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[Horizontally Opposed]

Hi everyone!

After fixing (thanks gritsop ) a few electrical problems caused by water in the relays my 33 is back to normal at last!

What's been bothering me for the last few days though is this:
I've seen a few other cars (like a peugeot 106 first series and 2 newer renaults) that when the engine is cold they keep the rpm high for some time.
My 33 does that too (I've even seen go up to 3000 rpm) but only if I don't press the gas at all during that time.
If I do, I doesn't matter if I rev hard or not, after pressing the gas the rpm goes back to idle even though the engine is still cold.
My car is the 1.4 IE with the Jetronic injection.
I'm guessing there's a problem somewhere...?
Also, lately the engine has no power at all when it's cold (I have to step on the gas just to rev to 2000 rpm). I can remember that a few months ago it had no such problem! It didn't matter if you had just started the engine or not it always had enough power to get you going easily.

[gritsop]

Hi,

When cold it is normal to have the engine working at relatively high rpms. When the weather is cold in the winter it can even go up to 1500 rpms. Actually I 've never seen in my car going up to 3000rps when cold ... Is this happening all the time or just once and never again?

The reason why the engine runs a bit high is the extra air solenoid valve. Its purpose is to give some extra air in the mixture for the first hard moments of engine warmup. When you press the pedal the valve simply closes and air quantity goes back to normal.
If you take a look at the valve setup (located under the intake maniford between cyl 1-3) you will see two hoses. First hose goes in the middle of the manifold - radiator side and second goes to the corrugated sleeve after the ECU. When valve operates air coming from outside is redirected via the valve to the intake, so extra air is sucked by the engine in addition to the quantity that is normally required. When valve is closed no extra air is given to the engine but only the normal quantity that is required.

That's why idle is around 950 rpms

Finally as for the loss of power , I once had such problem when cold. It turned out to be a "faulty" spark plug that when cold could not function as it should. When above 60C everything was OK. Changed all four and problem sorted out.

Hope I helped.

Regards,
_________________
Thanassis Gritsopoulos
1991 Alfa 33 1.4 IE
2001 Alfa 147 1.6 Distinctive

http://www.alfa-restoration.co.uk
Parts Shop: www.alfa-restoration.co.uk/shop

[Ben_nz]

I have that no-power-when-cold problem with my spare parts car. It's almost impossible to get anywhere during the first 5 minutes after starting the car unless you use a million rpm and slip the clutch heaps.
It's not worth me trying to fix the problem, but it's interesting to know that it's probably related to the ignition system.

[Horizontally Opposed]

Thanks Gritsop good idea!
It's about time I changed those spark plugs anyway so I guess I'll do it this week.

As for the extra air solenoid valve, shouldnt it stay open for some time (until the engine is warm)?
Are you saying that this is how the jetronic system is designed (because it seems somewhat inefficient)?
In a few other cars I've driven it doesnt matter if you press the pedal or not, the rpm is high for as long as it's needed.

I know the Jetronic is a rather old system but it doesn't seem that big a deal to keep the rpm high, since there is an extra air valve present and the system performs other processes related to time and temperature.

As for your question, actually I've seen the RPM go up to 3000 only two or three times but it always goes up to 1500 or a bit more when the weather is cold.

[gritsop]

Hi,

Actually that's how it works ... other Jetronic 33 Alfas do that thing.

When you have pressed the pedal and rpms go to idle, they stay at it and within a few seconds they do rise again till they fall again. This procedure is done for few times until the temp. has risen above 50C where the engine is not considered cold anymore.

Is your car doing such thing?

Regards,
_________________
Thanassis Gritsopoulos
1991 Alfa 33 1.4 IE
2001 Alfa 147 1.6 Distinctive

http://www.alfa-restoration.co.uk
Parts Shop: www.alfa-restoration.co.uk/shop

[bobbber]

Hi,

The extra air solenoid is open when the car is cold (and when you first start it).

It is heated by an electric element which then makes it close. This takes a while, but is faster than waiting for the engine to warm up. The valve therefore should not close after the first press of the accelerator, but after the element has had time to warm.

Rob
_________________
Fiat Bravo 165 Sport

[bobbber]

I'd check (first) :

Plugs

For any leaking pipes after the air flow meter

temperature sensor

the extra air valve itself

Any problems with this - let me know.

Rob
_________________
Fiat Bravo 165 Sport

[Horizontally Opposed]

Thanks very much guys!
I guess there's something wrong with the valve or the other things bobber mentioned because the rpm in my car only rise until I press the accelerator. After that it falls to idle and never rises again.
I'll try to find the solenoid valve from gritsop's description when I have more time during the weekend and see how it goes from there!
Thanks very much everyone!

Manolis

[bobbber]

Goto : http://www.alfa-restoration.co.uk/

and click 33 manuals. There are a couple of diagrams under the "Electronic Injection Testing/Servicing (Jetronic LE3)" which I hope are of help.

Rob
_________________
Fiat Bravo 165 Sport