I have an 89' gta maf, 355 , forged bottom,
afr 190 heads, tpis zz-9 cam, hardened pushrods, 1.52 steel roller 7/16 rockers, big mouth intake, large tube runners, edelbrock tes headers.
My problem is at aprox. 3000 rpm I have 8 degrees knock retard all the way up the rpm's. I took the car to get dyno'ed and found the car to get lean at 4200rpm. I called TPIS and was advised to find noise. Also have chip from FASTCHIP and knock sensor is the same. Advancing or retarding timing has no affect or does fuel pressure.
Note fuel pressure does not fall at 4000 and have 19lb injectors. When I held 3100 rpm for approx. 2 minutes in my garage my headers was glowing orange. Also note I have a slight noise at 3000 rpm with or without load that resembles something in the valve terrain.
please help

 

Well John, it seems to me you have a whole lot of engine for 19lb injectors.

Have you monitored the A/F ratio?

 

well the dyno did tell me it went lean at 4200. But TPIS is saying that the injectors is not the problem. they said solve the knock first.

 

Hey man,

TPIs is prolly right. I'm running 355
with 2.02 heads. Cam is like 280 or something. I'm running a little rich
at times with 22lbs injectors.. Base
timing 6`, computer advances to like 12-14.
No knocks.. I've run a scanner on the
car while driving it, and all my values are
pretty good. If you run higher injectors you'll prolly be ok at your 4200, but run rich on a downshift like me..

 

John,

Running lean causes higher combustion chamber temps, which lead to pre-ignition, which the knock sensor should pickup and retard the timing accordingly.

 

oxygen sensors have also been known to glow a header or exhaust manifold, this probally isnt your problem but should never be completly ruled out, I have worked on cars before that glowed the manifold on a 4 banger because of a bad o2 sensor.. good luck on finding your problem..Kevin

 

So basically you're trying to run that thing w/ either )or both) TPIS and fastchip chips.
I'd venture your problem lies in the chip just because it'd be foolish to look elsewhere when it has happened more often than not that a 'tuner's' chip was poorly done. Esecially with those small injectors running it, that only presents that much more of a problem to the tuner. Not that they can't be made to work, it just makes it that much harder.
...ed

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