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alfafan · Posted: Tue Jun 24, 2008 11:51 pm Post subject: 33 engine malfunction

Hi all

I have a very strange problem on my 33 SW.
It is a 1990 model with a 1.5 engine with hidraulic tappets.
The car idles perfect in cold an hot.
If I press the gas very slowly, it revs very well, very smooth from 850rpm to 6000rpm, so it has the cabs prefetly synchronized.

But if I drive de car and want to use low revs, its almost a nightmare.
For exemple if I put it in 2ª gear, and drive strait at 2000 rpm stabilized, it shakes like it has no gas and the car goes jumping, like the gas is comming the same way.
If I´m in some trafic lights, and put 1 gear and start driving, it looks like it doesn´t have gas and it is slow in acelaration, but if pump the gas 2 times for example, it goes mutch faster. I know its the accelaration pumps on de carbs. But even doing this it doesn´t go as fast as it should be, and it goes shaking, the acceleration cames “jumping”.
If I drive the car at more then 3500rpm it drives almost OK.
But even at high revs it is sluggish. It seams it doesn´t have the power.
When my Sprint had brokem rings it was faster and worked much better then this car, and it had 3 broken rings on the engine, 1 of the top in 3 diferent pistons!!!
I had some other carbed 33 and still have 2 Sprints, so I know these cars very well.
Other thing in this car, it is drinking gas like some drunk uses bear...
All my carbed Alfas do 8,5 liters to do 100km at a Speed of 140Km/h. This one is dooing 10 liters!!!
On city driving it does 14-15 liters!!!

I have lots of spare parts só I started changing parts, but always with the same results.

I changed:

Cabs (tried 3 pairs. Dellortos 40 and Weber 36 – I cleand all of them)
High tension coil
Fuel pump
Fuel rubber pipes on the engine
Air filter (new)
Checked air leaks
Checked for head gasket failure (everything OK, no water on oil, não oil on water, doesn´t drink water or oil)
Ignition distribuctor (tried 2)
Rotor (new)
Cap (new)
Leads (new)
Spark plugs (new)
Replaced big end bearings (were perfect, but I do this to every car I buy)
New oil and Filter when I replaced the bearings (no metal on the oil sump)
Went today to the Inspection (portuguese MOT) and the exhaust gases were fine

So I dont know what to do...
I´m lost in here.

Someone has a clue?

Regards

Carlos Oliveira

bobbber · Posted: Wed Jun 25, 2008 9:10 am Post subject:

Carlos,

Something in the new ignition parts is faulty from the factory? Perhaps the plugs?

Bob
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Fiat Bravo 165 Sport

Ben_nz · Posted: Wed Jun 25, 2008 10:18 am Post subject:

Do you have good petrol with the right octane rating? My car ran roughly at low rpm when I tried to run it on low octane fuel.
Is your engine drawing cold air?
Could it be something in the valvetrain like low oil pressure making the valves not open fully at low rpm? (I don't know if this is possible and I'm sure it would make lots of noise)..
Have you done a compression test?
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"Now, all that is left to do ... is wait that something else brokens, to fix up again!"

Ben_nz · Posted: Wed Jun 25, 2008 10:18 am Post subject:

Delete this post.
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"Now, all that is left to do ... is wait that something else brokens, to fix up again!"

alfafan · Posted: Wed Jun 25, 2008 11:16 am Post subject:

Bob,

Everything I change is fine.
I had the problem from start, and I replaced the parts trying to solve the problem.

Ben,

The petrol is new and has 98 octane, the best available. But if à use 95, is the same.
The engine is drawing cold air from the front.
It has very good oil pressure, não tappets clater.
I didn´t do a compression test, because I dont have the right Tool...

Regards

BigAl · P4 Joined: 06 May 2003 Posts: 2995 Location: U.K Surrey

have you checked the fuel return pipe for blockage?
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x2 33 16v
pictures http://www.alfa-pages.co.uk/viewtopic.php?t=5203

alfafan · Posted: Wed Jun 25, 2008 12:20 pm Post subject:

RFlower · Posted: Wed Jun 25, 2008 1:17 pm Post subject:

Have you checked the fuel supply lines and filter for kinks or restrictions?
There is also usually a filter bag on the end of the feed pipe inside the tank.

Also for any leaks on the carburettor or manifold gaskets where it could suck air? This would mean the carbs would have to be set rich to get correct idle. It would maybe pull OK with low throttle openings but mixture would be too lean with higher loads.

Regards

Richard
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Dick Flower, Nr. Carcassonne. '94 Trofeo 1.4 ie (F), '93 Imola 1.3/1.4 ie (now for breaking) (F), '91 1.7 ie (GB)(spare car), '86 Sprint 1.5 QV (F). '87 VW Syncro camper (F), '73 NSU Ro80 (F), '99 Fiat Seicento (F)

alfafan · Posted: Wed Jun 25, 2008 1:31 pm Post subject:

BigAl · P4 Joined: 06 May 2003 Posts: 2995 Location: U.K Surrey

If it’s the only 1 thing you haven’t checked, you could get some spare fuel line, about 50mm and block it off and remove return pipe and fit it there. Don’t forget to temporally block off the return pipe as well.
This is normally done with a 10 mm bolt and a jubilee clip to hold it in place.
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x2 33 16v
pictures http://www.alfa-pages.co.uk/viewtopic.php?t=5203

RFlower · Posted: Thu Jun 26, 2008 10:56 am Post subject:

BigAl · P4 Joined: 06 May 2003 Posts: 2995 Location: U.K Surrey

alfafan, did you sort it?
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x2 33 16v
pictures http://www.alfa-pages.co.uk/viewtopic.php?t=5203

alfafan · Posted: Tue Jul 08, 2008 9:48 am Post subject:

Oggie · Posted: Tue Jul 08, 2008 6:28 pm Post subject:

Your shakes can be caused by a warped clutch plate, seen this problem on almost every car i have owned , new clutch and the problem disappears for 30-40 thousand miles.
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PHAT 33