Smoke Test = Throttle Body Leak - Alfa Romeo Bulletin Board & Forums
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post #1 of 5 (permalink) Old 10-24-2018, 08:03 PM Thread Starter
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Smoke Test = Throttle Body Leak

I discovered that there is a leak coming from the Throttle Body of my FI 1985 Spider Veloce. Lightly pressurized smoke leaks out from each side of the Throttle Bolt near the Throttle Lever and on the other side at the Throttle Position Switch. I can't seem to find any info on the inner workings of the throttle body (or a parts list) after searching this BB and my shop manuals and several online parts shops.

Does the throttle body normally leak a little?

Is the throttle body rebuildable and if so where would one source the parts (maybe it only needs a few o-rings and a good cleaning)?

BTW the L-Jet Technical Document is awesome! While running though the list I decided to built my own very simple smoke machine (a jar with a few connectors screwed into the lid, soldering iron and mineral oil gym sock). I had already found the typical leak where the intake duct is bolted to the valve cover and used the test primarily to confirm the shoe goo fix worked. The L-Jet Doc also helped me discover and fix an intermittent VVT problem, as well as verify what was within spec and point out what needs more investigating (O2 sensor, TPS adjustment etc.).

Thanks,

C
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post #2 of 5 (permalink) Old 10-28-2018, 06:43 AM
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no, there are no o rings there.

The throttle butterfly spindle sits in a bronze bushing either side.
I had a spare inlet plenum in the garage so took a photo....this is from an S4, but should be the same.
If the leak is really small it might not matter too much.
One could remove the butterfly and slide out the spindle and grease where it fits thru the bushes I suppose.
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Dom - Alfa Spider 1990 S4 - formerly: Alfa 101 Sprint, 2600 Sprint, Montreal - family classics: Jensen Interceptor II, '58 Hooper RR Silver Cloud I, Shadow II, '60 Corvette.
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post #3 of 5 (permalink) Old 10-29-2018, 02:34 AM
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Smoke Test = Throttle Body Leak

Quote:
Originally Posted by spiderserie4 View Post
no, there are no o rings there.

The throttle butterfly spindle sits in a bronze bushing either side.
I had a spare inlet plenum in the garage so took a photo....this is from an S4, but should be the same.
If the leak is really small it might not matter too much.
One could remove the butterfly and slide out the spindle and grease where it fits thru the bushes I suppose.

You mention S4...

I thought the S4's were all fuel injected not carbs....

1973 GTJunior 1600 // 1983 GTV6 2.5 // 1992 Spider 2.0 // 2001 156 1.9 JTD
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post #4 of 5 (permalink) Old 10-29-2018, 02:38 AM
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Quote:
Originally Posted by chinocapuchino View Post
You mention S4...

I thought the S4's were all fuel injected not carbs....
they are indeed, as are all USA S3's (car in question here)

Photo is from an injection throttle body...just happens to be made by dellorto

ps: some S4s were also carbed, when 1600 versions...for some eu markets where car tax was very high over 1600cc....Italy, for instance, has many 1600cc S4 spiders with twin carbs

Dom - Alfa Spider 1990 S4 - formerly: Alfa 101 Sprint, 2600 Sprint, Montreal - family classics: Jensen Interceptor II, '58 Hooper RR Silver Cloud I, Shadow II, '60 Corvette.

Last edited by spiderserie4; 10-29-2018 at 02:41 AM.
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post #5 of 5 (permalink) Old 11-23-2018, 06:05 PM Thread Starter
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Thanks for the reply. I will dig more deeply into the throttle body when I send the Fuel Injectors out for cleaning/filter changing etc. I'll report what I find but it may be January before I have an update.

Cheers!
C

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