the mornings when its cold and the choke does not really help, i end up sitting with my foot on the pedal keeping it idling for around 3/5 mins before it will idle on its own and even then i need to drive a bit before it actually will idle on its own.

im busy replacing the head gasket and have the whole car in pieces so i thought i may as well see if i can get this sorted whilst im at it.
(im also doing tie rod rack ends)

ive given the carborator a good blowout with carb cleaner and that helped a little but not much.

ive replaced all the gaskets and wotnot in the carb (entire carborator kit)recently as well but its been this way since then, (before that it was much worse.)

 

[Seanlr]

just a quik note the vacum advance is also fine (checked it last nite)

 

[alexGS]

Couple of possibilities I can think of:

Blocked idle jet in carburettor, or faulty fuel cut-off control unit (if so equipped). Check by disconnecting fuel cut-off valve at base of carburettor - any difference? Remove jets from top of carburettor and blow out with compressed air. Maybe remove cover and check float level (top surface of float to carburettor cover should be 7mm, with floats hanging vertically).

Ignition timing - too far retarded will cause overheating and rough running. Without the vacuum advance connected, you should have five degrees advance (I think) for the 1108cc FIRE engine.

Air leaks - remove and re-fit inlet manifold, though if the head is off I guess you'll do this anyway.

Check cam timing. Fine notch in cam pulley should be at '42 minutes' (lining up with V-notch in cylinder head casting) with engine at TDC. If out by 180 degrees, turn engine one complete turn and recheck... If cam timing is out, ignition timing will also be affected.

Ignition module - prone to failure giving odd ignition timing symptoms. Try a replacement if you still can't seem to get the timing within limits.

Good luck!
-Alex

 

[Seanlr]

thanks, well thats my sunday gone better stock up on beers

 

[(CZ)enda]

Ad overheating:
a) Is the thermostat OK? Answer is probably yes, AFAIK faulty Uno thermostat does not cause overheating, but under-heating (hope this makes sense).

b) Does the ventilator behind the radiator work? Does it swith on at about 90°C?
Wiring can be checked by shorting the pins on cable connector, the ventilator must switch on even with ignition off.
To check the switch, it can be heated in a pan filled with water (do not submerse the contacts, obviously ). Thermometer used for making pickles comes handy to check the temperature, use a multimeter to check whether or not the switch works.

 

[whiggy94]

Hi, my uno recently had this problem and it was the thermostat!!! replaced that and its ben fine ever since.... u may as well do it anyway if your doin the cyl head... hope this helps!

 

[Seanlr]

thanks guys, due to a wedding this weekend my entire weekend was stuffed :bang: :bang: :bang: so ill be doing all this in the evenings (as well as the head gasket).

anyways i have a decent digital thremometer ill check all temps and cutoffs.

i have so much space between my engine and my radiator ive had people also suggest i put a 2nd or bigger radiator fan in. befre i do something like that, is it wise?

 

[Seanlr]

i have so much space between my engine and my radiator ive had people also suggest i put a 2nd or bigger radiator fan in. befre i do something like that, is it wise?

lol sorry pc geek what do you expect? (my pc sounds like a helicopter during takeoff with all the cooling ive added, mus say its pretty well clocked tho)

 

[alexGS]

Ah - yeah, not really necessary to have a second fan on the radiator... it'd be more effective to fit a cooler thermostat if the temperature bothered you (you can probably get a cooler fan switch as well).

In theory (thermodynamics) the radiator becomes more efficient the greater the differential between the radiator and the surrounding air (makes sense) - so therefore, as the coolant gets hotter - the radiator can actually shed more of the engine's heat! A slightly strange thought - of course it reaches a practical limit when the coolant boils and prevents circulation, not to mention the pressure forcing most of the coolant out...

By fitting a bigger fan/more fans, you would also be improving the radiator's efficiency - but currently, the thermostat probably spends most of the time partly-closed, and so the radiator's existing efficiency is probably not being utilised.

