 soot on the intake runners |
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| VaccaRabite |
 Mar 4 2020, 07:33 PM
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#1
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En Garde!  Group: Admin Posts: 13,441 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region  |
(IMG:http://www.914world.com/bbs2/uploads_offsite/live.staticflickr.com-1435-1583372025.1.jpg)
I'm not getting a lot of work done on my car this winter. Its been so mild I keep driving it every time I open up the garage to work on it. I'm getting oily soot on the outside of my intake runners, clearly burping out from the joiner hoses at the manifold. Why is it there, and is it something that I need to be concerned about? Zach |
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| Bleyseng |
Mar 4 2020, 10:03 PM
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#2
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Aircooled Baby! Group: Members Posts: 13,034 Joined: 27-December 02 From: Seattle, Washington (for now) Member No.: 24 Region Association: Pacific Northwest |
Is the engine backfiring?
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| Krieger |
Mar 4 2020, 10:10 PM
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#3
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Advanced Member Group: Members Posts: 4,705 Joined: 24-May 04 From: Santa Rosa CA Member No.: 2,104 Region Association: None 
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You have a wire unhooked. How old are those hoses? Are they hard and not sealing?
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| VaccaRabite |
Mar 5 2020, 07:15 AM
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#4
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En Garde! Group: Admin Posts: 13,441 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
QUOTE(Krieger @ Mar 4 2020, 11:10 PM)  You have a wire unhooked. How old are those hoses? Are they hard and not sealing? The wire is the grounding wire that you use to put a new firmware on the ECU. The hoses may be 45 years old. They were on the 1.8 parts I got from Joe a decade ago when this engine was built. If the engine is backfiring I don’t hear it. But it’s certainly possible. Zach |
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| Krieger |
Mar 5 2020, 09:07 AM
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#5
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Advanced Member Group: Members Posts: 4,705 Joined: 24-May 04 From: Santa Rosa CA Member No.: 2,104 Region Association: None
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Idk the numbers for the pressure changes that is experienced by the intake system, but it is all over the place. From idle with a good amount of vacuum to deceleration and the throttle plate closed with a larger amount of vacuum. Then there is also a reversion pulse when air is flowing back from the intake valve, under certain circumstances, toward the plenum. Just change those big hoses, or maybe clean up the soot and put some big zip ties or clamps on the hoses to see if the problem is eliminated.
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| JamesM |
Mar 5 2020, 10:21 AM
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#6
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Senior Member Group: Members Posts: 1,895 Joined: 6-April 06 From: Kearns, UT Member No.: 5,834 Region Association: Intermountain Region |
QUOTE(VaccaRabite @ Mar 4 2020, 06:33 PM) (IMG:http://www.914world.com/bbs2/uploads_offsite/live.staticflickr.com-1435-1583372025.1.jpg) I'm not getting a lot of work done on my car this winter. Its been so mild I keep driving it every time I open up the garage to work on it. I'm getting oily soot on the outside of my intake runners, clearly burping out from the joiner hoses at the manifold. Why is it there, and is it something that I need to be concerned about? Zach That is a little strange? Are you getting any kickback/resistance when cranking to start? What does your timing look like (cranking and timing table) |
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| Olympic 914 |
Mar 5 2020, 02:59 PM
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#7
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Group: Members Posts: 1,662 Joined: 7-July 11 From: Pittsburgh PA Member No.: 13,287 Region Association: North East States
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It would seem that a leak in one direction would also mean the possibility of a leak in the other direction. a vacuum leak.
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