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Lean running, knock boost limit problem. Any thoughts would be appreciated.
Basic Facts:
I am running a 1990 900t 5sp 207k miles with: stage 1 spg9 box, high perf saab distr, spg9 stage 1 injectors, rrfpr, k&n filter, nology wires, grp 6 exhaust. Replaced: amm(good used), O2 sensor, fuel pump, filter, .024 gap ngk7es plugs, cap, rotor, ECU. Idle timing at 16 btdc with no extra retard mods. Base boost only at approx 5.0 psi.
Symptoms:
I continue to hit the knock limiter as over the time I have upgraded from stock 2.5fpr to 2.8, to 3.0, to rrfpr. New injectors had little effect. Boost goes 3/4 red momentarily in 3rd and 4th, but sustained wide open throttle in 4th and 5th results in 1/4 to 1/2 red pulsing. Need to use Sunoco 94, because with 93 premium knocking starts at beginning of red. 104 octane boost helps. Recent state inspection indicated nox at limit, so I am pretty sure I'm running lean.
Here are the things that I'm questioning:
1) rrfpr needs adjustment. It is at setting as received from spg9. I do not have fuel pressure tester with banjo hook up, but am willing to do trial and error tweaks.
2)Used AMM, while better than orig, is still not right.
3) Got a bad injector from spg9?
4) Distributor advance/retard not right. Should I be at 14btc for this distr and boost set up. Will this affect mixture? (i know that spg9 retard unit would help, but would it just cover up the underlying lean condition?).
5)Catalytic converter problem? But even with knock problems, car is a rocket.
6) APC box too aggressive...I have not touched spg9 setting.
6) Wastegate spring worn out (diaphram holds vacuum and rod is free)???
7) APC solenoid problem - holds/releases vacuum OK and power OK, but I haven't cleaned it yet.
8) Maybe got a bad O2 sensor (was replaced at 130k miles, but new one made no difference in boost pulsing problem)
, Thu, 1 Mar 2001 13:40:28, Thu, 1 Mar 2001 15:00:39
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