If anyone's curious, the problem with my car is as follows:
Unknown reason for fuel load up. Cold start, car idles and revs fine. As it warms up, BUT BEFORE MOVING INTO CLOSED LOOP, you can watch the O2 mV start to creep up. Once it moves into closed loop, the LTerms and Sterms bottom out at 128 and 1 respectively on both sides. Under any type of fast throttle movement, I get an extreme cut-out which sometimes will be bad enough to stall the car out. Low RPM only it seems, as above about 3000 it's fine. Dyno checked A/F ratio to be starting at about a 10.5 and ending at a 13.0 at 6000 RPM (on the old motor) on the same tune that two weeks before had gone 13.0 up to 4200 where it gradually leaned out to about 14.0 at 6000 RPM.
Things that have been checked or replaced:
Opti (currently
on another for a DTC 36 High Res Pulse Fail)
Coil/Ignition Box
Plugs and Wires, twice
ICM (from my other car which has no running issues)
TB with good IAC and TPS
O2's (Currently converting to 4 wire heated units)
Cat (currently have an ORP on the car)
MAP Sensor
IAT shows fine via datamaster
Coolant temp sensor shows fine via datamaster
Car pulls 12-14 In/Hg vaccuum at idle, plenty
Fuel Pump was replaced with a Racetronix
Fuel Filter
AFPR (Hypertech, no leaking)
Fuel Injectors don't leak (SVO 30#)
TPS shows .49 @ idle
IAC counts are 30 @ idle
Brand new shortblock from AP Engineering as of Early July, motor has short amounts of idle time and about 25 miles of driving/diagnosing time so far.
This problem was there under my old motor (stock bottom end/Head/Cam) and is still present.
Reused compenents from the old motor were as follows:
Heads (refreshened)
Timing set (had about 500 miles of use, zero track time, 5 dyno pulls)
pushrods
rockers (although I have since moved from 3/8 SA to 7/16 NSA Pro Mags)
lifters
injectors
AFPR
opti
plug wires
coil/ignition box
essentially everything but the short block itself.
So the way I'm looking at it, I've checked almost everything. The car is fine when it's stone cold. But less than a minute into running, it starts to degrade.
I've got all of the rockers adjusted at zero lash, but I still get a sharp snapping sound from what sounds like a couple of different ones. As I was adjusting them last time, a couple felt completely different than the rest. If anyone's adjusted Comp R's, you know that as you tighten down the retaining nut, you hit a brick wall at a certain point, where it's extremely hard to tighten any more. On a few rockers, I never hit this wall, they just kept tightening. I DID NOT tighten them down this way, I only did this for curiousities sake. Some of them are very spongy (as it was put by another member today) while others are stiff, while at TDC on the respective cylinder. For comparison, it took nearly everything I had to compress a stock lifter in my hand with a pushrod, and a set of OEM's in a car I could not compress as they still had oil in them. Last time I tried this, my motor was hot too.
I'm thinking at this point that I've got a couple of lifters that aren't supplying enough pressure to open certain valves all the way up, causing a rich condition from not enough air entering into the combustion chamber. Does this sound feasible??
Unknown reason for fuel load up. Cold start, car idles and revs fine. As it warms up, BUT BEFORE MOVING INTO CLOSED LOOP, you can watch the O2 mV start to creep up. Once it moves into closed loop, the LTerms and Sterms bottom out at 128 and 1 respectively on both sides. Under any type of fast throttle movement, I get an extreme cut-out which sometimes will be bad enough to stall the car out. Low RPM only it seems, as above about 3000 it's fine. Dyno checked A/F ratio to be starting at about a 10.5 and ending at a 13.0 at 6000 RPM (on the old motor) on the same tune that two weeks before had gone 13.0 up to 4200 where it gradually leaned out to about 14.0 at 6000 RPM.
Things that have been checked or replaced:
Opti (currently
on another for a DTC 36 High Res Pulse Fail)Coil/Ignition Box
Plugs and Wires, twice
ICM (from my other car which has no running issues)
TB with good IAC and TPS
O2's (Currently converting to 4 wire heated units)
Cat (currently have an ORP on the car)
MAP Sensor
IAT shows fine via datamaster
Coolant temp sensor shows fine via datamaster
Car pulls 12-14 In/Hg vaccuum at idle, plenty
Fuel Pump was replaced with a Racetronix
Fuel Filter
AFPR (Hypertech, no leaking)
Fuel Injectors don't leak (SVO 30#)
TPS shows .49 @ idle
IAC counts are 30 @ idle
Brand new shortblock from AP Engineering as of Early July, motor has short amounts of idle time and about 25 miles of driving/diagnosing time so far.
This problem was there under my old motor (stock bottom end/Head/Cam) and is still present.
Reused compenents from the old motor were as follows:
Heads (refreshened)
Timing set (had about 500 miles of use, zero track time, 5 dyno pulls)
pushrods
rockers (although I have since moved from 3/8 SA to 7/16 NSA Pro Mags)
lifters
injectors
AFPR
opti
plug wires
coil/ignition box
essentially everything but the short block itself.
So the way I'm looking at it, I've checked almost everything. The car is fine when it's stone cold. But less than a minute into running, it starts to degrade.
I've got all of the rockers adjusted at zero lash, but I still get a sharp snapping sound from what sounds like a couple of different ones. As I was adjusting them last time, a couple felt completely different than the rest. If anyone's adjusted Comp R's, you know that as you tighten down the retaining nut, you hit a brick wall at a certain point, where it's extremely hard to tighten any more. On a few rockers, I never hit this wall, they just kept tightening. I DID NOT tighten them down this way, I only did this for curiousities sake. Some of them are very spongy (as it was put by another member today) while others are stiff, while at TDC on the respective cylinder. For comparison, it took nearly everything I had to compress a stock lifter in my hand with a pushrod, and a set of OEM's in a car I could not compress as they still had oil in them. Last time I tried this, my motor was hot too.
I'm thinking at this point that I've got a couple of lifters that aren't supplying enough pressure to open certain valves all the way up, causing a rich condition from not enough air entering into the combustion chamber. Does this sound feasible??