As for the PC, I once had problems with my AMD Athlon 1700+ running at 66 degrees (not overclocked) causing the computer to spontaneously lock up/reset. I bought a big solid copper Thermaltake heatsink with really loud, 7000RPM+ Volcano fan. That reduced the temperature to 64 degrees.

I spent about twice as much (as the heatsink) on a new Athlon 2500+ processor. I fitted the standard (small) fan on the plain anodised aluminium heatsink supplied. The temperature? 45 degrees. No more lockups/resets!

I think the moral is that if there is a problem, a better fan won't necessarily fix it

-Alex

 

[alexGS]

However, re-reading the original post, I have to say that I think you are right to suspect the fan if you only have problems when idling/stationary. Are you sure the fan is working to its original capability (should be quite fast ~5000RPM and pretty loud, louder than most other cars). However, it is normal for the fan to not cut in until the gauge reads approx. 100 degrees.

-Alex

 

[Seanlr]

lol im running my P4 2.66 Ghz @ 2.88Ghz (temp is 36'c) i would not recommend overclocking an amd tho.

my ram is 400Mhz im running it @ 436Mhz (+ .01 V as well)

one 220V extractor fan (the type they use in hub stacks and servers) to suck fresh air in from the front
one power supply type fan sucking the heat out of the pc by the cpu, the cpu fan and the power supplies fan and i have a cyclone fan on my graphics card blowing the heat out the back, wich really helps my stability (geforce fx550 wich came out without a fan???)


lol ok that was very off topic.

im going to check the thermostat and ventilator as well as everything else on this page (will jus print and take home 2nite) before i try any insane pc methods on my car.

got the haynes manual on friday so also going to be stripping and putting my carb 2gether again (built from 2 carbs a while back with no knowledge of carbs to fall back on and mostly did it by ear)

 

[Seanlr]

in summary.

carburettor
fuel cut-off control unit
Ignition timing
Air leaks
Cam Timing
Ignition module
thermostat
ventilator behind the radiator
Radiator fan speed

thanks

 

[Seanlr]

ok i found the problem thought id jus add it in here

the plastic pipes used in colder areas to increase the airflow/heat and help the car drive and start in the mornings (1 to engine 1 to air filter)

i took all these pipes out (as they were not doing anything 4 me in sunny sa)and the 1 wich attaches next 2 the radiator had a plastic thing wich it attached 2. thanks 2 not having the pipes 2 keep it up it fell infront of the radiator causing a airflow problem.

well im going 2 use this anyway 2 increase airflow slightly2 the air filter (has a cone shape on front that can be used)

thanks 4 all the help and i found a few other problems whilst in the process of looking 4 this silly 1 so was not a waste of time.

 

[alexGS]

Good to know. Have you tried flushing the cooling system also? Radiators don't fail often but they do occasionally get blocked.

I found your message rather challenging '2' read, with the double use of the numerals... must have taken ages writing like that... and you missed a couple of 'to's in (1 to engine 1 to air filter).

I must get you to explain "Fish or cut bait" some time
-Alex

 

[Seanlr]

Sorry about that, bloody got myself confused writing that.

i flushed the cooling system when i replaced my head gasket, firstly using water then by using a wet and dry vacumm cleaner whilst the head was still off. (blew as much of everything i could out then put the vacumm cleaners pipe (on blow) into the radiator cap's pipe and left it like that for a good 10 minutes.

worked a charm, got alot of slag and other rubbish out. also since then i have put nothing but anti freeze in (sunny sa, most people just use water with a bit of anti freeze to prevent boiling).


Fish or cut bait: Decide what u want to do/assert yourself or get the sh!tty jobs.

 

[alexGS]

That's a really good idea for flushing the system through the radiator! Thanks for that, we have a couple of industrial wet'n'dry vacuum cleaners at work.

'Fish or cut bait' - makes sense now

Cheers,
-Alex