General Fiat Uno power loss + starting problem??

[Karlakarl]

Hi,

I have a problem with my Fiat Uno. It is old (1989) but has ran fine until a few weeks ago. I have taken it to garage for repair but they didn't fix it. They did a few other repairs which they felt caused the problem that I had to pay for but it still runs bad.

The problem happened over night. I had parked it outside when I got home. During the night it was cold, some -10 degrees and still cold in the morning. In the morning I had to run the start engine until the battery was almost flat and it only started (like first starting on one cylinder - but my opinion was that it ignited evenly on all) when I put the gas pedal to the bottom, and I had to keep the start engine running although the motor ignited.

Then after starting, it stopped, if I didn't give a lot of gas. Then when driving it has no power. I cannot use the 5th gear. Top speed is about 90 and it only rans when I keep a high rpm. And even then it has little power (at low rpm almost no power at all). The strange thing to me is that it seems to run on all cylinders evenly but it has no power. When reaching full speed you can still give more gas (with the pedal) but without any power or speed increase - rather the opposite.

At the repair shop they said that it gets enough gas and the mixture is ok, but it has no sucking power. The valves were adjusted.

Then one thing more. when stopping the engine you always (with a couple of seconds delay) hear a bang!

Now, my theory is that there has came water into the (ignition) ditributor which when freezing has moved something which makes the ignition late (on all cylinders)?? Does this seem reasonable? I just cannot find a place to adjust this?

Can somebody please tell me where the fault is and what to do, because I don't want to take it for repair without result once again.

Thanks!

PS. Sorry if I haven't got all the terms right. English is not my mother tounge...

 

[andre79ge]

Very strange symptoms... it's strange because this big problem began fastly and without a signal...
Did you check vacuum advance unit on distributor? it's connected to the mixture intake (or probably carburettor) and it regulates advance linking advance with throttle position. If vacuum stuff is broken (I can't say it in English) you have engine not advanced (sparks run quite late) and this can cause poor performance. But I can't say if vacuum advance problems can cause a loss of power so big as yours. You can check your vacuum unit by doing the following:
Disconnect vacuum hose and try to suck from the vacuum unit: if it's OK you will experience a resistance (you can't suck air). If you experience the possibility to suck air, that means your unit is faulty. What about yours engine mileage?
The strange fact is the "BANG" you hear by stopping engine: it's from exaust intake? Consider that exaust mainfold BANGS usually mean that unburned fuel reached exaust collector: but collector is hot and so fuel start to burn very energetically causing bangs.
SO, if you have bangs from exausts, you can start to think to a ignition problem that causes a poor explosion/loss of sparks/faulty ignition of mixture. Then unburned fuel leaves the engine via exaust.
So you can check your distributor, ignition module (I think it's a mechanical module, with condenser and breakers... I don't know this module because my UNO is with breakerless module-fuel injection).
I hope to be helpful!
Andrea.

 

[Alex]

Following of from above.

Did the garage check the valve timing? Perhaps the cam belt slipped when you tried to start it when the problem started, have you checked the cam belt is tentioned correctly?

 

[Karlakarl]

Little time right now...

Thanks for your tips. I will take them into consideration. First I will try to replace the distributor rotor head. I tried to pull it off but it was stuck. Then when I got it loose it was broken Maybe it was jammed in the distributor (by ice??)). I'll look for a new one and then I'll do more checks!

Karl

 

[Morty Mort]

Check your cam. If the engine has overheated (a long time ago) the thin hardened layer of the cam is destroyed, making the cam not a cam any more, just a round cylinder shape. This does not open the exhaust valve (if it is one of these cams) and the exhaust has to come out somewhere, usually out the air intake. A bang occurs.

The headgasket on my Uno actually broke when idling !!! Had parked outside the hospital to pick up wife and kid, and let the car idle for 5 minutes when we talked. The car coughed, stopped and was unstartable. Only bangs and crackles. The gasket went between two cylinders! Read my post in the "Lets talk Fiat" forum (search for "compression failure").

First take the rocker cover off to check the cam.

Morten.

 

[Karlakarl]

Hi,


The soultion to the problem was that the cam belt had slipped. Then also the ignition was not correctly timed.

Now it runs as it used to run. More power and no bangs anymore

Thanks,
Kalle