irocdaddy

Hi All-
I just picked up a Auto X-ray and scanned the 89 Iroc/zz4.

The car runs real strong, but has lumpy idle and the rev's oscilate up and down a bit at idle. I would like to smooth out the idle . Here are the stats-

ZZ4 internally stock
52mm, 22lb. injectors-flowed/matched. big mouth intake/slp runners. no afpr. running stock fpr. accel 300+ ign. stock fan switch. I think a 180 thermostat. slp 1'-5/8 headers dual catco high flows. slp catback.

t56 6 speed conversion from auto. stock: 350/a4.
chip by tpis stage 6 (from the automatic days)

I plan on burning my own chip in the future.
Here are the scanned results. only captured at idle, operating temp.

coolant temp: 198.9 f.
throttle sensor: .41 volts
engine rpm: 733 (oscilates between733 to 860)
o2 sensor: 180 mvolts
02 cross counts 2
block learn 124
integrator 128
iac 54 steps
desired idle rpm 737 (for a automatic/350)
engine load 45
mat 93.2 f.
egr duty cycle 0%

(car is currently throwing code 32 at start up,then once I manually clear it it stays away until next start up?)

ccp duty cycle 0%
bat voltage 14.0
fuel pump sense 13.9 volts
spark advance 23.4
knock sensor 24
knock retard 0
injector pulse 1.6 ms
run time 697 sec.
map sens 1.92 volts
maf 6 gr/sec
bat volt high: no
fourth gear engaged
air divert solenoid on
rich lean flag lean (scanned a different time and it was rich)

closed loop operation.

With all that said, can I adgust/toon anything to better the variables here?

all are within ranger per the x-ray man.

Vader

The O² looks low. That could be a function of the TPS being low. You could try to bring the TPS up to 0.48V at a minimum, but that isn't going to help the DTC 32 situation. The IAC counts look a bit low, but acceptable, and that may also be an indication of the TPS/minimum air adjustment points. Just increasing the TPS to minimum may bring the target idle up a tad and increase fuel.

Just some questions...

Was the ECM in closed loop? With that run time and CTS, it should have been, but the low/lean O² and TPS may have kicked it to open loop at idle.

Are you running MAF? It's a little hard to determine.

Are you using the auto trans PROM in the manual? Does the SHIFT light act funny? Did you rewire the SHIFT light from the TCC relay line?

irocdaddy

Thanks Vader for checking this out.....

the car was in closed loop operation.
base timing at 6 deg.
the car's chip was burnt when the automatic was in it.
running maf.
i have no shift light hooked up.

it seems sometimes the o2 sensor will be rich and others lean. looks like the range on o2 is all over the place.

I am going to scan again, but lengthen the times per function to see if I can catch why the rpm cycle up and down so much.

I will increase the tps to .48 and see how she reacts.

Also plan on changing out the egr for the 32 code.
the car only throws this code when on cold start up, but won't reset itself. once warm, turn the car off then restart has no code until new restart the next day?

irocdaddy

Vader-
almost forgot; I had set the tps at .54 then why once the car is running in closed loop it goes down to .41?

irocdaddy

Also, what should the rpm at idle be with the stick shift?

850 rpm looks high.