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Alan L Alan L is offline
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Join Date: Apr 2006
Location: New Zealand
Posts: 2,894
"FINALLY!

about time alan. i regulate my air down to around 15-20psi and pressurize the WUR. you can also do this on the dist to check boost retard."

Sorry for absence - been out of country for 6 mths, and limited internet.
ANY small airleak will affect the AFR range most/worst at low throttle openings - because the air leak is a greater proportion of the air intake at that point, compared to WOT or inbetween. So you need to be sure there are no leaks - as Brain says - intake/injector blocks etc. They often crack over time/heat. Or the seals under them. Would pay to spend a bit of time assuring yourself theses do not exist - cracked vac hoses etc.
Dropping the CP (richening) covers a multitude of sins, but doesn't solve the original problem.
As Brian says, it would be really useful to see the CP when the issues arises. It may be the CP is floating high when the WUR heats up - heat soak when sitting would describe your last posted experience.
This problem is really frustrating to deal with. My SC even has a slight issue like this. I suspect in its case it is a slight imbalance in an injector - ie one running slightly leaner than the others. That is another thing you need to check - that all injectors are closely matched. There are threads on this, but on the 930 it really is worth spending a bit of time synchronizing them. If you have one or two flowing slightly low(er) than the others, bring them up to same flow. If you have one or two high(er) bring them down - and leave the others alone. The manuals generally talk about 10% tolerance. I think this is too wide for the 930 and really you can get it to 1-2% with patience.
Regards
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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