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Architecture & Porsche's
 
Join Date: Jan 2006
Location: Austin, Texas
Posts: 3,189
928 dyno tuning, reading spark plugs, cleaning injectors.

Hi Guys, I discovered something I need to share.

If you recall I was still tuning my 928 before the '09 OCIC show & when changing my spark plugs, I discovered that cylinders 2 & 3 appeared to be running lean by reading the spark plugs. Because of the placement of these injectors in the middle of the rail, and that the new Bosch 044 pump was now sufficient for my fuel needs, I suspected my fuel injectors & declined they dyno portion of OCIC event.
Well, I got a call this am from the injector rebuilder who does my injectors as he finished up inspecting/flowing/rebulding the 30's that were in my car at that time: #2 & 3 were only flowing 30% because of baked on carbon from excess fuel during tuning. Im very careful with my engine oil changes and reduced interval changes when tuning, so I'm not worried about my engine/oil. I believe this accumulation of carbon occured over time.

Now that I have that set back rebuilt, I'll replace them back into the car again so that they're nice & fresh before my final dyno tuning.

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Porsche Club Racing National Scrutineer
'89 Andial 951
'82 928R
'74 911 RSR 3.6
Old 03-10-2010, 08:26 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
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Join Date: Jan 2007
Location: florida
Posts: 487
Quote:
Originally Posted by MarkRobinson View Post
Hi Guys, I discovered something I need to share.

If you recall I was still tuning my 928 before the '09 OCIC show & when changing my spark plugs, I discovered that cylinders 2 & 3 appeared to be running lean by reading the spark plugs. Because of the placement of these injectors in the middle of the rail, and that the new Bosch 044 pump was now sufficient for my fuel needs, I suspected my fuel injectors & declined they dyno portion of OCIC event.
Well, I got a call this am from the injector rebuilder who does my injectors as he finished up inspecting/flowing/rebulding the 30's that were in my car at that time: #2 & 3 were only flowing 30% because of baked on carbon from excess fuel during tuning. Im very careful with my engine oil changes and reduced interval changes when tuning, so I'm not worried about my engine/oil. I believe this accumulation of carbon occured over time.

Now that I have that set back rebuilt, I'll replace them back into the car again so that they're nice & fresh before my final dyno tuning.
What pound injectors are you using?

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The beast 1984 928s twin turbo 5speed LSD/ 508.6RWHP 495RW ft lbs 12.5 psig manifold pressure, MS2 and EDIS-8 nikasil block JE 2618 pistons (TripleT). 2001 AUDI A6 4.2 chip 320 hp. 2002 CHEV Tahoe 4wd. 1971 sonett race car GT4 National Champion now GTL class car sold. The words of a Ford GT man. ( Damit i need to get some turbos)
Old 03-10-2010, 11:52 AM
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