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teefivonine · Alfa Arna Joined: 25 Mar 2004 Posts: 5

Hi there,

Hope somebody can help - this is my first post by the way. Sorry if i'm being a bit long winded.

Recently bought an 87 33 Veloce 1.7 8v, I drove it 150 miles from the place I bought it with no problems whatsover. (The car had only done about 200 miles over the last 12 months by the way)
Then the following day developed a huge misife when under load. Car started, idled and reved fine when stationary. I replaced plugs, dizzy cap, HT leads, rotor arm and tried a different coil. The problem remained. I then discovered the compression was down on one cylinder. I guessed it may have been a sticking valve so I changed the oil and put some additive in for sticking valves. After a small amount of use the misfire disappeared then a new one started.

The compressions seem ok now, but the misfire is now just at low revs (about 2.5 to 3.5k) if you accelerate you can drive through it. When at constant throttle on the motorway etc it misfires slighly as well.

Also when the car is ticking over, a kind of phhhhhhht noise occasionally comes from the carbs. Dont know if its relevant or not.

Its driving me nuts as I love the car.

ANY help will be appretiated

Cheers

Phil

lanciachris · Guest

when were the cambelts last done?

teefivonine · Alfa Arna Joined: 25 Mar 2004 Posts: 5

Dont know, I need to get them done really - i was hoping I could get her running right first.

Eddie W · Posted: Fri Mar 26, 2004 11:44 am Post subject:

Hi, sounds a little bit like a blocked idle jet as these control mixture quite high in the rev range on over run and light throttle. Here in NZ , with the change to unleaded the original fuel hoses degrade on the inside and send micro particles through that can block the very fine hole in the idles. As this occurs after the in line filter it doesn't help. Just a thought.
Regards Eddie
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Guest · Posted: Fri Mar 26, 2004 12:52 pm Post subject:

That will be worth a try then - is it a carb off job ?

Thanks for the tip

Toad · Alfasud Joined: 19 Mar 2003 Posts: 42

Check ignition timing.
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paulhide · Posted: Sun Mar 28, 2004 9:53 am Post subject:

Yeah, idle jets run up to 3.5k I think and then the main jets take over. If this is the problem take head off carbs, unscrew jets and clean them. They may continue to block if carbs need an overhaul. Not saying this is definitely the problem as if this were true the car would have great difficulty with tickover unless you play with the choke - something you shouldn't ever need to touch, but if the engine suddenly sounds great at 3.5k then follow this route.
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teefivonine · Alfa Arna Joined: 25 Mar 2004 Posts: 5

I'll definately try the idle jet thing - can anyone help me identify them on the weber carbs. Do they need to come off ?