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Jimmy Business
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 Posted: Thu Apr 24, 2003 4:25 am Post subject: Idle speed slow to return |
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Just recently I've noticed that my idle speed has been dropping back to about 1500 before eventually, slowly returning to normal. Happens once it's hot. They are 36mm idf webbers on a 1.7 8V conversion in an 86 - not sure which series....It has the moving instrument panel, electric windows etc.
I have custom K&N filters, modified and mounted on the original, pollished alloy ram tubes. The linkages feel pretty good, not sticky. The cable and action is very light and responsive. I feel that it may be something in the carbs themselves. Runs well otherwise. May be running just a tad rich, that's all. A little "blip" on the throttle doesn't help.
Kinda stumped and tend to be a little weary of mucking with carbs. Just wondering if anyone has any ideas or perhaps may have experienced the same thing.
-Jas
ps. Doesn't run lumpy when idle is high, so perhaps it is the linkages?!! |
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Guest
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| Posted: Thu Apr 24, 2003 7:58 am Post subject: |
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| Had the same problem. Carbs were out of balance with each other. Retuning and balancing carbs cured it. |
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Mixsynth
Alfa Sprint
Joined: 27 Mar 2003
Posts: 165
Location: Peterborough UK
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| Posted: Thu Apr 24, 2003 12:20 pm Post subject: |
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My '89 1.7 twin 40mm did exactly the same. Possibly just what the guy above says, rebalancing necessary. I never got round to that.
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Hugh B
'98 145 QV
'89 33 1.7 16V Veloce SportWagon (in hibernation)
16V conversion pics/videos - now updated with extra pictures and explanations |
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neo
Alfasud
Joined: 14 Mar 2003
Posts: 68
Location: Rijeka, Croatia
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| Posted: Thu Apr 24, 2003 1:37 pm Post subject: re |
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| Quote: |
| Just recently I've noticed that my idle speed has been dropping back to about 1500 before eventually, slowly returning to normal. |
Hi,
That is quite normal if the engine is hot and has been driven agressivly for some time.
Generaly if the revs are dropping too slow you have too rich mixture. If the idle is at about 1500 and stays that way you have the butterflys to much open. If the revs drop fast to 1500 and then slowly to 900 - 1000 when the car was driven hard then everything is OK. |
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micap
Alfasud
Joined: 14 Mar 2003
Posts: 62
Location: Denmark
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| Posted: Tue Apr 29, 2003 2:25 pm Post subject: |
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I have experienced the exact same thing the past couple of days, exept my idle stay at about 1500 rpm. Is this a balance problem too, or what could be wrong?
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/Michael
ex 89 1.7 QV
now 85 1.5 QV with 1.7 engine. |
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neo
Alfasud
Joined: 14 Mar 2003
Posts: 68
Location: Rijeka, Croatia
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| Posted: Thu May 01, 2003 11:11 am Post subject: re |
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| Quote: |
I have experienced the exact same thing the past couple of days, exept my idle stay at about 1500 rpm. Is this a balance problem too, or what could be wrong?
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Hi!
If the car doesn't shake then it isn't a balace problem. If the idle is too high all the times then check if the acceleration mechanism is stuck somewhere. If that's ok then you can lower the idle speed by acting on the idle screw on the carbs. There is 1 screw for each carb block. You can lower idle speed by unscrewing that screw equally on both carbs witouth affecting the balance.
If the car shakes then you need rebalancing and to do that you'll need a synchrometer. |
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ricardo
Alfasud
Joined: 13 Mar 2003
Posts: 43
Location: wellington .... new zealand
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| Posted: Thu May 01, 2003 1:17 pm Post subject: distributor weights |
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well yes it can be your carb balance but check also your dist,
the shaft can get dry as can the weights...these can stick giving advance and a high idle...........
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alfa romeo trofeo series new zealand, video site .
http://alfa-racing.blip.tv/
alfatrofeo blog and interesting stuff .... unofficial ....
http://alfatrofeo.blogspot.com/ |
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Guest
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| Posted: Thu May 01, 2003 5:06 pm Post subject: |
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| Okay. what's a dist? Guess it's something inside the carburettor but what? Maybe I should consider a carburettor rebuild. |
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nickus?
Alfa Arna
Joined: 13 Mar 2003
Posts: 20
Location: Kent,U.K.
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| Posted: Thu May 01, 2003 6:49 pm Post subject: |
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| dist=distributor(where ht leads go) |
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Guest
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| Posted: Thu May 01, 2003 9:16 pm Post subject: |
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| Ok, that helped. What exactly is there to check at the distributor? |
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