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Registered
Join Date: Sep 2012
Posts: 106
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Engine question
Hi everybody;
I've got a '79 930 with a modified engine - rebuilt with 3.4 pistons, SC cams, Kokeln turbo and intercooler, BB exhaust etc. The car did not even run 1k miles before I bought it and I like it more everyday. What worries me is a strange behaviour under partial throttle when on boost. The engine starts skipping and jerking as if it would hit the rev limiter on and off with a frequency approximately twice a second. When I floor the throttle it goes fast and strong. It seems to be happening more easily when going uphill - I think. Is it normal? I think not. Bad fuel delivery? starvation? I don't know. Could you guys give me your thoughts? Thanks, Last edited by Janusz1; 09-15-2012 at 02:53 PM.. |
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09-12-2012, 10:18 PM
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I've gone native
Join Date: Sep 2011
Location: Long Island, NY
Posts: 1,695
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Sounds like either a boost leak or ignition issue. I'll bet you have a leaking o ring at the IC.
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'07 997.1tt Blk/blk 600hp, bad to the bone |
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09-13-2012, 07:03 AM
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Registered
Join Date: Jul 2003
Location: Back in B'ham, AL
Posts: 3,459
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Welcome to the forum!
If you really want to get some answers and establish dialogues, you MUST FIRST post some pictures of the car and engine bay. FYI, that's rule #1 here for new members. |
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09-13-2012, 07:59 AM
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Registered
Join Date: Sep 2012
Posts: 106
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Sorry, I did not know this rule. Here are some pictures:
      I am very impressed with the knowledge you guys have. I am a car enthusiast doing as much DIY as possible for me, but I am totally unfamiliar with the turbocharging and this is my first turbo; I just enjoy immensly the way this car drives and how directly responsive it is (no turbo lag to talk about really). Please help me with my problem. PS Let me add I have an enhanced Fuel Distributor from Fuel Injection Corp. in Livermore, CA part # 810027, whatever it means. Last edited by Janusz1; 09-15-2012 at 02:58 PM.. |
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09-15-2012, 02:52 PM
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Nice car!
For me, it sounds like a fuel issue, too lean I suggest. Get an AFR meter and check, good help for diagnosis...
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Roland 930 Turbo '81 Too many modifications to list |
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09-15-2012, 04:37 PM
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Yes, I suspect leaness at miniumum throttle. Mine has always had this issue - AFR off scale at 16 under light throttle. When you give it a bootful you get a fuel dump, which cures it - but bit hard to drive between lights like that :-).
This opens up a heap of discussion issues - like what fuel system, what WUR, are the settings right etc. Alan
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83 SC, 82 930 (track) - Stock except for RarlyL8 race headers, RarlyL8 Zork, K27-7006, 22/28 T bars, 007 Fuel head, short 3&4 gears, NGK AFR, Greddy EBC (on the slippery slope), Wevo engine mounts, ERP rear camber adjust and mono balls, Tarret front monoball camber adjust, Elgin cams, 38mm ported heads, 964 IC. 380rwhp @ 0.8bar Apart from above, bone stock:-) |
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09-15-2012, 06:35 PM
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